AR-308 Shoulder Setback/Bump

[DarrellA]

Now that I have the over-gassing problem and ejector swipe problem sorted out, I want to get back to developing my handloads.

I'm seeing growth of around .008" in factory rounds (FGMM) fired 1 time. From an average of 1.620" fresh to 1.628" fired. Seems like a lot to bump back.

I have new Winchester brass measuring at 1.619" on average and new Norma brass measuring 1.616" on average.

Should I be sizing back to 1.620" or just maybe back .003" - .005" or so?

Thanks

 

[Mike3888]

Darrell, I think you'll be ok with the .003 bump back on shoulder. That's about all I do. Except I will bump a little further for hunting rounds.
That way you can walk the round into the chamber and finish with forward assist.( may not apply in your case )Your chamber will tell you what u need. Just make some dummy rounds. Have fun, glad u got swipe issues straight.

 

[Pinecone]

3 - 5 thou for gas guns will work fine.

As long as you only have one.

If you are loading for more than one, you need to size to the smallest chamber, or keep separate batches of ammo for different rifles.

 

[Speed3]

3 - 5 thou for gas guns will work fine.

As long as you only have one.

If you are loading for more than one, you need to size to the smallest chamber, or keep separate batches of ammo for different rifles.

This

 

[DarrellA]

Thanks! I bumped the shoulders back by .005" to 1.623". Next time I can get to the range we'll see how it works out. I think it will be fine.