CZ 527 in 7.62x39

[stolivar]

here is mine after sighting in. with WPA 124grain SP

the yellow tags are from my 22 that I could not get to work.

I sighted in after about 6 shots, it was so low when I put the scope on. this is sighted in with 2 inches high and will put me with about 4.5 inches low at 225 yards.

 

[Hunter2678]

Received mine finally yesterday, got lucky with some better than avg wood also. I had the DIP rail ordered a while back and highly recommend it as its a nice fit. Mounted a Weaver 4x38 on it along with some low weaver tactical rings. It required me to tap out the rear sight blade but that was easy to do. Broke it in yesterday and was hitting baseball sized rocks at 200 with regularity using tula 123 gn FMJ. This gun will need bedded IMO as its got a bit too much fore end flex for my tastes but overall a great little gun that fed flawlessly. Should shoot even better once done. Ill keep researching on threading it seems there might be some light at the end of this tunnel after all. Appreciate the information fellas.

 

[Erno86]

I believe my 527 is free floated al the way to the front of the receiver, though I haven't done the dollar bill test to check if it's all the way free floated. The bolt feels kind of stiff, though I heard it will work itself in over time. It's better to have a stiff bolt than a wobbly one.

 

[tobnpr]

Lilja shows what they call a factory reproduction having a muzzle diameter of .570. Your closest thread size that I can think of is a 9/16X24. That allows a major diameter of .5625 minus a couple of thousandths, assuming your barrel was cut concentric enough that it cleans up in only .0075" when indicated to your bore. That has a minor diameter of something like .520 which should give you roughly .105" thickness per side around your bore and if I'm remembering correctly (off the top of my head) .100" is considered a safe working thickness. I don't know what would happen to the harmonics with having the big heavy muzzle brake at the end of the long, skinny barrel. You won't be able to have it turned to match your barrel diameter as they do on heavier tapers.

It's not just barrel wall thickness (I do thread .30 cal military barrels in 9/16"- the FAL has been done that way for decades) but I would not do 1/2"...

What you failed to consider is the barrel shoulder. With a .570 OD (your spec), and a major of roughly .560, that leaves only ten thousandths barrel shoulder- five thou around the diameter. Suppressors and brakes are different animals anyway- but as an example, Silencerco requires a minimum .657 barrel diameter in their 9/16" threading specs:

https://s3.amazonaws.com/com.silencerco/support/thread-specs/rifle_thread_specs.PDF

One hundred thou (fifty around the diameter) larger than the major diameter is a general rule of thumb for suppressors. Often less is used- but it's important to have a substantial torque shoulder at exactly 90 degrees to the bore so the length/weight of the can isn't relying on the threads to hold it concentric to the bore.

At the end of the day it all boils down to clearances- baffle clearance, length of the can, all factor into being certain the can doesn't end up downrange or worse, bodily injury.

 

[dakota.potts]

Thanks tobnpr, that will be a good thing to keep in mind going forward. That would seem to make things more difficult

 

[Hunter2678]

I believe my 527 is free floated al the way to the front of the receiver, though I haven't done the dollar bill test to check if it's all the way free floated. The bolt feels kind of stiff, though I heard it will work itself in over time. It's better to have a stiff bolt than a wobbly one.

My barrel is free floated down to the rear sight band. I took the gun out of the stock last night and discovered that the bottom of the recoil lug had been bedded from the factory and the front action screw isn't pillared like the rear . Seems to be backwards IMO. Im still going to reinforce the rear tang and lug area with some devcon steel putty to make sure it doesn't gradually shift. My bolt moves effortlessly but I might hand polish the bolt body someday if I get bored just to get it super slick.

 

[jackstrawIII]

Just took delivery of my new 527 in 7.62x39 and it's a great gun. Went to clean the barrel, but I couldn't get my .30 cal cleaning jag to fit through the barrel... nor my .270 cal for that matter.

I ended up using the .243 jag to clean and season the barrel, and it was still difficult to force through the barrel. Is this normal??

It fired just fine, but I have no idea why I can't get the right sized jag through.

 

[Erno86]

You'll find that if you offset the cleaning patch on the jag, will make for easier sailing. Any undersized jag might need finger guidance help at the muzzle, so it doesn't hurt the crown when you reverse the rod. I use a 223 cleaning rod for patch work, and a 30 caliber rod for brush work.

I like my 527, in 7.62x39, that I just purchased last month, though the earlier models had more beautiful Turkish Walnut; but my stock ain't so bad either. It still feels wippy in my hands for offhand steel target fun, and the Mauser bolt likes to be worked vigorously.

 

[jackstrawIII]

I too was pleasantly surprised by the quality and figure in the wood. To find a rifle at this price with real Walnut was great in and of itself, but the nice figure is a huge bonus.