On an AR15 type rifle - if your brass ejects 1:00, 3:00, or 5:00, what does it mean?
I heard a cool explanation from Buck Doyle. What do you guys think?
I heard a cool explanation from Buck Doyle. What do you guys think?
What does the ejection path say about your rifle?
- Thread starter Matt Landfair
- Start date
JDRemf
Amateur
As i understand it, the ejection pattern is merely an indication of BCG speed in recoil. Ive heard many opinions about where a properly gassed and buffered AR should eject brass relative to a line perpendicular to the receiver, but dont know that there is a "correct" answer. I do know that my BCM middy dropped brass around 4 oclock with an H buffer. My CQBR throws at about 3 oclock unsuppressed and and between 1-2 oclock suppressed with an A5 extension and A5H2 buffer.
jryock
Amateur
Do a Google search for "ar ejection chart" and you can read all the back and forth associated with that. Generally it is said that from 12 to 3 is overgassed, 3 to 4:30 is perfect, and 4:30 to 6 is short stroking. Naturally there will be some variance depending on the rifle components, ammunition, and whether it is suppressed or not.
Barry in IN
Amateur
The old Highpower shooters used to say that on a Garand, the ejection pattern can tell you how the rifle is lubed. This was assuming US ball ammo was used.
I've always been a little suspect of that, since other things can have a similar effect. For example, a worn gas cylinder and/or op rod piston should send brass closer to 12:00, and a weak op rod spring should let them go the opposite way.
I have heard a couple of people say something similar about the AR family's ejection pattern and lube. I would think the same would apply regarding other factors having an influence. In fact, I would say there might be even more factors with an AR that would have an effect on the ejection pattern. Anything from gas port size to carrier weight to buffer type to...
I've always been a little suspect of that, since other things can have a similar effect. For example, a worn gas cylinder and/or op rod piston should send brass closer to 12:00, and a weak op rod spring should let them go the opposite way.
I have heard a couple of people say something similar about the AR family's ejection pattern and lube. I would think the same would apply regarding other factors having an influence. In fact, I would say there might be even more factors with an AR that would have an effect on the ejection pattern. Anything from gas port size to carrier weight to buffer type to...
Ejection pattern, and therefore the speed/force of the bolt carrier group is a good indicator of what's going on with the gas system.
While a 3 o clock ejection pattern is considered "ideal" for operation of the weapon, it is worth nothing it sucks for the guy to your right on the firing line, hahaha. As such I actually prefer a 2 or 4 o clock ejection pattern, both or which are slightly higher carrier speeds than ideal. A bit of extra power isn't that much of a concern on a duty rifle which may face harsh conditions and enviroments. While many shooters poo poo the gov spec gas ports which are generally considered "over gassed", one has to consider that gov weapons are expected to be reliable in much harsher conditions than most casual shooters can imagine.
Worth noting that with a 1 o clock ejection pattern, usually found on SBRs with suppressors, one needs to be very careful with ammunition, as the straining on the brass is fairly high. You're basically ripping the brass out of the chamber while it still under pressure, and the brass has "obturated" the chamber like it is supposed to. Case head separations and related funky malfunctions are common with reloads of poor quality, so it's best to stick to high quality first time fired brass with those kind of setups as i've learned.
While a 3 o clock ejection pattern is considered "ideal" for operation of the weapon, it is worth nothing it sucks for the guy to your right on the firing line, hahaha. As such I actually prefer a 2 or 4 o clock ejection pattern, both or which are slightly higher carrier speeds than ideal. A bit of extra power isn't that much of a concern on a duty rifle which may face harsh conditions and enviroments. While many shooters poo poo the gov spec gas ports which are generally considered "over gassed", one has to consider that gov weapons are expected to be reliable in much harsher conditions than most casual shooters can imagine.
Worth noting that with a 1 o clock ejection pattern, usually found on SBRs with suppressors, one needs to be very careful with ammunition, as the straining on the brass is fairly high. You're basically ripping the brass out of the chamber while it still under pressure, and the brass has "obturated" the chamber like it is supposed to. Case head separations and related funky malfunctions are common with reloads of poor quality, so it's best to stick to high quality first time fired brass with those kind of setups as i've learned.