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1/25/2018 7:38:29 AM
Posted: 5/8/2002 3:15:23 AM EST
A quick question for those knowledgeable about M1's.

In Shotgun News I have seen advertisements for chamber inserts that allow you to shoot .308 from a 30-.06 chambered M1. Is this safe / reliable? I am looking for a cheaper way to shoot my M1, but not if it could damage the rifle.

Any input would be appreciated.

Link Posted: 5/8/2002 3:30:12 AM EST
I haven't heard any pro's or con's, but I would think if they were any good at all, you'd hear a lot more hype about them.
Also, it looks like you would have a godawful lot of leade; something in the order of 13mm (about 1/2 inch).
Link Posted: 5/8/2002 3:48:31 AM EST
The U. S. military looked at inserts as a means of converting millions of M1's to fire the M14 7.62 NATO round. After numerous tests and extensive analysis of the concept, they "backed-away" from pursuing the insert idea. If you are looking to cut your cost of shooting, I would suggest that you consider reloading as a potentially better alternative.
Link Posted: 5/8/2002 3:57:33 AM EST
What I've heard about the inserts is that they were a stop-gap solution. Not a good thing. It severely increases the distance the bullet has to travel before it engages the rifling, and can cause accellerated throat wear.

Want a Garand in .308? Have it rebarreled.


Link Posted: 5/8/2002 6:25:27 AM EST
Link Posted: 5/8/2002 2:30:38 PM EST

The .308 cartridge case is slightly larger than the .30-06 case. So a .308 round is force chambered into the m1 chamber (a bad thing). Could have a failure to go into battery.

The inserts WILL eject with a cartridge case eventually leaving you with a serious problem and possible KB.

Forget it.

Champion's Choice sends their rebarrels out to a local armorer who does the work for them. He uses barrels made from Douglas premium blanks by Gene Barnett. They are absolutely top notch barrels. The only thing that will shoot better is a Kreiger...maybe.

The barrels are blued rather than parked, but that ain't a big deal. The handguard modification can be done for you for 15.00 additional. The rebarrel job'll cost you 200.00 plus shipping. Pretty great deal. Orion will cost you half again as much for a lesser barrel. The upside is that it will be parked and it'll be back in the mail to you inside the week if not the day. Champion's Choice has about a 6 week turn around time.

Link Posted: 5/8/2002 5:55:04 PM EST
There's an extensive write-up on the 30/06-308 chamber insert in Jerry Kunhausen's book The U.S. M1/M14 rifles.

The Navy wanted some 308 Garands, but couldn't get funding to buy new barrels, but research funds were unlimited. So, they spent several million of our dollars on the chamber insert project, which was a failure. (Oh,well, it's just taxpayer money).

There were two methods of inserts.
One was developed by FN, and was a heat/freeze friction fit method.
The U.S. method involved grooves in the chamber, with corresponding ridges on the insert. This was press fit, and then locked in by firing a number of over-pressure proof loads to expand the insert.

Neither method worked well, and lacked good accuracy. There were also issues with freebore, and the difference in the 308 vs 30/06 chamber and headspace.

The civilian-available inserts are a BAD idea, since even the two methods used above would often extract with a round. Firing a 308 in a 30/06 chamber isn't a real good idea. Since you would not see the insert ejected from the M1, this entire exersize is somewhat like Russian Roulette.
Link Posted: 5/9/2002 3:30:02 AM EST
Thanks for the input guys! You saved me some money and a possible injury. I will definitely be staying away from the chamber inserts, and will save up for a .308 barrel from Champions Choice.

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