aero precision m5 308 16” complete upper with aero m5 complete lower, aero bcg. i believe it has the 3.8 oz carbine buffer kit. ordered directly from aero precision. i believe it’s short stroking. it will fire 1 round, then won’t pick up the next. sometimes jamming. bullets drop basically straight down about a foot away in the 3 0'clock direction. when pulling the chhandle it locks back but not when firing 1 bullet in the mag. i’m not sure where to even start looking
- Thread starter kaydenlewis
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Read this whole thread: https://www.snipershide.com/shooting/threads/psa-pa10-308-experiment.7157812/
Here's a live fire short stroke test that's fairly reliable. It should be done using a sled, bags, bipod or tripod as attempting it freehand can be dangerous due to loss of control when firing.
Manually lock the BCG back and return the charging handle forward to latch. Load 1 round in a mag and insert mag. Pull down on the mag to make sure the mag catch is engaged. Push the bolt release to charge. While pushing hard on the lower portion of the bolt release lever with your thumb (same as manually engaging the bolt catch), fire the 1 round. If the BCG doesn't lock back, it's short stroking due to gas system or other issues like incompatible parts. If the BCG does lock back, it's can be an issue with the mag/mag spring, the bolt catch spring, or more common with your set-up, over-speed cycling. NOTE: With no mag and an empty chamber, push the lower portion of the bolt release lever while cycling the BCG. This will give you a slow-motion idea of how it feels and what to expect when doing the actual live fire test.
Many consider the Aero 3.8oz 308 short carbine buffer to be too light in weight. This can cause over-speed issues where the BCG out-runs the mag spring and/or bolt catch spring. The first thing I would try is a heavier buffer, I use mid-5oz buffers.
Manually lock the BCG back and return the charging handle forward to latch. Load 1 round in a mag and insert mag. Pull down on the mag to make sure the mag catch is engaged. Push the bolt release to charge. While pushing hard on the lower portion of the bolt release lever with your thumb (same as manually engaging the bolt catch), fire the 1 round. If the BCG doesn't lock back, it's short stroking due to gas system or other issues like incompatible parts. If the BCG does lock back, it's can be an issue with the mag/mag spring, the bolt catch spring, or more common with your set-up, over-speed cycling. NOTE: With no mag and an empty chamber, push the lower portion of the bolt release lever while cycling the BCG. This will give you a slow-motion idea of how it feels and what to expect when doing the actual live fire test.
Many consider the Aero 3.8oz 308 short carbine buffer to be too light in weight. This can cause over-speed issues where the BCG out-runs the mag spring and/or bolt catch spring. The first thing I would try is a heavier buffer, I use mid-5oz buffers.
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How many rounds do you have on the rifle? If it is infact under gassed it seems these things need 50 rounds or so to start working correctly. msgriff has a good idea to try first though.
Maybe bad extractor/ejector? Cases should kick out further than a foot.
The more I mess with these things it seems that no matter the real reason it's not cycling correctly, it always acts like it short stroking. Undergassed, overgassed, buffer tooo heavy or too light, whatever it seems to only throw the brass a short distance if it even ejects at all. And it fails to pick up the next round or fails to lock.
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