M1 Garand .308 Conversion

[enichols]

Hello all,
I have been thinking I would convert my Garand to a .308 using a Criterion commercial barrel, and having the thing installed by a gunsmith. Are there any other modifications necessary to the rifle to convert from a .30-06 to .308 aside from the barrel swap? Any modifications necessary to the operating rod or gas cylinder? I've seen a .308 magazine spacer block for sale on some sites which sell the barrels, but is this necessary?
Thanks for any information you can give me.
-Nic

 

[AK103K]

I just picked up a M1 .308 conversion. It came minus the "block" which I just picked up from Fulton Armory. If you have both 30-06 and .308's in clips, its a lot more comforting knowing the block is in there. If its not, a loaded 30-06 clip will go right in. Then again, if your not paying attention, a clip of .308's will go right in a 30-06 gun and if your really not paying attention and drop the bolt a second time, things could get exciting.

My rifles barrel appears to be close to GI dimensions, but its got a flat, match type crown on it. The rear of the op rod does appear to have been fitted to the barrel, so depending on what type barrel you go with, you may need to deal with that too.

 

[jaimeshawn]

All you need is the .308 barrel.

The .308 barrel will have a slightly larger gas port but you won't be able to tell unless you use calipers - the rifle will field strip exactly the same - it will load and feed as reliably as ever.

 

[Onmilo]

I have converted a number of M1 rifles to 7.62X51/.308.
I have used Wilson, Douglas, and Barnett Match barrels.

I can recommend that you set headspace at 1.636" and limit reloading cases to no more than three times maximum.
This headspace dimension will allow you to use .308 commercial ammunition and 7.62X51 Military dimension interchangably without any slamfire or chambering/feeding issues.
Set gas port dimension at .0890-.0900"

Use a Wolff extra power recoil spring.
I don't normally recommend these springs for a Garand but in the .308 caliber rifles they really aid in overall functioning.

Use the spacer, I like the steel and aluminum versions, the plastic ones do not last or stay in place for very long and end up causing more problems than they solve.

Use a .062 wide Match type front sight and you will probably have to fine tune its overall height with a file to gain absolute elevation in conjunction with the rear sight at ranges past three hundred meters

I suggest also stamping the rear sight base or the rear sight spring cover with the caliber designation so one can tell at a glance that the rifle is a .308/7.62X51 version.
Don't stamp the receiver, you never know, at some point you may want to convert the rifle back to .30/06. could be .243 Winchester or maybe .270 Winchester at some point,,,,

Load and keep your enbloc clips loaded with ammunition.
.308/7.62X51 ammunition uses a larger diameter case body and the spring steel enbloc clips can drag during feed cycle causing reliability issues.
It is best to start with brand new clips and take care of them.
Keeping them loaded prevents the spring steel from relaxing and improves feeding.
I don't recommend interchanging the clips you use for a .308 caliber rifle with the clips you use for a .30/06 caliber rifle, keep them seperated.

 

[NoahFN]

you may want to convert the rifle back to .30/06. could be .243 Winchester or maybe .270 Winchester at some point

Onmilo,

Are there any gunsmiths that actually do a .243 conversion? Do you happen to have any experience with an M1 in .243?

It seems like an interesting idea for consideration.

 

[Ian]

Roland Beaver's catalog includes Garands in about a dozen calibers, including .243, .22-250, and 7mm-08.

 

[Onmilo]

Douglas will special order manufacture an M1 barrel in .243 Winchester.
I haven't ordered one in some time but I am guessing the going rate is $350.00-$400.00 shipped.
Headpace and set up is the same as for a .308 but you don't need the Wolff extra power spring, the standard USGI operating rod spring will work just fine.
These barrels will have to be fit, turned and headspaced to your action, they are short chambered and you will have to roll or turn down the chamber shoulder to get everything to line up.
Don't expect sub minute of angle accuracy, this caliber in the M1 action tends to be a bit finicky, so it won't compete accuracy wise with a good bolt gun but they are minute of coyote or better.
80 to 100 grain bullets work best.