AR-15 Bore Cleaning

The "Gun Writer’s Union" requires every firearms journalist to write an article on the subject of bore cleaning and they have found me procrastinating. Part of the reason that I haven’t jumped into the topic is because with every gun writer out there having previously penned an article on the topic I felt that there wasn’t much left for me to say.

However, as I remember back over a decade of being the armorer for US Army Reserve Marksmanship Program I probably replaced as many barrels either because of neglect (causing pitting) or due to damage from improper cleaning as I replaced for being genuinely shot out. There are two really good reasons to clean the bore of any firearm. It improves accuracy and putting away a gun with a dirty bore is courting the formation of rust which will cause pitting, thus ruining a valuable barrel.

As a general rule, I would clean every time I fired the gun unless the round count was well below 20 and the gun was going to be fired a similar modest amount the following day. An example might be some hunting situations. Some experts claim that bore fouling is not cumulative, claiming no difference in the amount of fouling present after firing only one round compared to firing 500. That has not been my experience. If a team member retired and turned his guns in dirty, I inherited the mess.

It has taken me up to a day and a half of continuous work to get some of these badly neglected guns cleaned. I don’t claim that fouling gets so bad as to plug shut, but I do claim two shots foul more than one and 500 is worse. Severely fouled bores likely require abrasives such as J-B Non-Embedding Bore Cleaning Compound in addition to copper solvents. I don’t believe J-B itself harms barrels, but back and forth scrubbing will cause rod flex that wears at the lands. I have seen many barrels destroyed by this.

Ask any gun barrel manufacturer and I’ll bet they’ll agree. Remember that the land sticks up only about the thickness of a sheet of paper above the groove. Despite being made of hard metal it can be worn down by the movement of the rod, even coated ones. Frequent cleaning reduces fouling buildup, makes fouling removal easier, and reduces the chance of bore damage. We also maximize accuracy.

In The Competitive AR15: The Mouse That Roared author Glen Zediker recalls an Army Marksmanship Unit clinic where they presented their studies concluding cleaning every 20 rounds was necessary for peak accuracy performance. At the National Matches at Camp Perry all the military teams park their travel trailers together. Walk by at the end of the day and the AMU shooters will be diligently cleaning their rifles. Then look at the scoreboard and see who wins a large share of the events.

Those trophies aren’t "bought" just by spending a half hour cleaning as it takes years of diligent practice and ruthless application of shooting fundamentals to win, but why throw all that effort away by failing to clean the bore? I have personally machine rest tested many rifles whose first ten shot group (following one or two fouling rounds) after cleaning was their best.

I would also clean the bore, regardless of round count, if the gun was going to sit more than a tiny handful of days (especially in damp conditions) before being used again. Most of us store customer guns in a safe. Make sure yours is equipped with a good dehumidifying rod! Reserve Team Mini Test When I took over the weapons maintenance of the Army Reserve Service Rifle Team I began by machine rest testing all their National Match AR-15s. Leadership had told all the shooters to thoroughly clean before turn in.

At first, I took that at face value but when my results were so dismal I started looking closer at the condition of the uppers and found most of them far from clean. I began cleaning all of them and retested. Groups shrunk by a noticeable amount. I have lamented ever since that I did not keep before and after cleaning data because 135 rifles would have been a nice sample size. Unfortunately, I was short sighted and could tell that even after cleaning I had inherited an awful amount of work to straighten out.

I didn’t miss my second chance to get some data on bore fouling, however. A big name ammo manufacturer sent me samples for testing. Obviously they wanted our business and the feedback of a military team. I picked out three uppers, all immaculately clean, making sure both chrome moly and stainless steel barrels, and cut rifled and button rifled barrels were included. I started by firing two ten shot groups through the uppers with known lots of ammo to act as control groups.

I had 14 test lots to evaluate so, including the two beginning control groups, that accounted for a total of 160 rounds through each upper. To finish off, I reshot the two beginning

control groups and compared them to the clean gun starting groups fired with the same ammo. One gun’s dirty bore groups were 43% larger than when clean. The second upper got fatter by 61%. The third oddball shot 34% smaller groups at the end than it did at the beginning. That gun had a brand new barrel on it that had just been broken in. I cussed that thing all day because it was shooting horribly, nearly two minutes of angle, and was threatening to take it off and throw it in the trash.

