Evaluating Polygonal Rifling

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ccoyle

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Hello, folks. I would appreciate some advice on how to assess barrel wear in a polygonally rifled barrel, such as on a CZ 82 9x18. I understand that such barrels do not have the usual lands and grooves, but when I look down the barrel, what should I be able to see or not see? Would using a bore light make the subtle variations in contour more visible?

Thanks in advance.
 
When I look down the muzzle of mine in not too strong of light, at about 45 degrees I can see 'lands', but they are very faint. It helps a lot if just a bit of copper/lead fouling is on them. Looking from the breech end it looks almost perfectly smooth with some distortion, and the very highly polished bore does not help.

I recall years ago reading some folks received military CZ-82's with conventional rifling, because the importer thought they were shot out, and refitted new barrels... Can't remember if they were in 9x18 or .380. I don't think any .380/.32 ACP CZ82/CZ83 had chrome lined bores, and none were poly other than military CZ82's in 9x18.

If you purchase it, I might suggest you buy a new recoil spring set from Wolff. They used to sell a std and extra power spring set, but looks like you have to buy a three spring set now. Great all steel handguns with great CZ ergonomics.

https://www.gunsprings.com/CZ/82 & 83/cID1/mID16/dID92

Good luck.
 
I tried to find a decent photo for you but it seems my Google-Fu is failing me. What you should see is what would appear to be spiraling with very small hills and valleys which would be the rifling.

Here is a shot I found of a CZ82 barrel but the photo isn’t all that great.

B0505AF3-43B5-4D71-B694-A4C7DE88CABC.jpeg
 
You really can't "evaluate" wear on rifling visually - polygonal or otherwise. I wouldn't worry about it unless you can see something really out of spec in the bore or the accuracy from a machine rest is terrible. If you can take it to a range and hand it to someone who is a very accomplished shooter you can get an idea of the condition of the barrel with ammo that is in spec for that caliber.
 
Buddy the first time I saw a CZ83 in 9mm Makarov I thought someone ran a drill bit through it and took out all the rifling.
 
Buddy the first time I saw a CZ83 in 9mm Makarov I thought someone ran a drill bit through it and took out all the rifling.

Ha-Ha...JONWILL, I thought the same thing regarding my first Glock. I didn’t know they had polygonal rifling when I bought it.
 
Broached rifling makes the bullet rotate. Polygonal rifling kind of "suggests" that it do so. It HAD to be invented by the French.......

Have you ever recovered a bullet shot through polygonal rifling?
 
It is all but impossible to wear out the rifling of a pistol barrel. Quit worrying about it.

Given that there are numerous examples of Glocks that have gone well past the 100K mark, I think that you are right. Heck, Glock even has a range rental specimen that has run through somewhere north of 300K yet is still able to group within 3'' at 25m. Chuck Taylor ran more than 270,000 rounds through his personally owned 17; See Combat Handguns, Feb. 2011.
 
" it is all but impossible to wear out the rifling of a pistol barrel..." Except in the case of military surplus pistols from Third World countries where the armorers repeated slam the bore onto a steel rod in racks in the Armory. When buying those pistols you REALLY need to see it first. I have seen some amazing examples of trashed barrels and breechfaces from steel rods in a rack. But I get your point, wearing out a bore from shooting bullets through it is all but impossible. Unless it was made during the War for Independence.
 
Have you ever recovered a bullet shot through polygonal rifling?
I have only owned one gun with polygonal rifling and yes I have seen recovered bullets from it. But they were all .44 Spl. handloads running at maybe 850 fps. I have not examined one fired at 1200 fps. I personally feel that at handgun range (less than 25 yards) the type of rifling used is not really crucial to hitting a target (excluding long range slihouette shooting) I only shoot cast lead bullets and I just prefer cut/broached rifling. A lot of people say that I am weird though.
 
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The bullets I have recovered shot through polygonal rifling show enough conformation to the shape of the rifling that I don't think it's doing "suggestion" any more than land-and-groove rifling is. The bullet doesn't have any choice but to rotate along the rifling... there's no room for it to do something else.
 
Have you ever recovered a bullet shot through polygonal rifling?

