recommendations for SBR uppers (9mm, .22lr)

[rtruhn]

I know parts of this has been done to death in other threads, but I get great suggestions from you folks, so here goes.

Currently: I have a pre-281 Colt M4 SBR, 11.5" barrel and a 30.5" OAL. (Wow, the tax stamp was good for something!) I also have an Engage E4 pistol currently wearing a 10.5" 300BLK barrel.

The Idea: I'd like to acquire upper conversion sets in 9mm (preferably Glock magazines) and .22lr. Eventually, I plan to get/build dedicated "other" lowers for each (300BLK, 9mm, 22lr) and file Form 1s to have them as stand-alones.

Questions: I have several, naturally.

(1) Because this is a pre-ban SBR, can I legally use pistol-length barrels that would be less than 29" OAL? (Naturally, I will be able to put this into "initial configuration" on demand.)

(2) What manufacturers/models of uppers would you recommend - ones that are likely to work on a Colt 556 lower host or the E4 pistol host, yet also work with specific lowers in time?

(3) Is this plan nuts? Should I even bother?

Thanks in advance for sharing your opinions and recommendations!

 

[rbird7282]

Can't offer info on anything but the .22
Bought a Tactical Solutions upper from Engage with a short barrel and permanent shroud so it's not NFA. Threaded for a suppressor inside the shroud. Works great on my Engage lower. Talk to Nate and see what he can do for you.


Sent from my iPhone using Tapatalk

 

[Pinecone]

The question on your pre-281 SBR is whether BATFE says it is OK to go shorter without reflying paperwork.

I have always heard, longer is fine, shorter is not.

Pretty much any upper will work with any lower, they should all be made to the same specs.

 

[Wayne1one]

(2) What manufacturers/models of uppers would you recommend - ones that are likely to work on a Colt 556 lower host or the E4 pistol host, yet also work with specific lowers in time?

In regards to a dedicated 9mm upper you will probably want to go with a ramped bolt since they generally work with standard 5.56 hammers.

 

[bobthefisher]

Simply get a CMMG 22 upper and get a gunsmith to shorten and thread the barrel to your desired length. One of my friends just got a CMMG upper for $450 shipped off of GB. Nice upper at a good price.

 

[dontpanic]

I have never heard of a Glock magblock. You need a dedicated lower to use Glock mags. Using Colt mags and a ramped bolt, you will be GTG with your current setup.

The rule with SBRs is to be able to return it to the configuration stated when you got your stamp. Yours is a pre SB281 SBR. Have fun. (There will be people along shortly to disagree with this)

All your future SBRs will be limited to <29". At least until Engage wins thier lawsuit about this.

 

[ar15dave]

Not sure if anyone makes a Magwell block that take Glock mags for 9mm. I have an LRM-169 Integrall Suppressed upper and use a Hahn Magwell block. 9mmAR.com is a good place to get parts to build a 9mm AR15/M16.

I built my own 22LR upper or actually had one built after I bought the parts. Used CMMG dedicated barrel and 22 conversion kit with collar. Put on a free float handguard. Building it was more fun. But, if you want to buy one already built I would go CMMG as well.

Dave