7X57 group problem

[normmatzen]

I need some competant gunsmithing input!

I bought a cheap, knock around "sporterized" small ring Spanish Mauser in 7X57. The barel had been cut down to 21" and the stock trimmed back to sporter length. It has a one piece BSA weaver scope mount on it with a Bubba job of installation.
I took the gun to a local gunsmith to check it for head space and overall safety. They also shot it as well.

Well. after putting on a scope and bore sighting it, I went to the range. With my Savage 110 30-06 deer gun as well as my 243 WIN long range bench rest gun, I can usually get a gun to shoot in the black with 3-4 shots by first bore sighting, then shooting at 25 yd then shooting at 100 yds. Well, this gun shot a 5" group at 25 yd and wouldn't stay on paper at 100!
Went home and re-mounted the scope, one end required some shim stock between barrel and mount. Cleaned the bore again and reloaded more ammo. I am shooting 140 gr and 154 gr with mild "American" load 7X57. The SD of the shots is quite good by the way as far as MV. Also, the barrel does not look totally trashed. My eyes aren't what they used to be and I don't have a bore scope, but the barrel has distinct rifleing.
Tried again and same result. 5" group at 25 yd. This equates to 20" at 100 and that is what it shoots! I have a CZ52 pistol that will out-shoot this gun!

So, I piller and skim bedded the action. No change in accuracy!

Any ideas?

Norm

 

[shootsanything]

Norm,
I am not a gunsmith but I have been there. With the same cartridge interestingly enough. My small ring 7x57 would easily shoot 1.5 inch groups with factory ammo and I could get as good as .75 with hand loads at 100 yards. One trip to the range to test some new ammo and it was 3"+. I though crap - the barrel has finally had it. Went home, loaded some "tried and tested" ammo and grabbed a spare scope. On the way to the range I overpaid for some premium ammo as well. Tried mine and the factory stuff and still large groups with fliers. Put on a back up scope and all the problems went away.

Here is what I would do - try a scope you know works. If the groups are still large give up and look for another bargain. 5" groups at 25 yards tells me there is a BIG problem and if it cannot be solved easily the gun is not worth furhter work.

 

[shortgrass]

Find yourself a gunsmith with a bore scope. You'll be shocked and surprised as your barrel has , no doubt, been fired with corrosive ammunition at some time in its long existence. Yes, you can see the rifling with your eye, but, you can't see what is 'robbing' the accuracy.

 

[Robert]

Went home and re-mounted the scope, one end required some shim stock between barrel and mount. Any ideas?

Norm

Norm,

Shall we understand from that the scope is fitted also on the barrel?

R.G.C

 

[normmatzen]

No, I mis-spoke! The scope mounts are on the receiver as they should be!

Thanks all, I'll pack it over to the gunsmith and have him inspect the barrel with a bore scope. Maybe have him re-mount a proper scope mount as well!