Getting Revolvers Right

Anyone who does a great deal of revolver shooting will surely want to use cast bullets. The reasons are many, but simply stated, cast bullets provide some of the least costly reloads combined with some of the best potential results on targets or game. Also, good cast bullets give less wear on the barrel than any jacketed bullets, and over time, that makes a big difference.

Swaged, purelead bullets are fine for light loads, but mid-range and heavy handloads require harder metal to withstand the greater forces imposed on the bullet by the burning powder and by the dynamics of the gun itself. The successful use of cast bullets, however, rests on two critical dimensions. If these dimensions are wrong, you’ll have poor accuracy and/or bad leading. The critical dimensions are the outlet of the cylinder openings and the groove diameter of the barrel.

I’ve recently been reading Elmer Keith’s Gun Notes, two delightful volumes that contain most of what the grand old master—father of the .44 Magnum—wrote for Guns & Ammo magazine over several decades. Keith’s writing reminded me of lots of stuff I knew years ago, but forgot, and it explained some mysteries that have swirled around in my brain for many years—stuff I never bothered to look into until just recently. And when I did, man! Big surprise.

Some 30 years ago I was a member of a club in the Denver, Colorado, area that gathered twice a month for what we called the "Bower-Hansen Magnum Matches." Twice a month we shot at steel plates at 100 yards, 40 rounds per match, full-power loads. Most competitors used cast bullets. No one I knew used gas checks, which seem to be useless in revolvers. I competed with an S&W Model 29 with 6-1/2-inch barrel, and did well enough. But my old Smith always leaded severely.

The lead would stick to the rear part of the barrel and to the forcing cone, and often required scraping to remove it. A Lewis lead remover helped, but would not get it clean. I used a dry bristle brush to scratch out the lead between strings, and always got a bunch of lead out of my gun, no matter how hard I cast my bullets. I knew the barrel slugged 0.429 inch, and always sized the bullets to that dimension, but still got bad leading. I never bothered to ask myself why.

Years passed, and when I needed a short carry gun in Alaska, I had the factory install a four-inch barrel on that old six-shooter. The new tube also had 0.429-inch grooves, and With a low-cost reamer, the fix was simple. This made the gun a better shooter with cast bullets. The author feels he did not damage the classic 1907 Colt, because the alterations were invisible and made it a better gun. still leaded significantly. Eventually, I moved to Idaho, right across the street from Elmer Keith’s old ranch.

Keith’s books (and, probably, his ghost) brought to mind my Alaskan handgunning experiments, when I shot cast bullets into snowbanks, and in the springtime collected and inspected them. I learned then that everything Keith wrote about cast bullets in revolvers was correct. Normal cast bullets fired with medium or full charges of powder

upset to fill the chamber mouths before they ever get into the barrel. (Abnormally hard cast bullets don’t bump up, but have other problems.) In other words, no matter the size of the cast bullet when loaded, by the time the bullet reaches the barrel, assuming a stout powder charge, the cast bullet has jumped up in diameter to fill the chamber mouth.

This is good, because the tight fit thus restricts gas leakage past the bullet, which reduces gas-cutting of the top strap and reduces melted or softened lead on the sides of the bullet before it rams into the forcing cone and slides into the barrel. The chamber mouths have to be the same size, or slightly larger—no more than about one thousandth—than the groove diameter.

If the chamber exits are too big, the bullet arrives at the forcing cone being too big, and that can result in massive leading in the forcing cone and first part of the barrel. The degree of leading depends on the hardness of the bullet and on the At the left is perhaps the most famous of all cast-bullet handloads, the .44 Magnum with Elmer Keith’s load and the bullet he designed. Next to it is the hard-cast bullet itself.

The big one was recovered from snow, and was fired from the author’s well-dimensioned, accurate, and non-leading 500 Linebaugh. The next two bullets are commonly used in cowboy-action shooting, and that’s a .45 LC at the right, one of the most popular calibers for the sport. With the gun’s dimensions correct, these are all perfectly viable bullets. With incorrect dimensions and soft bullets, there will be leading.

