303 bullets in 7.62x39?

B

black_hog_down

New member
This is for a Ruger M77.
There are lots of competing theories on the exact caliber of this model of Ruger but most seem to agree that it is 310.
Is it safe to run 303 caliber (.312) bullets in a 310 barrel? What if it is closer to 308?
 
If neck diameter and throat geometry allow the cartridge to chamber with a .311/.312/.313 bullet seated, and you start low and work up as appropriate, it should be fine.

None of us can give you a guarantee that it's safe, as it's your responsibility to determine the safety of your own loads (and firearms).

But I will tell you that I used to regularly shoot .312" and .313" jacketed bullets, and .314" and .315" cast bullets (all of the previous intended for 7.62x54R or .32 handgun cartridges) ... in a .30-30 that slugged at .304"x.308".
 
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Heck I even tested 160 gr Sierra .308 spitzers in my Yugo AK47 with Benchmark powder and they shot great out to 200 meters. Good stability, I was surprised.
 
Sweet. That's what I figured. I'll start low and work up.
Anybody know where I can find RN SP like these? I see hard cast and I see the 180+ grain 303 bullets but nothing in the 123 grain range. These are PRVI and I think they are discontinued.
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Why don't you slug the barrel and make sure of the dimensions? I would want to know for sure and, in my opinion, refrain from .312" jacketed bullets in a .308" barrel (but that's just .002" extra of engagement, prolly no problems)...
 
Like mikld says, slug the barrel. Ruger made Mini-30's with .308" barrels, long ago. Then switched to .311" the way Comrade Kalashnikov intended. The 7.62 x 39 M77 dates from long after the switch.
"....324"..." That'd be a .314".
"...303 caliber (.312) bullets..." .303 Brit uses a .311" bullet. Not a .312. Issue is the barrel diameters on Lee-Enfields. They can vary from .311" to .315" and be considered ok. Commercial bullets and ammo comes in .311" or .312" with up to .314" cast bullet available.
"...nothing in the 123 grain range..." Lots of 'em. Hornady makes a .310", a .3105". Their .312" are for .303 Brit and 7.62 x 54R, et al. Sierra makes a 125(close enough) at .311". No$ler does a .310" they think is for the 7.62 x 39. Close enough too. Federal loads ammo, but doesn't sell bullets. Berry makes a .311" plated 123. Barnes does a 123 grain .310" TSX. They do a .310" 108 grain Frangible too.
Whole thing is about what's available locally and how much you want to spend.
 
PPU discontinued using and selling that bullet as a reloading component in the 7.62 x 39 ammo a few years ago an switched over to 123 gr. PSP.

There is lots of speculation as to what the actual groove dia. of the rifles bore is some say is .308 others have slugged the bore and came up with .309 and still other have written Rugers Engineering Dept. and have been told it .310 to .3115 to accommodate bullets from .308 to .313. So your best bet is to slug the bore and go from there, I always slug the bore on all my rifle to begin with and go from there as cast lead is all I ever really shot in them these day.

Basically if your rifle shoots the .310" dia. jacketed bullets best the ballistic tips or soft points are going to be your only choice.
 
123 grain round nose soft point are few and far between. No semi-auto uses 'em.
There are some .32 calibre RN pistol bullets, but those are light weight and too short.
 
Also the 7.65 Argentine is "303" as well as 7.7 Jap. Most of the brands of bullets I have purchased are right at .3115".
 
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