A long time ago I decided to build an SBR and went with the shortest length I could get at the time, a CMMG 7.3" 5.56 upper.

It functioned flawlessly, but the more I thought about it, the more I thought I should have gone a different route.  Shooting it wasn't too bad, but standing nearby when someone else shot it was borderline abusive, even with ear plugs under my earmuffs.  Another problem was that I couldn't find a suppressor with a warranty for that short of a barrel in 5.56.  It was more of a plinker than anything else, so ballistics weren't a huge concern, but were always in the back of my mind.

I considered pistol calibers, other barrel lengths, etc.  I eventually had the 5.56 barrel swapped out with an 8" .300 Blackout barrel and I'm really happy with the rifle as it is now.  I bought a Specwar 762 for it in the spring (in jail right down the road from me...) and found out that SilencerCo's warranty applies to 5.56 barrels down to 7".

So as I sit here looking at the old barrel (picture below that I took of it after it was removed), I'm trying to decide my best option.  Right now I'm considering:

A) Build a new upper around it and use the Specwar 762 on it.

B) Build a dedicated .22 upper with it and buy a rimfire suppressor.

C) Sell/trade for a 12.5" barrel.

I'm looking for anyone who has had experience with some of the options (or other options I haven't yet considered).  Would option A be practical at all?  I've heard the gun will beat itself to death with a suppressor on that short of a barrel in 5.56.  Anyone do this?

For option B, is the twist on a CMMG 5.56 barrel OK for .22, or would it be better to sell/trade for a different barrel if I want to go rimfire?

Thanks in advance!

Pic of the barrel:

I run a 7.5" Adams arms upper with saker 5.56.  I like it a lot but it is a piston.  I would probably just sell the barrel and put that toward a 4.5" cmmg .22 barrel.  I love that setup if you have a can.  No .22 can and I'd build that up with some cheap components and put a .22 conversion in it.  You can still run the 5.56 if you want.

what is the twist on the barrel?

do you own or plan to buy a rimfire can?

although your can may be rated for a 7" can, it's still going to come at the cost of accelerated erosion, which i'd be suprised if erosion is covered?

The best I can find, it looks like twist is 1 in 7.

I don't have a rimfire can, but plan on getting one.  Probably start looking for one of those in about 3 or 4 months.

All I know about the Specwar 762 and 7" barrels is what is on their list of barrel length restrictions.

I suppose I should contact them for more specifics just to be certain.

Dead air doesn't have a minimum for their sandman series.