Finally, just at the end of the test, it tightened right up. I theorize that it probably had a burr on the gas port that finally shot off. I don’t throw out data just because it fails to meet some preconception I may have, so I simply say that the average degradation in accuracy in my three barrel sample after firing a total of 180 rounds was 23% and let it go at that. That’s a significant amount and I certainly wouldn’t want to shoot a match with that kind of handicap.

Any statistician will tell you that my sample size is on the light side. Most of us would prefer at least a sample size of ten but I only had enough ammo to test three barrels. General Bore Cleaning Rules Carbon and copper are two forms of bore fouling and each is removed using slightly different techniques. 35" and caused a shooter to destroy anew barrel. Use a metal guide, such as the one pictured on the right measuring about 0.24".

Always remember, the removal processes can run substantial danger of causing damage to the bore. First, you’ll need a quality one piece straight rod of the correct diameter for the caliber. Don’t use a .22 caliber rod to clean a .30 caliber firearm as smaller caliber rods flex more. More flex equals more potential damage. One of my two Anschutz squirrel rifles is a .17 HMR and its cleaning rod flexes so much I can’t even drive a bore patch down the barrel from the breech.

I have to carefully insert the naked rod through the muzzle, put a patch on at the breech, and pull it back through the bore. It takes me forever to clean that thing. The rod needs to be just long enough to accommodate the length of barrel you are cleaning. Rods I use for 20" Service Rifle AR barrels are shorter than those for 26" barrels. Using longer rods to clean shorter barrels runs a greater risk of rod flex and accompanying damage. Rod handles must rotate freely.

You can save a lot potential crown damage by setting up two rods for each barrel length that you normally clean. The first rod is used with bore brushes and the second with a tip put on firmly with blue Loctite, keeping the tip from partly unscrewing over the course of the cleaning session. I have observed so many guys doing most everything right. They shove a patch through from the breech and remove it when it exits the muzzle but then in their haste to "get ‘er done" they yank the rod back up the barrel.

Rod tips will loosen during use, drooping down with gravity when exiting the bore. If you yank that thing back there is a good chance of boogering the bottom surface of the crown. Why run the risk? Get a second rod! Also make sure you have a clean shop rag or paper towel to wipe the rod down frequently while cleaning. Second is a quality bore guide. In Stoner platform guns these replace the bolt carrier and some are tight fitting with O-rings to help center them up. The best are made of metal.

I recommend either JP Enterprises or Wheeler Engineering. For you grown-ups, JP also makes a larger one for the AR-10. Avoid plastic bore guides. A competitor came to my Commercial Row shop at Camp Perry prematurely shot-out barrel. I bore scoped it and the back was almost completely void of fire cracking, indicating a modest round count. However, the lands were uneven at the back. I dropped a throat gauge in the back of the barrel and it went in clear to the handle!

As I continued to scope it I noticed other evidence of cleaning rod damage. I asked him to fetch his cleaning stuff. His one piece coated rod was the right diameter and not too long. I verified that it was straight and that the handle rotated freely. He said he used J-B but wiped the rod frequently. He had been using a plastic rod guide designed for the AR. The hole in the guide intended for a .22 caliber rod measured .35 caliber! This undoubtedly let his rod go crooked into the back of the barrel, damaging it.

He said he never felt anything abnormal, such as scraping the sides of the back of the barrel, during cleaning. Shooters can damage barrels without even realizing they are doing so. We gunsmiths can too! For rifles like the M1A, use bore guides that fit over or inside the front flash suppressor. Some are made of

Top: The M1A is cleaned from the muzzle. Note bore guide entering the flash suppressor. plastic, so occasionally measure the inside diameters to make sure they aren’t getting too worn. If you think the back of the barrel is easily damaged by a cleaning rod going in crooked you don’t even want to think about what will happen to the crown of the muzzle if subjected to similar rough handling. Don’t lull yourself into a false sense of security regarding bore guides.

Much like automobile seat belts and air bags, bore guides are good insurance but they are not foolproof. You still have to make a very conscious effort to drive the rod absolutely straight every time or it will go off at an angle and harm the bore. Next you will need a fair quantity of the right size bore patches, solvent of your choice, clean quality bore brushes, a clean chamber brush, some type of high pressure aerosol gun scrubber, and Windex without ammonia.

