.308 vs .310

[gunpoorboy1]

I'm reloading 7.62 x 39.
I've reloaded some Hornady # 30302 which is a 150 gr SST bullet and shot them out of my Ruger American Ranch Rifle, using the menu out of the Hornady 11th Edition Reloading Manual. The diameter of this bullet per the box and manual is 0.308.

Using the same book, can I load Hornady # 3140 which is a 123 gr interlock bullet with a diameter of 0.310, and shoot it out of my Ruger American safely?

The two different size diameters would suggest that I couldn't but if that's the case I'm confused as to why Hornady would supply menus for both bullets with different diameters in the same reloading section.

As always, I appreciate the help I always get from this forum.

 

[Suck My Glock]

When Ruger first introduced the Ranch Rifle Mini-Thirty back in 1984, cheap Chinese AKs cost less than the Mini-Thirty. If you bought a Mini-Thirty, it was assumed you were looking for a more 'premium' rifle and therefor a more accurate one. To achieve that, the conventional wisdom of the time said, the rifle must be able to be loaded for by handloaders, since there was not a lot of commercial non-COMBLOC "quality" ammo in 7.62x39. Not many .310 or .311 projectiles available either. Brass could be had from Lapua or Norma, but that was it. So Ruger decided to make the bores on the Mini-Thirty .308 so that American reloaders could cheaply and effectively come up with components to load for their Mini-Thirties.

But Ruger underestimated the power of cheap Chinese ammo on the buying habits of rednecks everywhere, almost none of whom were aware if the diameter differences. Ruger rifles started to come back at an alarming rate for warranty repair from dudes running hot surplus .311 ammo through their .308 bore Mini-Thrities. So after a while, Ruger quietly changed their bores from .308 to .310 on the Mini-Thirties. And they have all been that way since then.

Most of these recipes for .308 projectile 7.62x39 loads are leftovers from that time frame. Are they safe to shoot in .311 bores? Absolutely, although they might not be all that accurate. And while .311 projectiles will usually squeeze down to fly out of a .308 bore, if you MUST do this, be sure to start at the minimum loads first.

Historic fact from the WW2 Lend/Lease program with Russia;...we sent thousands of 1919A4 belt-feds to Russia chambered in 7.62x54R. But somebody didn't get the memo that their .30 caliber was different than ours. Thus, the bores on all the barrels were .308! When the 1919A4s arrived, the Russians excitedly loaded them up and test fired them at the range, and immediately they experienced exceedingly high pressures and failures. They mothballed them all and never issued a single one. Then in the 90s, they cut them all up and sent them here as parts kits. You could spot the ones that had been test-fired because they had bowed top covers from over-pressure case failures and exceedingly high rearward bolt velocities. Some parts kits still had the ruptured cases in the cosmoline-packed barrels.

 

[NBC_LT]

Historic fact from the WW2 Lend/Lease program with Russia;...we sent thousands of 1919A4 belt-feds to Russia chambered in 7.62x54R. But somebody didn't get the memo that their .30 caliber was different than ours. Thus, the bores on all the barrels were .308! When the 1919A4s arrived, the Russians excitedly loaded them up and test fired them at the range, and immediately they experienced exceedingly high pressures and failures. They mothballed them all and never issued a single one. Then in the 90s, they cut them all up and sent them here as parts kits. You could spot the ones that had been test-fired because they had bowed top covers from over-pressure case failures and exceedingly high rearward bolt velocities. Some parts kits still had the ruptured cases in the cosmoline-packed barrels.

Thanks for sharing this info, where did you acquire the historic fact about 7.62X54R in 1919A4's from? I have shot > 40k rounds of 54R out of Izzy .308 barrels over the years without issue. Troy from BarrelXChange in Illinois does those 1919 conversions to 54R to this day, as well as 7.62X39 and has both used rechambered Izzy .308 barrels, recently as well as new .311 Green Mountain Barrels. When talking to Troy, he only mentioned the Chinese re-fitting 1919's to 54R and having problems with the links, as the .308 links made by the Israeli's and later the US during the Vietnam era did not exist yet. I guess 54R did not like the 30-06 links very much, nor the belt feeding pawl used in the 30-06 guns - as using the Izzy links and Izzy belt feeding pawl are mandatory for shooting the BarrelXChange conversion. I'd like to share any source about the Russian use and top cover blow-outs you have with Troy, please let me know if you have a good reference to that historical fact. The only top cover blow out I experienced was while using .308, the breech cam cracked and allowed my gun to fire when not in full battery - luckily able to fix with a punch and hammer to the belt feed slide recess on the firing line after replacing the breech cam.

