Pretty simple topic. In a few months time I'll be working on a 10/22, I believe a recent enough model that the trigger guard is plastic. Thinking about changing out the stock, trigger and all that jazz. The main consideration I want to focus on for now is barrel. It has the standard 16in barrel. What barrel length is optimal for suppression and accuracy? Unsure about what optic I want so far. My range back home goes to 435 at the most. I'm not adverse to SBRing it. Also once I've figured out what length, should I just have my original barrel cut and threaded or buy a new barrel? Suppressor will be a Spectre II. Also what ammo is recommended? Thanks.

Also would like the diameter of the barrel to be as close or matching the diameter of the Spectre II which I believe is 1in.

"Optimal for suppression and accuracy" would be as long as you can (18-20").  I've read some folks saying over 20" barrels can quiet enough to almost sound suppressed.  I wouldn't SBR it if you are primarly interested in quiet.  
Bull barrels are 0.920" so match up well with suppressor diameter, but need a new stock or to relieve your stock.
Any standard velocity should be very quiet (especially in an 18-20" barrel).

 

I've often wonder just how short you could go and still have movie quiet with a high end 22 suppressor like the Mask, Element II or Spectre II.

I've never SBR'ed a 10/22 however I do have several Sb-X barrels which if I remember correct are around 12.5" plus the shroud. With the Mask both the Sb-X and 16" threaded bull  barrel both sound close to the same to my ears.

Now using my older 22 suppressor  the SB-X is noticeable louder vs the 16" thread bull barrel. I noticed the Mask is a ton quieter on a pistol so it figures it would be better on a shorter rifle barrel as well.

The ultimate is a Kidd 16" lite weight threaded. You have super accuracy and a short, light package. 16" gives the most velocity a 22 can produce.

I recommend CCI SV for accuracy and supression. I shoot it all the way out to 100 yards with great results.


ETA: Tactical Solutions Sucks

There are several different questions going on here but remember, subsonic rounds are truly hearing safe with 22LR, supersonic rounds still have the crack and many like myself wear plugs with supers.

Best barrel length for suppressed shooting is 4.5" - 5.0" as it will keep almost all 22LR subsonic. Only the stingers and hyper velocity stuff may break the sound barrier. This length let's you purchase cheap bulk pack ammo versus purchasing more expensive subsonic ammo.

Best barrel length for accuracy is kind of misleading. Accuracy isn't totally dependent on barrel length. I own some very accurate short barreled firearms. The extra length will mainly give you velocity over the short barrel. Short barrels are typically much more rigid than their longer counterparts which helps maintain accuracy as it heats up (not really a problem with 22LR though). Sight in your gun with your preferred ammo and it's given barrel length and you'll be good to go. If you don't want to SBR it the Tacsol SBX shrouded barrel may be an option as well.

Best ammo for a long barrel is Gem-Tech Subsonic 42gr. I've tried many subsonic and standard velocity 22LR and have found this to be the best in any barrel longer than 5". It functions and stays subsonic in my 10/22s and wife's MP-15/22. It also stays subsonic in my Ruber American 18" bolt gun.

Best ammo for a short barrel is anything that stays subsonic for little money!

For possibly the ultimate barrel check out the Liberty Pinnacle 2. It has 4.75" of barrel and the rest of the barrel is baffle stack. It's overall length is 16" so no SBR approval is required.

I've often wondered what a Noveske Flaming Pig would do on a long bbl .22" LR & subsonic ammo.  Increase back pressure, no doubt.

Best barrel length is integral.

Does it stay subsonic in a 16" barrel?