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Old 07-28-2012, 10:45 PM
Kerry Kerry is offline
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Default cz 204 american /20-222

If this has been discussed before sorry, Is there enough shank on factory barrel to re-chamber to 20-222? Also will the 204 magazine work or does a guy need to use a 222?

thanks

kerry
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  #2  
Old 07-29-2012, 01:26 AM
GLWenzl GLWenzl is offline
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Yes, definitely and i could only assume but would bet the farm it would feed fine. My very first CZ, a 527/222 was ordered only to be made into a 20-222. It came in with like triple x wood and just didn’t want to do anything to it but load up a few rounds. It shot so well and looks so nice it’s still a 222. Kind of wish that I had done the same to my 204 R now in hindsight….

Keep us posted on your progress, I like reading about the triple deuce-anything!

FFT

http://www.saubier.com/forum/showthr...=20222+feeding

http://www.saubier.com/forum/showthr...=20222+feeding

http://www.saubier.com/forum/showthr...=20222+feeding
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  #3  
Old 07-30-2012, 08:57 PM
20 EXTREME 20 EXTREME is offline
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Quote:
Originally Posted by Kerry View Post
If this has been discussed before sorry, Is there enough shank on factory barrel to re-chamber to 20-222? Also will the 204 magazine work or does a guy need to use a 222?

thanks

kerry
Hi Kerry,

I don't have a CZ527 American so can't comment. I measured the barrel from a CZ 527 Varmint Kevlar and it measures 0.987" at the threads and 0.990" ahead of the receiver right out to almost 2". There would be no problem rechambering to 20-222". Rechambering to 20 EXTREME you would loose about 3/4". You shouldn't loose that much going to 20-222 as it is quite a bit larger at the shoulder diameter so should clean up the 204 chamber a bit quicker.

Judging by what others have posted on the links provided you should have no problem with feeding. My 20 feeds great from a 223 magazine and the shoulder diameter and length is the same as that on a new 20-222 case.

I would like to thank the posters who provided links to information about the 20-222 and the 20-VTT variants. I hadn't seen these threads as most were before my time on Saubier. They did confirm a few of the things I had mentioned as advantages with my 20 EXTREME.

I wondered how the 20-221 FB (VT) feed from 223 magazines and Fireball confirmed my suspicions. The Sako 75 and 85 magazines will hold 7, 20 EXTREME, rounds and feeds them flawlessly and make for an awesome combination. I believe the Vixen and A1 only hold 6 but they load and feed like a dream. Still waiting on my A1 with Kreiger #3, 12twist in 24" chrome moly barrel.

Also there was one person who was looking to do a 20 based on the 222 with 23 degree shoulder to eliminate forming (I assume he meant fireforming) and neck turning. To bad the neck has to be trimed and the neck comes out at 30 degrees when forming the no turn neck or the 20 EXTREME it would be exactly what he was looking for.

Fireball eluded to the fact that he liked the 20 VTT that he made as it would accomodate the new Lapua 222 Match brass. While I found the 222 Lapua Match Brass to be thicker it had about the same weight dispersion as the Winchester 222 brass and had to have the necks turned. As well one has to watch for the donut that appears due to the thicker brass. I found no advantage as the Winchester brass gets more velocity with less pressure at 0.2 grains less powder. Remington brass holds another 1/2 grain of powder and gets over 100 fps more velocity without any case stretch. However to accomodate a fellow that just "had to use Lapua Match brass" I had a reamer designed to accomodate it with a No Turn neck. Ironically the LC 223 Nato brass Reforms into a perfect "No Turn" 20 EXT case although there is a bit more clearance at the base than necessary. We have not had an opportunity to build a rifle using this reamer so look forward to trying the two cases in that chamber.

