Modern Sporter dedicated rimfire upper UPDATE NOV 7

[driller212]

I would be much more inclined to get one of these rifles if I can stick it in more roles. 22lr pdw would be fun!

[scourge18a]

I am definitely going to have to look at dedicated 22 LR barrels and bolts.
Dammit...why didn't I order a third or 4th upper...

[jadam]

I have both a 9" CMMG and a 16" TACSOL barrel and BCG kit. The TACSOL is much nicer looking, with a light aluminum barrel shroud over the steel barrel insert versus the CMMG steel barrel. They both run well, the TACSOL better. Don't forget they barrel ends up about 1.25" shorter than a normal AR barrel of the same stated length. So the TACSOL is a good match for a 14.5" barrel and the CMMG is, well, short. I threw a flaming pig type device on the CMMG and am running it with an airsoft Colt Canada L119A2 rail that is actually quite good for the $150 I paid for it.

Both are reasonably accurate with CCI standard velocity. The CMMG runs 1" or slightly over, the TACSOL sub 1" at 50 metres.

[ColinD]

I'm Also very interested in building a dedicated .22 upper for the MS.
I'm assuming if a guy uses an adjustable stock, the measurement for NR would be with the stock fully collapsed?

[Mark-II]

I have a CMMG barrel/bolt and it's ok. I'm interested in trying a JP Rifles one, as it has good reviews.

I was going to go through the grey market, as the one Ca source I found was substantially higher, plus I do not want to pay for useless dust cover or high polish.

The chamber adapter kits are useless if your barrel runs faster than 1:12, IMO, and even then they are not accurate. Best to get a .22LR barrel, whatever one you decide to buy

We also need a source for reasonable price Black Dog mags. Only reasonable source I know of is not a reliable vendor any longer.

[rifleman762]

So if one was to build a 5" barrel dedicated 22LR with fixed stock and under 26" OAL, it should still be NR like a Mare's Leg or short KSG, correct? Is there a way to test this without risking a criminal prosecution? I stuck with over 26" OAL on my Rem 597 project just to avoid that risk...

[Kratos]

I'm Also very interested in building a dedicated .22 upper for the MS.
I'm assuming if a guy uses an adjustable stock, the measurement for NR would be with the stock fully collapsed?

Since an adjustable stock isn’t needed to operate the rifle and it’s easily removable (no tools required) you have to measure from the end of the buffer tube. That’s why most are going with a fixed stock (requires tools to remove). Our laws aren’t clear to be honest, but that’s how I understand it.

So if one was to build a 5" barrel dedicated 22LR with fixed stock and under 26" OAL, it should still be NR like a Mare's Leg or short KSG, correct? Is there a way to test this without risking a criminal prosecution? I stuck with over 26" OAL on my Rem 597 project just to avoid that risk...

No, it had to be factory if under 26” OAL. Putting it together yourself makes it restricted.

[onetwentyish]

Correct. If you intend to be under 26" and NR, it needs to be:
-not a centerfire semi auto
-factory built
-fixed stock (no folding or LOP adjustment)

[purplezuk]

I personally wouldnt go with. Conversion bolt setup if you are planning to go under 18.6".
I think you're asking for legal trouble since it can still fire 223 in less than 15 seconds.. it's a huge risk in my opinion.
Jp is the logical option here with their dedicated 22lr barrel

[alberta tactical rifle]

So if one was to build a 5" barrel dedicated 22LR with fixed stock and under 26" OAL, it should still be NR like a Mare's Leg or short KSG, correct? Is there a way to test this without risking a criminal prosecution? I stuck with over 26" OAL on my Rem 597 project just to avoid that risk...

We are still awaiting a reply from the SFSS guys for "the final word" in writing.
I suspect we will need to submit 1 for exam.