bossk95 Posted February 24, 2021 Share Posted February 24, 2021 (edited) What comp would work better for a 9mm minor open gun? I'm getting one built but not sure what to be looking for comp wise since I will mostly be shooting minor, I might shoot major PF for major matches but that would be the only time so I would want one that would be effective for both. Edited February 24, 2021 by bossk95 Link to comment Share on other sites More sharing options...
zzt Posted February 25, 2021 Share Posted February 25, 2021 So get a comp designed for major. The only disadvantage for steel challenge is you will be transitioning a slight bit more weight than necessary for minor loads. I shoot major and minor out of my Open guns. Link to comment Share on other sites More sharing options...
bossk95 Posted February 25, 2021 Author Share Posted February 25, 2021 5 minutes ago, zzt said: So get a comp designed for major. The only disadvantage for steel challenge is you will be transitioning a slight bit more weight than necessary for minor loads. I shoot major and minor out of my Open guns. Ok thanks, any design in particular that works better than another? Link to comment Share on other sites More sharing options...
021411 Posted February 25, 2021 Share Posted February 25, 2021 I used a Binary Engineering 2 port comp on my Open Minor gun. It's dedicated for 3 gun. Attached video was with 115gr RN with WAC. I have to look at my notes but I think it was around 138 PF or so. Real easy shooting. 9mm Open Minor on Vimeo Link to comment Share on other sites More sharing options...
Bakerjd Posted February 25, 2021 Share Posted February 25, 2021 I built a shorty open minor gun using a 4.5"OAL KKM barrel and Atlas 2 port Ti comp. Ammo is right at 132PF out of a sig P320 legion barrel and I dont knownwhat it would chrono in the open gun but it shoots flat and SOFT. hits steel Challange plates no problem though. Link to comment Share on other sites More sharing options...
zzt Posted February 25, 2021 Share Posted February 25, 2021 (edited) 14 hours ago, bossk95 said: Ok thanks, any design in particular that works better than another? So far I've liked this one the best. It is @Aircooled6racer's custom comp. There are a couple of things that make this unique. First the vortexes go up at an angle to the left and right and slightly forward. That leaves your view of the dot unimpaired for the second shot. Second, the chambers are well forward in the comp. That leaves room to put two 3/16" poppels in the comp behind the chambers in a V2 configuration. So no holes in the barrel or the slide. For reasons I don't understand, this comp stays cleaner than any of the others I've used. After about 7000 JHP major rounds I decided to see what it took to clean. I soaked a Q-tip in solvent and rubbed it around the bottom of the chambers. When I wiped it out I could see the machining marks on the bottom of the chambers. FWIW, my major load is a 115 JHP at 169 PF. Minor is a 124 at 144 PF. I have one gun optimized for major, and another optimized for minor. If I want to shoot major in the minor gun I have to change the recoil spring and Firing Pin Stop. Edited February 25, 2021 by zzt Link to comment Share on other sites More sharing options...
bossk95 Posted February 25, 2021 Author Share Posted February 25, 2021 33 minutes ago, zzt said: So far I've liked this one the best. It is @Aircooled6racer's custom comp. There are a couple of things that make this unique. First the vortexes go up at an angle to the left and right and slightly forward. That leaves your view of the dot unimpaired for the second shot. Second, the chambers are well forward in the comp. That leaves room to put two 3/16" poppels in the comp behind the chambers in a V2 configuration. So no holes in the barrel or the slide. For reasons I don't understand, this comp stays cleaner than any of the others I've used. After about 7000 JHP major rounds I decided to see what it took to clean. I soaked a Q-tip in solvent and rubbed it around the bottom of the chambers. When I wiped it out I could see the machining marks on the bottom of the chambers. FWIW, my major load is a 115 JHP at 169 PF. Minor is a 124 at 144 PF. I have one gun optimized for major, and another optimized for minor. If I want to shoot major in the minor gun I have to change the recoil spring and Firing Pin Stop. That looks kind of similar to what I had in mind for the comp I'm machining for myself, makes me feel a little better about it hearing a positive report on something similar. Just out of curiosity what are is your 9major load? Link to comment Share on other sites More sharing options...
