Gas volume/pressure?

[daved20319]

So was doing some ammo testing yesterday in my AR. Had some new loads I was working on, 69 gr. RMR OTM and AR-Comp powder, as well as some old 69 gr. SMK loads using CFE 223. The loads with AR-Comp, as well as some others with H335, all produced pretty much perfect ejection patterns, nice tight little pile of casings about 10' away at about 4:00. Different story with the CFE . Cases were ejecting at about 1:00, and only going about 5'. I was also getting a lot more noise from my buffer spring. I haven't used CFE 223 much, and I think this may be the first time in an AR, but is this typical? None of the loads were maxed, bullets were seated to spec, but my rifle was behaving like it was seriously overgassed. Which it isn't, it's a 20" bull barreled RRA varmint upper with a rifle length gas system, and a rifle length buffer tube and buffer. I've never had behavior like this from this upper, but I've mostly stayed with AR-Comp or H335 in my loads. Not really a biggie, I've never had particularly good results from CFE 223 and won't be buying it again. Mostly just curious if anyone else has gotten similar results with this powder. Later.

Dave

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[DizzyJ]

Did you chrono the loads?

 

[Stomper]

Sounds like you need a grain or two more in the CFE.

 

[DizzyJ]

Sounds like you need a grain or two more in the CFE.

Generally a 1 o-clock ejection pattern means it's cycling hard and hitting the brass deflector though I admit I'd think they'd go further than 5'

 

[Stomper]

Generally a 1 o-clock ejection pattern means it's cycling hard and hitting the brass deflector though I admit I'd think they'd go further than 5'

The 5' is why I said that.

Notice the 3:30 brass pattern (throws out to 10') from my 11.5" with all MILSPEC carbine internals "out of the box" running M193 & M855. Buffer and gas pressures present as spot on.


IMO, the CFE needs a little more poop added to throw that brass out further since the OP mentioned the loads were maxed.

Only real way to find out is make some loads lighter and some heavier.

 

[DizzyJ]

The 5' is why I said that.

Notice the 3:30 brass pattern (throws out to 10') from my 11.5" with all MILSPEC carbine internals "out of the box" running M193 & M855. Buffer and gas pressures present as spot on.
View attachment 1907871

IMO, the CFE needs a little more poop added to throw that brass out further since the OP mentioned the loads were maxed.

Only real way to find out is make some loads lighter and some heavier.

You're gonna put your eye out with that thing.

You sexy beast!