Eective Scope Mounting

My operation is in the "Venison Belt" in Northern Michigan. Deer hunting season is a very important event in this area. Generally, from the first of October through to opening day (November 15) hunters are scrambling to get their equipment ready for the hunt. One of the most common opportunities that presents itself to my business that I refer to as a "sight-in"; this is where the customer has a rifle, the desire to hunt, and needs it all thoroughly gone over, set up, and ready to go.

In my many years of installing and setting up glass optics on sporting as well as target rifles, I have taken the opportunity to read any materials on the subject I could find in the hopes of improving my final product. When I take on one of these sight-in jobs, I have distilled it down to only one approach. Whether it is a 22 Long Rifle or a 300 Winchester Magnum chambered in a light mountain rifle, the procedure and materials remain the same.

I do tell the customer this complete service is not inexpensive and assure him it will provide him with Bedding will get it right on. outstanding benefits. I let the customer know that the person working the counter at a big box store may well put the rifle scope on his rifle for free, however, sometimes "free" can be very costly in the end. As for the glass itself, I encourage the customer to provide the optic he has decided on. I am amazed at the current quality of Pacific rim optics.

I have discovered most of these optics are quite clear and have modern coatings. Unfortunately, durability is commensurate with cost. They all start out well enough but the lower end models tend to fail sooner, especially when mounted on high recoiling, light weight rifles. Unfortunately, this problem becomes compounded by the affordable "moon" scopes with the big objectives available today.

Since the newer optics are so much better than those of twenty years ago, I do encourage the customer to pursue anew rifle scope instead of trying to push an older model of questionable performance into service. I am surprised how little actual attention is given to a good solid stress-free optic mounting system. With many hunters and casual shooters, good mounting is an afterthought. A few thousands at the receiver end translates into inches at the point of impact end.

I have found dents and clamp marks on the scope body of systems I have removed. Rifle scopes with their ring sets misaligned or the turret adjustments at or near their maximum tend to give poor performance and fail sooner than those rifle scopes resting stress free and near nominal settings for elevation and windage. The mounting system of the rifle scope is a very critical component that is frequently glossed over in the active pursuit of sighing in accurately.

I have tried and abandoned several of the techniques to mount a rifle scope as stress free as possible. I have used the machined pointer rods, lapping rods, and even a custom reamer made for that purpose.

Top Try to estimate the eye relief needed before the customer comes for a fit-up. Bottom After the customer has been informed of what the procedure is and his equipment brought into the shop, I take a good look at what was already installed. I check the pre-drills both They helped but just weren’t as effective as I had expected. I have found the procedure that follows to be the most effective I’ve used thus far. factory and aftermarket. I have located a number of discrepancies at this point with customer rifles.

One example, I’ve found it is not uncommon to find bits of soda cans trimmed and slipped into the mounting system in an attempt to get the scope to align with the rifle.

If the discrepancy is not severe, I will continue, moving my attention to the unit itself, checking stock fit, tightness, and action operation, all to Setting the cross sticks before bedding aids in stretching the rubber bands evenly over the scope using both hands at once, minimizing scope roll. ensure the unit itself is in good working order and up to the task. I follow this with a thorough barrel cleaning all the way down to the bare steel.

I then borescope the chamber, leade, bore, and crown to see if there are any problems that may directly impact accuracy. If necessary, I will take digital photos of any areas that may look questionable as well as areas that are as they should be and email them to the customer. If the issues are significant, decisions are made and agreed upon as to how to proceed. A quality borescope really pays off for this kind of work.

As you can see, this is much more thorough than the freebie job offered by a big box store counter clerk! Scope Mounting I have chosen to use the Weaver mounting system as it is so adaptable and readily available. I have found Weaver’s Tip-Off design

(the steel strap over the top with the two screws on the one side) to secure the most unruly recoiling light rifles. This system also is favored by many in our industry because they work. It is also a system that has extension models that will accommodate the eye relief of the individual shooter. I clean the mounting threads and fixing screws with a non-residue solvent (everyone has a personal favorite) and pipe cleaners.

I go ahead and mount the bases to the unit and tighten to the recommended torque and secure using blue Loctite. I then select a ring height that will provide minimal clearance of the scope objective to the top of the barrel and an eye relief that I think will suit the customer’s fit needs. When this is ready, I call the customer for a fit.

In the shop, I have the customer adjust the loosely mounted scope while sitting in the bench position and the optic set at its lowest power magnification to find an ideal eye relief and then the highest power, followed by a check in the standing/ offhand with the optic again set at lowest and highest power. I use a pencil to mark the scope at the front ring in each position and generally have four markings from each check on the scope body from this.

While the customer is still there, I set the scope eye relief to an "average" of these marks unless the customer specifies a preferred setting. During this eye relief adjustment, it is not uncommon to need to open another package of extended rings to get a good eye relief for the customer. This step alone seems to really give the customer an idea of how important a good fit really is. Our area is heavily wooded and snap shots are often required.

