AR-15 Bolt Catch not functioning correctly

[ChuckD]

I recently assembled a lower (TM-15 80%) and the bolt does not lock to the rear on an empty magazine. I have tried 3 different bolt catches, same result. I have used one of these in another lower & it functions fine. If I hold the bolt catch down with my finger it catches. Has anyone seen this before? I am thinking of drilling the hole that the spring & plunger go in a little deeper (very little) - this will give the bolt catch a little more travel (higher) - any thoughts on this?

[bohoki]

yea it sounds like there is some crud behind the spring causeing it to be more powerful than the magazine spring

i assume you tried other magazines

heaven forbid you might have run into an ar-180 hybrid magazine

[ChuckD]

yeah, I tried 3 different magazines and all 3 work in other AR's.

[SJgunguy24]

Does it move freely in the slot and does it travel as far as it needs to when compared to the other guns.

[ChuckD]

It does move freely in the slot. Compared to other guns I can't see the difference. One thing I failed to mention in the first post: I also took the upper off, inserted a magazine, and was able to push the bolt catch manually a little farther than the magazine did by itself.

[vw69turbobug]

can you lock it in place manually ?...

[ChuckD]

VW: yes

[Seesm]

Sometimes the bolt has a heavy chamfer tha will not allow the bolt to hold open easily on the bolt catch area... I had a ar308 that was like that...

[ChuckD]

Results:
Final test before drilling - I removed the bolt catch & reinstalled with no spring at all: worked prerfectly. This confirmed to me that there was indeed to much pressure being applied by the bolt catch spring.

I drilled the hole out. I drilled a very little, then test, repeat. I had to do this more times than I expected to, and removed more metal than I expected to, but I did get it to function properly. I took it to the range last night to test while actually firing & it functions perfectly. Just to be thorough I held it upside down and fired several rounds just to ensure there was still enough pressure on the bolt catch to prevent it from engaging when it was not supposed to - also functioned perfectly.

Thanks for the replies.

[Bullets&Whitewalls]

I had the exact same problem with my bolt catch on a TM 80% I switched to another one that I had from another lpk and it works fine now. I didnt think about re drilling. good to know! I will give it another shot now!