Shooting 54R out of the 1919 is awesome, especially at night!!!!! Night shooting the 54R makes one heck of a flame out of the muzzle. Can't wait to try out the .311 barrels that Troy had made for 54R and X39 at the next Big Sandy.

 

[Suck My Glock]

Historic fact from the WW2 Lend/Lease program with Russia;...we sent thousands of 1919A4 belt-feds to Russia chambered in 7.62x54R. But somebody didn't get the memo that their .30 caliber was different than ours. Thus, the bores on all the barrels were .308! When the 1919A4s arrived, the Russians excitedly loaded them up and test fired them at the range, and immediately they experienced exceedingly high pressures and failures. They mothballed them all and never issued a single one. Then in the 90s, they cut them all up and sent them here as parts kits. You could spot the ones that had been test-fired because they had bowed top covers from over-pressure case failures and exceedingly high rearward bolt velocities. Some parts kits still had the ruptured cases in the cosmoline-packed barrels.

Thanks for sharing this info, where did you acquire the historic fact about 7.62X54R in 1919A4's from? I have shot > 40k rounds of 54R out of Izzy .308 barrels over the years without issue. Troy from BarrelXChange in Illinois does those 1919 conversions to 54R to this day, as well as 7.62X39 and has both used rechambered Izzy .308 barrels, recently as well as new .311 Green Mountain Barrels. When talking to Troy, he only mentioned the Chinese re-fitting 1919's to 54R and having problems with the links, as the .308 links made by the Israeli's and later the US during the Vietnam era did not exist yet. I guess 54R did not like the 30-06 links very much, nor the belt feeding pawl used in the 30-06 guns - as using the Izzy links and Izzy belt feeding pawl are mandatory for shooting the BarrelXChange conversion. I'd like to share any source about the Russian use and top cover blow-outs you have with Troy, please let me know if you have a good reference to that historical fact. The only top cover blow out I experienced was while using .308, the breech cam cracked and allowed my gun to fire when not in full battery - luckily able to fix with a punch and hammer to the belt feed slide recess on the firing line after replacing the breech cam.

Shooting 54R out of the 1919 is awesome, especially at night!!!!! Night shooting the 54R makes one heck of a flame out of the muzzle. Can't wait to try out the .311 barrels that Troy had made for 54R and X39 at the next Big Sandy.

This from a machinist buddy (no longer living) who previously was U.S. Army officer veteran of Vietnam who was a real gun nut and military historian. He spent nearly all his spare dimes and pennies in the early 90's buying up cheap Chinese imported stuff and building new stuff from it. He was a personal friend of Don Bell down in Tucson who owned Omega Weapon Systems, which was one of the earliest importers of the Chinese surplus weapon kits and parts in the late 70s and early 80s. Don had been to China personally to inspect his goods before he bought them and got a lot of the straight skinny directly from them about this when he bought those kits. The Russians dumped them on the Chinese, who then had to figure out how to make them work. Don is dead now, so it can be told that U.S. Customs didn't pay very close attention to his shipping containers full of cut up guns when they were imported. They would delve about halfway through the containers, see nothing but cut up receivers, then call it good and close it back up. The Chinese slave laborers who did the demilling were not detail oriented, and there many, many not fully destroyed guns in those shipping containers. Neither did many of them have any serial numbers at all. I personally saw crates and crates of SKS rifles with no markings whatsoever. Those were different days.

 

[NBC_LT]

Thanks SMG, never heard about the origin of the Chinese 1919's in 54R coming from Russia - just talked with Troy about the mechanics of the 54R conversions and heard from him about the Chinese failure to get them to work properly. If you happen to find anything I can share with the 1919A4.com forum, please let me know.

Also, the .308 Izzy barrels do wear out quickly. I can get a .308 FMJ 6 inches down the muzzle of my oldest barrel at this point. That chrome lined barrel probably having about 12k rounds through it. Man, I do miss this the $0.22 per round days of 54R from Howie at UNAmmo, bought three stacks of crates 6 feet high and popped a wheelie back to Tucson in 2015 when they hit $0.33 per round.

 

[leadman1]

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