igolfat8 Posted February 25, 2016 Share Posted February 25, 2016 (edited) So I am building a 9mm AR. Which brake or comp have you found to be the most effective? I realize each has different design goals. I will be using mine for rapid fire steel plates so fast target acquisition is my top priority. I should also mention that I need 1/2" - 36 threads which greatly reduces my options. Edited February 25, 2016 by igolfat8 Link to comment Share on other sites More sharing options...
Moltke Posted February 25, 2016 Share Posted February 25, 2016 I don't know about threading requirements but have you looked at the comps on 9mm open pistols? They seem to work pretty well. Link to comment Share on other sites More sharing options...
igolfat8 Posted February 25, 2016 Author Share Posted February 25, 2016 I have ... but I should also mention that I would rather have a steel comp / brake. I have worn out several aluminum [pistol] comps. Link to comment Share on other sites More sharing options...
Moltke Posted February 25, 2016 Share Posted February 25, 2016 Not being an open shooter I didn't realize they were aluminum, I figured they were steel... Wow Link to comment Share on other sites More sharing options...
jon49erfan Posted February 25, 2016 Share Posted February 25, 2016 a heavy one. since there will be little gas to work the comp, at least the weight on the muzzle will help keep it down. Link to comment Share on other sites More sharing options...
igolfat8 Posted February 25, 2016 Author Share Posted February 25, 2016 Not being an open shooter I didn't realize they were aluminum, I figured they were steel... Wow They do make steel comps for 1911 / 2011 style pistols but most poly pistols use aluminum comps. Link to comment Share on other sites More sharing options...
LilBunniFuFu Posted February 25, 2016 Share Posted February 25, 2016 UM tactical is in the works of testing out their tunable 9mm comp. Running their .223 and 308 ones are stupid fun and fully expect to have the same performance out of a 9mm one. Link to comment Share on other sites More sharing options...
T Bacus Posted February 25, 2016 Share Posted February 25, 2016 (edited) Currently helping a friend set up a gun for pcc. We chose one of the Armalite comps for his gun. I opened the exit holes to 9mm and we sent it and the barrel out to be shortened, pinned and welded to 16". When done it will look just like one of the 13.5" Armalite rifles. Will post pictures when it's finished. As for the op's original question, look at the JP 9mm comp. I think best effect will come from maximum frontal area for the gas to work against. With pistols you want to keep the muzzle down so upward porting is effective. With rifles you want to push the gun forward so wide flat ports that vent to the sides work best. Edited February 25, 2016 by T Bacus Link to comment Share on other sites More sharing options...
Alaskapopo Posted March 4, 2016 Share Posted March 4, 2016 Honestly it does not matter on a 9mm carbine get the one that looks the coolest because that is really all they do. Link to comment Share on other sites More sharing options...
JAF1680 Posted March 7, 2016 Share Posted March 7, 2016 It depends on the load you will be shooting. Everyone said it didn't matter so I ordered one that looked sort of like the JP on my other rifle. It made a difference in muzzle rise and the speed I could double tap a target. I am running high gas open 9mm loads with Longshot. It is the Steel TANKER Muzzle Brake, the finish is not as nice as the JP but when everyone said it wouldn't matter I wanted something to protect the threads when it was getting tossed in a barrel. Link to comment Share on other sites More sharing options...
JAF1680 Posted March 7, 2016 Share Posted March 7, 2016 I did not use the jam nut provided I used a standard crush washer and it has been working so far. Working out the right load for your weight of buffer may help more then the comp. When shooting some light loads with a fast burning powder almost no gas came out of the sides of the comp (that could be seen) and the recoils was lighter but the red dot moved higher on the target between shots. Link to comment Share on other sites More sharing options...
igolfat8 Posted March 7, 2016 Author Share Posted March 7, 2016 JAF - Would you mind sharing your load specs? Are you running the same load in your pistol as well? Link to comment Share on other sites More sharing options...
