Rifle went from 1/4” to 5”??

[jsthntn247]

Yep, sho did. What's next bed the rail? This dang 35 Whelen has already broken a set of Leupold rings and now the steel base that's loc tighted down? Man this is frustrating. Tried to post a video of the rail shaking back and forth but can't figure it out.

 

[sedancowboy]

I now glue most of my rails on. I use JB Weld and bed them but I don't use any release agent. I tighten the screws just until I feel resistance as they bottom out. As the JB Weld cures a bit I will back them off to make sure the screws are not stuck. After the JB Weld cures completely I will torque the screws down to spec. I have yet to have one move or come loose. If you ever need to remove the rail heat it with a heat gun and pop it off.

 

[Darryle]

Here's my new regimen

Scope Base Bedding

Scope Base Bedding

In an ideal world, the bottom of your new Murphy Precision Scope Base, would fit the top of your rifle action perfectly, with no gaps, or misalignment. Unfortunately in the real world, this level of fit isn't likely. Most modern rifle actions are machined to fairly close tolerances, but before the common use of CNC machining equipment, tolerances were much looser. In addition to any errors in the original machining, most rifle actions are polished afterward to remove any tooling marks. While this leaves a pleasing finish, most freehand grinding and buffing can lead to errors of several thousandths of an inch in critical areas. Without bedding, the only solution is to tighten the scope base screws enough to warp the scope base and rifle action sufficiently to make close contact. This warpage can lead to a host of accuracy robbing problems in both your rifle action, and scope.

When properly bedded, high strength epoxy resin fills any small gaps that may exist between rifle action and scope base, allowing full contact with both members in a relaxed state. As an additional benefit, the epoxy resin bonds the scope base the the rifle action, eliminating any recoil stress on the mounting screws.

Equipment Needed

Brownells Acraglas, JB Weld, or Devcon Metal Filled epoxy compound
Release Compound (Floor wax is acceptable)
Paper Towels / Rags
Paper Plate / Cardboard / other mixing surface.
Acetone for cleanup

Procedure

Step 1:

Before getting anything messy, it is a good idea to dry fit the scope base to your rifle action. Make sure the scope base fits properly with all four provided Torx screws lightly snugged. Do not continue if there are any large gaps, overhangs, or misaligned screw holes.

Step 2:

After you have verified the dry fit of your scope base and rifle action, it is time to prepare the base, screws and action for bedding. First, thoroughly clean the underside of your scope base, and upper surface of your rifle action with an acetone or alcohol soaked rag. Be careful not to touch these surfaces again with your bare hands. Then, apply a liberal coating of release agent or floor polish to the scope base mounting screws. (Failure to follow this step may result in stuck / impossible to remove scope base screws.)

Step 3:

Mix a small amount of epoxy bedding compound according to it's directions, then place all four scope base screws into the scope base to be bedded. Apply a thin layer of bedding compound to the underside of the scope base between and around all mounting screws. (Don't worry about applying too much, as any excess will be cleaned off later.)

Step 4:

Apply scope base with bedding compound to your rifle action, and begin tightening the center two screws until the base appears to be all the way down, and you can just feel the screws begin to tighten. Then tighten the outer two screws until they just make contact.

Step 5:

Wipe off any excess epoxy with rags, then clean up any reside with acetone soaked rags or Q-tips. Epoxy may continue to seep from underneath the scope base for an hour or two, so this step may need to be repeated. Once clean, set action aside for 12-24 Hours to allow epoxy to fully cure and harden. (Consult epoxy manufacturer regarding cure times.)

Step 6:

Once epoxy resin has cured, torque all four mounting screws to the recommended 15 inch-pounds.

That's it! Enjoy your properly bedded scope base.

 

[Outlaw6.0]

@Darryle

I've heard of this process many times over the years & yet to hear of any issues. If Murphy Precision is recommending it, i'm all in. That dude really knows what he's doing.


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[Outlaw6.0]

Yep, sho did. What's next bed the rail? This dang 35 Whelen has already broken a set of Leupold rings and now the steel base that's loc tighted down? Man this is frustrating. Tried to post a video of the rail shaking back and forth but can't figure it out.

Believe it or not, i've only seen 2-3 broken rings in all of my life. All of them have been Leupold. Now, i'm not saying that Leupold's are a problem or that the issue only exists with them; perhaps it was just coincidence.

If bedding your rail isn't something you are comfortable with, I would highly recommend having your local gunsmith (or non-local for that matter) open up your pic rail screw holes to 8-40. Larger screws, more clamping power, easy-peasy.

