midatlantic Posted October 22, 2020 Share Posted October 22, 2020 Took my almost just completed open gun to range and found most of the bullets keyholed. I say almost cause I discovered the throat needs to be reamed as I can only load 124 blue bullets to about 1.14 and 125 HAP to about 1.12 before they hit the lands. Loaded a variety of rounds, with between 6.8 and 7.4 HS6 and at the above OAL Velocity ranged from 1310 to 1405. Didn't see signs of over pressure. I think at least. Crimp is same as I use on all my 9mm rounds. I was thinking that I probably pushed the OAL and I wonder if the bullets were touching the lands upon chambering. Would that cause key holing? shot about 50 rounds and maybe 10 shot fine. I know I have lots more work to do but any thoughts appreciated. And anyone got a 9mm throat reamer they want to sell? Link to comment Share on other sites More sharing options...
outerlimits Posted October 22, 2020 Share Posted October 22, 2020 1 minute ago, midatlantic said: Took my almost just completed open gun to range and found most of the bullets keyholed. I say almost cause I discovered the throat needs to be reamed as I can only load 124 blue bullets to about 1.14 and 125 HAP to about 1.12 before they hit the lands. Loaded a variety of rounds, with between 6.8 and 7.4 HS6 and at the above OAL Velocity ranged from 1310 to 1405. Didn't see signs of over pressure. I think at least. Crimp is same as I use on all my 9mm rounds. I was thinking that I probably pushed the OAL and I wonder if the bullets were touching the lands upon chambering. Would that cause key holing? shot about 50 rounds and maybe 10 shot fine. I know I have lots more work to do but any thoughts appreciated. And anyone got a 9mm throat reamer they want to sell? before you do anything, check for bullet strikes on the baffles on the comp. were the groups bad as well? Link to comment Share on other sites More sharing options...
midatlantic Posted October 22, 2020 Author Share Posted October 22, 2020 (edited) didn't see strikes on baffles - and I reamed the comp after installation. Groups that did not keyhole were good. Otherwise nope. They were bad. Edited October 22, 2020 by midatlantic Link to comment Share on other sites More sharing options...
Texvet16 Posted October 22, 2020 Share Posted October 22, 2020 Did you do a drop test of the round to the chamber? Link to comment Share on other sites More sharing options...
midatlantic Posted October 22, 2020 Author Share Posted October 22, 2020 yeah, which is why I think I may have pushed it too far. they were right on edge, but don't know if that would cause it. Link to comment Share on other sites More sharing options...
Aircooled6racer Posted October 22, 2020 Share Posted October 22, 2020 Hello: I think your bullets are hitting the comp. Take a look at the through hole in the comp on the top. Try shooting at shorter and longer distances to see if the key hole gets smaller and bigger. Thanks, Eric Link to comment Share on other sites More sharing options...
Part_time_redneck Posted October 22, 2020 Share Posted October 22, 2020 What kind of gun? I would fight one thing at a time and ream it first. Determine max OAL with a few dummy rounds and load with a little slack. Eliminate that variable to begin with. Link to comment Share on other sites More sharing options...
texasdawg Posted October 22, 2020 Share Posted October 22, 2020 Hopefully the chamber was reamed to the correct depth and not for 38super? Comp strikes maybe,,, Link to comment Share on other sites More sharing options...
Sarge Posted October 23, 2020 Share Posted October 23, 2020 2 hours ago, Aircooled6racer said: Hello: I think your bullets are hitting the comp. Take a look at the through hole in the comp on the top. Try shooting at shorter and longer distances to see if the key hole gets smaller and bigger. Thanks, Eric Agreed. When I was having problems with a loose comp it was really hard to see any evidence of bullet strikes. Gunsmith tightened comp up and checked reaming etc and everything was good to go. Link to comment Share on other sites More sharing options...
MikeBurgess Posted October 23, 2020 Share Posted October 23, 2020 Comp strikes in my experience are slight and very hard to see unless there is catastrophic miss alignment. Link to comment Share on other sites More sharing options...
midatlantic Posted October 23, 2020 Author Share Posted October 23, 2020 Ran reamer through comp for second time. Attached to barrel of course. EGW reamer for 9/38. New. Comp is not moving. All rounds passed the plunk test. Fired another 30-40 rounds, HAP 125 and Blue Bullets 124 tc. Most still keyholed, none was accurate. At 15 yards sprayed all over 12 x 8 inch target. All advice welcome. If rounds are still striking the comp, as appears likely, what's the solution? Find a 10 mm drill and drill out comp? Link to comment Share on other sites More sharing options...
BoyGlock Posted October 23, 2020 Share Posted October 23, 2020 Oversized bore or undersized heads? Link to comment Share on other sites More sharing options...
midatlantic Posted October 23, 2020 Author Share Posted October 23, 2020 Its a Jarvis barrel. Should be good. I was thinking of a getting a .358 or .359 reamer for the comp holes. 10 mm is .39 but shouldnt need to go that large? anyone ever do that? Link to comment Share on other sites More sharing options...
outerlimits Posted October 23, 2020 Share Posted October 23, 2020 32 minutes ago, midatlantic said: Its a Jarvis barrel. Should be good. I was thinking of a getting a .358 or .359 reamer for the comp holes. 10 mm is .39 but shouldnt need to go that large? anyone ever do that? .368 is GTG Link to comment Share on other sites More sharing options...
Powder Finger Posted October 23, 2020 Share Posted October 23, 2020 3 minutes ago, outerlimits said: .368 is GTG Yes need at least 10 over Link to comment Share on other sites More sharing options...
Aircooled6racer Posted October 23, 2020 Share Posted October 23, 2020 Hello: Ream with a letter drill "U" first. If it still key holes move up to 3/8". Thanks, Eric Link to comment Share on other sites More sharing options...
Bwilmot Posted October 29, 2020 Share Posted October 29, 2020 Are both types of bullets key holing ? Link to comment Share on other sites More sharing options...
titandriver Posted October 30, 2020 Share Posted October 30, 2020 Remove the comp if possible then fire your rounds to see if they are still key holing. I'm bettin' they won't! Link to comment Share on other sites More sharing options...
midatlantic Posted November 2, 2020 Author Share Posted November 2, 2020 I reamed all three baffles in the compensator with a .3850 reamer and solved the problem. Took off a smidgen more than the EGW 9mm/.38 reamer. Link to comment Share on other sites More sharing options...
Sarge Posted November 2, 2020 Share Posted November 2, 2020 (edited) 53 minutes ago, midatlantic said: I reamed all three baffles in the compensator with a .3850 reamer and solved the problem. Took off a smidgen more than the EGW 9mm/.38 reamer. Ta-dah!!!!! Edited November 2, 2020 by Sarge Link to comment Share on other sites More sharing options...
Chillywig Posted November 3, 2020 Share Posted November 3, 2020 (edited) On 10/22/2020 at 4:37 PM, midatlantic said: didn't see strikes on baffles - and I reamed the comp after installation. Groups that did not keyhole were good. Otherwise nope. They were bad. Did you ever notice any evidence of the baffle strikes? What did you use to peak in there? Edited November 3, 2020 by Chillywig Link to comment Share on other sites More sharing options...
midatlantic Posted November 3, 2020 Author Share Posted November 3, 2020 Nothing that I could see. Would have figured I could see something. The .3850 reamer took off very little metal. Almost as tho all it did was change the aerodynamics of the bullet - maybe reduced turbulence? Link to comment Share on other sites More sharing options...
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