What modifications do you try for firearms to cycle subsonic Ammunition?

[CDR_Glock]

For my Ruger Mark IV, I am replaced my firing pin to titanium from SS, my recoil spring to a Volquartsen lightweight.

For my Ruger 10/22 I am changing my firing pin, recoil spring, extractor, and bolt handle from Kidd.

I just wonder what you do with your AR15 rifles or your Tavor? Do you change your buffer, buffer spring, and add an Adjustable gas block?

 

[greyling22]

I haven't needed to change anything to shoot subs in my 10/22. On my mkii, most everything not labeled hyper velocity has stayed subsonic. Heck, out of the rifle, even standard velocity has stayed subsonic.

For an AR style, 22lr is blowback, the gas block is not involved. When I had issues cycling low powered blackout rounds I cut a couple coils off my buffer spring and it worked perfectly.

 

[dogtown tom]

"Subsonic"= velocity less than +/- 1,100 feet per second.
Nearly every .22 rimfire cartridge is measured from a bbl length of 18-20".

Sooooooo……….if that same ammo is subsonic in a rifle, it will definitely be subsonic in a handgun.
Even "high speed" .22 stays subsonic in a handgun. (Rem Golden, CCI MiniMags, etc)
Some of the hyper velocity .22 may go supersonic (Stinger, Yellowjackets, etc)

I would highly advise going slowly on swapping out parts. Do one at a time and check results.
I too have a Ruger MkIV and several 10/22's...…...haven't had to swap anything.

 

[MachIVshooter]

Much of the ammo labeled as "subsonic" is still basically full power, just running a heavier bullet, like Gemtech 42 gr, CCI 45 gr., Federal AE 45 gr.

I've never had any trouble with those loads cycling any semi-auto, and CCI standard velocity will cycle most. The one that usually requires modification is CCI Quiet .22, which is only 710 FPS with a 40 gr. My Beretta NEOS will run it bone stock, but most others won't even extract & eject reliably.

 

[Elkins45]

I own several 10/22s and all cycle subsonic CCI reliably with stock springs.

 

[Ryanxia]

I've heard several people mention that the supersonic .22 rounds out of a pistol are subsonic because they aren't reaching enough speed in that short of a barrel but I can tell you from first hand experience that there is an audible difference in loudness between supersonic and subsonic rounds out of a .22 pistol suppressed.

Anyways, as far as AR's go, here are a few options in no particular order;
Going to adjustable gas block (reduce overgassing). There are lots of types, some vent gasses vs restrict them, also some get fouled up easier than others which can be a problem if you want to be able to regularly adjust the gas block (vs a set it and forget it).
Buffer spring/buffer changes (slightly heavier will delay lockup and give slightly more time for gasses to exit through the barrel).
There are suppressed bolt carrier groups now, my friend has had good luck with Bootleg's suppressed BCG, you can adjust settings without taking it out of the gun. That one seems to make a difference.
Recently a friend of mine has started experimenting with pig tail gas tubes for the extra dwell time (for example a pistol length pig tail which basically has the same length of tube as a carbine length).
Sidecharging AR uppers don't seem to me to help much but I have limited experience (theory being that gasses leak through the standard charging handle opening).
Someone makes a charging handle that has a specific contoured groove that is supposed to redirect the gasses away from the face.

There's a user on here Mistwolf that has started some pretty in-depth threads on this and seems to be pretty knowledgeable.

 

[jmorris]

“Standard velocity” 40 gn .22 long rifle will be subsonic out of both. Will run fine out of stock Ruger pistols and rifles.

 

[Ryanxia]

One other thing I think worth mentioning is that Aguila super colibri rounds are insanely quiet and although they won't cycle a semi-automatic, they don't push the action back enough to cause a malfunction so its kind of just a slick single shot but at half the sound of CCI standards.

 

[dogtown tom]

I've heard several people mention that the supersonic .22 rounds out of a pistol are subsonic because they aren't reaching enough speed in that short of a barrel but I can tell you from first hand experience that there is an audible difference in loudness between supersonic and subsonic rounds out of a .22 pistol suppressed....

Well, of course there's a difference.
Just like there's a increase in "loudness" from a .22CB/BB > .22 Short > .22LR.
The main reason to use "supersonic" .22LR in a semiautomatic pistol is reliability, because not all .22LR semi autos will function reliably with standard velocity or subsonic ammunition.

 

[Skylerbone]

For the 10/22, bolt lightening to reduce mass and polishing to decrease friction.

 

[FL-NC]

I fired standard velocity in my 22-45 with the can and it was still very quiet. My 22 rifle and 300 BLK are bolt action.

 

[Armorer 101]

As you register the can and not the rifle or handgun you may use a can on several ARs, bolt guns or handguns. With ARs the end result should be quiet, full function. Full function is a trick at times, so far most of what I do has been covered, except that I rub down the exterior of the bolt and BCG with 600 wet/dry and adjust recoil springs, buffers and gas blocks. Plus I have used oversized bullets. Example, in the 6.5 Grendel I use Cacarno 160s at .267 set so short they clear by using the throat, gives me full function at subsonic. In the 300BO I use 220 gr hard cast flat base with a double powder coating on a pre sized .309 bullet unlubed.

Now on 22 LR I use a 16.5 inch 510 Remington single shot that I built from some extra parts with a crossfire scope and there is a lot of difference between standard and subsonic velocity in that 510 out past 50 yards. Recently I have been using the Winchester 45 gr subsonic black copper plated, it stabilizes and shoots .25 inches at 75 yards, quietly. I have various critters on the farm that need dispatching at distance, quietly.

I have multiple F1 builds that I have done over the years and a Liberty Torch QC that I purchased from the nice folks in GA. If you can clearly hear the bullet hit the target paper at 50 yards it is subsonic.
Ed

 

[jmorris]

I just wonder what you do with your AR15 rifles...

You have to be a lot more specific about what you want to do.

Going from supers to subs with a number of different AR 15 calibers takes nothing. All it take for my 458 and 300 AR’s is a mag loaded with different ammunition. If you are looking to cycle a .223/5.56 AR with subs, you’ll have your work cut out for you and should post how you did it if you ever get it functioning as intended, without just using a .22 conversion.

 

[dh1633pm]

Had to use low power springs and a light buffer to get heavy 300 BLK rounds to cycle the action in an AR. I guess you could also adjust the gas. It was easier to adjust the rifle for the loads being used.