Saco 74, 223AI Sticking Cases

A

alpinebob37

Guest
I have a Saco M 74 223 that I had modified to the 223AI, it shoots well but about half the time the bolt cannot be pulled back and needs a mallet blow or a screwdriver blade carefully wedged between the receiver bridge and the bolt handle cam.
I have had the smith that did the chambering job go over the rifle with his Hawkeye and other tools and he can't find any reason for the problem.
It does not matter whether I am fireforming regular factory .223 or shooting my hand loaded .223AI loads. I have examined the fired cases with a 6X loupe and see no differences between the sticking cases and the free extracting ones. Same results when I "miked" them at the neck, shoulder along the case and the head area and can't find any differences. When I chamber the sticky cases they stick again and have to be forced(pried) out of the chamber between .140" and .312" before the bolt can be drawn back normally.
I am about out of ideas...
Any help most appreciated,
 
On a factory round how hard is it to close the bolt ? The chamber may be too much of a crush fit on a factory round.
Also your reloads sound like they need resizing . How clean is your brass ?
Are there any pressure signs on the primers of the reloads ?
Scrub out the chamber then clean up a fired case that is sticking . Then setup your full length resizng die or body die to size it down a bit at a time until it chambers with some resistance on the bolt. Then clean it up again and black it up with a magic marker and rechamber and extract it. See if the case is headspacing on the shoulder or jaming at the base .
What can happen with AI chambers is the sizing dies can be a bad match for the taper of the chamber and the case is
jaming at the base but not headspacing on the shoulder fully then blowing forward at the shoulder which can cause a jamup on extraction.
 
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