[wbond]

Which 9mms have polygonal bores? I like polygonal bores.

I know that Glock and Kahr do. What others?

===================================

Note: My original message was the above.

Due to various questions and comments, I'm adding a little more detail below to explain my interest:

===================================

Polygonal bores allegedly give about 40 fps more velocity from same ammo than land and groove. That's important for my anemic 9x18s. The CZ-83 9x18 has chrome plated polygonal bore. Nice.

As for accuracy, I'm not sure that matters. However, I can say my CZ-83 9x18 is amazingly accurate, even at distances you'd never think of using that small a gun at. My CZ-83 9x18 is my only polygonal and it's also my most accurate gun. Coincidence? Don't know.

Polygonal bores last longer too. That's an accepted fact. The greater velocity is considered accepted fact by some and rumor by others. I don't know for sure about the velocity claims. As for accuracy, I don't know if it's more accurate, but I know mine is very accurate.

Lastly, I also like chrome plated bores. Since polygonal bores have less surface area (i.e. - they're smoother) they are easier to chrome plate. There is nothing nicer than a chrome plated polygonal bore, in my opinion. A stainless steel polygonal poor would be nicer yet, but I don't know if that exists.

My CZ-83 9x18 is both polygonal and chrome plated. I love it. The chrome plating makes it very easy to see if it's dirty and prevents rust (wet climate).

Since my CZ-83 9x18 polygonal is my favorite, I figure I'd like to try a 9mm Para with polygonal.

Anyone know which 9mm Para polygonal bore guns are chrome plated-lined inside? Are there any stainless steel polygonal bore guns?

[Ohen Cepel]

I think Hk's do also.

Never gave it much thought.

Beretta's don't, at least not the models I'm familar with.

Why the fascination?

[usp9]

Some CZ models also.

[Jeff Timm]

The Kahrs do, but the economy models have conventional rifling.

Geoff
Who has a KP9094N. :D

[Grayrider]

Some Tanfoglio/EAA models, older Baby Eagles.

GR

[Zero_DgZ]

Lookin' down the bore of a Beretta PX4 and it looks polygonal to me. Gonna have to check the official specs.

Glocks are, too, aren't they?

[Highland Ranger]

Why the fascination?

Issues with lead rounds no?

[Walt Sherrill]

The ONLY czech-made CZs with polygonal barrels are the CZ-83s (and then only in 9x18, I think) which aren't being imported, right now. None of the 9mm CZ have ever used polygonal barrels, that I'm aware of -- even the CZ-100.

There are several guns with "CZ" in their names (made in Italy, made in Yugoslavia, etc. Some of them might have done polygonal barrels, but I don't think so.)

Some of the Magnum Research Baby Eagle guns did do polygonal during the late 90's, but they now seem to be using conventional land/groove barrels.

Glock and H&K are the main one, now.

Most folks, including handloaders, prefer to avoid polygonal barrels.

[backlash]

Are all the H&K's polygonal?

[candr44]

My CZ-75 compact has a polygonal bore and is very accurate. The CZ-82 in 9x18 also has a polygonal bore and is being imported and sold at s.o.g.

[gudel]

my HK USP 9 has polygonal bore.

[Troy26]

DISCLAIMER...I'm about to sound like an idiot.

What's the difference between teh polygonal and conventional type?

[Braden]

Glad I'm not the only idiot. ;)

What he said. What's the difference?

[Highland Ranger]

From Wikipedia (http://en.wikipedia.org/wiki/Polygonal_rifling):

Polygonal rifling is a relatively new type of rifling wherein the traditional lands and grooves are replaced instead by "hills and valleys" in a polygonal pattern, usually a hexagon. This has many advantages over the traditional form of rifling, in that it deforms the bullet less while also sealing the gas slightly better, resulting in a slightly higher muzzle velocity in most cases. Because the bullet is less deformed, it provides less surface area for the wind to push against and thus it is more accurate at long range. Also, as a result of the fewer sharp edges pushing against the bullet, the barrel life is extended compared to that of a traditionally rifled barrel.

This type of rifling, however, has drawn criticism from various law enforcement agencies because, unlike the deformations traditional rifling leave on a bullet, deformations left on a bullet by polygonal rifling cannot be used to identify which gun fired the round. As a result, many of these agencies forbid the use of polygonal rifling so that shots fired by the officers may be identified as such.

Another disadvantage to polygonal rifling is that firing lead bullets through the barrel results in an accumulation of lead — a phenomenon known as "leading", that can lead to poor accuracy or even barrel failure.

The most notable manufacturer to create barrels with polygonal rifling is GLOCK, though there are others that manufacture them as well, such as Kahr arms and Heckler and Koch.

[Highland Ranger]

another link: http://www.firearmsid.com/A_bulletIDrifling.htm

[Seven High]

I do not understand why a firearm manufacturer would use polygonal rifling as opposed to conventional. If Barsto can produce a conventionally rifled and fully supported chamber barrel for Glocks, then Glock should also, if for no other reason than civil liability.