rayw1128 Posted February 25, 2021 Share Posted February 25, 2021 Bossk95, hope you don't mind if I piggyback a question onto your post... Does the burn rate of a powder make much difference in effectiveness of a compensator in minor 9mm ammo? I developed a load that gets me about 135 pf in a non-comped gun and it shoots really well. Its 4.3 grains of Sport Pistol behind a 124 grain bullet. Just picked up a single port comp'd 2011 and heard that a slower burning powder will likely shoot flatter. So I am debating if I want to try and develope a new load with maybe Auto-Comp or CFE Pistol. But don't know if I will see much benefit to go through the trouble of new load development (especially in these times)... Link to comment Share on other sites More sharing options...
MikeBurgess Posted February 25, 2021 Share Posted February 25, 2021 35 minutes ago, rayw1128 said: Bossk95, hope you don't mind if I piggyback a question onto your post... Does the burn rate of a powder make much difference in effectiveness of a compensator in minor 9mm ammo? I developed a load that gets me about 135 pf in a non-comped gun and it shoots really well. Its 4.3 grains of Sport Pistol behind a 124 grain bullet. Just picked up a single port comp'd 2011 and heard that a slower burning powder will likely shoot flatter. So I am debating if I want to try and develope a new load with maybe Auto-Comp or CFE Pistol. But don't know if I will see much benefit to go through the trouble of new load development (especially in these times)... yes the more powder the more gas you are getting to the comp. a load with 3.5 grains of clays will have about 1/2 the gas of a load with 7 grains of CFE, also slower powders will have higher muzzle pressures also making the comp more affective. Link to comment Share on other sites More sharing options...
bossk95 Posted February 25, 2021 Author Share Posted February 25, 2021 Anyone know what the angle of the cone needs to be also? Link to comment Share on other sites More sharing options...
zzt Posted February 25, 2021 Share Posted February 25, 2021 2 hours ago, bossk95 said: That looks kind of similar to what I had in mind for the comp I'm machining for myself, makes me feel a little better about it hearing a positive report on something similar. Just out of curiosity what are is your 9major load? Once fired RP headstamp cases, CCI 500, 10.2gr SWMP, 115 HAP JHP, 1.161" OAL. Minor, twice fired major cases picked up after practice, 7.0gr VV 3N38, 124 JHP or RN heavy plate, 1 145" OAL. 1 hour ago, rayw1128 said: Bossk95, hope you don't mind if I piggyback a question onto your post... Does the burn rate of a powder make much difference in effectiveness of a compensator in minor 9mm ammo? I developed a load that gets me about 135 pf in a non-comped gun and it shoots really well. Its 4.3 grains of Sport Pistol behind a 124 grain bullet. Just picked up a single port comp'd 2011 and heard that a slower burning powder will likely shoot flatter. So I am debating if I want to try and develope a new load with maybe Auto-Comp or CFE Pistol. But don't know if I will see much benefit to go through the trouble of new load development (especially in these times)... Yes, but. How much gas you can use is really determined by the efficiency of your comp, the number of ports in it, and the number of poppels. The general rule of thumb is the gun will shoot softer and flatter right up until you have more than a trickle of gas jetting out the front of the comp. Go past that point and the hit to your hand will be harder. You now have a 1-port comp, so there is a limit to the amount of gas the comp can clear before a lot exits the front. Your load should be fine in the 2011 with a change of recoil springs. Remember, one of the functions of a comp is to direct gas up to flatten the gun. As such, the redirected gas is no longer available to help cycle the slide. I have to run a 7 lb. recoil spring to run my 144 PF load in my minor Open gun. BTW, it is easy to find out if a slower powder will 'work' your comp better. If you don't have a slower powder, borrow a little from your friends. Look in a manual and build a load that runs about 135 PF. Shoot eight of them and decide if the gun feels softer and/or flatter. Then shoot one into the white side of a no-shoot with the comp less than 2" away. If you see more than a light splatter, you made too much gas for your comp to handle. Back it off a little. If only a little splatter, try another batch with 0.2gr more of that powder and repeat. BTW2, there is no law that says you cannot break these guidelines. I shoot with a guy who runs a minor comp'd Open gun for steel challenge. He loads 115 to 155 PF using WAC. He doesn't care a whit about the increased recoil. He went for flatness above all else. Link to comment Share on other sites More sharing options...
