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Posted: 1/27/2007 5:51:10 AM EDT
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Ok, I've been lurking for a while. For a *very* long while, as you can see from my registration date.... Still, BRD is starting to set in. I picked up the stripped lower several (4?) years ago from Quantico Arms, back when I lived in NoVA. It's been collecting dust since then, but I finally got the bug to build it up... So, here it is: http://i151.photobucket.com/albums/s131/bdaleray/AR15-012707.jpg Eagle Arms stripped lower from Quantico Arms LPK from RB Precision ARFX stock ERGO grip DPMS 16" Low Pro upper used from EE Leupold VX-1 1-4x scope Leupold high rings And the worst part, I still haven't shot it yet... Hopefully next week if I get the chance.... |
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I finally shot it today. It mostly went well, but a couple of odd problems. I shot about 30 rounds of winchester .223 and 30 of guatemalan 5.56. 1. I shot the winchester first - for the first 10 rounds or so, the trigger didn't 'reset' until I worked the safety. I released the bolt, it chambered the 1st round, and went bang like normal. On the second round, the trigger was slack. I then placed the trigger on safe, then back to fire, and then the trigger would release the hammer and fire the round. This happened for most of the 1st 10 rounds, then mostly went away. After that it mostly fired like normal, with only one or two repeats. Q: So, why? Is this simply a symptom of needing to break the parts in? Or is there something I should take a look at? 2. I loaded up the last 19 guat. rounds into the magazine. I loaded that into the rifle, released the bolt holder, and pulled the trigger. I heard a 'click' but no bang. After waiting a bit, I attempted to open the bolt with the charging handle, but it wouldn't budge. I was at a range that deals with a lot of military guns, and had a gunsmith around. He looked at it, took the upper off, and applied a screwdriver (?) to lever the bolt open. There was a round in the chamber, but no strike to the primer. He (the gunsmith) took a quick look, and saw nothing apparently wrong. After he put things back together, I went and shot the last rounds. The 'problem' round fired just fine. Q: So, what happened? Any guesses why? Thanks! |
| Since you are asking for guesses and a gunsmith already checked the upper, this newbie's guess is that there might be something wrong in the buffer/buffer spring/buffer retainer pin area. I would check that area and I would also check that the trigger and hammer springs are installed correctly. |
For your problem #1, check the spring that is held by the grip, and pushes against the pin that pushes on the safety lever. If you had used one of the springs for either take down pins in there, it would not have enough pressure on the pin/safety to hold it in place. It could allow the safety to rotate a little from recoil and prevent firing. Moving to safe then back to fire would reset it back. Don't ask me how I know  . I had a first build once... |
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#1 - I'd say your disconnector was holding on to the hammer, and no releasing it when the trigger is released. You need to perform the safety checks as described in my BIY article tacked at the top. Offhand - I'd guess a bad part in the FCG, or you are missing the spring between the trigger guard and disconnector. There is no normal breakin required for the FCG - they should work righ out of the box. Perform the safety checks - if they fail, and you arent missing anything - send the FCG back and get a new one, if that is an option. #2 - Sounds like it could be a couple things. Are you sure that upper has a NATO 5.56 chamber? A lot of DPMS barrels are .223, and might have problems shooting 5.56 ammo like guat. It could be that the bolt just didnt lock all the way on that chambering.... especially since you could not extract the round, or, that round had some defect that caused it to not fully chamber and stick. You should have seen a light dimple from the free floating pin just from chambering it. |
How can I tell if I used the wrong spring? If possible, I'd rather not take both detents out just to compare all three. Still, I'm headed to a gunshow this weekend, so I'll see about getting a new spring there, and just swap them out. edit: Are the proper dimensions listed anywhere? Outside diameter of the spring? Relaxed length? I've got a micrometer, and I'm not afraid to use it......
#1 - Thanks - I'll do the safety checks as described. #2 - Per the ammo oracle website "DPMS marks their barrels ".223", though they actually have 5.56 chambers." How do I know, short of getting a cast made? Thanks for all the input, ya'll.... |
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