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CZ Utility Rifle 204 Short Chambered.
Long Winded Warning. I started with a CZ American 204. Removed the CZ stock and replaced it with a Richards Microfit straightline thumbhole in economy black walnut. I wanted to cut the weight everyplace I could without doing the unthinkable. [Plactic Stock.] "My choice" The original piece of wood they sent me weighed 3lb & 4oz with a 2&1/2" wide forearm. I cut the length more of a carbine length. About one inch shorter than the factory stock. I like a short buttstock, so I cut the original butt pad off drilled two 7/8 inch holes in the butt about 6" in depth for weight reduction and replaced the buttpad. I kept the 2 & 1/2" varmint width on the forearm but trimmed it all I thought I dare. The final stock configuration weighs 2lb & 2oz. [ about 2 oz less than a CZ stock.]I pulled the barrel and cut the chamber end about 0.230 and run a chucking reamer in the neck 0.100 depth to get that much closer to the riflings. I did not check this exactly since I was only interested in cutting the chamber to exactly the same dimensions as my 20 Bulldog CZ Varmint. In order to do this I first set the headspace with a case from the other rifle and intensionaly left the outside of the barrel a few thousands long, to be cut exact later. I wanted to use the same 223 brass and maybe even the same loads. I then cut the barrel length to 19" and recrowned it to a 90 degree recessed. I installed the barrel back on the action. I then made a unigauge for checking headspace. I did this with a piece of aluminum cut just slightly smaller than the chamber with the end designed to contact the chamber 1/2 way up the shoulder. The other end of the gauge is threaded for a long set screw and then another piece the size of the cartridge head threaded and screwed onto the other end of the set screw. I then put this gauge into my original chamber and adjusted it to the exact length. I then measured the exact length of the gauge. I then did the same to the new chamber. I then knew I needed to remove 0.0074 from the outer ring which would give me the exact length pluss one thousands to be gained when tightening the barrel into the action. I worked up a load that shot around 3/4" at 100yd while this rifle was a 204 Ruger just so I had something to compare it to after the rechamber and barrel shortening. I fired it and my other 20 Bulldog yesterday. I first worked the new rifle up to my leftover prairie dog loads. Set the Redfield Illuminator BDC 3 to 9 scope in for 1& 1/2" high at 100 which should make me close at 200yd. I set the crono up and the info on the box of loads said 39gr Sierra BK @ 3700fps. I got an average reading with the new short barrel right at 3500fps. I then shot from the same box with the 26" varmint barrel and it was reading right at 3600fps. I shot these before in warmer weather. May be the cause for slower readings. I was surprised there was not more velicity loss with the barrel 7 inches shorter. As far as accuracy these loads grouped a little better than my 204 loads before the remodeling. I did put pillars in the stock but have not bedded it as of yet. I think it only appropriate I call her Shorty. Kenny
IMG]http://i32.tinypic.com/11j56x5.jpg[/IMG]
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sicero I pride myself in being able to make decisions with little information. Last edited by sicero; 02-10-2008 at 07:44 PM. |
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pictures??????????????????????????????????????
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I post here because it keeps the riffraff away. 'Life's Journey is not to arrive at the grave safely in a well preserved body, but rather to skid in sideways, totally worn out, shouting, Holy sh!t... What a Ride! |
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20 Bulldog
Hi Kenny,
Hey, I really enjoyed your write up on the CZ 20 Bulldog. Found it really interesting. I sure envy you being able to operate a lathe and chamber barrels. I have a shooting friend that has all the equipment to do the work, but he's very new to shooting, reloading etc. Afraid neither one of us would know where to start. tx al |
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Al, Something like the short chambered 204 lends itself to beginners. It might sound like a lot of work and I guess it is but each part of it is simple. As far as machinist goes I am a HH. [ hobby-hacker or Ha-Ha ] To have a gunsmith do this to the rifle and the reloading dies would be more costly than rechambering with a better reamer back to 204, Tac 20, Bobcat or Duster. Kenny
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sicero I pride myself in being able to make decisions with little information. |
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