02-03-2018, 07:47 PM
Just my troubleshooting steps and experience.
The above steps will usually solve most issues. After that I would swap out the BCG. Again it's very easy to do if you have a spare.
I've tried multiple length gas systems at extreme temperatures in different barrel lengths and different types of factory ammo. The hardest ones that I've found to tune are subsonic 300 blackout pistols. Typically I can get an AR to function correctly with factory ammo by using a quality non-adjustable gas block and standard buffer weights and springs just by eliminating any faulty parts or correcting any assembly issues. While changing buffer weights and springs may solve an issue, it makes me wonder if it is actually covering up a problem (assuming you are using factory ammo). I can see changing buffers and springs for a specific load or a specific use (suppressors, competition, etc...), but off the shelf ammo should run with standard parts.
- Clean the rifle. Sounds obvious, but it does make a difference. About 80% of the guns that come to me for repair (not just ARs) are simply dirty. A good clean and lube and the rifle functions correctly. About half of the ones that are actually broken, I can trace the failure back to a lack of maintenance.
- Try a different mag. Actually try a few different mags. It's the easiest thing to swap and many issues are mag related.
- Try different ammo. I had a shipment of faulty .223 ammo once. About every 5th to 10th round was bad. They would fire but not cycle the bolt fully. Talk about a pain in the butt to figure out. It did it in any gun. Swapping ammo resolved the problem.
- Swap lowers. It is really easy to do. See if the problem follows the lower or the upper. I had a batch of mis-marked buffer springs once. They were supposed to be standard AR15 carbine springs but they weren't. This helped me find the issue.
- Inspect the gas block. This is especially true for home builds. Mis-aligned gas blocks, gas leakage and poor quality import gas blocks are the second most common area of problems that I find.
The above steps will usually solve most issues. After that I would swap out the BCG. Again it's very easy to do if you have a spare.
I've tried multiple length gas systems at extreme temperatures in different barrel lengths and different types of factory ammo. The hardest ones that I've found to tune are subsonic 300 blackout pistols. Typically I can get an AR to function correctly with factory ammo by using a quality non-adjustable gas block and standard buffer weights and springs just by eliminating any faulty parts or correcting any assembly issues. While changing buffer weights and springs may solve an issue, it makes me wonder if it is actually covering up a problem (assuming you are using factory ammo). I can see changing buffers and springs for a specific load or a specific use (suppressors, competition, etc...), but off the shelf ammo should run with standard parts.
Engineer, FFL and Pastor