Lousy groups

[bob4wd]

As you can shoot well enough with a different Mosin, we can assume that you are not the problem. And if the rifle is OK at the front end, the trouble could be in the back end. The rifle may be badly worn in the throat, in which case you may need to go to hand-loaded ammo, as most factory ammo uses boat-tails.

Find out the maximum possible cartridge length - the method has been described several times in these forums, so search it out. If the max. length, i.e. the point where the bullet is just about touching the lands, is so far out that the bullet is completely free of the neck of the cartridge case, then the rifle will never shoot well with that bullet. Basically, the bullet has a substantial free flight in the worn throat, hits the transition cone at an angle, is engraved crookedly, and comes out of the muzzle with a skew that means the POI is all over the place! Hence the extraordinarily large group, which nevertheless has the centre in th emiddle of the target.

For a very worn throat, about the only pracatical answer is to use a flat-based bullet with the largest diameter that can be safely used in the chamber and the longest possible cylindrical section. The best choice is the Hornady #3130 flat-base round-nose 174gn bullet with a diameter of 0.312". They seem to be rare these days, but I think there is one from Speer that is similar.

A very good thought indeed. All of the bullets I used are flat base, and are loaded on the long side but not fitted to this rifle specifically. Will go though the process and check ‘em out!
As for bullet types the lead loads were of three diameters; .312, .313, .314, all 180 grains and gas checked.owder was 2400, 14,and 18 gns. The ball was pulled Russian 150 gns. Flat base. Didn’t measure diameter. Charge from Lyman manual, min. Load of H4895, I forget the weight and am away from the bench right now.
It’ll be a couple of weeks before I get to try anything, on my to Phoenix for the big gun show coming up this weekend. Will report back.
I don’t really know why I’m trying to make this gun shoot when I’ve got a perfectly good one ( not a Century POS, by the way, but a fine semi-real one to shoot), but it’s a challenge that is becoming an obsession!