Baikal MP 94 regulation - 11/16/13
I wanted to try out a combo gun for a while so I picked up a MP94 at Bud's for $475. I read all the way through this forum and others to find out how to get it shooting where I wanted. It is 12G over 30-06 and at 50 yards with iron sights the rifle barrel hit 10" lower than a rifled slug, with a scope the variance changed to 17" lower than a slug at 50 yards. The difference here is the difference between the height over bore of the irons verse a scope. It is impossible to have both barrels hit same point of aim with 2 different height sighting systems.
Next step was to determine which slug and which rifle load to use. I bought every different slug I could find and found out they all hit within 2" difference at 50 yards, so I picked a Winchester 1oz at 1600 fps. The rifle shot best with a handload of H4350 and a 180 Hornady spitzer. If I let the barrel cool all the way between shots I could put 3 shots into about an inch at 100 yards.
And the most important thing- the gun shot both barrels to the same windage, thankfully, cause that would not be easy to correct. I wanted the slugs to print between 1-2" hi at 50 yards and the rifle to be on at 100 to maybe 1" hi. I would not be shooting much past 100 with the rifle and not past 60 with a slug. So I checked the rifle at 50 with a zero at 100 and at 50 it printed .5" low. So there is my goal - shoot both barrels at 50 yards and have the slugs hit 1-2" hi and the rifle to be .5" low to dead on (at 50 yards).
I decided most of my shooting would be with a scope so I would have to accept a larger dispersion between barrels with the iron sights.
Now, the barrels were hitting 17" apart at 50, so I needed to make up between 15-16". I started by removing the wedge pin between the barrels. It came out easy as there was no tension at all on it. It was not wedging anything, just taking up space. So I called USSG and ordered some new wedges. I figured their gunsmith was probably an idiot ( and I was right) so I ordered 3 wedges. I gave them the exact dispersion between barrels and the size of the current wedge. I said send me what they thought I needed, then send me 2 more wedges even bigger. They wound up sending me 2 wedges smaller than my current wedge and one wedge slightly larger but way smaller than I needed. Total waste of time.
So i decided to cut some shim stock from a stainless steel shim kit I got from Brownells. I just cut it to fit the flats between the barrels where the wedge goes. Trial and error determined that .025" of shims in conjunction with the original wedge worked perfectly. And when all assembled you could not see the shims at all. The rifle barrel now hit dead on at 100 yards, about .5" low at 50 and the slugs hit 1" hi at 50 yards. I am ready to hunt!
The shimming process did not change the windage and both barrels still printed with the same windage. The shimming did make the rifle barrel much more sensitive to temperature, probably due to the greater stress it was under. But if I waited till it was cool between shots, they all hit very close.
Next step was to determine which slug and which rifle load to use. I bought every different slug I could find and found out they all hit within 2" difference at 50 yards, so I picked a Winchester 1oz at 1600 fps. The rifle shot best with a handload of H4350 and a 180 Hornady spitzer. If I let the barrel cool all the way between shots I could put 3 shots into about an inch at 100 yards.
And the most important thing- the gun shot both barrels to the same windage, thankfully, cause that would not be easy to correct. I wanted the slugs to print between 1-2" hi at 50 yards and the rifle to be on at 100 to maybe 1" hi. I would not be shooting much past 100 with the rifle and not past 60 with a slug. So I checked the rifle at 50 with a zero at 100 and at 50 it printed .5" low. So there is my goal - shoot both barrels at 50 yards and have the slugs hit 1-2" hi and the rifle to be .5" low to dead on (at 50 yards).
I decided most of my shooting would be with a scope so I would have to accept a larger dispersion between barrels with the iron sights.
Now, the barrels were hitting 17" apart at 50, so I needed to make up between 15-16". I started by removing the wedge pin between the barrels. It came out easy as there was no tension at all on it. It was not wedging anything, just taking up space. So I called USSG and ordered some new wedges. I figured their gunsmith was probably an idiot ( and I was right) so I ordered 3 wedges. I gave them the exact dispersion between barrels and the size of the current wedge. I said send me what they thought I needed, then send me 2 more wedges even bigger. They wound up sending me 2 wedges smaller than my current wedge and one wedge slightly larger but way smaller than I needed. Total waste of time.
So i decided to cut some shim stock from a stainless steel shim kit I got from Brownells. I just cut it to fit the flats between the barrels where the wedge goes. Trial and error determined that .025" of shims in conjunction with the original wedge worked perfectly. And when all assembled you could not see the shims at all. The rifle barrel now hit dead on at 100 yards, about .5" low at 50 and the slugs hit 1" hi at 50 yards. I am ready to hunt!
The shimming process did not change the windage and both barrels still printed with the same windage. The shimming did make the rifle barrel much more sensitive to temperature, probably due to the greater stress it was under. But if I waited till it was cool between shots, they all hit very close.
