As I mentioned elsewhere, I recently purchased a CZ model 455 bolt action with bull barrel, chambered for.22 RF. I have also purchased two .22 RF barrel liners 27" long with 1:9 twist rates.

The 455 has a kind of barrel attachment similar (if you squint your eyes) to the Ruger 10-22. In other words, it's a slip fit held in place with two screws. Here are some pictures of the barrel out of the 455 receiver.







You can see where the grub screw hits in the picture below.


And here's the 455 barrel beside a 10-22 barrel.




(I should have taken a picture of the barrel in the receiver to show how it looks when attached. I'll post that picture later.)

As you can see, there's not a lot similar between the barrels except concept. The stub of the 455 is larger in diameter than the 10-22 stub by about 20 thou (if I remember correctly). The nature of the attachment is quite different. If I were to want to mill one of my 10-22 barrels with the 1:9 twist to fit the 455, I would have to cut the 10-22 stub off at least, and I'm not sure right now about the 10-22 half-dovetail for its clamping block. Hence the barrel liners. I'll just get a barrel blank, drill it out for the liner OD, insert the liner, chamber the liner, and mill it to fit the 455.

As you might imagine, while my intent is to turn this into a BOLT ACTION rifle, purpose-built to shoot the Aguila 60-grain SSS, I really couldn't resist shooting it "as is". I would have shot the SSS out of it, but I'm 99 44/100% sure they would have key-holed, as NO other .22 RF I own will shoot the SSS without it key-holing unless it has a 1:9 twist barrel. And none have that twist rate except my 10-22s. BUT, I COULD still shoot subsonic bullets. :D

I have several brands of .22 RF ammo that offer subsonic ammo. One of them is Remington. This is the Remington ammo:


It is advertised as having a MV of "1050 f/s" for the 40-grain HP bullet.  I was curious about whether it could get that velocity or not, and I had pretty low expectations for precision.

Since I was interested in the MV of the ammo as well as the precision capabilities of the rifle, I strapped the MagnetoSpeed on the muzzle and fired 9 rounds. The first 4 - after bore-sighting - looked like this:

(Remember, in my yard, targets at 35 yards, and the outside of the "4 ring" is 2.058" wide. The OD of the "8 ring" is 0.52".)

I adjusted the scope, and these are the next 5 shots:

Note the "average miss" values: The AVERAGE bullet missed the point of aim by 0.06" in windage and 0.10" in elevation. The biggest miss was right of PoA by 0.39" and low by 0.23". :D Alas, that 40-grain bullet only has 98 ft-lbs of energy AT THE MUZZLE, and more significantly, it's a hollow point.

I am tickled to death with those groups! Even at 35 yd. And guess what the average MV for the 9 shots was... 1051 f/s, with a standard deviation of 28.5 f/s!

Here are the Excel spreadsheets that provide the details.
Here's the spreadsheet for the first four shots before adjusting the scope:


Here's the spreadsheet for the second five after adjusting the scope:


And here is the spreadsheet with the means subtracted ("centered" without regard to scope adjustment), and the targets combined.


I LIKE IT! This is the way "it" is supposed to work!

Paul

PS - Also note that in the first group of four, the 'flier' was the one with the 1014 MV. In the second group, the 'flier' was the one with the 1010 MV. There's another nail in the coffin of "ammo" being responsible for the fliers.

Paul

That breach face looks eggzaktly like the old Remington breach. Their barrel was/is held in by a tapered cross pin tho. To get the action out of the stock of my Nylon 11 you must remove the barrel

I think you found "it"

RJ

shoots well!

Here is an interesting solution for the 455 negating need for milling, all done on the lathe.




lilja Anschutz




Prolly will not be using iron sights....




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Great! Now just how quiet compared to a regular .22?

That's a very interesting solution to the milling issue. It doesn't mitigate the bbl length issue, but is does make milling significantly easier.

Rick, I shot those 9 rounds without ear protection and did not feel like I should have been wearing muffs or plugs. Certainly no supersonic 'crack'. I think with a moderator, the sound would be VERY quiet.

Again though, most folks that haven't been around moderators have only "Hollywood" to rely on for representations of 'reality', and we know what that means. With only rare exceptions, a moderated rifle shooting subsonic .22 ammo would 'turn heads' within 100 to 150 yards. "Silent" is not only not possible, it's not the goal. "Quiet" is the goal. Actually, THE goal has three parts: PRECISE, LETHAL, and quiet. Too bad this precise and relatively quiet ammo fails the third prong of the three-pronged objective.

I will probably try that "lathe solution" on that "new", ratty-looking 10-22 barrel I just bought for $14. I might still mill the extractor slots. I don't like that skinny-looking breech even if Anschutz does.

Paul

Skinny looking breech has one downfall, you can easily damage it dry firing!
Wouldn't be much of a problem to machine it with a shroud for the bolt.





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Rick, no noisier than an air rifle, in fact the noise the bullet makes on impact is 'noisiest' bit!