Full length dies below SAMMI dimension?

[rmiked]

I just resized some 7 PRC cases using Hornady full length dies. The brass is Hornady factory ammo once fired. After full length sizing I’m measuring 0.530” at base (above case head); SAMMI dimension is 0.532”. Aslso the neck is 0.314”; SAMMI is 0.317”. Is this normal to be a few thousandths smaller? Inside neck diameter is 0.281” which gives 0.003 neck tension which sounds reasonable.

 

[918v]

What was the fired dimension? The point is to make the resized case fit the chamber and extract after the next firing.

 

[rmiked]

Neck OD fired is 0.319”. Base diameter is 0.530”, no change. An unfired Hornady round is 0.529” at base and 0.313” OD neck. So this Hornady factory is below SAMMI dimensions new. I guess I’m within normal.

 

[Evintos]

I just resized some 7 PRC cases using Hornady full length dies. The brass is Hornady factory ammo once fired. After full length sizing I’m measuring 0.530” at base (above case head); SAMMI dimension is 0.532”. Aslso the neck is 0.314”; SAMMI is 0.317”. Is this normal to be a few thousandths smaller? Inside neck diameter is 0.281” which gives 0.003 neck tension which sounds reasonable.

Yes. Cartridge dimension tolerance -0.008"

 

[918v]

The .530” sized base dimension is going to cause sticky cases eventually. You might wanna look into getting a tighter sizer die.

 

[Rocketmandb]

You might wanna look into getting a tighter sizer die.

Non-Hornady. When they were all I could get for my 300 PRC, I found that they're a little over-sized.

 

[Doom]

The Case dimensions are maximum. Most dies will size slightly less than the maximum dimension. The chamber dimensions are minimum.