I recently purchased a slightly used colt light weight upper to finish a budget minded project. The upper is a m4a2 with light weight barrel, small pin, a2 flash hider and no bayonet lug. The bolt is marked mpc and looks new, the carrier is cut straight back.
My question is there any drawback to the straight cut carrier? Is it worth it to switch to a auto carrier?
The purpose of this rifle is just a simple plinking fun gun.
Thanks
That Colt “half” BCG was designed to mate with a Colt lower with a sear block. If your lower does NOT have a sear block, you don’t need it. For the most part, an FA BCG is a reliability improvement.
“Worth” is somewhat of a subjective term. If the half BCG works, run it until it doesn’t – especially for a range toy!
Clearly, if one were to select the parts from scratch for HD or SHTF, most of us would choose the FA BCG with an H buffer (for a carbine-length gas system) in a MilSpec RE.
Hope that helps.
I won’t replace a Colt half moon carrier with an aftermarket 16 carrier.
I have two guns with half moon carriers. I definitely prefer a 16 carrier if building from scratch, but the emasculated carrier works just fine on a lower with in spec parts.
I actually milled the bottom of my bc flat and cut the top shroud to 1/2" long to cut weight and reduce the oscillating mass…it worked great! The gun is not overgassed but if there was ever a poblem you could install an XP spring or replace that weight with an H, H2, or H3. I know what Colt designed it for but sure has given other inspiration as well! Besides, I’m not sure I would replace a Colt part with any other for any reason (an integral internal part).
Sparky
Thank you for the information!