CFE223 and 120 SMK questions.

[Tin Cup]

[A5BLASTER]

I think you have a gas issue with your rifle. That load charge should have been slinging those cases out.

[Tin Cup]

[tdbru]

TC,
did your upper come with an adjustable gas block? if not, then there are other possibilities. one of them might be that the gas port (hole) in the barrel is smaller than nominal and you're not getting enough gas to run the BCG. if you search the threads, you can find out, i believe, what the correct barrel gas port diameter is. i'm sure there are other possible explanations but wiser folks than i will need to weigh in with those.
-tdbru

[Tin Cup]

It has the click adjustable gas block. No instructions on what way to turn it for more or less gas. An answer on psa website says to turn it clockwise for more gas and counter for less. Sounds backwards to me.

[Tin Cup]

From the site.

BEST ANSWER: Clockwise to close it ( more gas). Counter clockwise to open it ( less gas). to adjust properly, close it all the way, then open it until the rifle DOES NOT cycle, then close it one more click

[tdbru]

TC,
if the design is intended to bleed gas off, then closing the bleed hole down allows more gas to run the bcg.
-tdbru

[Tin Cup]

[Labrat198]

Something seems off.

Sounds like you have a gas issue, but I would expect you to have issues picking up the next round if it was just a gas issue.

I still consider myself a novice reloader and with AR's, but whenever I've had gas issues it usually is the enter cycling process not just with ejection.

[Tin Cup]

Something seems off.

Sounds like you have a gas issue, but I would expect you to have issues picking up the next round if it was just a gas issue.

I still consider myself a novice reloader and with AR's, but whenever I've had gas issues it usually is the enter cycling process not just with ejection.

[A5BLASTER]

31.2 grains of cfe223 is near max for just about any bullet in 6.5 grendel.

I'm almost positive you have some kind of gas are rifle issue.

Having used cfe223 with several grain weight bullets from 12 inch all the way up too 25 inch barrels, it should be ejecting your cases at that load.

[Tin Cup]

[empTshell]

I have a PSA 18" upper and have not had the issue you are describing. I have the adjustable gas block but I have not had to mess with it. My brother also got a 18" PSA upper and it sometimes does not pick up the next round out of the mag. He had to send it back to PSA. I know he just got it back but I don't think he has shot it to see how it preforms now.

[LRRPF52]

bullet construction has something to do with it and the GMX is bundled in with the 120-123 class bullets.

You're correct about the 120gr GMX being bundled in with the other 120-123gr bullets, which is why the 129gr cup and core bullets have the 31.7gr data with the same powder.

Depending on your chamber and brass volume, you can load the 123gr cup and core Hornady bullets anywhere from 31.0-32.0gr. Best to do a pressure ladder and see if there are any departures from the trend, or stay in a working window of cyclic rate.

There's also a chance your extractor might have sharp lips on the corners and is hanging onto the brass.

I would tune your extractor and take off those edges if they are present.

Depending on the brass lot and type, the rims can get bound up between the extractor lip and extractor groove, especially with Lapua brass, which has less of a chamfer on the edge of the rim.

Also, I've found that things start to get out of control with 18" MLGS when pushing the upper loads with CFE223 and 123gr bullets for some reason.

No problems with a 16" MLGS, but 18" MLGS needs a way to choke the gas as you stuff more slow-burning ball powders into the case. They hit the port with higher pressure, which makes it want to unlock sooner that what is ideal.

[Tin Cup]