Can someone help interpret this Mosin bore slug?

[nvahalik]

Finally had a chance to slug the bore on my Mosin... forgive my terminology if it is incorrect.

Land to land measure: .3015 inches
Groove to groove measure: .314 inches

Should I consider reloading .311 or .312 bullets? I assume that the standard .30 bullets are okay to shoot but I shouldn't expect the same level of accuracy that a slightly large bullet would give me. Right?

 

[nicholst55]

Ideally, you should shoot .314" bullets, but nobody offers jacketed bullets in that diameter. You could cast your own, and/or paper patch them to that diameter.

I would shoot the largest diameter bullet that I could find; Hornady offers a .312" 150 grain bullet that I've achieved excellent results with.

 

[azar]

+1 to what nicholst55 said.

I just slugged the bore of my Mosin last night as a matter of fact (after having it for about 6 years). Mine also slugged out to 0.314. Loading the .311 or .312 diameter bullets will likely give you your best results. The selection is limited, but there appears to be a few good choices in there. If I were to start loading the Mosin Nagant today I'd try these:

180 grain Sierra Pro Hunter .311 (B.C. 0.411)
150 grain Speer Hot-Cor .311 (B.C. 0.411)
150 grain Hornady Interlock .312 (B.C. 0.361)

After that you have a number of 174g-180g round nose bullets, a match bullet, an FMJ, a few TSX's and even a 215g Woodleigh round nose. There are also all the 7.62x39 bullets (.3105 diam) that you could attempt to use. For me, I'd try the .311 and .312 first.

 

[nvahalik]

The Lee 7.62x54R dies should handle everything up to .311, right? Anything bigger than that would require the .312 expander die?

It won't hurt to shoot 30 caliber rounds through it though, right? They just might not be accurate past a certain range?

 

[918v]

You can shoot 308 bullets without pressure issues, but they won't be as accurate as 314 bullets. I recently began to shoot 357 bullets in my 9mm for the same reason, and accuracy improved by 30%.

 

[joustin]

You may find that that the .310's are fine, Mosins can be weird that way.

 

[NuJudge]

For cast bullets, I like cast bullets to be .002" over groove diameter. I have loaded .314" cast bullets in ordinary RCBS seating dies, but it might not work for you.

CDD

 

[DWFan]

Beartooth has .314" cast bullets..
http://www.beartoothbullets.com/bulletselect/index.htm
Look at .303 British/7.7 Jap listings

 

[ArchAngelCD]

With the numbers you got from the barrel I agree loading a .311" bullet would probably be best. I would try to stay away from .308" bullets just because the accuracy will probably be poor. You might want to give those .314" bullet a try "DWFan" linked to.

 

[Cosmoline]

You may find that that the .310's are fine, Mosins can be weird that way.

Ditto that. You don't know till you've tried an array of weights and bullet types. The bore dimensions are not the only factors involved. Sometimes it comes down to mysterious harmonics in the barrels or magic pixie dust.

 

[creepiE]

Grafs has some .311 Prvi bullets that price out $22 for a 100.

http://www.grafs.com/product/266821

Also, I have reloaded .311 with my Classic lee loader.

 

[joustin]

Ditto that. You don't know till you've tried an array of weights and bullet types. The bore dimensions are not the only factors involved. Sometimes it comes down to mysterious harmonics in the barrels or magic pixie dust.

Heh magic indeed, .308's shoot very well up to about 75 yards in my .310 barrel, farther than that will probably require a better bullet.