Multiple caliber adapters

[Byron]

This isn't exactly reloading, but I figure someone here will know.

I ordered a multiple caliber adapter for my 30-06 from Cabela's today. It's called a semi-permanent adapter to allow use of 7.62x39 ammo in a 30-06. Will this work ok? Are there any safety/accuracy issues? Will the cartridges be extracted with the existing bolt? My gun is a Ruger MR-7 bolt action 30-06.

Thanks for your help,
Byron

[Mr. 16 gauge]

Personally, I would NOT use it....the bullet diameter for the .30-06 is .308 inches, wwhile the bullet diameter for the 7.62x39 is .311. I have heard of adapters that would allow the firing of subcaliber cartridges (.30 carbine in 30-06 or 30/30, or .22 magnum in a 22/250), but this using a larger diameter bullet bothers me.

[muzzleblast]

YES MR 16GA. IS RIGHT TO A EXTENT ALSO OTHER FACTERS COME INTO PLAY HERE AS WELL.THESE MAY FIRE THRU THE GUN OK BUT TOLERANCES ON THEM MAY CAUSE HEADSPACE PROBLEMS IN LONG TERM.ALSO ACRUACY MAY BE AN ISSUE FROM THE START DUE TO THE VELOSITY AND TWIST ON THE BARREL.AS WITH ANY FINE FIREARM WHEN EVERYTHING IS A PRESISSION FIT IT ALL FALLS IN LINE.

[Byron]

Mr. 16GA,

0.311" is 7.90mm. 7.62mm is .300".
Why is it called 7.62 if the diameter is 0.311"? Doesn't seem right. If it's really oversize, I probably wouldn't use it. Lapping my rifling out doesn't seem like a good idea.

Please explain the size thing.

Thanks
Byron

[Mr. 16 gauge]

Byron;
Yes, you are right--.311 is NOT a 7.62, it is closer to a 7.7.
Sorry, but you will have to ask the Soviet Military authorities; I have NO idea why the called it what they did. The other Russian military cartridge of the time, the 7.62x54 rimmed round, IS a true 30 caliber--this is the round that was used in the Mosin-Nagant rifle and the Dragunov sniper rifle. The only clue that I have is that back in WWI, the Mosin-Nagants were classed by "lines", each line being .10 callibers, or a 3 line rifle would be a .30 caliber. Since the AK-47 and 7.62x39 round came out shortly after the chaos of WWII, maybe it was the closest thing that they had to a reliable system? Maybe someone out there with more knowledge of military rifles can give some more insight.
Prior to the 7.62x39 round becoming popular in the U.S., nobody made a bullet for this cartridge. U.S. reloading data gave loads for .30 cal bullets in the 110 to 125 grain range. Since these bullets were undersized, accuracy ranged from so-so to downright poor.
Foresighted thinkers at Ruger designed thier Mini-30 rifle to take advantage of this by having a barrel that "tapers" from .311 to .308 diameter. However, I have not heard of any of thier other rifles having "tapered" barrels.
Just out of curiousity, why do you wish to shoot 7.62x39 ammo out of your .30-06?
Guess we will have to have the 7.62x39 featured as a "cartridge fo the week" before to long.

[Byron]

Mr. 16,

Thanks for your reply. The only reasons I want to do this are the novelty and the cheap ammunition. 7.62x39's are $75 for 500, or 15 cents each. 30-06 are 50+ cents a piece. The short answer is, "Just for messin' around."

I figure people must be shooting them out of their 30-06, else Cabela's wouldn't be selling the adapter in their shooting supplies catalog. Does Pat E. come around here? I'd like to hear what he has to say, too.

Thanks again,
Byron

[Pat Eddinger]

Byron.
You will have a couple of things going against you with the 7.62X39 in your 06'.
The issue of .003 undersized bore is a non issue really,as most quality target barrels are sometimes .004 undersized.
Twist rate for your 06' is 1-10.which will spin the little 123gr bullet like a top,and most likely it will cause accuracy to suffer a bit.
Next is the extraction issue.You are going to have to single feed and single extract.
The inserts are kinda neet,but for cost savings 10gr of unique under a 110gr plinker is lots cheaper and accuracy can be outstanding.
One warning with the inserts.CLEAN your chamber real well after use!Lots of gunk and carbon works around the insert and if left there will cause sticky operation with 06' ammo.Also realize that most of the surplus ammo on the market is semi-corrosive or slightly corrosive.So get out the soap and water and clean like crazy when you are done.
No point in letting some cheap plinking cost you a good bore.
Good luck to ya!
Pat