The bullet in the next chamber would have been squeezed too small for the barrel without this simple modification. condition of the barrel, in addition to the dimensions of the revolver’s chamber outlets and groove diameter. Of course, misaligned chambers can add to the problem, but in my experience most of the leading problems with revolvers comes from improper dimensions, not misalignment. If the barrel is slightly rough, as when new or neglected, that makes for lead deposits that can be very hard to remove.

Fire-lapping will result in a smooth bore to which not much lead will stick, but if the dimensions are just plain wrong, you’ll always have a problem with leading, even though it may be relatively easy to remove. What were the dimensions of my old Model 29’s chamber mouths? I had absolutely no idea. Yep, I owned that six-gun about 30 years and had no idea what it measured. A few days ago, I slugged the chambers for the first time (see sidebar).

They were 0.433 inch, or four thousandths larger than the barrel’s groove diameter. So for three decades I have been blow ing oversize bullets into the bore, with resultant severe leading at the beginning of the barrel. If I was too casual about the lead mix, I got bullets that were too soft, and leading got much worse.

With too-hard bullets, the leading diminished, but I found these too-hard bullets were brittle, and when they ran into a steel ram in silhouette matches they would fragment and not bring the target down. This was relatively harmless in the grand scheme of things, but did little for my confidence. So one important criteria for cast bullets is to get them fairly hard, but not too hard. If you can mark them easily with your thumbnail, they’re probably too soft for best results in medium-to-heavy loads.

I always used Keith’s classic SWC configuration for my cast bullets in that Model 29. As soon as I knew what the cylinder dimensions were, a light went on over my head. Armed with my new-found awareness, I measured half a dozen of my revolvers, and got more enlightened. A few of the good ones were my .500 Linebaugh, an ancient Smith & Wesson revolver chambered for.38 S&W, and my S&W stainless Model 625-3, all of which had near-perfectly matched cylinder outlets and grooves.

Another fine one was a brand-new Ruger Blackhawk in .45 LC, currently undergoing testing, and it shoots very well. These are among my most accurate revolvers. Then things got ugly. I found a S&W .357 Magnum with 0.356-inch grooves and 0.358-0.359 chamber

AGGDB15 AG DBI Spread Ad (pick up from 10/04 issue)

AGGDB15 AG DBI Spread Ad (pick up from 10/04 issue)

Barrel Slugging Simplified How do you slug a barrel? The easiest way is to secure a box of pure lead balls suitable for muzzle-loading handguns. I use Speer’s 0.375-inch round balls for .357s and smaller guns, and the 0.457-inch balls for larger barrels up to .45s (see photos below). First, clean the barrel making sure there is no leading in the bore, because that gives a false reading. A few rounds of jacketed-bullet ammunition fired through the bore will probably suffice to remove stubborn deposits of lead.

Then, clean the bore and coat it with oil. I use WD40, but any oil will do. Don’t dry the bore out. Next, place a suitable lead ball on the muzzle and hit it with a small hammer. Go easily to avoid banging the muzzle of the gun with the hammer. If you are worried about smacking the bore, use a wood block between hammer and ball. The lead will enter the bore and flatten out, and usually leave a ring of lead behind, which does no harm.

Use a wood dowel or suitable brass or steel rod and continue tapping the lead slug through the bore, and catch it on rags or a small towel placed within the open crane of the gun. That’s to make sure the soft lead won’t be distorted as it flies out the back of the barrel. With good barrels, you’ll be able to push the slug most of the way through the barrel by hand. With question able barrels, you’ll find a tight spot where the barrel is screwed into the frame.

These are best dealt with by fire-lapping, a discussion for another time. Once you have your slug, it should be easy to get a measurement of the widest dimension. Be sure to use a good micrometer. If the bore has odd numbers of grooves and lands, you might find it easier to measure by rotating the bullet slowly in the jaws of the micrometer, while decreasing the indicated measurement a thousandth (or less) at a time.

Hold the measurement steady, and rotate the bullet, feeling for the touch of the bullet on both micrometer anvils. Keep closing down the micrometer until you get the measurement. This is how I measure five-groove S&W barrels, and it seems to work well. For the cylinder outlets, you can use anew ball, or actually use the same one you just used by first smacking it on a flat surface with your hammer to bump it up to a fatter dimension.