With bore brushes, make sure the windings in the middle of the brush never terminate at the front, exposing their rough ends that can dig into the bore. Ammonia-free Windex is used after each cleaning to remove two types of solvents. Petroleum-based bore solvents can contribute to carbon fouling. Copper solvents have ammonia in them and trace ammonia left in the bore can combine with chemicals in the burning of gunpowder to form a substance corrosive to barrel steel.

I use Hoppe’s Bench Rest 9 Copper Gun Bore Cleaner to remove copper during normal cleaning after break in. Bench Rest can be left in overnight. So while it isn’t as fast acting as some other copper solvents it is a lot more forgiving. I normally clean indoors and am always involved in other gunsmithing chores while waiting on solvents to react with copper. If a fifteen minute project turns into thirty I don’t have to worry about Bench Rest damaging a fine rifle bore.

That said, there are a lot of good bore solvents out there. Follow the recommendations of their manufacturers. Avoid mixing different brands of solvents. For example, avoid using Hoppe’s No. 9 on a bore brush to remove carbon fouling (a good thing) and then following it with Shooter’s Choice Copper Solvent or Sweet’s 7.62 on a patch for copper fouling. Before email, Boots Obermeyer sent his customers a letter typed on a real typewriter and mailed with a real stamp.

He documented ruined gun barrels that had been damaged by the sort of example I just used above. It seems that mixing solvents can result in unintended compounds that can be harmful to the barrel. You can, however, use Hoppe’s No. 9 on a brush to get the carbon fouling and follow it immediately with Hoppe’s Bench Rest to get the copper, or use regular Shooter’s Choice on a brush followed by their copper remover. Stay with the same brand of solvent.

I have never heard of J-B Bore Cleaner having any adverse reactions with solvents because it uses abrasives instead of chemicals to get fouling out. Literature Search In "Gas Gun Barrel Break-In" (October 2014) I lamented that almost everything in the literature about barrel break-in was tailored to guns without gas ports and blindly mimicking such technique won’t prepare gas port area properly, leading to potential barrel damage. I see a similar situation regarding bore cleaning.

Almost all of our bore cleaning techniques date back to the turn of the 20th Century. Solvents have been improved but techniques are based on .30 caliber rifles. The Krag was adopted as the standard issue military firearm in 1892, followed by other .30 caliber rifles such as the Springfield, Enfield, Garand, M1 Carbine, and M14. Not until 1961 did our military use anything smaller. The adoption of the M16 saw the military drop way down to a .22 centerfire, among much nay-saying and predictions of doom and gloom.

All of the discontinued military firearms, with the exception of the M14, were sold as surplus to American shooters and sportsmen. Foreign military arms such as the .303 British and 8mm Mauser were imported and sold on American markets. When I started deer hunting in the 1960s I killed my first buck with a Model 98 Mauser that my dad had brought home at the conclusion of WWII. I remember all of the old surplus military firearms in common use in Pennsylvania woods, many of them using the issued iron sights.

From 1892 to 1961 American troops returned from service with the bore cleaning "skills" taught to them in basic training, all designed

for .30 caliber firearms. They passed those "skills" on to their family and friends. When we finally changed to a .22 nobody questioned that perhaps our cleaning practices needed to be revised. I also remember Pennsylvania hunters in the 1960s lamenting "deer shortages" and sought to close doe season. About a half-century later, with an estimated Pennsylvania deer population exceeding 1.2 million, I still hear similar suggestions from big game hunters.

This flies in the face of the fact the state has the highest number of deer/car collisions nationwide, exceeding 100,000 with an average of 10 human fatalities annually while ranking ninth in total traffic miles driven in the U. S. Our annual harvest exceeds 300,000 deer.

I had the good fortune to study defensive pistolcraft at Gunsite when Jeff Cooper ran it and both bore cleaning and wildlife management always remind me of something he said over 30 years ago, "Times change quickly but men change slowly." What changes in basic techniques do we need to make for cleaning .22 calibers? First, the last three issue .30 calibers (Garand, M1 Carbine, and M14) required cleaning from the muzzle.

Most shooters realize that they need to clean the AR-15 from the other end but it doesn’t hurt to reinforce this. Second, bore guides. I never saw one issued during my decades-long military career outside of the shooting teams. Bore guides are like studded winter tires on ice, great insurance but not foolproof.