Once the customer is satisfied with the fit I put a narrow (2-3 mm) white tape stripe on the scope just in front of the front ring set. This tape will stay on the unit all the way out the door. I take the selected ring set and scuff the contact area of the scope ring where it will meet the scope body. I then secure the ring bases (I refer to them as saddles) to the bases securely, taking care to preload the saddles forward against the slot wall in the bases to make sure recoil cannot shift them on firing later.

I clean the scuffed area with a non-residue cleaner and begin taping off the sides, edges, and top of the receiver itself with a masking tape, trimming with a snap-off knife as needed. I use J-B Weld as the bedding agent for several reasons. The most significant is the ability to clean up and trim this bedding before it gets too cured to work easily. J-B Weld is a bonding product so the releasing agent used is very critical; it is possible to get a scope glued in if a quality releasing agent is not used.

I have found a thick coating of Brownells Acra-Release to be up to the task. Do not skimp on this! Before proceeding further, I set-up my elastomeric (rubber band) retention system. I use two stout wooden pieces (cross sticks) to stretch rubber bands over each made from three craft or popsicle sticks glued together. Be certain the sticks are strong enough as a broken stick during this process really makes a mess. I secure the sticks as cross sticks to the action without the scope in place. Hav-

Far ing the sticks ready to go really helps when setting the scope. At this point I apply a heavy coat of Acra-Release to the scope body anywhere the J-B Weld may contact and set it aside, taking care to not disturb the film layer. I mix the J-B Weld according to package instructions and apply it to the scuffed saddle area, being careful to work out any potential voids. I then gingerly set the scope straight down into the J-B Weld, confirming excess J-B is oozing out around all the sides of the saddle area.

I keep the white tape stripe from earlier a little ahead of the front saddle. Make every attempt to not allow the scope to rotate as that may make removal more difficult. With the scope set straight in and not rotating, stretch rubber bands evenly over the top of the scope and over the tips of the cross Three-shot targets were the norm but currently not practical. sticks simultaneously. This helps keep the scope from rotating. I apply the rubber bands equally and evenly over both scope ring sets.

Put a small quantity of excess J- Bmaterial aside on a card as an indicator of cure rate. Note, it seems the sample does cure a little faster than the material in the job so take that into account. It is now time to wait for the J-B to cure. Depending on temperature, it may be 6-20 hours to reach a workable consistency. I like it to be soft enough to take on a fingernail dent with some effort, but not too soft. There is a pretty good margin of allowable error here. When cured, remove the rubber bands and save them.

Now comes the moment of truth. Try to pull the scope straight up from the saddles. If it resists, I use two soft pine wedges to slide carefully under the scope body against the receiver. It usually does not require this step, as just a firm, steady upward pull should do it. After the scope is removed, clean any stubborn J-B off of the scope body and reapply a thin layer of release agent for the final curing step.

If there are misalignments between the scope bases and/or rings, it will be readily visible by thin and thick areas of J-B. This particular previously mis-drilled 99 receiver of many years ago did benefit and zeroed very well from this procedure. Turn your attention to the saddles. Carefully remove all of the tape and trim the excess J-B from the edges of the saddles. Dust out any debris from the saddles, making certain they are clean, and reset the scope with the thin layer of release agent applied back in.

The J-B Weld is still somewhat soft at this point. Reapply the rubber bands as before and let the assembly cure for 24-48 more hours, depending on the ambient temperature. There may be situations where rings other (Continued on page 21)

than Weaver rings must be used. Most other ring systems will benefit from this procedure as well. A mounting system, where the fixing screws are located through the saddles, can be easily dealt with by filling the access holes with clay bedding putty before applying the epoxy bedding. The thin bedding compound over the putty will trim out best after the full cure has taken place. After curing is complete, remove the rubber bands, and clean the saddles and scope body of all residual releasing agent.

This is also a good time to set the adjustments on the scope to nominal. This can be done by counting clicks stop to stop and dividing by two. Or, better yet, use a mirror and the "ghost reticle technique" to get a nominal, centered adjustment for both elevation and windage. With the saddles and scope body clean, dust a light layer of powdered rosin in the saddles where the scope will rest and set I then boresight with a conventional spud-type laser out to 70 yards.

It is not uncommon, with this bedding method to find the previous nominal adjustments of the scope are quite close as they are. This is always a reassuring find that the scope will be operating well within the limits of it’s internal adjustment range. Most of my customers prefer I finish the job with an actual fired target. Generally I do this with a 100-yard, three-shot group fired from a rest after confirming zero with the customer’s preferred ammunition.

I have found the use of a barrel cooling fan device to speed Upon pick up, I remind the customer of the benefits as well as the limitations of this process. The scope and rings can be removed as a unit and replaced later with a minimal, if any, shift in point of impact. Additionally, as long as the ring bases (saddles) are left in place, any similar sized scope replacement will benefit from this bedding process.

Unfortunately, if the rings are separated from the receiver as well as from the scope, the bedding benefits will be compromised. I then ask the customer to monitor the white tape ring to see if the scope should start to shift on recoil and notify me for adjustment if it does. With the rosin in place, scopes stay put without having to overtighten the scope ring caps. I regularly receive repeat work on customer’s other units as well as their referrals. This system is reliable and works well. AG