barrel length?

by bj , Thursday, July 02, 2015, 21:25 (3372 days ago) @ rob

I'm not familiar with that powder but I've noticed that powder burn rate plus bullet weight has to be matched to the position of the gas port in the barrel. With a fast burning powder and original 20" barrel you sometimes don't get enough gas pressure at the port for reliable ejection. Maybe a short barrel and slow powder could go the other way and have too much pressure at the time of ejection.

Also assuming that the chamber is reasonably clean- An AR in this country will run for a long time without problems but eventually the chamber will get dirty enough to offer too much resistance to ejection.

I've noticed a lot of products on the market related to extractors- springs, o-rings, etc. I don't know how necessary they are because a stock AR can be very reliable but maybe it is worth a little time to make sure the extractor system is operating properly.

Weather these days is very hot, which will aggravate pressures. Do you have a chrono? Your cases and/or gun may not show pressure signs but if you are getting velocities that are out of character for your load your pressures might be a bit high.