Problems with my essential arms-15 trigger...

[joemama]

Well I went to the range the other day and everything was working perfect. That is, till my trigger started freezing up. there were a few times when i just had to pull it extremely hard and it fired. Other times it wouldn't budge. I pulled the upper off and did a function test on the lower and it worked fine, put it back together and it would work perfect for a bit then it would start freezing up again. I got a RRA lower parts kit in it if that makes any difference. Anyone got any ideas on what might be happening?

[dreyna14]

How many function tests did you do with the upper off? Can you get it to freeze up with the upper off?

[ar15barrels]

Sounds like you popped a primer.
Remove the offending pieces of primer from the lower receiver.