Issue with .300aac Lee FCD

[possom813]

I've used the Lee FCD for .30-30 and .30-06 with no issue, but using the .300aac FCD, and I can spin the bullet after the crimp has been applied, no matter how much pressure I apply.

The cases are Lake City, all have been annealed. The bullet I'm using is a Nosler 125gr BT, but the same issue happens when using a 311410 and 31141, after the crimp is applied, I can still spin the cb's as well.


Any ideas?

[MT Chambers]

Why would you use that, it's not necessary, you need to make sure that the case neck has enough tension on the bullet at the SIZING stage, and forget the crimp.

[Jupiter7]

Who's dies are you using?

I've had zero neck tension issues with any formed brass to date. I've yet to anneal any brass. And have noticed that converted LC xm193 brass is annealed about halfway down the brass, when formed my LC brass appears to be annealed 300aac brass.

[possom813]

RCBS SB .300aac Dies

[Jupiter7]

Can you over-anneal brass? Have you test against non-annealed brass. I'd start eliminating processes and figure where your loosing tension. I'd doubt it's the dies, but it could be. Maybe pull apart your dies and measure. Also, if you have .223 dies, try a resize in a .223 die before forming.

[tomme boy]

Measure your expander. I have some 30cal dies from RCBS that came with the expander from a 303 brit or 7.62 Russian. It should measure 0.306"-0.307" If it is wrong, call them and they will send out the right ones.

[blikseme300]

I have not had any problems with the FCD with both j-words or cast but there is a slight possibility that the die is out of spec. I would give Lee a call and discuss this issue. I forgot to add: I do use a FCD for 300blk and it can over crimp on CB's if the die is set too deep. The groove between the petals/fingers does not close all the way when set for the boolits I use and the crimp is positive.

[Frozone]

I have had the same problem, it seems to be a combo of freshly annealed brass and an overzealous neck expander, not the FCD.
You have to admit, the neck brass is pretty thin on a 300 blk.
I switched to a lyman M die for expansion, that solved the problem for the worst of it. Neck tension improved after the first firing also.

[John Boy]

Any ideas? Age old issue for those that don't FL size the brass then use their calipers to measure the case ID and bullet base diameter.
If you don't have, strongly suggest neck expansion plugs and Expansion Die to form the cases so there is a 0.001 to 0.002 neck tension on the bullet... Any Time One Uses New Bullets in Cases Previously Shot With a Different Bullet