zzt Posted February 25, 2021 Share Posted February 25, 2021 6 minutes ago, bossk95 said: Anyone know what the angle of the cone needs to be also? Cones are typically 1.5" long. They taper from .699" in the front to about .565" at the rear. There is no rule that says they cannot be longer or shorter. Shorter reduces weight. Take a look at a Scheumann barrel bump and you'll see how whacky you can get. Link to comment Share on other sites More sharing options...
bossk95 Posted February 25, 2021 Author Share Posted February 25, 2021 Just now, zzt said: Cones are typically 1.5" long. They taper from .699" in the front to about .565" at the rear. There is no rule that says they cannot be longer or shorter. Shorter reduces weight. Take a look at a Scheumann barrel bump and you'll see how whacky you can get. Awesome, thanks! Link to comment Share on other sites More sharing options...
MikeBurgess Posted February 25, 2021 Share Posted February 25, 2021 4 minutes ago, zzt said: Cones are typically 1.5" long. They taper from .699" in the front to about .565" at the rear. There is no rule that says they cannot be longer or shorter. Shorter reduces weight. Take a look at a Scheumann barrel bump and you'll see how whacky you can get. I hope you mean about .585 or more, the threads are .575 that said the EGW cones I have used come over sized and will need to be turned to fit your slide. normally I do this with a file and fine sand paper with the barrel fit to the comp and the comp held in the lathe take a little off and test fit the slide repeat till its a nice fit all the way to full lock up. Link to comment Share on other sites More sharing options...
Lastcat Posted February 25, 2021 Share Posted February 25, 2021 2 hours ago, MikeBurgess said: I hope you mean about .585 or more, the threads are .575 that said the EGW cones I have used come over sized and will need to be turned to fit your slide. normally I do this with a file and fine sand paper with the barrel fit to the comp and the comp held in the lathe take a little off and test fit the slide repeat till its a nice fit all the way to full lock up. Mike how much of a gap do you allow between the Comp and the Slide? (.004, .005, .006, etc....?) Link to comment Share on other sites More sharing options...
MikeBurgess Posted February 25, 2021 Share Posted February 25, 2021 1 hour ago, Lastcat said: Mike how much of a gap do you allow between the Comp and the Slide? (.004, .005, .006, etc....?) Till it fits. it all depends on how long the cylindrical section is and to a lesser degree depth of lock up (barrel to slide angel) like I said I mount the barrel and comp assy in the lathe and file and sand till it fits the way I want. Link to comment Share on other sites More sharing options...
bossk95 Posted February 25, 2021 Author Share Posted February 25, 2021 4 hours ago, MikeBurgess said: I hope you mean about .585 or more, the threads are .575 that said the EGW cones I have used come over sized and will need to be turned to fit your slide. normally I do this with a file and fine sand paper with the barrel fit to the comp and the comp held in the lathe take a little off and test fit the slide repeat till its a nice fit all the way to full lock up. How do you fit the cone? Do you leave it as a cone or do you fit a straight diameter? Link to comment Share on other sites More sharing options...