I trust these guys with my life:

GUNSMITHING SERVICES: 8-40 Optic Base Threads for Remington M700 and Winchester M70

A nagging side effect of production grade receivers is the tendency for certain features to be machined slightly out of position. The 8-40 optic base hole upgrade is intended to resolve this issue. By aligning the receiver bore to an axis on the milling center, we are able to correct position...

www.longriflesinc.com

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[HSmithTX]

I would add that you should check your scope rail to make sure it is flat and true BEFORE you bed it to the receiver, I have had rails from very big name trusted companies that aren't flat out of the package. Each time I contacted them, and they sent me a new rail. Bedding a rail that isn't flat will put stress in the scope and rings that they do not like when you torque everything down and especially so if that rail is bedded.

If it is a two piece base attachment I will mount the scope in the rings and the rings to the bases, THEN bed the bases. This aligns the bases to the rings and the scope to take all stress out of them. If you can't reach the base screws with the rings on you will have to make alignment studs out of longer screws, then a big rubber band around the scope and stock to hold everything together while it cures. Take scope out of rings, rings off bases, remove the studs and replace with the correct screws.

 

[Willys]

I've used green loctite sleeve retainer for mounting bases over a dozen times on 338-378 & Lapua's and have never seen a failure. The thick stuff (high viscosity) preferred not the thin seeping/wicking stuff. Its 3800 psi sheer strength and you torque screws immediately - I like rail to steel not rail to jb weld.

 

[jsthntn247]

I bedded the rail. No problems on first trip to the range. Hopefully it holds for my draw hunt. Took 10 years to finally draw a tag. Missing would really suck. I have to use a 35 caliber rifle at the place so I'm stuck with this one. Good thing is it shoots 200 grain hammers light out. Just need everything to stay together.

 

[Fiftydriver]

I bedded the rail. No problems on first trip to the range. Hopefully it holds for my draw hunt. Took 10 years to finally draw a tag. Missing would really suck. I have to use a 35 caliber rifle at the place so I'm stuck with this one. Good thing is it shoots 200 grain hammers light out. Just need everything to stay together.

Likely it will work loose again. Only way i have found to properly prevent this from happening long term is to pin the rail to the receiver. Easy to do. When i started working with Defiance to build my Raptor receivers to my specs i demanded this to be done. Now they do it on all their Rebel receivers. Before this i was pinning the bases on Rem 700s and all custom receivers. For example, on my big XHS rifles use BAT and Stiller receivers mainly, install 3 or 4, 1/8" heat treated steel pins through the rails and into the receivers. Probably over kill as two would likely do the job but as with all my creations, overkill when it comes to strength and rigidity is a good thing. Simple fix, just pin the rail to the receiver and problem solved. Then you may need to deal with ring slippage on the rail next!!

 

[RidgeTop]

In over 60 years and 100 rifles/scopes I have never done any more than wash screws, screw holes, mating surface with alcohol. Never broke anything and nothing comes loose. Heavy recoil include BPS 12ga 3" Win Supreme slugs, Weatherby Mk V .340WbyMag.

 

[WeiserBucks]

Then you may need to deal with ring slippage on the rail next!!

How are the rings going to slip on the rail? They're lugged.

 

[Fiftydriver]

How are the rings going to slip on the rail? They're lugged.

If there is no muzzle brake then there will be no ring slippage as there is only positive g forces produced when the rifle is fired. If however there is a quality muzzle brake, the negative g forces can cause the rings to slip on on the rail. Very few rings are a perfect fit in the rail slots. Most rings can be slide back and forth between the rail slots. When a rifle is fired, the recoil energy forces the rifle backward, as such so is the rail base and rings and finally into scope. Once the bullet passes through the muzzle brake, the rifle is dramatically decelerated. The base, rings and scope want to continue in their rearward movement and will unless they are physically prevented from doing so.

now, many muzzle brakes are not effective enough to cause this, however most quality modern partition style brakes like my Painkiller brakes certainly cause this problem. The lighter the rifle, the worse it is, the heavier the scope, the worse it is. As such there must be ring to rail support for positive and Negative g forces to keep a scope solidly in place.

this is the main reason i always use two sets of nightforce ultralight tactical rings on my Raptor LRSS rifles in my wildcats over 7mm Allen Mag and use three rings on my big Stalker magnum rifles. on the Raptor, 2 rings are positioned to control recoil energy (positive g forces) and two rings are positioned to control negative G forces. Best method to keep optics solidly in place permanently. With my Stalkers, two rings support recoil, one negative g forces.

again, with some brake designs such as the radial port brakes, this is not an issue but highly effective brakes in the right rifle/scope combo can cause real issues.

 

[Fiftydriver]

In over 60 years and 100 rifles/scopes I have never done any more than wash screws, screw holes, mating surface with alcohol. Never broke anything and nothing comes loose. Heavy recoil include BPS 12ga 3" Win Supreme slugs, Weatherby Mk V .340WbyMag.

When it is a problem and it certainly is a problem with some combinations, pinning the rail is an easy fix. There is a reason most top quality custom receivers have pinned or integral rails.