I have seen plenty of AR-15 bores trashed even with properly-sized bore guides as they do a great job protecting the upper receiver but cleaning rod damage can still occur anywhere past the front end of the guide. Third is cleaning rod flex. This is the biggie but can be counter intuitive. It is hard convincing shooters that it is not the friction of bullets passing in the bore of a firearm that causes barrel wear.

It is even more difficult to convince them that a cleaning rod, even coated ones, flexing and scraping against the paper thin lands of a gun barrel will cause more wear than shooting. The smaller the diameter of the cleaning rod, the greater the flex. Just compare a .30 caliber rod to a .22 for stiffness. Big difference! Cleaning rod flex will manifest itself mostly with tight, new bore brushes.

Bore brushes are our most common abrasive cleaner for removing baked-on carbon fouling but tight ones offer stiff resistance and that can easily cause rod flex. I’ve measured some new .22 center fire bore brushes at about 0.235". Most lands are 0.219" and standard grooves are 0.2240". Think of that brush half way down the bore and the rod flex between the brush and the front of the bore guide, just in the critical throat area. That rod flex will cause the lands to wear unevenly and accuracy will degrade.

Thicker .30 caliber rods resist flexing with bore brushes more. I see more of a problem with shooters using rods that are too long and those cleaning longer barreled firearms requiring longer rods that flex more. When those long rods are at the back end of the stroke, the arms of most people are hyperextended to where the ability to keep the rod centered will be compromised to some degree.

Having been a drill sergeant, a competitive shooter, and a military armorer, however, I have had more than the average opportunity to watch others clean ARs. Some smaller shooters starting anew bore brush down from the chamber it can often strongly resemble a beginning driver attempting to operate a manual clutch. The vehicle starts and stops in spurts. I see that with bore brushes also. Some advice from gun barrel manufacturers to ease this. First, bore brushes offer the greatest resistance on the first use.

Thoroughly flush the crud out and reuse them until they wear out. A brush that has been recycled once or twice will just require more strokes than a fresh brush. Second, use plenty of nonammonia solvent on the brush and bore. Dry bores are harder to push a brush through. Stop brushing when it appears that the bore is drying out. Third, .22 brushes can be had in multiple sizes. Some are sized for tighter rimfire bores, measuring about 0.226".

Standard centerfire grooves are 0.2240", though I use a custom groove of 0.2245" on my 90 grain gain twist barrels. A rimfire bore brush would get the lands rather nicely but barely reach the grooves. Unfortunately, fouling occurs in both. On the plus side, rimfire brushes will offer less resistance and should cause less rod flex in a .22 centerfire firearm. Like a used full caliber brush, however, they will require you to use more strokes to get hard baked carbon fouling out.

Fourth, substitute nylon brushes and some of the new hotter "gee-wiz" solvents. The nylon brushes offer less resistance and cause less rod flex. Montana X- Treme Copper Killer works well with nylon brushes for copper, though nylon isn’t as good about hard carbon fouling. Another time cleaning rod flex manifests is scrubbing the bore an abrasive pastes like J-B. Most folks push a patch of it forward until it almost exits the muzzle and then pull it back to the front of the chamber.

I see very little rod flex on that stroke. The flex comes the second time when you stop pulling it and begin pushing it forward. The rod is extended clear out the back of the bore guide and your arm is hyperextended, leaving less ability to guide the rod straight forward. You probably won’t feel much flex but the lands of the barrel will. Cleaning rod damage can be diagnosed when the bore scope reveals one or two lands wearing down more than the others.

That is proof positive the rod isn’t driven straight down the bore. Make a conscious effort to slow down and really try to send that rod straight!

25") and cleaning rod (about 0.20") will still permit the rod to be driven crooked. Fouling Types Copper fouling gets all the press and most of the worry. I think that is because of its reaction with ammonia solvents and the bluish-green coloration it leaves on patches. The other component to bore fouling is carbon fouling. It doesn’t shout out its presence like copper and often hides in the shadows and corners where lands and grooves meet.

Unless you have a bore scope you may not know for sure when you have it all out. Some shooters claim that the two types of fouling are laid down in layers and without vigorously removing the carbon part you won’t be successful getting all the copper. Carbon fouling is baked on whereas copper is stripped from the bearing surfaces of bullets. Carbon needs some type of abrasive and copper is commonly removed with an ammonia solvent, although abrasives like J-Bare also effective.