MikeBurgess Posted February 25, 2021 Share Posted February 25, 2021 6 minutes ago, bossk95 said: How do you fit the cone? Do you leave it as a cone or do you fit a straight diameter? I leave a short section that is cylindrical, I think EGW has about 1/8" or so left cylindrical and I try to leave it that way and just reduce it till it fits and locks up. the last one I fit while I was witting the cone in the lathe I used that opportunity to face off the back of the comp to close the gap to the front of the slide (slide already had the 1 deg cut so this was easier than resetting that up and trimming that part in 1 rev of the comp is .025" Link to comment Share on other sites More sharing options...
Lastcat Posted February 25, 2021 Share Posted February 25, 2021 28 minutes ago, MikeBurgess said: Till it fits. it all depends on how long the cylindrical section is and to a lesser degree depth of lock up (barrel to slide angel) like I said I mount the barrel and comp assy in the lathe and file and sand till it fits the way I want. Thanks Mike, think I'll go with .005" all around. Link to comment Share on other sites More sharing options...
bossk95 Posted February 25, 2021 Author Share Posted February 25, 2021 4 minutes ago, MikeBurgess said: I leave a short section that is cylindrical, I think EGW has about 1/8" or so left cylindrical and I try to leave it that way and just reduce it till it fits and locks up. the last one I fit while I was witting the cone in the lathe I used that opportunity to face off the back of the comp to close the gap to the front of the slide (slide already had the 1 deg cut so this was easier than resetting that up and trimming that part in 1 rev of the comp is .025" Ok awesome I was wondering how that fit worked, so since I am planning on machining my comp from an EGW blank would it be better to cut the comp before or after I fit it to the barrel? Or does it matter? Link to comment Share on other sites More sharing options...
021411 Posted February 26, 2021 Share Posted February 26, 2021 From today. Compared to the previous video I posted, my barrel now has two 3/16” holes before the comp. This was 147 PF. My grip wasn’t firm or was I meaning to drive the gun. It also has a plastic grip. Recoil spring is a 7# variable and the MS is 15# (Wolff). https://vimeo.com/516989621 Link to comment Share on other sites More sharing options...
MikeBurgess Posted February 26, 2021 Share Posted February 26, 2021 19 hours ago, bossk95 said: Ok awesome I was wondering how that fit worked, so since I am planning on machining my comp from an EGW blank would it be better to cut the comp before or after I fit it to the barrel? Or does it matter? personal preference. if your going to tri top you may want to fit it all the the slide and then machine it at the same time as you do the slide cuts for perfect alignment, if you go this way locktight it on before you start making cuts I made that mistake once Link to comment Share on other sites More sharing options...
MikeBurgess Posted February 26, 2021 Share Posted February 26, 2021 19 hours ago, Lastcat said: Thanks Mike, think I'll go with .005" all around. .005 seems like it would be quite a bit. I try to hit zero clearance at lock up Ill measure what a couple of mine are at tonight. see you at the match tomorrow? Link to comment Share on other sites More sharing options...
Lastcat Posted February 26, 2021 Share Posted February 26, 2021 28 minutes ago, MikeBurgess said: .005 seems like it would be quite a bit. I try to hit zero clearance at lock up Ill measure what a couple of mine are at tonight. see you at the match tomorrow? Thanks Mike. I wish, got my Open Gun out. New barrel getting plated and slide getting zig racker dovetail up at JPL's. You always put on great Matches in Dundee, Ore. Great times there and the people are really good to chill with. Hopefully I get parts back next week then get to TCGC and Dundee next month. Cheers. Link to comment Share on other sites More sharing options...
bossk95 Posted February 27, 2021 Author Share Posted February 27, 2021 18 hours ago, MikeBurgess said: personal preference. if your going to tri top you may want to fit it all the the slide and then machine it at the same time as you do the slide cuts for perfect alignment, if you go this way locktight it on before you start making cuts I made that mistake once Ouch...that was probably a nasty crash . How much locktight do I need to use? Link to comment Share on other sites More sharing options...
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