small base die for .308 in an M1A

[jmm03]

Hello all, is it necessary or can I just full length size ? I can do either. I have loaded 5.56 in an AR with no problems just full length sizing, and have been loading for bolt guns for years, mostly neck sizing.I do use Wilson case gauges and I would assume, (which I don't like to do...) that a case that fits to gauge should be fine, but any advice is appreciated. Thanks, Jim

 

[SeabeeKen]

Only you and your rifle can answer that. Try ammo fl sized and see if it feeds and you will have your answer

 

[pdog2225]

Only you and your rifle can answer that. Try ammo fl sized and see if it feeds and you will have your answer

Use the small base die.A few years ago I had my m1a rebarreled and when I got it back I used my gauges on it and the bolt would close on the no-go gauge.I called the gunsmith up and was told they use a different set of gauges.I asked why and was told to prevent from firing out of battery. We do not stop and look at the charging handle after each shot,to make sure the bolt is closed.I accepted that and am still shooting it. Pdog2225

 

[jpjulian]

The guys who were mentoring me when I was a beginning Highpower competitor advised to use a small base die for my M1A. In the years since I've heard it was unnecessary but my guess is there was a reason the small base die was recommended for so long and by so many. I suggest you do the same.

 

[SeabeeKen]

Use the small base die.A few years ago I had my m1a rebarreled and when I got it back I used my gauges on it and the bolt would close on the no-go gauge.I called the gunsmith up and was told they use a different set of gauges.I asked why and was told to prevent from firing out of battery. We do not stop and look at the charging handle after each shot,to make sure the bolt is closed.I accepted that and am still shooting it. Pdog2225

My national match M-1A feeds and shoots great with just normal sizing die. Below is the reply to my email to Forster asking about their national match dies.

The National Match die is not a small base die. It is reamed with the same reamer as the standard 308 die, but reamed to a depth that is .003” less than the standard die. If the standard die and NM die are set up the same, the NM die would bump the shoulder by .003” more.



The small base die is reamed with it’s own reamer to a depth equal to that of the standard 308 die. This reamer is identical from the standard except all body diameters are .003” less than the standard reamer. This will eliminate any cycling issues in semi autos.

 

[Liven The Dream]

Yes .
Best written answer is in the old Speer #8 Reloading Book.

If need to see it PM me a photo will come your way!

 

[243winxb]

See RCBS on small base dies

 

[Texas Solo]

Use SB die. Simply put, why risk it not chambering?

 

[chkunz]

I shot the M1A/M14 in competition for many years, many rounds and many barrels.
The small base die will not hurt anything but sooner or later if you shoot enough, it will save you some grief.