Got a used 27 with 2 maga. in great shape, shoots great, accurate, shot about 100 rounds at least of Winchester FMJ target loads, flat nose. But it fails to feed the last round from the magazine. This is on both mags., both mags have a + 0 Pierce pinkie extension. This is the only problem and it is consistent. Slide hangs open on the last round. Pushing the slide in does not do it, I have to pull it back to have it chamber. There are no other failures, only on the last round. Any help, ideas? Behaves fine when full magazine is hand cycled in the gun.