257 Ackley case length headspace gauge
- Thread starter wyoming70
- Start date
I got mine from Pacific Tool & Gauge. Took forever to get. 16 weeks.
There is also 4D Reamer Rental.
Have used them several times now. No complaints!
If you have the standard 257 Roberts go/no-go gauges, the go is the no-go guage for the AI.
Strange as that sounds.
The reasoning is you want a slight interference fit at the neck/shoulder junction on the standard case.
Doing it this way holds the case against the bolt face. No need to seat the bullet out while fire forming.
There is also 4D Reamer Rental.
Have used them several times now. No complaints!
If you have the standard 257 Roberts go/no-go gauges, the go is the no-go guage for the AI.
Strange as that sounds.
The reasoning is you want a slight interference fit at the neck/shoulder junction on the standard case.
Doing it this way holds the case against the bolt face. No need to seat the bullet out while fire forming.
Last edited:
The main reason Ackley stated for why he did this was to allow factory ammunition to be safely used. This means that the factory case will headspace on the neck/shoulder junction of the AI chamber, not the traditional datum line on the shoulder. This means that to do it correctly as Ackley intended you cannot simply re-chamber a factory chamber, you must set the barrel back first. Still, some gunsmiths will just run the new AI reamer in and call it good.
.
100% INCORRECT.
Headspace and Ackley Improved Cartridges – P.O. Ackley
ackleyimproved.com
Edd
Gold $$ Contributor
I'm not a Gunsmith but if I was was using standard gauges to set an AI chamber, I would want the go gauge to be a snug fit in the chamber.
Man, either change or delete this post. I realize it’s truly an honest mistake but an uninformed person might read this and do something dangerous.
I’m not hating on ya brother!
Might want to edit that. No tellin' who will read it.
I edited it.
Thank you all for pointing it out!
AckleymanII
Gold $$ Contributor
New cases may vary in headspace length, I like a crush fit. Some would like a .004 crush fit, but I do not think it is enough and prefer as much as .010. My first 22/250 AI, I had the gunsmith set it up with a .025 crush fit because that is about how much neck you loose when fire forming...I had no problems.
I believe a std go gauge for an AI is with a .004 crush fit on a new case.
I believe a std go gauge for an AI is with a .004 crush fit on a new case.
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