98Z5V Posted February 17, 2012 Report Share Posted February 17, 2012 The BCG did not open or appear to move.Easy way to find out if this is the case. Chamber a round, then close the ejection port door. If the BCG doesn't even move, that door will still be closed after recoil. If the BCG even moves a little bit, it'll kick the door right open. Quote Link to comment Share on other sites More sharing options...
tlcoy1911 Posted February 17, 2012 Report Share Posted February 17, 2012 Oil the bolt, and carrier rails to the point of runoff. Check your empty cases for any sign of damage.How hard did the action open with the case in the chamber?My barrel is 25" with rifle lenght gas system, and i think my port size is #51 drill (I'm not at home to check my info, could tell you for sure on Mon.)I'm using 55gr nosler partitions but it was to cloudy for my crono to read the day I was shoting it, so I'm not sure about the fps.I had a little problem with my ammo, was trying to use a heavier crimp for this auto, and had a few rds with slight neck crush, which caused them not to chamber, my lee factory crimp die came today. Quote Link to comment Share on other sites More sharing options...
cdnick Posted February 17, 2012 Author Report Share Posted February 17, 2012 When looking at the gas port and taking the flat end of the drill bit in the port, the only one I could get in was the 1/64 bit or .0625". I opened it up to 5/64 or .078". When shooting tonight the following would happen (same case in both pictures, last round fired): This occurred on all but one round fired, the first round. That round was ejected but the bolt did not lock open on the empty magazine. All cases appear normal and nondeformed. So my question is does anybody have the average gas port size for an ar-15 and the average size for an ar-10? Quote Link to comment Share on other sites More sharing options...
98Z5V Posted February 17, 2012 Report Share Posted February 17, 2012 Barrel Length (in) // Barrel Diameter (in) // Distance from Muzzle (in) // Min Port Size (in) // Max Port Size (in) 11.5 // 0.625 // 3.850 // 0.081 // 0.089 11.5 // 0.750 // 3.850 // 0.086 // 0.094 14.5 // 0.625 // 8.375 // 0.063 // 0.078 14.5 // 0.750 // 8.375 // 0.070 // 0.086 16 // 0.625 // 8.375 // 0.063 // 0.078 16 // 0.750 // 8.375 // 0.070 // 0.086 20 // 0.625 // 6.875 // 0.086 // 0.093 20 // 0.750 // 6.875 // 0.093 // 0.096 24 // 0.825 // N/A // 0.089 // 0.089For 5.56mm Colt's gas port sizes are: * 10.5" - .093 * 11.5" - .081 * 14.5" - .063 * 16" - .063There's alot more gas in a 22-250, so I wouldn't rely on those numbers (5.56 stuff) strictly... <dontknow> Quote Link to comment Share on other sites More sharing options...
tlcoy1911 Posted February 17, 2012 Report Share Posted February 17, 2012 Was this gun shooting fine, then all the sudden it started the malfuctions? Quote Link to comment Share on other sites More sharing options...
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