.22-250 AI Case Variance

[Doug in Alaska]

I purchased a 100 new Remington .22-250 cases to fire-form for my newly re-barreled rifle (.22-250AI). The cases have been fire-formed and shot a few times using the Ackley Improved loads. Case length varies between 1.8760" and 1.9100. Thus, I haven't been able to trim the cases yet. Just wondering if any of guys have had this problem? I don't enjoy trimming cases but it would be nice to have consistent length. I think my Lee case trimmer for .22-250 trims to 1.902" so do you have any idea of about how many firings it takes for the case to lengthen enough to trim? I realize it would probably depend some on the load.

 

[arkrunner]

What load are you using in your AI. I have found similar results but have been using assorted brass. will trim and sort with I'm finished fireforming. thanks elton

 

[Doug in Alaska]

If you get the same results as I have while fire forming, your brass will be nowhere close to needing trimming. I've fired around 300 rounds and my best loads are narrowed down to four different loads. One using a 50 gr. Hornady VMax, two using 55 gr. Berger Varmint Match Grade, and one using 55 gr. Sierra Blitz King bullets. I'm at work now and don't have the recipes available but I can share them if you give me a day or two.

 

[MagnumManiac]

You're results are typical of any fireforming. You will most likely see that your case necks actually shrink when fireformed, this is normal as the brass is pulled out of the neck and into the shoulder as it's blown out.
I have been running my 22-250AI with Rem brass and have not needed to trim them yet, in fact after 5 firings they still haven't reached 1.900" yet, the AI design arrests neck stretching quite considerably over standard tapered cases.
It may take another 5 firings to stretch enough to require trimming, who knows, it may even take another 10!
It really doesn't matter much, I have had no accuracy issues with the brass being different lengths by a few thou', and them being shorter even than the trim to length makes no difference to function of the brass.
gun)

 

[Doug in Alaska]

Thanks for the info. The AI is turning out to be a tack driver so I guess I won't worry about the brass being different lengths.

Thanks again for input.

 

[TOM H]

I could be wrong but isn't the 22-250AI trim length 1.892"

 

[MagnumManiac]

I could be wrong but isn't the 22-250AI trim length 1.892"

No, that's the maximum length!
This measurement is what the brass normally shrinks down to upon fireforming, so it became the standard. My chamber is at 1.912", the original 22-250 length, it supposedly gives me a longer neck, but I haven't reached that length yet! I haven't even reached the trim to length of 1.902" so far!
gun)

 

[TOM H]

No, that's the maximum length!
This measurement is what the brass normally shrinks down to upon fireforming, so it became the standard. My chamber is at 1.912", the original 22-250 length, it supposedly gives me a longer neck, but I haven't reached that length yet! I haven't even reached the trim to length of 1.902" so far!
gun)

There a reason you haven't reach 1.902". Your blowing the case body wider and moving the shoulder forward as most Ackley cases do. Your just reforming the case to a different dimension and that comes from case length vs stretch the brass. My 22-250AI brass length is 1.890". I think Nolser has a diagram maybe Sierra does also on the 22-250AI case that they have loading data for.

My 22-250AI dia at the start of the shoulder mikes .454" vs .413" on a new Win 22-250 case and the case neck length for the AI is .250" vs .248" for 22-250.

You might want to get a reamer print from your gunsmith to confirm that case length. My gunsmith gave me a factory 22-250 case fired in the AI chamber as he has with some of the other AI rifles he chamber for me.

 

[TracySes23]

I could be wrong but isn't the 22-250AI trim length 1.892"

The newest Sierra manual give the specs for maximum case length to be exactly the same for the 22-250 & the 22-250 AI at 1.912"

Spencer