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Posted: 6/21/2005 6:41:24 PM EDT
| Wife and I assembled an AR from a baggy of parts I found under the bench and a new DPMS lower. I had a military NATO Colt upper. Put it together w/new DPMS bolt and all was well. After some sighting in, we hit golf balls at 15 yds. She enjoyed the whole process so much she asked if we could put another one together since we still had many parts. Got another DPMS lower and had to get an upper this time as I only had a NATO barrel. This bolt/carrer will not recoil far enough to eject the empty. I changed to another new bolt. Same exact thing. I put a used FA Colt bolt in and it will eject the empty but doesnt come back far enough to pick up a shell from the magazine. I interchanged lowers w/each semi bolt and the FA bolt, including using the Colt FA lower. Each time the upper that wouldnt cycle didnt again and again. I removed the front sight and checked the gas hole thinking of a possible obstruction in barrel or gas hole. Both clear as is the new gas tube. Where do I go from here???????? Possible to drill the gas hole larger?????? What size is it supposed to be any way???????? Other uppers worked correctly in semi and full w/ammo we had........ |
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I had a bolt and carrier that would eject an empty case but wouldn't come back far enough to strip a fresh round and would not lock back after the last round. Turns out my buffer spring was a little too long. I cut one and a half coils off the spring and all is well. I have run about 1,500 rounds through it with absolutely NO FTE's or FTF's. Just a thought, MadDog 
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| Keep in mind,guys, I tried this upper on several known lowers that all worked properly, including a FA Colt w/ FA bolt.. Changing lowers means changing recoil springs. Only thing not changed is the gas tube. It is new and I could find no obstruction. I have another and will change it and test again...... |
| It sounds like the rifle is shortstroking. Check your gas key and make sure it is tight. Also, check the chamber and make sure it isn't rough and that it isn't too tight. Does the bolt carrier slide back and forth freely in the upper receiver? What make is the barrel? |
| Everything works freely. I have used two new bolt/carriers assemblies from DPMS and the gas keys are tight and staked. I also use a well used FA bolt. Incomplete bolt travel w/all 3, best w/FA bolt. I have asked before, what size is the gas hole in the barrel supposed to be????? By the way, the barrel is a Colt chrome lined marked NATO 1/9......... I have another front sight/gas fitting that I am going to put set screws in the side of to use as an easy remove to experiment with.............. Comments??????? |
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