I've posted this to other groups to no avail.Maybe you guys know.

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I want to get a 22 short rimfire,24" bbl that will only shoot CB caps.What is the preferred twist rate for that cartridge?Thanks.

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I've shot a bazillion of them in 16" twist tubes. Were I specifically chambering for the CB round,that is the twist rate I'd employ.

I've given serious thought to building a CB short specific Marlin 39A and that is the route I'd personally choose..............

The Marlin 39A is what I'm shooting now but it seems to get alot of lead buildup right in front of the bullet in the chamber after a few hundred rounds.I figure if I build an Encore with a 22 short chamber I can resolve that.I was told that a 1 in 20 twist would be better than a 1 in 16 for the CB cap.I don't know,that's why I'm asking.Thanks for the reply.

'Tis the lead buildup you mention,that has had me scheming a CB short specific chamber in one of my 39's. Plus the accuracy advantage associated with shortening that tremendous leap to the rifling.

As a curiousity,I went and pulled a bunch of projectiles out of a batch of CCI CB shorts I have on hand. Weights average 30.3grs and length is about .385" long.

Were it me(and it ain't),I'd err on the "safe" side and retain a 16" twist. I'd rather have a coupla extry RPM's as opposed to keyholes and I could not give you a definative answer on where the threshold lies in relation to this chambering and that projectile,as far as it's minimal stabilization twist rate.

I still crave a S/S barreled and fluted 16" twisted 39A in a laminate stock,as an eye poppin' Play Toy............

Thanks for the post.I never thought to rebarrel my 39A.I figure I could get my Encore loaded up with the CB caps and have a real winner.Not much involved to set up my Encore with a .22 short chamber,is there???

I believe the 1/20" twist would be better, if you can find one! Assuming the BB or CB cap ammo is all you will ever shoot through it!!

My reservations would be that the CB propels largely the same projectile as the 22lr(30gr bullet),at much abbreviated velocities.

Less twist would not HELP stabilization of such a projectile at lesser speeds and the 16" in my opinion would be miles from "too much" and much closer to "better safe than sorry".

Your mileage may vary...............

I have been following this thread for quite a while. I guess I just don't get it.

I've been using the CB caps of various case lengths for years, many years. Using the short case CBs? Clean the gun. Don't want to clean the gun? Use the long case CBs. In fact it is easier to get the long case CBs in my area than the shorts (I had to look for them). Remington's now discontinued CBees were in the LR case, CCI makes a CB on the LR case and the Aguila Colibri and Super Colibri are made on the LR case. So, why would you want to make up such a gun? (other than just because you can, in which case you don't have to ask us, just do it)

Neither do I see the need for a slower twist. Would you not need a faster twist? No. Why (you ask)? Because the bullets are typically lighter than LR fodder being 20-29 grains as opposed to 30-40 grains (for LR) and at slower speeds (400-700 fps) than the LR stuff which goes 1100+ fps. Maybe, just maybe, the ammo is designed to work with the 1-16" twist standard in LR bores.

I have several older and newer .22 LRs in which I shoot both the Short case and LR case CBs. All will do very well indeed with at least one brand of the CBs at ranges at which this ammo can ethically be used on game.

If I've missed something, please point it out. Even after "talking" it out here, I still don't get it.

The appeal of the CB short for me,when housed within a full length 39 is simply capacity. A typical 39,will house 27 of them in the magazine.

You have not lived until you have called in a giant herd of Crows,to a good hide and go to swatting them away with a stealthy CB short spewing 39A. Have killed over 50 in one setting,multiple times and 86 is my best.

I'd look to retain capacity,while improving accuracy and that were/is my mindest. Though my purpose is a niche application,it is a tool without peer and a CB short specific chamber would enhance the end result,in my opinion.............

Capacity and report,are both benefits of the CB short in the 39. Both attributes up the odds,when trying to wipe out a herd of Crows.

I've shot all the "stealth" 22lr rounds and none match the CB short for a quiet report.

I think to extract the potential of the CB short,as far as mechanical accuracy,it is only fair to grant it a chamber specifically geared towards it.

I've noticed the potential of the CB to group better,when exiting a 22short specifically chambered rifle. Another reason that I've craved a CB specific 39,for some time now.

Likely not something that would interest others,but I know what I'd like and why.............

I guess the economical thing to do would be to get the long rifle chamber and shoot the full length long rifle CB caps in it.I don't turn away the idea of the CB short specific chamber but Hobie brought up some interesting points.Resale value would be the other advantage,although I don't sell ANY of my guns. The matter of twist still seems quite perplexing to me.I don't want to make a gun that costs alot of $$$ and have it not "be right".If I got the long rifle chamber in 1 in 16,it would be one hell of a squirrel rig,as well as a CB long specific rig for rats and other vermin.I love my Encore and want to have nothing but the finest thought out rig possible.You guys have been extremely helpful in answering my questions and need to be applauded for it.Thanks again.Now if I could just get it built for less than an arm and a leg....