All,

I have a mauser that has been giving me some strange accuracy problems, and I think I may have finally identified the problem.

I will describe the nature of the accuracy issues, but first wanted to find out what you guys though would be the resultant effects. That is to say, I didn't want to lead the witness(es) first.

So, what I think may be the problem resides in the rear tang. I believe that the rear tang is too "tight", without adequate clearance behind it. It appears as though it is bearing against right up against the inletting. Luckily the stock, which is wood, has not cracked. I believe that the fit os do tight there that the recoil lug may not be making even contact with its recess in teh stock.

So, the question is, if this were, in fact, the case, what sort of impact, if any, would you expect for this to have on accuracy?

As a follow-up question, how much clearance would you be appropriate between the rear tang and the inletting? Assuming you wanted a nice clean look of course, no some huge gap back there.

Thanks,

Bob

If the back of the recoil lug is not making full contact with the stock, you will more than likely have an accuracy issue. As far as the clearance between the tang and the stock, I've found that .015" - .020" is enough. If the action is properly inletted and bedded there should be virtually no back and forth movement. I've inletted some actions chambered for low recoiling rounds with almost no gap at the tang and have yet to split a stock. Hard kickers, I think, do need a bit of gaposis.

Take some high spot bluing or inletting black applied to the back of the recoil lug and the back of the tang and do a trial fit. That should show you if you have a fit problem relating to the recoil lug. If you get some black in the tang area you can relieve it until the recoil lug sits against it's inlet properly and you have enough clearance behind the tang to slip the tip of a dollar bill between the metal and wood. If you don't see any black in either area then you have another problem in some other area. Black the whole bottom of the action and check again. Also make sure you don't have any of the action bolts rubbing the wood anywhere. Let us know how it works.

Just try a little squish of Acraglass behind the recoil lug. One other thing that seems to elude a lot of accuracy problems is the bolt handle; make sure when it is in the closed position that is does not contact the stock.

Be sure in bedding the recoil lug on a Mauser that the base of the lug or the front of the lug does not touch the stock or bedding compound. Put electric tape on the front and base of the lug when you put it in the bedding. Kudude

The purpose of bedding is to provide for a low compliance and repeatable connection between barreled action and stock. The recoil reaction is then of a larger mass.

We built a .223 on a 1903 Turk Mauser that will reliably put 5 shots into 1/2" at 100 yards with 35 gr bullets. Because of the ratio the small ratio of bullet to barreled action mass, and becuase of the small recoil energy velocity, glassing was not needed.

When the same actions push a 220 gr 8mm bullet at 2500 fps, the benefits of glassing are noticeable.

What does it all mean?
1) It depends on how much recoil you have.
2) Most people can't calculate compliance, they just perform the glassing ritual.

Guys,

Thanks for the comments and suggestions!

I had put some inletting black on the tang, which pretty well confirmed my observations that there was no clearance there. I did not apply to the recoil lug though....duh. I will do that over the weekend and see. If that looks suspicious I will relieve a bit at the tang and shoot her to see what happens.

So, how has it been shooting...

basically, it strings out horizontally about 3 to 4 inches at 100 yds, with about only 1 inch of vertical dispersion. This is with a bunh of different types of ammo and different weight bullets. Also with three different scopes and two different set of mounts. This inconsistency is very consistent..

So I know it is not the scope and mounts. There is also no significnat or uneven lateral barrel to wood contact that can be found.

Perhaps the most unusual part is that it will sometimes shoot two separate groups. It did this the past weekend, on alternating shots no less. It was quite impressive. I know that most would say this is a scope failure, but I KNOW this is a good scope, and it has done it with another GOOD scope.

My thought was that it may be toggling somewhat on the tang, and it it is not fully and squarely contacting at the recoil lug it may be toggling with each shot. I dunno, but it seems like it could happen.

Has anyone seen anything like this?

I will let you guys know what happens after I give it a bit of clearance at the tang.

A Mauser / most bolt actions properly bedded should only make contact with the stock in 3 places, the bottom of the tang, bottom flat of the front ring and the recoil lug eg. pillar bedding. The barrel if free floated about the first 1 to 2 inches from the receiver should make contact. If not free floated same from the receiver + the stock tip (at varying Pressure) till max accuracy is achieved - 1 to 3 lbs. --- John 303.