I start with a quality metal bore guide in place by pushing about three patches wet with Hoppe’s No. 9 through the bore to flush out powder residue. I go after the carbon fouling first with strokes of a clean, straight, quality bronze bore brush wet with more Hoppe’s No. 9. Nylon bore brushes aren’t aggressive enough to get the baked-on, hard carbon fouling out. Nylon is ideal with ammonia solvents and push easier, causing less rod flex. Don’t use hot ammonia solvents with the bronze bore brushes.

Modern bronze is typically 88% copper alloyed with 12% tin. Hot ammonia solvents will attack the copper, the prime ingredient in the bore brush. Some folks have fancy formulas for how many brush strokes should be used based on the round count since the last cleaning. I just stroke until the brush seems to be drying out. Then I flush the bore out with a couple more patches of Hoppe’s No. 9. Never try to reverse the direction of a bore brush when it is inside the barrel.

At that point I switch to attacking the copper with patches of the hotter Hoppe’s Bench Rest. While I wait for the ammonia in the Bench Rest to chemically react with the copper in the bore I take the bolt carrier assembly apart and throw it and the charging handle in the ultrasonic tank and let it do the cleaning work. I run a patch of Bench Rest through the bore every 10 or 15 minutes for as long as I am getting coloration indicating copper is being removed.

Most chemical reactions occur more vigorously in higher temperatures. I live in north central Pennsylvania and we enjoy about two days of summer in a good year. Having tried cleaning outdoors during colder seasons, it is nearly impossible to get the copper out. Even after soaking with solvents for protracted period the copper persists.

My bore cleaning is done inside and I sit my containers of copper solvent on a radiator (no open flame) to keep them warm when my furnace needs to run those other 363 days of the year. Once satisfied all copper has been removed, I clean the chamber with a clean chamber brush and high pressure aerosol gun scrubber. Note, many gun scrubber products contain chemicals that effectively "kill" a copper solvent’s ability to attack copper.

Don’t get in a hurry and clean the chamber between patches of the copper solvent as some of these aerosols inhibit the solvent, tricking you into believing all the copper is out. While you have the aerosol out, hose excess solvent from the muzzle and flash suppressor. Accumulated gunk can encourage the formation of rust or exacerbate first shot fliers. You may need to supplement the aerosol with cotton swabs or a shop rag.

Finish up the bore and kill all solvents with a patch or two of nonammonia Windex followed by about four clean, dry patches. J-B Bore Cleaning Compound is a paste with fine abrasive. I don’t believe the paste itself hurts bores at all. J-B is used in back-and-forth scrubbing, reversing the direction of the patch just before exiting the muzzle and a second time near the throat of the barrel.

Reversing the patch the first time near the muzzle from a pushing to a pulling motion doesn’t cause much rod flex but when reversing the second time at the back of the barrel from pulling to pushing a significant amount of rod flex will occur. That rod flex can cause a lot of damage to the lands of the barrel. Use a little less muscle and slow down your stroke to minimize rod flex. Almost every barrel will require cleaning with J-Bat some point.

Barrels are extremely variable and there are no hard fast rules or round counts for any symptoms. First, if you use more than a dozen patches wet with copper solvent and the bore still isn’t copper free, use some J-Band then return to the copper solvent. Second, a sudden loss of accuracy with no other factor being identified. This often happens with neglected bores and I saw it frequently as team armorer. My advice was to use J-Band try again.

With few exceptions, that normally restored the gun to its former tack-driving accuracy. Lastly, a sudden unexplained rise in chamber pressure with blown primers. If no other factor accounts for the change

this can mean a buildup of fouling just forward of the throat, most common with neglected rifles. J-Bin short back and forth strokes two or three inches in front of the chamber usually restored chamber pressures to normal. Preserving The Barrel Rust leads to pitting and can start within a handful of days. Corrosion can happen regardless of barrel steel type. One of the best ways to avoid it is to clean the bore, chamber, and barrel extension after each firing.

Then, if the gun is going to be stored for more than a few days, apply something to the barrel to ward off corrosion. Brownells conducted a great study on this topic a few years ago (bit.ly/1hh5tt U). WD-40 scored well, as did Boeshield T-9. For storage, I saturate a clean patch with Boeshield and work it back and forth a few times to burnish the bore’s pores. Early in that burnishing process when the patch is really saturated with the liquid I deliberately let it exit the muzzle.

