Forster Go Gauge question

[shinjin]

I tried a factory 22-250 REM in my 22-250 AI mauser and it cycled just fine. I did not fire cause I like to be careful with things that go bang.

I bought a Forester Go Gauge in 22-250 to check the headspacing. Instructions say, "if it closes easily on the gauge the rifle has the correct headspace and will accept MAX SAMMI spec cartridges.

It won't close even with the extractor removed per instructions.

Does this (likely) means my rifle is  SHORT CHAMBERED?

OR because it is an Ackley Improved I need to do something else....?

[squirrellluck]

I believe the bolt should close on the gauge  The AI can be done to a standard 22-250 chambering. I would check the standard round you chambered for deformation caused by chambering. After saying that let me qualify it by saying my experience is with the 30-06AI but I believe all the AI's were done on existing chambering enabling the ability to shoot standard ammo as well as improved. But wait around a minute and someone will be along to correct me   Correction! I was corrected in the wildcat section

[gunnut69]

The AI rounds are chambered tight so that when a standard round is fired it will fit OK and firing it will form it correctly but it will not stretch the case just ahead of the web. The problem is caused by the AI having a steeper angle on the shoulder. The Datum line on the case moves which changes the real headspace measurement. To chamber an AI round the standard course of action is to set the barrel back a thread and then do the rechamber to AI. If this is not done the AI case produced by firing a standard round in the AI chamber will be longer than it should be. Reloading with standard AI dies will set the shoulder back an unexceptable amount each time and generally2-3 reloads is all you will get.. It is possible to get along with this situation but the chamber would still be out of spec. Your rifle sounds just fine.. Good luck.

[shinjin]

So, you think even though the Forester Go Gauge wont work the chamber is good to go because it is Ackley Improved?

[gunnut69]

Remember the guage is for a standard 22-250 and the chamber is already inproved. The datum line is at a certain diameter and a certain distance from the bolt face abutment on the rear of the guage. The AI chamber has a different datum line and while the standard case will chamber and headspace OK it fireforms to fit the NEW chamber.. Since a standard 22-250 chambered without problem there is no problem.. Shooting a standard round will form an AI case and reloading with proper AI dies should produce correct ammo that can be reloaded many times without over working the brass.. Remember the GO_Guage checks for a too short chamber, one that won't allow the bolt to close on a case. Since this rifle finctions fine with standard 22-250 ammo (which it should) you should have no problems.. Always use the correct reamer for the chamber, in this case a 22-250 AI..

[shinjin]

OK, now I understand what you mean.  Thanks everybody. Two weeks ago we used 223's and 22-250's to Pacify a Pairie Dog village. Cleansed it of Al-kidawg Assassins! 

We had the 223's for out to 300 yards and the 22-250's for out to 500 yards. We had a blast and helped several Ranchers with their Pest problem.  The 22-250 AI is perfect for the work with its added range!

[gunnut69]

Sounds like a great time.!! Good shooting!

[shinjin]

Will I need Ackley Improved Dies to reload 22-250 AI or can I back off my lee dies and just neck size the fire-formed cases?
,

[gunnut69]

You can neck size brass to avoid overworking the brass and get by for a while but eventually the cases will have to be bumped back a bit as the brass will no longer enter the chamber without force and then you will certainly need a full length sizer.. Collet dies or any die used as a partial sizer should work for a time but not permanently.. Tells us how that little darling does. Pics??

[Johle]

Shin
 
The accepted standard for headspace on Ackley Improved chambers is minus .004 inch. In other words the chamber should be .004 inch too short to close on a standard headspace guage.
 
There is very little support of the case at the datum line (which is the neck shoulder junction) before fire forming so it is required that we lightly crush fit the case to prevent the firing pin from driving it forward thus causing excessive headspace. Once fire formed the case is fully supported at the shoulder.