MarkCO Posted September 17, 2015 Share Posted September 17, 2015 Exactly what I was going for in the design. Matched with all of the low mass parts, I wanted to keep the muzzle down, the weight low and the concussion to a minimum...plus last as long as a barrel. Mark, is there any good way to tweak to reduce downforce? The square port on the top can be opened up more. But I would try doubles on target. I have yet to see anyone have it overdrive except using NATO loads. A faster powder helps. Link to comment Share on other sites More sharing options...
CJW Posted September 17, 2015 Share Posted September 17, 2015 Exactly what I was going for in the design. Matched with all of the low mass parts, I wanted to keep the muzzle down, the weight low and the concussion to a minimum...plus last as long as a barrel. Mark, is there any good way to tweak to reduce downforce? The square port on the top can be opened up more. But I would try doubles on target. I have yet to see anyone have it overdrive except using NATO loads. A faster powder helps. My "up close and personal" ammo is Atlanta Arms 55gr---don't know what powder they use. Both my g/f and I noticed a tendency towards down-left on follow up shots, but I need to test it out a bit more to see how it looks on paper under game conditions. Link to comment Share on other sites More sharing options...
MarkCO Posted September 17, 2015 Share Posted September 17, 2015 In more cases than not, that is due to the gas system and too much pressure in the case as the bolt is unlocking. That is creating a torque. While people attempt to adjust that by "tuning" the comp, it is better to fix the root cause. Link to comment Share on other sites More sharing options...
CJW Posted September 17, 2015 Share Posted September 17, 2015 In more cases than not, that is due to the gas system and too much pressure in the case as the bolt is unlocking. That is creating a torque. While people attempt to adjust that by "tuning" the comp, it is better to fix the root cause. Okay, how do I find that root cause? 55gr Atlanta Arms ammo, Stretch 16 barrel with the included gas block, RCA lightweight BCG, and (as of this point) stock JP Silent Captured Spring. (Need to play with spring strengths because right now lockback is intermittent on an empty mag.) Link to comment Share on other sites More sharing options...
Vlad Posted September 17, 2015 Share Posted September 17, 2015 In more cases than not, that is due to the gas system and too much pressure in the case as the bolt is unlocking. That is creating a torque. While people attempt to adjust that by "tuning" the comp, it is better to fix the root cause. I never thought of it this way, but where does the torque come from? I would assume if the case was still sealed to the chamber the bolt wouldn't try to torque it out, it would slip around the extractor groove until it is unlocked and starts moving backward. It can't be from the rear of the lugs because the bolt is being pushed forward initially as the carrier is pushed back, so the only places left would be contact between the forward face of the lugs and maybe the cam pin slamming into the carrier? Help me understand this please. Link to comment Share on other sites More sharing options...
MarkCO Posted September 17, 2015 Share Posted September 17, 2015 The cam pin acting against the slot in the carrier when the case is still sealed. If you play with loads on a sled and look for it, it is noticeable. You get a little torque no matter what, but a good deal more if the pressures are high during unlocking. It is also more noticeable with slower powders like Varget. Sure, if you are large and grip it tight, you won't see this. I never noticed it until my son started shooting and had the same thing happen, we tweaked the load until the torque was gone...and I was then faster on splits. Link to comment Share on other sites More sharing options...
Vlad Posted September 17, 2015 Share Posted September 17, 2015 Gotcha, the more I thought about it the more the cam pin seemed like the likely suspect. Shooting 2600fps loads with 55gr bullets always torqued the gun less then 68gr at 2850 but I didn't think about it to much and assigned to bullet/barrel torque or maybe extra gas at the comp, but it does make sense that violently spinning metal bits inside the receiver affect it as well. Link to comment Share on other sites More sharing options...
MarkCO Posted September 17, 2015 Share Posted September 17, 2015 Yep. That is one reason why it is harder to shoot a gas gun for precision. You have 3 additional (mechanical) recoil impulses to deal with and two of them have an angular component. Exacerbating the first one with high chamber pressures at unlock is not beneficial for speed or precision. When you consider the tune on an AR, the lowest pressure you can get and the proper volume coming through the gas port of the barrel yields the best performance. Link to comment Share on other sites More sharing options...
louu Posted September 17, 2015 Share Posted September 17, 2015 What powder do you use for the boy Mark? Link to comment Share on other sites More sharing options...
MarkCO Posted September 17, 2015 Share Posted September 17, 2015 What powder do you use for the boy Mark? AA2200 in a Stretch16 barrel. Link to comment Share on other sites More sharing options...
louu Posted September 18, 2015 Share Posted September 18, 2015 Thanks Mark I'm gonna have to give some a try. Link to comment Share on other sites More sharing options...
SCAR Posted September 20, 2015 Share Posted September 20, 2015 I've been running a Nordic Corvette comp the last couple seasons. It works pretty well and lower cost. Super loud just like it should be. RO's love it! Link to comment Share on other sites More sharing options...
ihocky2 Posted September 23, 2015 Share Posted September 23, 2015 A little late to the party, but I am a big fan of the Lancer Nitrous. Comes with different size jets for the top ports to tune it easily. Very flat and soft shooting with this comp though a little loud and worse for the RO. Link to comment Share on other sites More sharing options...
SCAR Posted September 26, 2015 Share Posted September 26, 2015 I've noticed a few people this year running the Armalite comp with tunable screws. I think I might give one of those a whirl for next season. Oh wait, I just bought a new 3GN18" so I guess I will be running one for next season. Yeah for me! Link to comment Share on other sites More sharing options...
TonytheTiger Posted October 10, 2015 Share Posted October 10, 2015 What powder do you use for the boy Mark? AA2200 in a Stretch16 barrel. Thread revive + thread drift: what is your AA2200 load Mark? Link to comment Share on other sites More sharing options...
stick Posted October 10, 2015 Share Posted October 10, 2015 I use the SJC Titan. No complaints Link to comment Share on other sites More sharing options...
CJW Posted October 11, 2015 Share Posted October 11, 2015 I use the SJC Titan. No complaints WHAT????? Link to comment Share on other sites More sharing options...
Garmil Posted October 11, 2015 Share Posted October 11, 2015 (edited) I like my taccom. Shoots flat, Small, light,not terribly loud, adjustable, clean looking with no crush washer or locknut. Edited October 11, 2015 by Garmil Link to comment Share on other sites More sharing options...
stick Posted October 11, 2015 Share Posted October 11, 2015 I use the SJC Titan. No complaints WHAT????? What is ?????I use the SJC TITAN Comp for 3gun. I like it and I don't have any complaints against it. Sent from my SM-N900V using Tapatalk Link to comment Share on other sites More sharing options...
CJW Posted October 11, 2015 Share Posted October 11, 2015 I use the SJC Titan. No complaints WHAT????? What is ?????I use the SJC TITAN Comp for 3gun. I like it and I don't have any complaints against it. Sent from my SM-N900V using Tapatalk That was just me asking you to repeat yourself, because I couldn't hear you over the sound of your Titan. [emoji1](I have a rifle with a Titan, too. Works well, indeed, but not very...social.) Sent from my HTC One_M8 using Tapatalk Link to comment Share on other sites More sharing options...
adamge Posted October 11, 2015 Share Posted October 11, 2015 CJW, I would argue that. The Titan is a big talker. Link to comment Share on other sites More sharing options...
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