Then tap or press it through the cleaned and oiled chamber from the rear toward the front, again being careful to catch it without distortions. A dial caliper stuck into the front of the chamber is not the way to measure the chamber mouth. If the chamber mouth is the same as or a thousandth larger than the groove diameter, consider yourself lucky. If it’s a sound gun, that revolver should work very well with cast bullets sized to the exact groove diameter.

outlets. It leads badly, but ongoing fire-lapping is helping it. Other bad ones were a couple of old Model 25 S&Ws which have always leaded, both of which had chamber outlets of 0.458 inch and groove diameters of 0.451. And there were others. However, the biggest surprise was a 1907 Colt Single-Action Army, which had 0.455-inch grooves, but its original cylinder had chamber outlets of only 0.451.

This old six-gun has delivered acceptable accuracy, around 3 inches at 15 yards, but I always got some unexplained fliers. The barrel, though somewhat worn and pitted, showed slight leading here and there along its length, but never near the forcing cone. Now I know why. The bullet arrived at the barrel sized down to 0.451 inch, and then hit the high lands of the old Colt here and there along the bore, and managed to get straightened out well enough to shoot passably.

Unfortunately, there is no easy fix for a situation where the cylinder is too big for the groove diameter of the barrel. Fire-lapping can help in some cases, and will at least make lead removal easier. One could perhaps plate the cylinder up and then ream it, or it might be possible to make a chamber insert that would have to be sweated in and then reamed to the correct final dimensions. This could easily cost more than the gun is worth.

Practically speaking, one would have to live with the condition and either put up with leading, or shoot only jacketed bullets through the barrel. This will ultimately shorten the barrel life, but would be a viable solution for people who shoot only occasionally. Of course, the best solution would have been for me to have measured the old M29 when it was new, over 30 years ago, and then have asked the factory to fit anew cylinder with the correct dimensions.

The unique problem with the old Colt SA was easily solved. Along look through gun-supply catalogs revealed no chamber reamers of the correct 0.455-inch size. I could help the mismatch, but not fix it with the fairly costly reamers commonly available through gunsmith’s supply houses. But because I do some occasional machining on projects other than guns, I had the wonderful KBC Tools & Machinery catalog on hand www. kbctools.com).

This company sells milling and lathe cutters, all kinds of machinery and tools, and also a vast selection of reamers. One page of the thick catalog had what I wanted. On that page were listed over 1,000 chucking reamers in one-thousandth-inch increments (and some with finer increments), within the range from 0.0300 up to 0.9995 inch. The amazing thing is, all these reamers are in stock, and range in price from about $10 up to less than $50 for the biggest reamers.

A few of the interesting gunny sizes include: 0.3560, 0.3570, 0.4100, 0.4110, 0.4300, 0.4305, 0.4515, and for me, 0.4550 inch. And if you can’t find what you need, they’ll make you whatever you need for a surcharge of 30 percent. How can you beat that?

In addition to machinery and tooling, the KBC Tools & Machinery catalog contains many odd and hard-to-find tools, shim and bar stock, power tools, clamps, gauges, calipers, abrasive wheels, lathes, milling and drilling machines in all sizes, and most of the tools and machinery anyone would need for gunsmithing and/or other machine work. Want a ten-cent pin? They’ve got it. How about a $42,000 centerless grinder? They’ve got that, too.

In my dealings with them over the past four or five years, I’ve found them to be thoroughly professional. I promptly ordered a 0.4550-inch reamer for my old Colt. The reamer arrived in two days and cost about The company stocks thousands of reamers, many in sizes that are well suited to gunsmithing. $18. I immediately took it to the cylinder of the old Colt, using my drill press and a secure fixture to hold everything firmly. Then, with the new dimensions, I shot the old Colt again.

To my utter joy, it no longer threw those unaccountable flyers. The average group size was reduced to about 2 inches, which in light of the worn barrel is pretty darned good for a gun approaching the century mark. I don’t believe I messed up an old historic Colt in this case. The gun shows evidence it has been worked on significantly in days long past, and my work only made it a better handgun. And the work was essentially invisible anyway.

By the way, in a half-dozen old Colts I’ve measured, common groove size is on the order of 0.452 inch, not the commonly assumed 0.454. The only way to be absolutely certain of what you have is to measure it. If by chance you find the cylinder outlets too small, it can be an easy task to get your revolvers just right, and that makes for better shooting and happier customers. ■