I pull it back into contact with the muzzle and crown and hold the cleaning rod by the shank and spin it several times, coating the crown. I have found that the crown is a common place for rust to form and even modest pitting there spells death to accuracy. Every gun writer admonishes (it’s in our union contract) that you should never pull a dirty patch back into contact with the crown of the barrel. I agree, but we have just cleaned the barrel so that patch of Boeshield T-9 won’t be dirty!

Then I spray a good shot of the Boeshield aerosol directly into the chamber and barrel extension, turn the rifle around and hit the front of the muzzle, crown, and flash suppressor. The night before going to the range, spray the chamber, flash suppressor, and the front of the barrel with a shot of high pressure gun scrubber and follow with a patch of non-ammonia Windex through the bore and then a dry patch.

First Shot Fliers The one downside to bore cleaning is that your first shot or shots will go outside of a normal group. I don’t know of any way to prevent this other than firing dedicated fouling shots until the barrel settles down. Police and military sniping situations, hunting, and some competitions can make dedicated fouling shots impractical or impossible. On top of that, different firearms require varying numbers of fouling shots.

I have watched this fouling business extensively with the AR-15 and the vast majority of guns, regardless of barrel steel, manufacturer, or type of rifling, seem to foul in just one shot. A rare gun may require two but I very seldom see one requiring more. My .17 HMR Anschutz squirrel rifle requires three shots and I have tested some M24 sniper rifles in .308 that wanted up to five fouling shots. What causes first shot fliers? There are many theories. One has to do with gun powder residue.

People smarter than I am in chemistry say that certain gun powders lay down a trail of residue upon firing that acts as a lubricant for the passage of the next bullet. Supposedly this offers less resistance to the next bullet and the second round after cleaning should exit the bore faster than the first. In Rifle Accuracy Facts author Harold R. Vaughn posits that we can expect an increase in muzzle velocity between 50 and 75 feet per second with the second shot.

I have seen low velocities with first shots after cleaning when running my chronograph so I was not surprised when I read others shared the experience. Like any other competitive shooter, for decades I cussed first shot fliers and their impacts on my scores.

As a shooter I felt that harsh ammonia solvents like Sweet’s seemed to cause my first shot fliers to be more severe than when I cleaned with milder solvents, so I wondered if a scientific study would back up my theory and identify solvents that would help keep the first shot from wandering so far. I decided to start keeping records on first and second shot velocity. I didn’t just grab rifles and head to the test shed to accomplish nothing more than gather chronograph data.

I simply recorded the readings as part of my normal test firing of guns over a two year period. During that period I sampled 132 barrels, stainless and chrome moly, cut and button rifled, three, four, five, and six groove. I also varied ammunition types of match, hand loads, and issue full metal jacket ball. All of the ammo in the test used naked bullets without moly coating. Various ball and stick powders were represented as were a number of common bullet manufacturers.

From a statistician’s point of view it might have been better to eliminate all this stack up of variables but from a real world perspective these are the conditions that shooters are going to encounter. I also cleaned with a bunch of common bore solvents and used some substances that I know shooters use to condition their bores or preserve them against rust during storage. Of the 132 barrels tested, 88 behaved as Mr. Vaughn predicted. The second shot was faster than the first.

The most dramatic was a gun whose second shot was faster than the first

by 168 fps. Why did the remaining 44 (1/3 of the sample) behave differently with the first shot being faster than the second? I expected this to happen part of the time because of the natural variation in velocities that occur within any ammunition sample. All of my tests were conducted using 20" Service Rifle barrels with fat gas gun chambers. That combination is noted for causing variations in muzzle velocities of ammo shot in such barrels.

I figure any ammo that will shoot 10 rounds in such barrels with no more than 30 fps between the slowest and the fastest is pretty darn good. I often get ammo in here that spreads all to 100 fps in such barrels. That aberrant 1/3 of my sample may have been coincidence that for those 44 barrels (or at least some of them) I randomly happened to select what would have been the faster round and fired it first. Perhaps it had just a little more gunpowder in it.

Then I just happened to randomly select around that shot slower second. But that happened during the test we should expect it to happen in real life as well. I don’t think we should overlook the possibility that sometimes barrels just don’t behave according to expectations and they won’t shoot the first shot after cleaning slower than the second or subsequent shots. I’ll summarize my study by saying the chances of having the first round on a clean bore being faster are about 2:1.

