Mosin Targets... Vertical Stringing... Help?

[Josh Smith]

Hi All,

I'm stumped here.

This is today's shooting. It's just surplus light ball bullets, pulled, over 45 grains of Varget and a Federal primer. This is from a clean bore, and this rifle shoots low with a clean bore.

10 shots. Square is 1"; circle is 2". 60 yards, prone, front support, fire five, stripper clip, five more, as fast as I can BRASS, about every two seconds:

http://i1147.photobucket.com/albums/o560/Smith-Sights/Targets/Untitled-3.jpg

Prior to that, a 174 grain Hornady o.312" Match over 51.2 grains H4350, same distance:

http://i1147.photobucket.com/albums/o560/Smith-Sights/Targets/June2360yardsmeasured.jpg

But 174 grain jacketed round nose o.312" bullet, under increasing amounts of Varget, this is the best I could get, and the vertical stringing is really bad though it's an improvement over the lighter loads. If I recall correctly, these are 44 and 44.5 grains, pretty much overlapping each other. 10 shots:

http://i1147.photobucket.com/albums/o560/Smith-Sights/Targets/verticalstringing.jpg

Do I just keep increasing until I max out or find a load that doesn't string? Where do I go from here?

Thanks,

Josh

[tomme boy]

Barrel heating up looks to be part of the problem. Trigger on Mosins are hard to be consistant.

[Larry Gibson]

Is the stringing sporatic between shots or does the group "walk"?

Larry Gibson

[303Guy]

60 yards, prone, front support,The front support could be the problem. I've got a No4 LE that was very sensitive to fore-end grip. It seems much better after re-bedding. The POI did shift quite a bit which confirmed to me that it was a bedding issue. That doesn't mean your rifle has the same problem but it's worth checking I would think.

[Josh Smith]

Hi Guys,


The front support could be the problem. I've got a No4 LE that was very sensitive to fore-end grip. It seems much better after re-bedding. The POI did shift quite a bit which confirmed to me that it was a bedding issue. That doesn't mean your rifle has the same problem but it's worth checking I would think.

I stopped resting it on the lower handguard and rest it on the main stock. Have for years... but you're right, that would cause it in this rifle.

It almost seems as if I'm not driving the bullet fast enough with the Varget. The best group came from a 174 grain match bullet going about 2500fps with H4350, and the 150 grain bullets are pushed about that speed with Varget.


Is the stringing sporatic between shots or does the group "walk"?

Larry Gibson

Well Sir, the top target is really not as representative as it could be. Those three fouling shots at the bottom should be discounted. It was a clean, oiled bore and it will usually sink all of them into where those four are right now. That is to say, I do about 1.2MOA on a regular basis with 150 grain bullets over 45 grains Varget, like this:

http://i1147.photobucket.com/albums/o560/Smith-Sights/Targets/March27sightinscored.jpg
80 yards or so

These are open sights by the way. No optics.


The trigger is no longer an issue. It's a two-stage M39 style only I built it with roller bearings, and it's a much better trigger than any Mauser.

I do shoot with 20/45 uncorrected vision.

It's almost as if it doesn't like heavy bullets with Varget, but with slow powders only. Would that be possible? Maybe I should load up a few of these with H4350 and see what happens?

Thanks,

Josh

[tomme boy]

Switch to a Mag primer. Thats what I had to do to a couple of my Mosins to make them settle down. Also dont try to reach the lands. The mag primer an seating the bullets to book specs seemed to help ignition.

The only thing I can think of why the above worked for me is because of how long the throat is. I think it helped build pressure before the bullet entered the lands. The throat is so long, the bullet has released from the case before it even touches the rifling. Can't prove it, but it worked for me an a couple of friends.

[legend]

this is interesting as i too shoot a mosin 91/30 .

[Larry Gibson]

Have to concur that Varget with the 150 gr J bullet may not be burning efficiently. I use 48 gr H4895 under the Hornady 150 gr .312 SP in Norma cases with WLR primers for 2927 fps out of my M39 Finn. That load is slightly slower and has slightly less PSI than the Norma factory 150 SP load which ran 2979 at 45,600 psi(M43) out of the same M39. Accuracy with both was excellent at 1.5 moa with the issue sights at 100 yards.

Larry Gibson