Built first AR, having trouble cycling

[burritooo]

I'm just having trouble with getting my first AR build to cycle. It's definitely in the lower, and likely in the buffer/tube. Charging handle doesn't even let me pull back the BCG after firing a round. Have to force it open.
Did the same problem using my lower with a friend's upper...
What do you think it could be?

I have looked through the forum and haven't found any other similar issues yet.

 

[Mr. Booshie]

I’d check for:

Hammer sticking
Set screw in the lower, if yours has that, (for upper receiver tension) too tight.
Bent buffer tube.
Buffer retainer too tall and catching BCG.

Lower machined out of spec causing BCG not to alight with buffer tube.

 

[burritooo]

Hey thanks for the advice. I'm not sure what the "set screw in lower" means, though. I live in Roswell too.

 

[Cohutta68]

Does the buffer slide freely? As in, can you use a wooden dowel and push the buffer all the way to the back of the tube and back freely? Does the buffer retainer pin look OK? Do you see any scratching or abbrasions where something is hitting something else?

Does the trigger operate and reset properly when not installed on the upper?

 

[hwb111]

Is your hammer facing the correct direction? Theflat side should be facing the bcg.

 

[Bushwhacker]

Hey thanks for the advice. I'm not sure what the "set screw in lower" means, though. I live in Roswell too.

Several lowers have a screw in them that acts as a wedge to tension against the upper to reduce slack between the two for a tighter lock up.


As mentioned earlier I'd for sure check your buffer retainer. It should only be high enough to hold back the buffer spring and buffer. Also I'd check your buffer tube/endplate/castle but. Making sure there is nothing interfering with proper bcg cycling there as well. Assuming you changed complete uppers, make sure you try a different bcg as well

 

[Bushwhacker]

Is your hammer facing the correct direction? Theflat side should be facing the bcg.

More good advice

 

[burritooo]

Is your hammer facing the correct direction? Theflat side should be facing the bcg.

Yes. Yes it is.

 

[burritooo]

Several lowers have a screw in them that acts as a wedge to tension against the upper to reduce slack between the two for a tighter lock up.


As mentioned earlier I'd for sure check your buffer retainer. It should only be high enough to hold back the buffer spring and buffer. Also I'd check your buffer tube/endplate/castle but. Making sure there is nothing interfering with proper bcg cycling there as well. Assuming you changed complete uppers, make sure you try a different bcg as well

The buffer retainer... so it might be too high? How would I end up lowering it?
Also, how would I be able to check if there's nothing interfering with the BCG cycle? Have definitely used two different complete uppers with two different BCG.

Had trigger reset issues before that, and gunsmith fixed the trigger part that wasn't resetting (it was a brand new Anderson trigger)

 

[Mr. Booshie]

Hey thanks for the advice. I'm not sure what the "set screw in lower" means, though. I live in Roswell too.

I’ll be home tomorrow after 5, if you want we can meet up and check it out together.