My agency is considering switching our conventional 5.56 ARs to 300 Blackout with ~10.5 inch barrels. Although I’m willing to consider alternatives, it seems to me that it would be most economical while (hopefully) ensuring reliability to purchase barreled upper receivers for the conversion.

Thoughts? Considerations?

If I’m right, suggestions on good quality, but not necessarily top tier components?
Any reason to not use the existing bolt carrier assemblies?

I would suggest buying complete uppers and not trying to do barrel switching in house.
I have had good luck with R R but also got some PSA in the mix.
They all seem to run well.
I do not own a blackout,never liked it but I do own a 9X39 but that is an expensive way to go.

quote:

Originally posted by 45 Cal:
I would suggest buying complete uppers and not trying to do barrel switching in house.

I agree; barrel switching was the first suggestion that I recommended against.

Talk to Aero Precision's le sales and ask about an agency purchase. I think you'll find theyre quite reasonable and good quality.

quote:

Originally posted by sigfreund:
My agency is considering switching our conventional 5.56 ARs to 300 Blackout with ~10.5 inch barrels. Although I’m willing to consider alternatives, it seems to me that it would be most economical while (hopefully) ensuring reliability to purchase barreled upper receivers for the conversion.

Thoughts? Considerations?

If I’m right, suggestions on good quality, but not necessarily top tier components?
Any reason to not use the existing bolt carrier assemblies?

Why switch to 300blk, and why 10.5" barrels? Is suppressed use a consideration? I hope the answer is no, but are subsonic loads a consideration?

Most people will tell you to go with an adjustable gas block, but for a department it's easier to work with a company that knows how to select gas port sizes and just tune the buffer weight as needed for the duty ammo and be done with it, and have less points of failure.

Have your armorer check headspace and run through the BCGs before reusing them. Good opportunity for a full teardown and inspection, new extractor springs and gas rings, etc. No reason to not reuse them if they pass inspection and the 5.56 guns are being retired.

If you're betting your life on it I would avoid "budget" choices and go with solid factory built uppers.

Admittedly this might sound like a brand shill, but I would recommend giving a call to Sons Of Liberty Gun Works and talking to Kyle or Mike about what you need. They have extensive LE services including armorer service/training, loaner guns, T&E, trade-ins, and discounts for officers. Some of the most approachable guys I've talked to, very knowledgeable, and a quality-first mindset.
https://sonsoflibertygw.com/agency-purchases/

We looked at the FN 12” 300blk uppers for unsuppressed supersonic use but decided to stick with the 14.5” 5.56 FN rifles because everyone around us is still 5.56. We’re budgeting for new rifles this fall. I’m still going to push the 300blk but it’s not looking good.

I would also consider barreled uppers or new guns. Building them is fine and all, until you have to do a bunch of them and deal with the teething issues.

One thing I would also think about is how your lowers are marked. Does the agency want lowers marked 5.56 with 300 uppers? Do you trust your people to not somehow mess it up. The biggest concern I have with 300 is the potential to confuse ammunition and damage something or hurt somebody. Even as an agency-wide change, do your people take their rifles home? How many have 5.56 at home?

How much admin time are you willing to put into cobbling guns together versus just buying new ones, particularly if whatever you have will have reasonable trade value?

I also agree that SOLGW is worth talking to.

I purchased 2 Aero M4E1 uppers from Primary Arms during the holiday season for what I think were great prices, to complete 2 lowers I built. A 16" 5.56 mid-length and an 8" 300blk pistol length, both with the Atlas S-One handguards.

I actually shot the 300blk today and it ran great with supersonic and subsonic rounds, suppressed and unsuppressed. The rounds were cheap Magtech 123gr and 200gr. Both rifles have an H2 buffer and Toolcraft DLC BCG. Other than adding a Rugged brake on both uppers and suppressor friendly charging handles, everything else is factory.

I have read about some people having issues with Aero, but from my small example, the M4E1 uppers are GTG.

I purchased mine from Midwest Industries....VERY PLEASED!!!!!

quote:

Originally posted by Rustpot:


Why switch to 300blk, and why 10.5" barrels?

I'm curious too. You just doubled (or thereabouts) your rifle ammo budget

Personally, I would get complete uppers and not have to worry about swapping bcg's around.

Keep us posted!

quote:

Originally posted by Rustpot:
Why switch to 300blk, and why 10.5" barrels?

Not my idea, but I was able to get approval for complete uppers, not merely barreled receivers or just barrels and swapping ourselves.

Thanks to everyone who has made suggestions.

We have a BCM and it has been great. I also have a BCM carbine in 5.56. The SBR is a 9 inch though, and it looks like they don’t offer a 10.5, just 9 and 12.5. So I’m just posting to say how much I think of the quality of these guns.

This message has been edited. Last edited by: tomgun,

BCM, Son's of Liberty, and Rosco would all be my 1st choices. I believe Aero is putting out a solid product as well