While there is not much load data on the 20-222 and 20 VTT what is posted confirms my suspicions that the extra case capacity does not offer much velocity, if any, over the 20 EXTREME. This is what I refered to as "Optimal" case capacity. One person posted a load using 21 grains of RL7, Rem 7 1/2 primer,Rem 222 brass seated 0.200" in a 20-222. While the 20 EXT case would be full with 21 grains I easily get more than 3700 fps from a 24" barrel using 20 grains. Here is the only ladder test I did with RL7.
[IMG][/IMG] I had a real good load at 20.3 grains, 91% load density, with low ES and SD and didn't get any pressure signs until slight primer flow at 20.6 grains. Seven targets shot, in a ladder test, that averaged 0.37" with two at 0.25" is a good indication of the inherent accuracy of this cartridge and that is likes RL 7. The only problem with RL7 is that I experienced quite large lot to lot variations and temperature sensitivity, compared to H 4198, and got up over 4200fps the next time I tried the 20.3 grain load. Loads posted for the 20 VTT LN showed similar results with the 32 V-Max at 3890 with 22 gr 4198, 3835 with H 322 and an estimated 3976 with 22.6 grains of RL7 showing best accuracy.

Some 20 EXTREME loads fromm slow to fast for comparison. [IMG][/IMG][IMG][/IMG[IMG][/IMG] More to post, only allowed 4 pictures, but should be more than enough for comparisons.

A few of my other suspicions were confirmed but I won't mention them.

Last edited by 20 EXTREME; 07-31-2012 at 05:41 PM. Reason: correct typos
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  #4  
Old 07-31-2012, 03:45 PM
sicero sicero is offline
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Kerry,
Unless you have the luxury of doing it yourself, it is probably best to leave it as a 204.
You only have 1" of barrel in front of the reciever with the CZ American.
Mulerider "Greg" shortened a 204 chamber by running a .232 chucking reamer
into the neck area so the .222 neck could be left full length and also in the process reducing the freebore by .100.
Then he cut the end of the barrel so the necked down .222 case fit.
Doing it this way the barrel was shortened aproximately 1/4".
He now has thicker brass, making the original 204 chamber a tighter fit.
He cut the end off his $30, 204 dies the same amount. This also requires opening the neck of the dies a little because of the heavier necks. This can be done with a common twist drill.
I have done the same thing using .223 brass.
Potential accuracy has more to do with your barrel than
I do have the neck reamer if anyone is in need. Kenny
L to R
17 Remington short
.204 short with .223 case
.223 Rem
.204 Ruger
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  #5  
Old 08-01-2012, 06:59 PM
Kerry Kerry is offline
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Kenny
I don't have the luxury of doing my own work, i think i understand what your are saying, the 222 is.357 below the shoulder where the 204 is .360 with the additional .158 length, with that said how much would have to be cut off to run the 20-222 reamer in? do you have to cut all the old chamber off? if it was the varmint barrel it could be done. i was wanting to do this cheap might have to buy a barrel or as you said leave it as a 204

thanks

kerry
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  #6  
Old 08-02-2012, 01:03 AM
GLWenzl GLWenzl is offline
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Kerry, that rifle I was talking about in post #2 , (the 204R varmint) I bought it new shot a total of 40 factory rounds down the tube and then had it made into a 20 Habu Shrew which is nothing more than a 20-221 Improved with radius shoulders and the barrel was set back to where it left me an OL of 25 1/16”. The parent 221 FB case being somewhat shorter than the 222 case but I forgot about the 222 case having I smaller diameter shoulders than the FB and 204R in that post. That said here is a quote I saved from a guy on another site,

Quote:
I have a cz varmint that was a 204 ruger. Barrel set back and chambered in 20-222. Was a 26" barrel cut back to a total length of 22".

I’m not sure what he did and I personally like the longer barreled rifles.


couple more 20-222 links in case you haven’t seen them. actually looking at this from the stand point of rechambering my 20-HS to my original dream of a 20-222 since you and a few other power mentors have been talking this nasty 20-222 talk!

http://www.saubier.com/forum/archive...hp?t-3043.html

http://www.saubier.com/forum/showthr...204ruger+20221
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