Old Mauser sporter question

[bartonlong]

I am finally getting around to converting an old turkish Mauser from 8x57 to 8mm-06 Ackley improved. I cut off the old long (29") barrel to 22" and discovered the bore wasn't concentric with the outside of the barrel. I have trued, crowned and lapped the barrel using brownells crowning kit and it looks good. I jsut ordered the chamber reamer and headspace gauges. Any of you run into this problem before? I thought about it and if the crown is good I don't see any reason why this won't still shoot good. The barrel is in otherwise good shape, no pitting, good strong rifling, exterior is straight. Let me know if anyone else has had any experience with this.

 

[jimmyraythomason]

I haven't encountered this particular problem with a Mauser barrel but it should not effect performance at all,IMO.

 

[Jim K]

Well, it might. If the barrel bore is straight at the point it was cut, the only effect would be possible inaccuracy due to uneven heating of the barrel. BUT, if the cut has been made at a point where the bore is going off in a different direction, the gun may be accurate, but you might never be able to get it sighted in (you might need a rear sight set a foot to the side to zero the rifle).

To see what I mean, consider the muzzle as being at some point on a curve started back in the barrel. In the original barrel, the bore curved back to the center and was straight several inches before the muzzle so the bullet exited going straight. But now the bullet will exit going the direction of the last inch or so of the bore, which means it may go off to the side. The gun may be accurate, and shoot good groups, but where that group will be is anyone's guess. You might try a bore sighter and get an idea of how far off it will be.

I would try the rifle and see what happens, but I suspect that to get any good results, you will have to rebarrel the rifle.

(FWIW, off center bores are uncommon, but not unknown; I have seen several.)

Jim

 

[jimmyraythomason]

Again this is just a guess but I would think any effect would be minimal. Barrel mounted sights MAY be affected but there again I don't think it would be much. IF you are looking for a sub-moa gun I agree with the barrel replacement. Shooting it will tell the tale as Jim suggests.

 

[Savage99]

Bartonlong,

The "ackley improved" part of the project is a waste of time and money.

Just shoot that old gun as a 57mm.

 

[fguffey]

When heat is applied to the barrel by firing it will not have a choice, it will curl because the mass is greater on one side than the other.

The 8/06 AI reamer will clean up the 8mm57 chamber, then it comes down to which Turkish Mauser. If the rear of the receiver ring has a notch in the top rear I would leave it chambered in 8mm57, if the rifle is a Model 38 and the bore is not centered I would replace the barrel with an 6.5mm55 barrel, you could contact http://www.hoosiergunworks.com/ for a replacment barrel.

A receiver wrench and a barrel vise, in my opinion, would have been a better choice than the reamer and the 8mm06 for the Mauser in my opinion is a better choice than the AI version. If there was a problem with the 30/06 or the 8mm57 the 8mm06 corrects both.

F. Guffey