From experience running the optimized gas port of the bcm 14.5, i find the lighter carbine buffer gives a smoother cycle, less harsh, faster follow up shots due to the lighter mass of the buffer. I think thats why some companies like JP make low mass bcgs etc. For their race guns.
Running a carbine and/or low mass bcgs on an overgassed gun can be a problem though which is the problem i might be facing now with a particular upper.
I'm not saying that it's not the magazine, but you have to be running super fast to outrun a good condition magazine.
The M321 port firing weapon has a cyclic rate of over 1200 rounds per minute, which is about 200 rounds per minute faster than a rifle that would show issues with cleanly ejecting the fired cartridge (leading to intermittent "stove-pipes"). The Mk18 (depending on generation) runs at around 850-900 rounds per minute, which can bump up to around 1,000 rpm or more when suppressed, and magazines are *usually* not the failure point if they're up to snuff. If you are using PMags, you're probably safe up to 1500 rounds per minute, but you're likely to find the mechanical limit of the Stoner operating system before you hit the limit of the PMag.
I've had it for sure. My first SBR (20 plus years back), there weren't many options on short barrels. I got a Sabre Defense 11.5 with a port over .080. This was so far back it was pre retard o-ring in the extractor patch for these nightmare ports.
I was probably running a carbine buffer to make things worse because heavier buffers were just starting to pop up. That gun was so brutal to shoot. It would regularly outrun the mag follower.
"What would a $2,000 Geissele Super Duty do that a $500 PSA door buster on Black Friday couldn't do?" - Stopsign32v
Colt 20 round mags have weak springs , right out of the box, FYI. Gen 3 Pmags in 20 rounders solved my problem one time in one such issue. And who knows with other no name mags. I cheat and run A5 buffer system and feel they are the holly grail of buffer systems. Probably overkill in many situations, but no downside other than spending $100 vs $35 or whatever.
PB
"Air Force / Policeman / Fireman / Man of God / Friend of mine / R.I.P. Steve Lamy"
Acceptance range and average performance are different things, and basing the cyclic rate on a full 30-round magazine (fixture dependent as well) will give a different implication of carrier velocity than directly measuring carrier velocity. Part of the issue is that people don't think about carrier velocity, so it's easier to base the observation/discussion on cyclic rate, since the average reader would basically need to mentally equate the relative speed.
I was giving general reference numbers with systems in current service.
The M4 ejector has issues if running over a relative 1,000 RPM.
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