[Walt Sherrill]

As I understand it -- but this may be incorrect -- polygonal barrels are very effective for a given diameter, but are less expensive to manufacture. Then too, the vast majority of handgun shooters buying new service pistols probably DON'T shoot lead. So a lower-cost alternative which does not suffer performance degradation, is arguably a good business decision.

One acquaintance, a master level (professional) shooter uses lead in his Glocks -- losts of rounds -- without problems. He says the secret is sizing the bullet to the barrel, as some barrels have overlarge dimensions -- and that extra space allows more hot gases to hit the lead and that causes leading.

[gudel]

I do not understand why a firearm manufacturer would use polygonal rifling as opposed to conventional. If Barsto can produce a conventionally rifled and fully supported chamber barrel for Glocks, then Glock should also, if for no other reason than civil liability.

I don't understand how a design that is almost a century old, still have problems either. :rolleyes: After several manufacturers trying to improve it, you would think by now they would have worked out the kinks! What's up with that?

This glock unsupported chamber is much ado about nothing perpetuated by certain individual for his own interest. How come my Glock 22 didn't blow up on me? Explain this!

Back to original topic, All my HK's have polybore, including my new P2000.

[SnakeEater]

I like the fact that polygonal rifling gives better velocity than standard rifling.

[Walt Sherrill]

Candr44 wrote:My CZ-75 compact has a polygonal bore and is very accurate. The CZ-82 in 9x18 also has a polygonal bore and is being imported and sold at s.o.g.You have a truly unique CZ-75 Compact.

I've had several Compacts and have one now. None of the ones I've seen (or ever heard of) had a polygonal barrel. Be sure to let CZ know about it.

I've been a moderator on the CZ-Forum (5400+ member as of today) for a number of years, now, and we have many "Compact" owners on the CZ Forum -- but yours will be the first one anyone has encountered or mentioned. It might have some collector value if its a "factory-made" barrel; its certainly unusual.

(The CZ-82, on the other hand, is essentially the same gun as the CZ-83, created for military use. The 83 is the only polygonal I've encountered, but it makes sense that there are 82s made the same way -- '82 being the year of introduction.)

[atblis]

not sure that's really true. I've heard it said before.

CZ barrels are hammer forged, but they are not polygonal (from what I've seen).

I suspect Steyr might use polygonal rifling.

[default]

As I understand it, all GLOCKs, and HK USPs after November '94 do. The manufacturers pitch it as a high-tech barrel-rifling technique that seals the gases behind the bullet in the barrel more fully and produces higher velocities and better accuracy in a given barrel length than conventional rifling. Their detractors claim it is cost-saving measure. I suppose there may be a grain of truth to both positions. I recall that when I bought my USP (I was pretty technically ignorant at the time - probably still am, but improving), I thought, "Wow...polygonal rifling. This is the pistol of the future. To the hovercar!" :D Needless to say, I had no real idea of the difference, and I still don't know if the claims of "better seal", etc., are true, or what kind of savings there are from manufacturing barrels with polygonal rifling.

From a practical perspective, lead bullets are generally not recommended in polygonally-rifled barrels due to accelerated lead build-up and potential resultant overpressure problems. As for myself, I find them quicker to scrub clean than the conventionally-rifled barrel in my 1911, although that may have nothing to do with the rifling. :)

[Highland Ranger]

I have found the same things with respect to my USPs and 1911's - maybe it make a difference.

[blackpanther]

my HK USP 9 has polygonal bore.
Pre 93 has conventional hammer forged.

Ed

[candr44]

Walt, my CZ-75 compact is original. the barrel is stamped with the same serial number as the frame [ #D88xx] and it is definately polygonal. It is a dual tone that I bought from a retired fl. state trooper. It was obviously carried alot but not fired much.

[Walt Sherrill]

I wasn't being a smart-$$$ when I wrote what I did. Yours is the first 75 (in any form) that I've ever heard of with a polygonal barrel. Period. And I've been moderating on the CZ Forum for years. That's very, very unusual -- and I don't know of another like it anywhere.

Two tones are also rare -- but seen from time to time.

And its really rare to find one that has been used by a police department, anywhere (perhaps only off duty), because unless its a Compact D (also called the PCR), its got a safety, and most police departments like decockers. If its got a decocker, its a model more commonly called a 75 Compact D or PCR (Police of the Czech Republic).

Some factory one-of-a-kind guns get loose from time to time. Maybe you got one of those.

[Joe D]

Gosh, does this mean I have to stop shooting lead bullets in my Glocks?

[Walt Sherrill]

One acquaintance, a shooting instructor and Master-level IPSC/USPSA shooter, shoots a lot of Glocks, and shoots a lot of lead. He says the secret is properly sizing the bullet to the barrel. He never has problems with leading.

[rageofangels]

DISCLAIMER...I'm about to sound like an idiot.

What's the difference between teh polygonal and conventional type?


I didn't know either.

