S&W M&P 15-22 SBR -- How short would you go?

[Cannon500]

If it was yours, what barrel length would you choose? I'll be shooting it with a Sparrow 99% of the time if that affects your answer.

[Bendersquint]

If it was yours, what barrel length would you choose? I'll be shooting it with a Sparrow 99% of the time if that affects your answer.

4"

[T-Rex]

What's the rail length on the M&P? 10"?
The sparrow is 5" and it will thread about 1/2" so if you make the barrel shorter than 5-1/2", the suppressor will be inside and hard to remove.
Are you planning to get another rail?

I'd recommend lining the suppressor up with the rail to achieve the length or "look" you're going for.

[rimshaker]

Short enough so that any high velocity bulk 22LR ammo is coming out subsonic.... less than 4.5"

[Cannon500]

What's the rail length on the M&P? 10"?
The sparrow is 5" and it will thread about 1/2" so if you make the barrel shorter than 5-1/2", the suppressor will be inside and hard to remove.
Are you planning to get another rail?

I'd recommend lining the suppressor up with the rail to achieve the length or "look" you're going for.

There are aftermarket barrel nuts available that allow the use of standard AR furniture. I'm sure I can find a free-float tube to match just about any length.

[RMears 45]

Why change the quad at all ? Any good bandsaw would make short work of that polymer quadrail. Basic math suggests you want a 9 inch total barrel length so use a bandsaw and trim the rail to 8 inches, sand the cut off smooth and reassemble. If you are very careful you can probably re-use the factory barrel support after enlarging the hole.
The reason I recommend cutting over replacing is the barrel threads are plastic and I would try to use the nice lite factory quad. .... oh yeah almost forgot the receiver has like 1000 tpi so you will twisting a while.

[Joker31D]

I plan on making mine 10.5" because I have shot all different lengths of M4's and it always worked the best and allowed me to stabilize the carbine without giving up length, my buddy has a 7" and it works fine, I'd almost buy the pistol version and add a stock before paying for the barrel to be cut, or buy a barrel for the pistol.

[JeffWard]

Short enough so that any high velocity bulk 22LR ammo is coming out subsonic.... less than 4.5"

This.... CMMG makes a dedicated 22LR barrel in 4.5". That's what's on my newest toy.

JW

[Joker31D]

I dont know that I would tailor my rifle around make hi-vel ammo std vel, just buy std vel 22's, I have been able to find more std vel stuff lately than hi-vel. I shoot CCI STD Velocity, it works great, doesnt beat the chamber up(Not that its brutal or anything) and stays SUBsonic. I shoot some older rifles so I buy STD velocity to avoid damage (Had an incident where a Stinger accidently met a Beautiful High Standard, factory shortened and threaded, Vietnam era ex military pistol and it was ugly) i'm not saying that this would ever happen to a 15-22, its just nice to buy std velocity for using a can and hi-vel for non-suppressed. I dont even buy Hi-velocity anymore, I bought a 17hmr for small game and a 204 for medium.

[Aaron]

I dont know that I would tailor my rifle around make hi-vel ammo std vel, just buy std vel 22's, I have been able to find more std vel stuff lately than hi-vel. I shoot CCI STD Velocity, it works great, doesnt beat the chamber up(Not that its brutal or anything) and stays SUBsonic. I shoot some older rifles so I buy STD velocity to avoid damage (Had an incident where a Stinger accidently met a Beautiful High Standard, factory shortened and threaded, Vietnam era ex military pistol and it was ugly) i'm not saying that this would ever happen to a 15-22, its just nice to buy std velocity for using a can and hi-vel for non-suppressed. I dont even buy Hi-velocity anymore, I bought a 17hmr for small game and a 204 for medium.

Most standard velocity stuff will shoot sub-sonic in pistol length barrels anyway.

[rimshaker]

I dont know that I would tailor my rifle around make hi-vel ammo std vel, just buy std vel 22's, I have been able to find more std vel stuff lately than hi-vel. I shoot CCI STD Velocity, it works great, doesnt beat the chamber up(Not that its brutal or anything) and stays SUBsonic. I shoot some older rifles so I buy STD velocity to avoid damage (Had an incident where a Stinger accidently met a Beautiful High Standard, factory shortened and threaded, Vietnam era ex military pistol and it was ugly) i'm not saying that this would ever happen to a 15-22, its just nice to buy std velocity for using a can and hi-vel for non-suppressed. I dont even buy Hi-velocity anymore, I bought a 17hmr for small game and a 204 for medium.

22LR standard velocity/subsonic ammo are harder to come by, and priced more. Like 9-12 cents/rd on average.

Whereas bulk high velocity rounds can still be easily found for 4-7 cents/rd, depending who's having the sale.

[Joker31D]

I havent seen hi-vel stuff in years but Remington target and cci Quiet22 and Standard Velocity are relatively easy to find for me. Havent even tried hi vel from my P22 barrel, will it stay subsonic? I literally havent tried it, because I cant find Mini-Mags, my Walmart put up a sign saying that its a waste of time to ask when it came in last, it was before the employees that work there were hired.

[rockman96]

I haven't found anything that Quiet22 will cycle in, and HV is almost all I see anywhere.

To the point of SBRing a M&P-22, why not just build a real AR dedicated .22 upper? Don't misread this... If you are in the stamp game, the few extra bucks it would cost you to build a dedicated upper wouldn't really be of any concern, would it? And then you would have a real AR SBR.

To echo what others have said, don't go over 4.5". I know for a fact that 5" will still give you some 'crack', although it seems to be more transonic than supersonic.

[strobro32]

My 15-22 is cut to 4.5".

This weekend we put it to a fouling test. We shot 850 rounds with a Specrtre 2 and Remington Golden Bullets. Besides 11 light primer strikes and 2 duds, it never failed to chamber or failed to extract. I ran out of ammo but I think it could have shot more.

The 15-22 has much better bolt system than the AR 22 kits or the 10/22.

[rckshrk]

Mine is 5.5"... had the rail shortened too. I can't remember the new rail length but I end up with about a 1" of Spectre 2 sticking out the end. Shooting mini mags exclusively, I start getting sonic cracks at temps below 60F.

[GHEN]

Where are the pics of all of these cool SBR .22 ARs?

GHEN

[AlabamaPaul]

Here's one...

[T-Rex]

[Joker31D]

where did you get the skeleton grip?

[rankhornjp]

I went 5.5".

[Cannon500]

Since my thread came back to life, I guess I should post my finished product. I went with 4.5" -- 23" OAL as shown.

[paper9]

These look great, I wonder if slide fire or a bump fire stock works with the SBR length.
Is the pistol variant of the 15-22 available for purchase?

[telero]

These look great, I wonder if slide fire or a bump fire stock works with the SBR length.
Is the pistol variant of the 15-22 available for purchase?

15-22P isn't manufactured any more. They seem to be going for around $600-700. Less expensive to buy a 15-22 rifle, SBR it, and have the barrel chopped and threaded.

[paper9]

I wonder if suppressed slide/bump would function? The barrel would be 4 - 7 inches.

[Cannon500]

I wonder if suppressed slide/bump would function? The barrel would be 4 - 7 inches.

The one I posted above runs pretty well with a slidefire -- better than it did as a full-length rifle.