sccritterkiller 473 Posted March 27, 2013 Author Report Share Posted March 27, 2013 That sounds like a stopping point. That is what I was thinking....but that thinking thing will get me in trouble... I will have plenty of time over the long weekend to do some extensive testing.....I will post up a report as soon as possible. Quote Link to post Share on other sites
evlblkwpnz 3,418 Posted March 27, 2013 Report Share Posted March 27, 2013 That sounds like a stopping point. +1 Quote Link to post Share on other sites
sccritterkiller 473 Posted April 2, 2013 Author Report Share Posted April 2, 2013 (edited) So finally had time to test yesterday....It runs universal out of the drum!!!! Went thru 250 rds of low brass and 50 rounds mixed of slugs and 00 buck. You can definitely tell when one of the 1600 fps slugs goes down range.. Only had a small issue...On the high brass rounds the extractor was hanging up...It wouldn't let the round come flush with the bolt, and the bolt would not close or cycle back to eject the round...I could take my pocket knife and pull the extractor up and the shell would go flush and the bolt would close and I could fire the round....only happened 3 to 4 times....I thinking I need to take the bolt apart and clean it.....never had this problem before....I am probably close to 1000 rds and I have not stripped the bolt to clean.... Happiness is a pile of empty hulls!!!!! Edited April 2, 2013 by sccritterkiller 1 Quote Link to post Share on other sites
HotShot308 11 Posted April 2, 2013 Report Share Posted April 2, 2013 So finally had time to test yesterday....It runs universal out of the drum!!!! Went thru 250 rds of low brass and 50 rounds mixed of slugs and 00 buck. You can definitely tell when one of the 1600 fps slugs goes down range.. Only had a small issue...On the high brass rounds the extractor was hanging up...It wouldn't let the round come flush with the bolt, and the bolt would not close or cycle back to eject the round...I could take my pocket knife and pull the extractor up and the shell would go flush and the bolt would close and I could fire the round....only happened 3 to 4 times....I thinking I need to take the bolt apart and clean it.....never had this problem before....I am probably close to 1000 rds and I have not stripped the bolt to clean.... Happiness is a pile of empty hulls!!!!! Congrats!!! Quote Link to post Share on other sites
dubya 198 Posted April 2, 2013 Report Share Posted April 2, 2013 You can definitely tell when one of the 1600 fps slugs goes down range.. You got that right! I opened up my 4 port gun last week and holy crap those high brass slugs kick! Good thing I'll only shoot them at deer and won't feel anything anyway. Quote Link to post Share on other sites
Voltia 375 Posted April 3, 2013 Report Share Posted April 3, 2013 That "jet effect" is contrary to fluid mechanics and will matter not at all. What moves the piston is gas PRESSURE, not velocity of the flow through the jets. The comment about the backward cant not scraping wad is accurate. I can't remember my nozzle equations at the moment (long day), but I think I can make the point like this. When the gun goes off, the gas is expanding towards the muzzle, yet the gas jets still work, even though they are pointed away from the expanding gasses. This is because the gas is pushing in all directions, against the wad, against the barrel, against the bolt. The only way for it to go is out the bore, and out the jets. Minus the short time it takes to pressurize the gas block, it then pushes against the puck, and it moves to the end of its channel, providing the impulse for the op rod. The plug adjusts the pressure by limiting the path into the block. Since a gunshot is a transitory event, the jets meter the gas via I'm assuming the mass flow rate = area * velocity equation with the velocity, I guess, somewhat constant. More area, more gas, as we all know. But, direction doesn't matter. I think the only dangerous thing that he could have done is limit the sealing ability of the plug at the closed off position, and maybe made it run a little gassier on that setting. Just musings of a tired engineer on the road, your mileage may vary. Quote Link to post Share on other sites
Nephilim7 107 Posted April 3, 2013 Report Share Posted April 3, 2013 Great explanation! What gets me is that the behavior of fluid through nozzles vs. diffusers inverts (flip-flops) at the speed of sound. This should make things very unreliable around 1130 fps or so. I suppose the gasses would flow through the ports (smaller surface area) at a velocity much greater than the muzzle velocity of the projectile. Smaller, more numerous ports seem to be ideal for consistent metering of fluid pressure as well as debris reduction. Larger ports approach the diameter of the muzzle, reducing (in theory) port gas velocity and repeatability. Thanks for helping me realize that! I really like the simplicity of design displayed in these things. 1 Quote Link to post Share on other sites
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