The bore solvent that gave the least amount of average velocity spread in the study was Hoppe’s. I recommend it. I remembered the theory about gunpowder residue creating a lubrication effect and tried two bore conditioners to see if they lay down a surface promoting more velocity in first shots. I burnished moly bore conditioner into the pores of the barrel, even though I was shooting naked bullets and followed that with dry patches to remove the excess. I also did the same with Tetra Gun Grease.

Tetra won out easily and velocities proved most consistent with it. Army Reserve shooters had been experimenting with Tetra Gun Grease to lessen bore fouling before the big, short-lived moly bullet craze. When moly bullets came along they dropped the Tetra, but when moly went out of style they forgot about Tetra. I hadn’t. First Shot Flier Uncertainties Mr. Vaughn predicts the first shot following cleaning to be 50 to 75 fps slower than the second.

Using a 20" Service Rifle barrel and an 80 or 90 grain bullet as an example, an AR-15 would place that first bullet about 6" low at 600 yards and the 10-ring on the MR-1 target has a 12" diameter. If a shooter were unaware of this he might well place his first shot from a clean barrel just in 9-ring at 6 o’clock. If he called the shot good and adjusted off of it (a full minute) his second shot could easily end up just in the 9-ring at 12 o’clock.

His first two shots could put him down two points and he might be well on the way to losing the match. Those of us who have shot in the real world, however, know that first shot fliers don’t just go straight down towards 6 o’clock per the velocity theory. I have seen them go to all four corners and everywhere in between. There remains a fair amount of uncertainty as to where that first shot will end up.

As long as ammo is kept consistent and cleaning methods don’t change some guns are known to place that first shot in the same general area most of the time. Competitive shooters and snipers tend to keep fairly good data books. By referring to them you may be able to see patterns of placement for first shots. Hunters are not known for keeping good records. Perhaps they need to start. If you are shooting any gun with a flash suppressor, they love to cling to solvents and gobs of J-B.

Both will exacerbate first shot fliers. Be sure to spray out such areas and the face of the muzzle with high pressure aerosol gun scrubber before heading to the range. Supplement with cotton swabs and a rag as necessary. If you are shooting in competition and the match allows sighters, always place more faith in the second sighter than the first. Remember to use the same kind of magazine for sighters as for when you shoot for record.

Keep your bolt carrier clean and well lubed as it has an influence on shot placement. In some matches and shooting disciplines competitors change ammo during the course of fire. As an example, High Power shooters often shoot a magazine-length 77 grain bullet for stages and change to a 80 or 90 grain round for 600 and 1000 yard courses. Changing gunpowders from ball to stick (or vice versa) or even changing bullet brands can cause the first shot following the change to be a flier!

Let’s say a shooter is using 77 grain Sierra bullets and ball powder for his 200 and 300 yard lines and then switches to a Berger 90 grain with stick powder for long range events. This can cause the first shot to go out of the normal group. Shooters need to be aware of this additional flier possibility and make copious notes in score books relative to the location of the first shot when switching ammo types. Isonite and Melonite are trade names for salt bath nitriding processes.

The bath creates a nice blackened finish on the outside and inside of the barrel. Regular bluing doesn’t cover the bore, just the outside. A lot of claims are made for these processes and I am not here to debate them. I started having barrels processed with a salt bath for the USAR Team in hopes that it would help me to eliminate some of the corrosion and pitting I was experiencing with barrels my shooters neglected.

I have had about 100 barrels processed and am pleased to report that not a single one of them had rust form inside the bore. A real side benefit I wasn’t expect-

ing is that bores treated with either process clean up real easy! The less that you have to do to get the fouling out the less the potential damage to the paper thin lands. The nitriding process can be done on stainless or chrome moly but the plant will need you to identify the barrel metal you send them as the processing differs. You also need to perform a proper break-in before the salt bath.

Be sure to carefully bore scope the barrel after break-in to ensure that every last trace of copper has been removed in your final cleaning afterward. Any trace copper that remains can interfere with penetration of the chemicals in the processing. As far as the use of corrosion inhibitors I would use them exactly the same in nitrided barrels as other barrels. Like the bore guide, the salt bath is just an insurance policy and isn’t foolproof.

Unfortunately, the process does add significantly to the end cost of a barrel so many customers will not choose the option. Complete your American Gunsmith collection. Or read up on a special subject! A limited number of the following