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Range Report on CZ-455 With New 1:9 Twist Barrel Liner
Old 09-17-2017, 07:07 PM
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Default Range Report on CZ-455 With New 1:9 Twist Barrel Liner

So as some of you are aware, even though I have a couple of Ruger 10/22s that shoot the Aquila SSS cartridge pretty well, I have been trying to 1) get a 1:9 twist barrel for a .22 RF bolt gun, (, and 2) get a subsonic load for the .22 Hornet. ( And here is another thread about the purchase of a CZ-455 in pursuit of #1 above.

As I mentioned in one of those other threads, I found a fellow that makes .22 RF barrel liners with 1:9 twist rifling, and ordered two (his minimum). I installed one in an old milsurp 8mm take-off barrel. (The 5/16ths (0.312") OD of the 27" liner fits 'perfectly' in the 8mm (0.315) bore.) A little epoxy, and voila'!, I have a .22 RF barrel, 23 inches long, with 1:9 twist rifling, that I can machine to fit a CZ-455 receiver!

After doing all of the liner installation and machining the breech for the 455, the initial shots were pretty darned poor. I was certainly disappointed. However, after doing a little detective work, I was able to find the problem and fix it. (It was a burr INSIDE the muzzle. Still not sure HOW that happened, but it ain't there now, I assure you!) The next shots were "OK", but nothing to 'write home about'. There were two possible causes for the mediocre groupings: 1) The liner was just "mediocre" , or 2) it just needed to be "shot in". Hoping for the latter, I have been putting some bullets through the barrel for the past two days. Yesterday, I put some "diamond dust" on five rounds and shot them first. (That's how I found the muzzle burr.) After fixing the burr, I shot 50 rounds of some bulk Winchester, copper-washed bullets, with a advertised MV of 1280 f/s. Again, nothing special about those groups. But then I wasn't expecting anything special from that ammo. Although, if you look here: you can see that that ammo shot pretty well from all three of those rifles.

So today, I decided to put another 50 rounds through the barrel for some more "sweetening" of the bore as j0e_bl0ggs would say. This 50 would NOT be copper-washed, but rather "lead with wax". I chose to use CCI Subsonics with an advertised MV of 1080 f/s. j0e_bl0ggs also suggested that since my real interest was in the Aguila SSS, I should shoot some SSSs before I shot the CCIs, and then again after I shot the CCIs, and see if there was any improvement. So... I shot 10 SSSs, then 5 Norma subsonic rounds, then 25 CCI subsonics at one point of aim, and 25 at a second PoA. Then 5 more SSSs and 5 more Normas. Here are the targets.
The first 10 SSSs:

I adjusted the scope after the first 5, and "settled down" a bit too. Notice the "1-in-5" flier!

The first 5 Normas:

There are 5 shots there, I assure you.

The first 25 CCIs:

The second 25 CCIs:

The "after" Normas:

And the "after" SSSs:

A nice group, no doubt, BUT... Notice the "1-in-5" flier AGAIN!

It certainly looks like things got better. HOWEVER, I must point out that after I finished shooting all of the CCIs, I was not comfortable with my "hold", and I changed my shooting rest from a 1-point system (support only at the receiver just in front of the magazine), to a two-point system (support at the receiver AND support at the butt). The two-point system was a bit steadier. SO... some of the improvement seen might be due to the better rifle support. However, I don't care. Those groups are GOOD. I'll take them from a barrel I "made"! ("Made" = Installed liner and machined breech for CZ-455 receiver.)

I think I have found my bolt action, "long" barreled, fast twist, .22 RF rifle that can shoot the Aguila SSS with a precision I am satisfied with.


PS - I don't have any SSS MVs to report yet though.

Then you will know the truth, and the truth will set you free. John 8:32

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Last edited by gitano; 09-30-2017 at 02:30 PM..
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