ar15 selector switch problem-HELP!

[LCU1670]

building two ar 15 lowers (80%) installed in each a doublestar lower kit, in both lowers the gun will fire on safe. I had one cmmg lower parts kit, took out the doublestar hammer-trigger-selector switch and replaced it with the cmmg parts, all is fine on that one lower, passes function tests.

the lowers are cotes, and I had a very knowledgeable guy guide me in milling out the lowers.

Is it just the fact that doublestar parts kits are no good? Or am I missing something?

What should I do to fix the other lower and make it safe?

Also, I tried a timminey drop in trigger kit in the other bad lower, and tried to use the doublestar selector, again, the hammer fell on safe. (I did not try the cmmg selector with the timminy trigger, got tired of taking things apart over and over- so I thought I would ask more knowledgable people!!!)!!

Thanks for all your help!!

[LCU1670]

Any help?

[buruli]

If I understand it correctly, you got one lower to work correctly i.e. the safety works, when you switched to the cmmg parts. This seems to indicate that the holes are drilled in the right place. Sounds like something is wrong with the double star parts. I think the next thing I'd do is put the cmmg safety into non-functioning the gun with the double star hammer/trigger assembly. This would give you a clue if the problem is with an out of spec hammer/trigger or an out of spec selector.

[Reelemup]

If I understand it correctly, you got one lower to work correctly i.e. the safety works, when you switched to the cmmg parts. This seems to indicate that the holes are drilled in the right place. Sounds like something is wrong with the double star parts. I think the next thing I'd do is put the cmmg safety into non-functioning the gun with the double star hammer/trigger assembly. This would give you a clue if the problem is with an out of spec hammer/trigger or an out of spec selector.

Or out of spec mechanics

[bohoki]

sounds like the safety hole was drilled too high in relation to the hammer and trigger pins

i would buy some of that aluminum solder and fill the hole on both sides grind it flat and re-drill

[ar15barrels]

Compare/Check the selector hole and trigger pin hole locations on both lowers.
Are they the SAME height from the trigger pin on both guns?
If they are different heights, that's your problem.
Solution varies depending on what the problem REALLY is.
You can weld-up and re-fit the tail of the trigger to fix a too-high selector hole.

[LCU1670]

Thanks!

[LCU1670]

Was thinking, what about: JPFC-S Adjustable/Reversable selector switch??

[VytamenC Tactical]

Compare/Check the selector hole and trigger pin hole locations on both lowers.
Are they the SAME height from the trigger pin on both guns?
If they are different heights, that's your problem.
Solution varies depending on what the problem REALLY is.
You can weld-up and re-fit the tail of the trigger to fix a too-high selector hole.

this is more than likely the problem. i have actually tig welded the safety selector and refit it to stop it from firing of safety. let me guess you were the 2th or 3rd lower to be done on a jig with no drill bushings.

i have also seen where the hammer and trigger pins were off and you get a multi burst every time you pull the trigger.

[VytamenC Tactical]

Was thinking, what about: JPFC-S Adjustable/Reversable selector switch??

this may fix your problem as far as the safety issue. however i would do a function test on your lower as well to check for other problems with the hammer and trigger pin location

[LCU1670]

Thanks again!!

[LCU1670]

this is more than likely the problem. i have actually tig welded the safety selector and refit it to stop it from firing of safety. let me guess you were the 2th or 3rd lower to be done on a jig with no drill bushings.

i have also seen where the hammer and trigger pins were off and you get a multi burst every time you pull the trigger.

The jig had bushings, but I did see a bit of wear!

[LCU1670]

Was reading some other threads, people wrote that sometimes you need to stone the front part of the disconnector, where it meets the flat part of the trigger, to lift the back of the trigger up, so it is closer to the selector.

Is this correct.

[dchang0]

At this point, you should measure, measure, measure. Check the hole positions against the specs on a blueprint using a pair of calipers.

[LCU1670]

Thanks, where can you safely download a blueprint? I tried a couple of times by googling, each one had some sort of spyware and had to uninstall a bunch of junk!