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  #1  
Old 05-04-2012, 09:24 PM
Ben B
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Got rid of those 1/2 x 20 threads.....



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I had been using the commercially available 1/2 x 20 to 1/2 x 28 thread adapters to attach my Gemtech Alpine suppressor to both of my CZ452 16 inch threaded actions in 22LR and 17HMR.

With both actions and more so with the 17HMR, I was finding a great deal of residue (or just plain crud) collecting on the end of the barrel and in the space between the barrel end and the adapter after each range session. With my Sako Quad, the Alpine connects directly to the 1/2 x 28 threads of the Quad barrels and the residue blows into the suppressor with minimal collection on the barrel end. The look is also much cleaner on the Quad without the use of a thread adapter.

The total length of the "16 inch" CZ barrels when measured from the closed bolt face to the end of the barrel is actually closer to 17 1/2 inches. With the extra barrel length to work with, I had my local gunsmith cut the 1/2 x 20 threads off the end of the barrel and then recut the barrel threads to 1/2 x 28. A nice crown was also machined on the barrel end. The overall length of the barrels less the old 1/2 x 20 threaded area, is now just over 16 1/2 inches. I picked up both guns earlier this week and took them both out to the range today.

The 452 in 22LR with 1/2 x 28 threaded barrel end.






The 452 in 17 HMR with 1/2 x 28 threaded barrel end.




Both actions with the Alpine attached.






I have read a couple times that the CZ barrels have tapered bores so I was a little worried that the cut and rethread might have some effect on accuracy. With the scopes back on and the guns sighted in, I can say that the 22LR action shoots at least as well as it did before the barrel work and the 17HMR probably shoots just a bit better now than before the barrel work.

Ben

Last edited by Ben B; 05-04-2012 at 09:48 PM.
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Old 05-04-2012, 09:36 PM
PO2Hammer
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I would say 'cool stock, neat gun', etc... but I'm too envious of you guys who live in suppressor friendly states/countries.
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  #3  
Old 05-04-2012, 10:49 PM
Ben B
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Got rid of those 1/2 x 20 threads....

Quote:
Originally Posted by PO2Hammer View Post
I would say 'cool stock, neat gun', etc... but I'm too envious of you guys who live in suppressor friendly states/countries.
Yep, even here, I still had to setup a Trust for the acquisition.

Ben
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Old 05-04-2012, 11:33 PM
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Talking

Nice job. I am irritated that the 452 "American" uses European threads.
I like the 1/2 x 28 threads much better for being standard in the US.
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Old 05-08-2012, 12:07 AM
Ben B
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Did a bit of range testing with the 452 22LR...

I had the 452 22LR with the newly cut 1/2 x 28 threads and crown out to the range today. I normally shoot CCI SV in this gun, but wanted to try some SK Match at fifty yards. After a couple of pull throughs with the bore snake, I took 15 to 20 shots with the SK Match to foul the bore and sight-in for a fifty yard zero. The following target was then shot at fifty yards with a single shot to each bull.





Looks like this little 16 inch light weight is going to be a pretty good shooter!

Ben

Last edited by Ben B; 05-08-2012 at 12:24 AM.
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  #6  
Old 05-08-2012, 04:16 AM
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What's your level of satisfaction with your scope? I think I have the exact same one (Nikon Prostaff Rimfire 3x9 BDC) and I would give it a C+/B-.


.....very nice shooting BTW.
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Old 05-08-2012, 06:29 AM
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Looks to be shooting well.
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Old 05-08-2012, 07:48 AM
jim46ok
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Certainly looks like <moa @ 50 yds. That's very good. To me, the test is at 100 yds, and near 1" group. A loss in accuracy because of the cut will show at 100 yds..... Very hard to get perfect wind conditions to allow that. Great shooting!
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Old 05-08-2012, 08:05 PM
Ben B
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Quote:
Originally Posted by JimCameron View Post
What's your level of satisfaction with your scope? I think I have the exact same one (Nikon Prostaff Rimfire 3x9 BDC) and I would give it a C+/B-.


.....very nice shooting BTW.
This one is very clear and bright. Focus is sharp across the entire field of view. Almost as good as my Burris Timberline. As I remember, I paid about $150.00 for the Nikon and it beats anything else I own in that price range hands down. While the BDC reticle is nice and thin, I think it would be better if the drop down aim points were dots or hash marks vs the circles....but I knew what the reticle looked like prior to the purchase. The ballistic calculation for the reticle on Nikon's website is also nice.

Ben

Last edited by Ben B; 05-08-2012 at 08:39 PM.
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Old 05-08-2012, 09:44 PM
IsaacCarlson

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The suppressor on the laminated stock looks like it is drooping.

Have you checked to make sure it is straight?
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  #11  
Old 05-08-2012, 09:52 PM
glocker17
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So it is really a 17.5" barrel. Why does CZ call it a 16". Thats the only reason I never considered on, I thought it wouldn't have enough left to rethread.

This is good news.
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  #12  
Old 05-08-2012, 10:58 PM
Ben B
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Quote:
Originally Posted by IsaacCarlson View Post
The suppressor on the laminated stock looks like it is drooping.

Have you checked to make sure it is straight?
Perfectly straight on the gun...but I do see what you are saying when looking at the picture. The droop must be optically generated by the angle of the camera and having the suppressor close to the edge of the picture.

Last edited by Ben B; 05-08-2012 at 11:03 PM.
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  #13  
Old 05-09-2012, 07:48 PM
IsaacCarlson

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yes, the camera lens is giving the slight fish eye lens effect.
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