Necks not expanding?

[Geno C.]

I just finished up a 22-250 AI for my oldest boy. He's 7. We loaded up 100 rounds to fire form some brass. A batch of 55gr vmax over h380, 68gr hpbt over RL15, and 75gr amax over RL15. I got it sighted in a shot a few groups of each. Brass formed perfectly except one thing, the necks are still too small to let a bullet slide into the fired case. I've never had this happen forming AI brass in any of my others. Anyone else ever had this happen? I haven't shot the formed brass yet to see if they expand after that or not.

 

[KYpatriot]

How much neck tension exists before resizing?

 

[mrspradlin]

Sounds like it might be a tight neck and the necks might need to be turned down some.

 

[arnie19]

Look real close at the mouth and see if there slightly rounded in ,this would mean cases are too long .Either way ,tight neck or long cases you are looking for trouble .

 

[dauntedfuture]

If the cases are too long then you can get a small reduction in diameter at the case mouth and they need to be trimmed as already suggested. If they are new sized cases and you cant get a bullet in you will need to take a look at your dies; a sized case ID should be .224 - .001 to .003 for neck tension or .223 to .221. For a bolt gun .001-.002 is fine. If your fired cases are coming out so you cant get a bullet in, you will need to turn the necks; you must have .001 or better clearance on the necks so that the bullet can release. for a .22-250 AI, Im not sure I would waste a barrel fire forming brass before shooting gophers or deer etc., most of the time the rifles will shoot just fine when fire forming brass without ill effects, you just use non-AI data.

 

[Geno C.]

These are fired cases I'm experiencing this with. The new cases I only run an expanding mandrel to make sure the case mouth is round. It is possible I need to trim the cases. I don't usually trim before they are formed but there is a first time for everything.

I'm not wasting barrel life just to form cases. I'm testing bullets and powder combos to try and find potential accurate combos. It's enabled me to eliminate the 75 amax in this barrel and lead me to look into the 68gr hpbt more because I'm getting ragged hole groups at book max for normal 22-250 loads.