messin' with the Mosin

[Dumpstick]

After several years of not being interested, I pulled the Mosin-Nagant out of the safe a few months ago. I am interested in shooting at OKCGC Military Bolt-gun matches. Not that I have any delusions of being top-dog, I just want to go shoot.

It's a 1930 91/30 Hex Tula, and I got it in 2012. I cleaned to cosmoline off, and it's sat since. Dark bore, some pitting, good rifling. HORRIBLE trigger - long, gritty, heavy. A plain-jane arsenal refurb, nothing special.

I wanted to try it, so I got some brass together (including some I got from a forum member -thanks Darren!). I loaded up The Load - 13gr Red Dot (Promo in my case), and fired some rounds. 150gr Hornady .312 jacketed something or other.

1607 fps, spread 44 fps, StdDev 16.3 fps.
Actually a good load on paper, very efficient, as seen by the numbers. Didn't shoot all that well, but it could be me - the trigger on this pig is terrible. I spent some time on the trigger, smoothed it up with 400 and 600 grit sandpaper. It's MUCH better now. Still long, but not gritty, good break.

I wanted to try some other loads. I have 2 cases of surplus ammo I purchased back in 2012, sitting in the shed. I figured I'd sell 'em, use the money to purchase material for the handloading this pig. I listed the case here, no interest.

I don't want to waste this ammo, but I also don't want to get hammered with 2950fps loads at the bench. I decided to try another way.

I pulled down 10 rounds of the 1951 Russian light ball (149gr steel-jacket lead core), weighed the powder. Avg charge was 49.5gr of some stick powder that looks remarkably like IMR4895.
I dropped the charge 15%, to 42gr, and reassembled the ten rounds.

2345 fps, Spread 32 fps, StdDev 15.8 fps. Another very efficient round. It shot like carp. 6"+ patterns at 25 yds. However, it didn't beat on me.

I went back, pulled down another 20 rounds, dropped the powder charge to 40gr (down ~20% from original). Fired 2 ten round strings

String 1 - 2 errors, so 8 rounds recorded -
2250 fps, Spread 151 fps, StdDev 45.6 fps

String 2 - 10 rounds recorded
2327 fps, Spread 136 fps, StdDev 46.7

The efficiency of the load is dropping - the numbers are getting worse. The deviation is triple what it was, and the spread is 5 times what the heavier load was.

And it shot like a dream, at least at 25 yds. I wasn't trying for accuracy, just getting numbers. I walked to the target after the first string - 2.5" group. I tried more on the second string - 1.5" with a flyer that brought it to 1.75".


Top "group" is the 42gr load.5 shots.
Bottom 2 are marked, with the 40gr load. 10 shots each.

I'm getting some soot around the neck of the fired cases. Go figure, the steel case isn't sealing well with a reduced charge. I won't go any lighter on the powder charge.

Methinks it's time to move back to 50 yds to practice more. I've got another 120 loaded.

 

[dlbleak]

Nice write up Paul. I'm curious as to your final results. Are you going to attempt an cast loads?
I just bought a Lee.312 mold but haven't molded any up yet.

 

[Dumpstick]

Yes, the goal is to cast for it. I was eyeballing that Lee 312-160 too.
I really need to just get used to it first. I have 1400+ rounds of surplus I plan to use to do just that.
The trigger is unbelievably long. I need to figure out a way to two-stage this thing.

 

[Dumpstick]

Some thoughts on the factory powder -

I mentioned that this powder looks remarkably similar to IMR4895.

Looking in the Lyman #48, it shows a 7.62x54R load for a 150gr jacketed soft point - start at 42.5gr @2438 fps.
At 42gr of factory powder, I was getting 2345 fps.


Many recommend using .308 "start" data if none is available for the 54R with whatever powder one may have. The case sizes are similar, .308 to 54R, with the 54R being slightly larger. The slightly larger case of the 54R will result in somewhat lower pressure, so one doesn't get into trouble.

Lyman #48 also shows a load for .308 starting with 40.0gr @2403 fps.
At 40gr factory, I was getting roughly 2275, averaging the 2 strings. Keep in mind , I'm using steel jacket ammo, not copper.

These data are very similar to what I got from the 54R. I think the factory powder is very close in burn rate to IMR4895, and I will use the leftover powder in a manner similar to IMR4895, without getting to max loads.

 

[swampratt]

I tried The Load in my 30-06 Not accurate at all.
I dropped it down to 11.5gr and cast 170gr Lee gaschecked bullet at 1400fps with 11.5 and very good accuracy.
I say drop The Load down and see what you get.
I used jacketed bullets with 11.5 in the 30-06 and they were 150fps slower or so.. accuracy was not as good as the cast.

No crimping in any of the cases.
All cases are annealed each time.. Neck ID and OD are checked and brass sorted in that manner first.
This measuring is done after sizing is done.

You can have cases that the alloy is slightly different and even after annealing will have different springback .
Andrei Mitini Cleans house there as does his wife sometimes.

I kind of wish sometimes I had a military bolt gun to play.

 

[dlbleak]

Check out the mosin trigger fix on youtube. You place a thin washer under the trigger screw to reduce travel. I'll see if I can find it and post

 

[dlbleak]

 

[Dumpstick]

Funny, I'm not one much for U-tube, I never looked for a video like that. I wish the guy would shut the he77 up, and just get on with it. What I want is a short block of instruction, not a dissertation about how his wife found whatever at the store.

That shim doesn't reduce travel, it reduces effort - the weight of the trigger pull. It moves the sear/spring away from the trigger.

That being said, I did figure out the sear shim, and cut one from a soda can - .004" thick. I installed it, but I did it at the same time I installed the smoothed trigger, so I really cannot tell if the shim made a difference or not. I don't want to go too thick, I can see slam-fires coming down that road. However, I think .004" is a bit thin. I'll keep trying. I think I have some old copper washers from brake hose connections, I'll see how thick they are.

The spring - that's a good idea. I tried one from a staple remover, but the inside diameter is small. Before I try drilling it out I may see what else I have around here.

Thanks Darren !

 

[Wyatt M]

I've been on the same path for about 6 months now. The spring behind the trigger is a modification that the Finns did to Soviet captured rifles. After not finding any chip clip springs to my liking, I eventually just made one from a hairpin / bobby pin, by wrapping it tight around a Phillips screwdriver and then cutting the ends off. It worked surprisingly well. You might also try letting the barrel cool down between shots, if you aren't already. After 3 or 4 shots my mosin' s barrel heats up and it strings it's shots vertically, really bad.