doublegunshop.com - home Forums General Discussion Classic & Custom Single Barreled Sporting Rifles @ doublegunshop.com OA little OT - Ackley Improved

The AI chambers are designed to be chambered slightly shorter at the juncture of the neck and shoulder than the parent standard cartridge, ~0.005" or thereabouts IIRC. This is so that a factory cartridge would be safe to fire in the Improved chamber without any risk of a head separation. You are SUPPOSED to have a slight difficulty in closing the bolt on a factory cartridge but perhaps not THAT much difficulty(G), hard to say without a hands-on.

This is the reason that most smiths will insist upon setting the barrel back a thread when rechambering to the AI configuration, in order to achieve this very slight reduction in headspace.
Regards, Joe

I tend to agree with J D above and the other poster from Georgia. There is going to be some resistance, although you should not have to force the bolt down. If you are getting the case to chamber without great difficulty, go ahead and load some rounds and fireform them. The brass will flow to the proper location, and the difficulty in closing the bolt should disappear after the initial firing. This assumes you are only getting fairly minor resistance, if you have to really force the bolt down, face off the shell holder and size the shoulder of the case back a bit.

Or buy the Redding shell holder set which lets you adjust this dimension. The should be listed in the Sinclair catalog if Redding does not show them online.