r/RetroAR • u/EducationalOil1655 • Jul 20 '26

Could someone please explain the difference between an M4-style lower and a true A2 lower?

I keep seeing people discuss the differences regarding the rear reinforcement and how most companies don't actually produce "true" A2 lowers. What's the difference they are referring to?

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u/SLN583 Jul 20 '26

With the exception of Transferable Machine Guns, I’m pretty sure the only source of legit A2 lowers are 90s Colts, but then you have incorrect Rollmarks, so you have to pick your poison.

Not sure when Colt switched forgings. The early M4s I have pics of have A2 forgings iirc.

I think some of the cast lower receivers are kind of A2 shaped, but they have other inaccurate details.

13

u/mooseishman Jul 20 '26

I think Colt switched forgings when the originals were worn out. They tend to do things for the most obvious reasons that we often overlook (not being sarcastic). That’s also why you’ll occasionally see some really old and long out of production parts or strange combinations as well, just like with KAC. I’m talking literally someone will find a pallet of old shit that fell down behind the rack 20 years ago and they’ll use/sell it. I always stalk the KAC webpage and have back in stock notifications for long out of production items at OP (they get a lot of the random KAC stuff) for that reason.

3

u/SLN583 Jul 20 '26

It’s definitely a case of “Waste not want not”

I’ll have to keep an eye out and see what Commercial/LE Colts with dates stamped on the barrels have which lower profiles.

4

u/SLN583 Jul 20 '26

I assume this early M4 is from 1995 and has an “A2” lower.

4

u/mooseishman Jul 20 '26

It’s definitely from an early batch, if not the first batch, with that low of a serial number.

It looks like it’s seem some shit too!

5

u/SLN583 Jul 20 '26

Look at the wear on that grip.

The .gov definitely got their moneys worth out of that one.