My rifle grooves are 311, the lands are 300, what size bullets do I use?

MuscleGarunt · June 20, 2009, 04:32 PM

Should I use 308 bullets or 312 bullets?

Thanks.

sc928porsche · June 20, 2009, 04:34 PM

Jacketed bullets....... .311
full lead bullets........ .312

MuscleGarunt · June 20, 2009, 04:43 PM

Thank you. I read somewhere that you should average the the lands with the grooves assuming the lands will push material into the grooves. Under that logic I should use a 308 bullet. I feel that you should match the bullet to the groove for a better fit though.

It's good to have a second opinion though.

Thanks for the input.

Stargazer · June 20, 2009, 06:00 PM

If it is a 7.62x39 or 7.62x54 I would use .312" bullets.

MuscleGarunt · June 20, 2009, 06:34 PM

It is a Finnish M39 Mosin-Nagant 7.62x54R

NuJudge · June 20, 2009, 06:52 PM

If you are considering cast bullets, not jacketed, you may want to go larger than .312", and at least slightly run the bullet into the rifling. The throat is likely larger than .311", and likely larger than .312". Lead bullets are a lot weaker than Jacketed, and they need the support of the bullet being close to throat diameter, and perhaps in the rifling slightly.

The explanation I've always been told is that Lead bullets tend to slump or bend a little on firing, and if they do they'll fly wide.

CDD

**Mal H** · June 20, 2009, 07:01 PM

For lead bullets, you can use .311 or .312. For jacketed bullets, I think you can use good old .308's. The accuracy of the rifle will give you the best clue as to which ones to use.

If you didn't get the measurements by slugging your barrel, you might want to do that in order to get more precise measurements.

MuscleGarunt · June 20, 2009, 07:06 PM

I did slug the bore. Factory specs state a 310 bore but mine is a hair bigger which is fine with me.

June 20, 2009, 04:32 PM	#1
MuscleGarunt Member Join Date: May 20, 2009 Posts: 75	My rifle grooves are 311, the lands are 300, what size bullets do I use? Should I use 308 bullets or 312 bullets? Thanks.

June 20, 2009, 06:52 PM	#6
NuJudge Member Join Date: October 17, 2005 Location: SE Michigan Posts: 86	I like to have cast bullets fit the throat, not grooves If you are considering cast bullets, not jacketed, you may want to go larger than .312", and at least slightly run the bullet into the rifling. The throat is likely larger than .311", and likely larger than .312". Lead bullets are a lot weaker than Jacketed, and they need the support of the bullet being close to throat diameter, and perhaps in the rifling slightly. The explanation I've always been told is that Lead bullets tend to slump or bend a little on firing, and if they do they'll fly wide. CDD

June 20, 2009, 04:34 PM	#2
sc928porsche Senior Member Join Date: May 29, 2008 Location: now living in alabama Posts: 2,433	Jacketed bullets....... .311 full lead bullets........ .312

June 20, 2009, 04:43 PM	#3
MuscleGarunt Member Join Date: May 20, 2009 Posts: 75	Thank you. I read somewhere that you should average the the lands with the grooves assuming the lands will push material into the grooves. Under that logic I should use a 308 bullet. I feel that you should match the bullet to the groove for a better fit though. It's good to have a second opinion though. Thanks for the input.

June 20, 2009, 06:00 PM	#4
Stargazer Senior Member Join Date: August 6, 2006 Location: Republic of Texas Posts: 506	If it is a 7.62x39 or 7.62x54 I would use .312" bullets.

June 20, 2009, 06:34 PM	#5
MuscleGarunt Member Join Date: May 20, 2009 Posts: 75	It is a Finnish M39 Mosin-Nagant 7.62x54R

June 20, 2009, 07:01 PM	#7
Mal H Staff Join Date: March 20, 1999 Location: Somewhere in the woods of Northern Virginia Posts: 17,067	For lead bullets, you can use .311 or .312. For jacketed bullets, I think you can use good old .308's. The accuracy of the rifle will give you the best clue as to which ones to use. If you didn't get the measurements by slugging your barrel, you might want to do that in order to get more precise measurements.

June 20, 2009, 07:06 PM	#8
MuscleGarunt Member Join Date: May 20, 2009 Posts: 75	I did slug the bore. Factory specs state a 310 bore but mine is a hair bigger which is fine with me.