JAF1680 Posted March 8, 2016 Share Posted March 8, 2016 I am running an Xtreme 124 RN and 5.4 grains of Longshot with Win. small pistol primers OAL of 1.137. This is the same load I use in my Steelmaster and limited gun for for 3 gun. I was getting 1140 fps ave. from the pistol. I have also tried a few 124 FP Rainer but they are touching the rifling at 1.070 OAL and are a little sticky to pull out of the chamber if not fired. They function and eject just fine. Both loads have a reasonable amount or muzzle blast for a pistol load. I took video this weekend of my wife at a local match and the gun had no muzzle rise with these loads. Link to comment Share on other sites More sharing options...
JAF1680 Posted March 8, 2016 Share Posted March 8, 2016 I have also been shooting Freedom Munitions124s and they have very little muzzle blast but have a softer recoil. The dot does rise a little though. This load might be faster on steel but not as fast to double tap a paper target. Link to comment Share on other sites More sharing options...
colbyjack Posted March 12, 2016 Share Posted March 12, 2016 Just curious since I'm not a open shooter. I just got the PCC recently. The comp is leading a bit. Running production lead and coated bullets. How do you remove the leading in the comp? Or do t worry about it and shoot? Link to comment Share on other sites More sharing options...
igolfat8 Posted March 12, 2016 Author Share Posted March 12, 2016 How do you remove the leading in the comp? Remove it. Put it in a small plastic container. Soak it for a couple days in a 1:1 mixture of white vinegar and peroxide. Lead falls right off. The residual mixture is poisonous so wear rubber gloves and dispose of properly. Link to comment Share on other sites More sharing options...
JAF1680 Posted March 14, 2016 Share Posted March 14, 2016 In the past I only shoot lead when reloading 40 and 45 but when I started loading 9mm for open guns lead became more of a hassle. Loading plated for compensated guns may be an option you will want to look into. With the increased velocity, leading in the barrel may also be more of problem. Depending on load I saw an increase in velocity of 150 to 300 fps in the PCC. I shot the ammunition through a factory Glock 19 and a 9mm Ar with a 16 inch barrel. Some exceeding 1500 fps out of the PCC. Link to comment Share on other sites More sharing options...
gose Posted April 11, 2016 Share Posted April 11, 2016 As for the op's original question, look at the JP 9mm comp. I think best effect will come from maximum frontal area for the gas to work against. With pistols you want to keep the muzzle down so upward porting is effective. With rifles you want to push the gun forward so wide flat ports that vent to the sides work best. I have the JP 9mm brake on my AR. Even with 3n37 behind 115s, it's effect is really negligible . Link to comment Share on other sites More sharing options...
bmiller Posted April 11, 2016 Share Posted April 11, 2016 I was able to hit 165 pf with a 105 grain bayou over the weekend. Link to comment Share on other sites More sharing options...
gose Posted April 11, 2016 Share Posted April 11, 2016 I was able to hit 165 pf with a 105 grain bayou over the weekend. With 3n37, my 115gr@1200 fps open 3gun load is almost 1400 fps, so I dont doubt you However, with the brake not doing much to help it seemed like more gas just increased recoil and muzzle flip Link to comment Share on other sites More sharing options...
bmiller Posted April 11, 2016 Share Posted April 11, 2016 (edited) I have been playing with different brake designs. I don't think that there is enough gas to do much about recoil. That being said, I think there is enough gas to reduce muzzle climb. This project seems similar to my 12 gauge brake. Conventional wisdom on the Internet says they don't work. The brake I designed and built makes my shotgun shoot flat with hotter ammo. To my shoulder it doesn't do as much for recoil. I have found turning up the wick on my pcc indeed yields much more recoil than you would expect. The gun shoots basically as flat with mid range loads. I hope to do some more testing this week. These little buggers sure are fun! Edited April 11, 2016 by bmiller Link to comment Share on other sites More sharing options...
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