FTEj
Possible/Probable causes:
Short cycle...Not highly likely since the GI Springfield's OEM recoil spring is
about 13 pounds. Could be a tight slide impeding free recoil. When the parkerizing gets worn off the rails, it'll smooth up quite a bit. Lots of CLP
Breakfree and 500 hand-cycles...recoil system and barrel out of the slide...
will do a pretty good job. CLP/J&B slurry will do it better and faster.
Extractor hook too deep and not releasing the case. Sharp corner on the bottom of the hook doing the same thing. Measure the hook tip depth. More than about .035 inch can cause release problems. Put a light radius on the bottom corner of the hook so the case can twist free easier when it hits the ejector. This one's most often seen with extended ejectors, but can show up with standard ejectors under the right circumstances...such as:
Ejector mislocated...either too far to the rear or too far inboard.
Excessive extractor tension/Extractor hook located too close to the breechface centerline. Usually causes failures to go to battery too, but not always.
Case releasing too low, with the case striking the lower edge of the ejection port before it can get loose from the extractor. Since the gun is a GI clone,
with the high port...this one's probably gonna be your bug. The problem can usually be corrected by radiusing the bottom corner of the hook, but sometimes a new ejector is the only cure. I used an Ed Brown extended ejector, shortened a little, to correct the ejection issues on mine.
Case rim diameter too large. Usually happens with brass that's been reloaded a few too many times. The rim grows a little with each load/shoot cycle.
Measure the rim diameter on the next case that hangs up. It shouldn't be more than .480 inch for best function, and .475 is better.