AR15 LOWER RECEIVER DIFFERANCES

**motorolahamm** · 11-22-12, 19:24

Why is there a diff in the mill work of these two lowers ??? one seems to be milled all the way back. and the other has a space in between

thanks guys

Attachment 14205

Attachment 14206

**motorolahamm** · 11-22-12, 19:25

will not let me upload photos

**polymorpheous** · 11-22-12, 19:27

It's called a sear block.

**motorolahamm** · 11-22-12, 19:36

what one is better to have pic 33 or 44 thought it sear block lol, just kinda escaped my mind

**polymorpheous** · 11-22-12, 19:54

Both will be fine for a semi-auto rifle.

**motorolahamm** · 11-22-12, 19:56

Originally Posted by polymorpheous

Both will be fine for a semi-auto rifle.

one if them is a BM lower the other a Colt 6920. can the one with the block take a F/A carrier

**polymorpheous** · 11-22-12, 20:10

They both should be able to.

**akioty10** · 11-22-12, 21:34

Either will work with a fa carrier, the one with the extra alum has a sear block. This is so you cant put a sear in it and make it a automatic ....3 shot burst...etc. I'm going to guess the colt id the one with the seat block?