Just recently did that; bullets from Walthers PPQ 45acp shot in mulch out back; could hardly see any marks at all....on some bullets, none, on another, one or two very faint. Dang thing shoots accurate tho, and is easy to clean after shooting my lead reloads.
 
Point isn't "marks." It's not cutting into the projectile - it's squishing the projectile into a shape that conforms to the barrel. If the number of flats is even, you should be able to detect this pretty easily with calipers. If not, rolling it across a flat reference surface may make it very clear.
 
Here is a shot I found of a CZ82 barrel but the photo isn’t all that great.

Thank you. I'm not an expert by any stretch on examining used guns prior to purchase, but I do like to take a peek down the bore to see if everything looks okay, and like some of the comments have suggested, when I looked down the bore of a CZ 82 and saw what appeared to be, well, nothing, I first thought that there might be something amiss. It did essentially look like a smooth-bore, and I thought there must certainly be a hint of some rifling to see. Mind you, I had heard of and read about polygonal rifling, but I had never seen it before, so it was a new experience. So, thanks for the info and the discussion -- I now feel more confident should I ever decide to plunk down my cash for such a firearm.
 
The bullets I have recovered shot through polygonal rifling show enough conformation to the shape of the rifling that I don't think it's doing "suggestion" any more than land-and-groove rifling is. The bullet doesn't have any choice but to rotate along the rifling... there's no room for it to do something else.
I’ve got two 9mms and one 45acp with polygonal rifling. I’ve recovered bullets from all three. I agree, polygonal rifling seems to be a very positive engagement between bullets and rifling and considering the accuracy of all three, I have to assume it does a fine job of stabilizing projectiles, at least at pistol velocities.

It’s really easy to clean also.
 
As mentioned here, and I agree, they sure clean up easily... And I have never seen a barrel with less tendency to lead in the first place, than my CZ82 with 95 gr LRN... And they are PLENTY accurate to boot. Nice bonus it seems too, is that poly barrels seem to give higher velocities for a given length and same ammo... Whole lotta plusses to me, even if the bore looks goofy, and fired bullet shanks kinda weird :).
 
The bullets I have recovered shot through polygonal rifling show enough conformation to the shape of the rifling that I don't think it's doing "suggestion" any more than land-and-groove rifling is. The bullet doesn't have any choice but to rotate along the rifling... there's no room for it to do something else.

More important than what the recovered slog looks like is the accuracy of the firearm. I've owned a number of poly rifled guns, to include Glock, HK, and both full size & baby Desert Eagles. None of them had problems stabilizing bullets and producing good accuracy. The most accurate handgun I own other than the full size Desert Eagles is my Tanfoglio Witness Limited 10mm, which is also poly rifled.
 
The most accurate handgun I own... is my Tanfoglio Witness Limited 10mm, which is also poly rifled.

Same here, with the possible exception of one of my S&W revolvers. No problem stabilizing even heavy 220-grain bullets, eats jacketed, plated, and coated without complaint, etc.
 
Glad someone like MachIVshooter came along to say accuracy is what matters.

Several people who rebuild and/or maintain a lot of guns for orgs that actually gauge find pretty marginal relationships between wear and accuracy. Sure, at a certain point the wear induces danger or reduced efficiency, but these are really, really worn out guns generally so the barrel is not the worst of the problems really. Shoot it. If accurate: keep shooting it.

For a handgun, I'd never consider the barrel to be truly a wear item. You'll replace a dozen sets of springs, half a dozen extractors, and the frame before the barrel wears out.
 
For a handgun, I'd never consider the barrel to be truly a wear item. You'll replace a dozen sets of springs, half a dozen extractors, and the frame before the barrel wears out.

Barrels are a wear item for some competitive shooters, but they generally only get replaced once or twice before the slide is replaced, and frame life may be at an end about that same point. They will generally start to lose a little velocity as well as a touch of accuracy as the bore gets opened up.... but we're talking 10's of thousands of rounds. For service-grade guns, the hassle of refitting/replacing the barrel and all the other stuff that will be due for replacement at the same time (your Xth replacement of all springs, etc.) plus increased slop in the rails/slide-frame fit, etc., means it's usually more sensible to just replace the gun. For someone who has $5k in the gun, spending $500 to replace the barrel may be very sensible.
 
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