22 ARC dimension issues in AR 15

[Trnelson]

22ARC 77g TMK in newly resized and trimmed Starline brass. At resizing I'm measuring 0.426-0.427" at the shoulder, these chamber and extract 100%. After seating the bullet I'm seeing 35-40% of the cases measure 0.427+-0.429" so they mostly chamber but are difficult to extract, with the others still holding around 0.427+/". After a Lee FCD operation just kissing the case with zero cam over nearly all of those are 0.428+-0.430" with a hit or miss chambering and a very difficult extraction of a non-fired case.
My thought is maybe lube the bullet at seating and back off the FCD or eliminate it? I also tried loading a few into 6.5 Grendel and haven't seen anything out of the ordinary. Am I barking up the right tree gents?

 

[Dmagna]

No, sounds like you have a seating problem. Either crushing with the seating die or your neck tensing is so high you are crushing. What brass are you using?

 

[Trnelson]

No, sounds like you have a seating problem. Either crushing with the seating die or your neck tensing is so high you are crushing. What brass are you using?

New Starline 6.5 Grendel sized down and then trimmed to 1.520". That seems to be the case that it's collapsing the shoulder at bullet seating and a bit more at crimping.

 

[Zen Archery]

Annealing?

 

[can1010]

have to turn the starline 6.5 Grendel to .2495 on a loaded round for the .254 chamber neck, the brass is just too thick for the 22ARC. the shoulder is .431 so your .427-.430 should not be a problem.
turn brass, aggressive chamfer, and graphite in neck before seating should eliminate the problem.

 

[Trnelson]

Annealing?

Band new brass.

 

[Trnelson]

have to turn the starling 6.5 Grendel to .2495 on a loaded round for the .254 chamber neck, the brass is just too thick for the 22ARC. the shoulder is .431 so your .427-.430 should not be a problem.
turn brass, aggressive chamfer, and graphite in neck before seating should eliminate the problem.

Yep. Im starting to compare the arithmetic

 

[Dmagna]

Can you slide a bullet into a shot case?

 

[Mike D Texas]

have to turn the starline 6.5 Grendel to .2495 on a loaded round for the .254 chamber neck, the brass is just too thick for the 22ARC. the shoulder is .431 so your .427-.430 should not be a problem.
turn brass, aggressive chamfer, and graphite in neck before seating should eliminate the problem.

I resize Starline 6.5G to 22 ARC and have not had to neck turn anything. Feeds and ejects well in my Faxon barrel.

 

[can1010]

I resize Starline 6.5G to 22 ARC and have not had to neck turn anything. Feeds and ejects well in my Faxon barrel.

different barrel, chamber, and lot of brass. chamber neck .254, sized and loaded .2535 avg. most tight chambering but definitely no clearance for expansion when fired.
you more than likely have a looser chamber, that's good it saves a step.

 

[Trnelson]

Can you slide a bullet into a shot case?

Yes, but there is a bit of resistance

 

[Dmagna]

Yeah. Sounds like you might need to turn. I wouldn't do it yet, but maybe find a different brass that works. I hate turning brass

 

[Trnelson]

Yeah. Sounds like you might need to turn. I wouldn't do it yet, but maybe find a different brass that works. I hate turning brass

Me too! It's like watching paint dry, concrete set, and mud puddles dry up on a job site.
I went with only Hornady cases for my 6.5 Grendel and Starline for the 22ARC so as to be able to readily identify them in the wild with certainty.

 

[Dmagna]

Alpha has brass soon. I would assume lapua 6.5 gren bass is too thick as well