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Posted: 8/8/2014 7:31:57 AM EDT
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I need some help diagnosing what might be wrong with my first lower build.
I am having light strikes with .223 upper and failure to feed with dedicated 22LR upper. Bizarre part that it happens on the second round, i.e. when I rack the slide everything is fine, then with .223 upper I would have light strike or FTF with 22LR upper, then if I rack the slide next round goes fine and it repeats... Uppers are fine since they work fine with other lower. I was blaming buffer spring (since with 22LR it looked like the bolt was not moving back fast enough or was locking too soon) but I swapped it with buffer spring from working lower for no effect. I checked hammer spring (http://www.ar15.com/forums/t_3_66/561432_Light_Strike__need_some_help_diagnosing_.html) and it looks properly installed. Is there any other common novice problems? The LPK is PSA and now I am blaming hammer spring (feels kinda too stiff vs. spring in working lower). Any other ideas? Thanks. |
| Check your disconnector spring makes sure it's not upside down and be sure the hammer spring isn't installed backwards and that it's legs are resting on the pin correctly. Use the functioning lower as a guide, if you see something different about the lower that's FTFing on you change it. Are you using lighter springs on a milspec trigger? If thats the case put the milspec springs back in. |
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There is no way of checking disconnector spring without taking hammer out, isn't it?
I am pretty sure my hammer spring is installed correctly, and from what I could see looking at both lowers everything looks the same. However it is really hard to see disconnector spring... Springs are stock PSA LPK... Am I supposed to lube trigger group? Because I didn't, but now I put some oil on hammer pin and hammer spring feels about the same as on working lower, though I've been cocking hammer for way too long to trust my feel... Let see if some oil would help... Thanks. |
| I had a problem like this just a few months ago. I tried different mags and switched from steel to brass. On the steel first round fired then click. Dropped mag ejected round, put different mag in same thing then I tried one more same results. Changed to brass and did the same thing. Lubed BCG good and tried the brass again, it shot 28 rounds without a failure, and 300 rounds and counting no issues. I believe it just needed broke in some |
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Quoted:
Sounds like this, I had mine in backwards and swore that it was correct but it wasn't. Would only fire 2-3 out of a magazine (not in a row). Must have been the softest primers. Hasn't had a hiccup since. http://oi43.tinypic.com/2hd1kqb.jpg Quoted:
Quoted:
Hammer spring backwards. Sounds like this, I had mine in backwards and swore that it was correct but it wasn't. Would only fire 2-3 out of a magazine (not in a row). Must have been the softest primers. Hasn't had a hiccup since. http://oi43.tinypic.com/2hd1kqb.jpg 90% of the time this is the problem |
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Turned out to be disconnector spring upside down... :)
I still don't understand why it did light strikes, but once I put some oil on hammer pin (and perhaps worked the bolt in other lower) it started to slam fire and that made me rebuild and see that disconnector spring was upside down... Thanks everyone. |
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Quoted:
Turned out to be disconnector spring upside down... :) I still don't understand why it did light strikes, but once I put some oil on hammer pin (and perhaps worked the bolt in other lower) it started to slam fire and that made me rebuild and see that disconnector spring was upside down... Thanks everyone. I called that one....glad you got it fixed. |
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