7.62x54R for Mosin Nagant 91/30?

[AmbulanceDriver]

Ok. I've run into a bit of frustration here. I've been trying to work up a load for my MN 91/30. Here's the basic components:

Sierra 150gr SP bullet (.311")
Wolf Gold Brass
CCI 250 primers
Accurate 4350 powder

All the firing was done at 25 yards to get a feel for the loads.

Last week, I went to the range, and had the following loads worked up:

48.6gr: horribly innacurate (softball sized pattern at 25 yds) and about 6 inches high and 6 inches left
49.6gr: same as above
50.6gr: somewhat better, 3-4 inch pattern, only 3 inches high and 3 inches left.

Then, I hit what I thought was the sweet spot:
51.6gr: Extremely accurate, hitting at point of aim, 3 rounds in a group about 1 inch across (had a flier)
52.6gr: same as above, but 4 rounds.

So this last weekend, I decided to try to narrow it down a little better, went up with 4 different test loads:

51gr, 52gr, 53gr, 54gr.

This is where the frustration comes in. For all four of those loads, the bullet impacts were either dead on, or 6 inches high and to the left. When they hit high and left, they formed the softball size pattern. When they hit dead center, 1 inch groups were what I got. Unfortunately, there was NO prediction as to whether a rounds was gonna go high and left, or dead on. Seemed to be completely random...

Any suggestions? Ideas?

I slugged the bore, and it's at .313" groove to groove. The rifle feels tight fit wise, no slop in the handguard or stock. The bolt fit is good, not overly tight but snug.

 

[NCsmitty]

I see a couple things here that could be part of the problem. The bullet really should match up better to your bore size and the powder you are using would work much more efficiently with heavier bullets. The best velocities can be obtained with a slightly faster powder such as Varget or IMR4064 and powders in that burn rate spectrum. I'm sure there will be others that disagree on the powder. My main concern is the bullet fit, and the largest diameter bullets made to fit the 303 Brit might give you better results. I see Hornady has a .312 dia 150gr. but you only know by trying. I know it's frustrating, but sometimes just trying different components will make the difference. Keep us posted.

NCsmitty

 

[gandog56]

The six inches left sounds about right if you are shooting without the bayonet affixed. Most 91/30's were sighted in with the bayonets and having the bayonet off does affect where the bullets go.

 

[Bartkowski]

gandog may be right, but my 91/30 shoots right on at 100 yards no bayonet.

 

[fireflyfather]

I see bullet casting in your future. That needs to be fed with something in the .313 to .315 range with cast lead (gas check & lube), or at least .312, preferably .313 jacketed bullets (good luck finding them).

The other thing you might try is the Ed Harris "The Load" (using 13 grains of red dot as a reduced load). He reported getting acceptable results with even .308 jacketed bullets in a mosin because the faster powder upset the bullet base into the lands more than slower powders. This is one of my two go-to loads for the 91/30. You'll only get about 1600fps with that bullet weight, or maybe a shade less using jacketed bullets. You'll also save quote a bit on powder, about $0.15 per round, depending on where you buy your powder.

I've used that charge with 150gr jacketed, and 160gr cast bullets with some success.

Here's a link to the original article:

http://www.yesterdaysweapons.com/phpBB2/viewtopic.php?t=203&sid=a189949a489545a7bb3e73ff68d1dc55

Ed later suggested using 2400 for the same purpose, but if you're cheap like me, the red dot (promo actually) is about as good as it gets for cost-efficiency.

Oh, and I recently discovered that the front sight on my 91/30 was loose. Explained a LOT. I don't shoot much high-power rifle, so I figured it had to be my shooting that sucked......replaced the sights with microclick mojo sights, and am doing better now, but have yet to test it beyond some 25 yard off hand fire. I advise against moving the front sight back and forth, as that's what caused mine to get loose (I hated the bayonet-fixed sight-in, and "fixed" the problem by re-sighting it with bayonet off.....oops).

 

[AmbulanceDriver]

Well, as I played around with the rifle tonight, I did notice that my front sight is loose... sounds like the Mojo Micro-clicks might be in my future as well. I was thinking about scoping this rifle, so that may be an option as well....

 

[FieroCDSP]

The six inches left sounds about right if you are shooting without the bayonet affixed. Most 91/30's were sighted in with the bayonets and having the bayonet off does affect where the bullets go.

I was under the understanding that that only applies to the M44. I'm sure barrel harmonics can affect the shot in a 91/30, but they were made to shoot straight without the bayo, so that probably won't have a serious effect on them.

The M44, OTOH, was designed for short range and infantry charges, so you'd naturally be fighting with the bayo extended. Failure to extend the bayo on the M44 can result in (if I remember right) up to two feet variance at 100 yards, just from the barrel harmonics.

6" at 25 yards seems a bit off, especially from a 91/30. There's something else going on there, as indicated by his shots that were on.

 

[jr45]

My 91/30 also shoots high and to the left w/surplus ammo. Definitly try some .312 diameter bullets. Mine sluged at .314 (can not find any that size) and shots pretty close to center when using Hornady's .312 174gr round nose bullets over 43 grains of Hodgdon's H4895.

 

[fireflyfather]

Yeah, a really loose front sight could result in your zero changing if you lay the rifle up against something in the upright position, or on its side. I don't know if it would change between individual shots, however. I suppose it's possible.

The mojo sight comes in two versions: rear aperture using factory front sight, and dual aperture. Obviously, only the dual aperture version will fix the front sight problem. The new front sight is actually too large for the fixture. You have to slowly file away metal until it fits your rifle. This allowed me to get a VERY tight fit (perhaps too tight, but I'd rather have that problem than the opposite). The nice thing about these sights is that the rear sight is fully adjustable for both elevation AND windage. Range adjustments do not require any tools after initial sighting in, and they are FAST. A little weird lining up two round holes and centering the target in them, but you get used to it fast. I'm going to have to switch back to black colored bullseyes, though, as the red ones don't contrast enough with the white paper when looking through front aperture. Before I used red targets to contrast with the front blade sight (black).

Scoping a mosin is a pain, unless you want to go for a scout-type mount. With a normal scope mount you have to drill, tap, and bend the bolt. After that forget about stripper clips (I never load rounds by hand anymore...strippers are so much faster/easier). Plus, you can never get the rifle back to original configuration. All I have to do is remove front sight, replace old sight (maybe with a shim of some sort to prevent looseness), and replace old sight. Only have to drift out one pin.

I will warn you about installing any type of rear sight replacement (scout scope mount, mojo sight, etc). The spring is STRONG, and it's a pain in the butt to install the rear sight without a vice.