[atblis]

CZ was selling the 6" machine pistol barrels weren't they? I wouldn't be surprised if those were hammer forged polygonal barrels to help cope with the extra wear. Conceivably, one of those could have ended up in a pistol

[candr44]

Walt, I didn't think you were trying to be a smart a$$. Sorry if you took any offense. I really don't know the history of this pistol other than what I know about the person who sold it and that it was obviously carried alot. To tell you the truth I don't care if it is rare, or original, polygonal or conventional rifeling, or it's history. All that matters to me is I like this gun and that it's accurate and reliable. It has made a cz fan out of me along with my cz 83.

[hksw]

Quote:
Originally Posted by gudel
my HK USP 9 has polygonal bore.

Pre 93 has conventional hammer forged.

Ed

Hammer forging does not mean polygonal rifling. It is merely one of a number of processes to produce rifling into a bore. Conventional rifling can be produced with hammer forging.

Here are the general configurations of the bore cross section of some types of rifling.

http://www.thehighroad.org/attachment.php?attachmentid=35947&d=1140630313

[usp9]

Thanks, that is a great post. May I ask where the diagram came from. If it is a web, what is the web address?

[Walt Sherrill]

Walt, I didn't think you were trying to be a smart a$$. Sorry if you took any offense.Nope, no offense taken -- and given, I hope.

My second message, after having reread my first response, was an attempt to NOT come across as a smart-a$$. It was a serious observation.

CZs with polygonal barrel are about as common as SIGs or S&Ws with polygonal barrels.

[hksw]

During my luch hour, upon reading this thread up to my initial post, I drew the diagram using MS Paint. Didn't take long.

[wbond]

I think Hk's do also. Never gave it much thought. Beretta's don't, at least not the models I'm familar with. Why the fascination?
Polygonal bores allegedly give about 40 fps more velocity from same ammo than land and groove. That's important for my anemic 9x18s. The CZ-83 9x18 has chrome plated polygonal bore. Nice.

As for accuracy, I'm not sure that matters. However, I can say my CZ-83 9x18 is amazingly accurate, even at distances you'd never think of using that small a gun at. My CZ-83 9x18 is my only polygonal and it's also my most accurate gun. Coincidence? Don't know.

Polygonal bores last longer too. That's an accepted fact. The greater velocity is considered accepted fact by some and rumor by others. I don't know for sure about the velocity claims. As for accuracy, I don't know if it's more accurate, but I know mine is very accurate.

My CZ-83 9x18 is both polygonal and chrome plated. I love it. The chrome plating makes it very easy to see if it's dirty and prevents rust (wet climate). Poly + Chrome = Nice

Since my CZ-83 9x18 polygonal is my favorite, I figure I'd like to try a 9mm Para with polygonal.

Anyone know which 9mm Para polygonal bore guns are chrome plated-lined inside? Are there any stainless steel polygonal bore guns?

[wbond]

I just read a fellow's post about using lead bullets in his Glock.

I'm not a gun expert, but I know that is Verbotin!

I just took an NRA basic handgun and concealed carry class required by State of Oregon to get my concealed carry license. The NRA teaches this course.

Great 4 hour class. 2 hours of book learning and demos. 2 hours of shooting instruction and live fire. Awesome for $35. I wish my home State of Washington offered a similar class. The coverage of laws related to OR state laws about concealed carry and self defense were really helpful.

The two NRA instructors both warned that lead bullets are forbidden in polygonal rifled bores.

They said at a range where these guys are range masters, a local cop was shooting his Glock with lead target rounds. His gun blew up in his hand and he had to go to hospital for serious hand burns. He kept is eyes due to required shooting glasses.

The gun was blown in half with grip being one piece and slide and upper being other piece. We were shown a photo of another Glock that same thing happened to at another shooting range.

The instructors said the moral of the story is DO NOT use lead bullets in a polygonal bore. If you have been doing this, clean your barrel with a good lead removal chemical followed by a good powder removal chemical. Then have your gun inspected closely by a gunsmith or by the company that makes it. Then STOP shooting lead bullets in your polygonal.

Those NRA instructors apparently say all this stuff at every class, but made a big point of it at this class because I have a polygonal CZ-83 9x18 and another two people had Glocks.

Lead Bullets + Polygonal Bore = Potential Big Trouble

However, if you stick to copper jacketed or steel jacketed copper washed bullets, then polygonal bore is superior. If it's cheaper to manufacture polygonal bores, then that's another good point in favor of polygonal.

For 9x18 ammo, polygonal bores are especially helpful because polygonal can stand up to steel jacketed bullets better than land and groove. Since steel jacketed 9x18 is common, polygonal is extra helpful to 9x18 owners.

Polygonal bores are awesome, if you don't shoot lead bullets. I don't want to shoot messy lead bullets anyway. So for me, polygonal is best.

[wbond]

Polygonal barrels are superior in many ways, have one weakness. They don't like lead bullets. Using lead bullets in a polygonal is proven dangerous and the manufacturers of polygonal strongly warn against it. Glock specifically warns against it because Glocks have blown up from the practice in the past. Don't use lead bullets in a Polygonal. That's asking to be called lefty.

The NRA, or at least the two NRA instructors who taught my class, strongly warn against lead bullets in a polygonal barrel.

Your friend is playing with fire. Based on what you said, so far he has the expertise to flirt with disaster and get away with it, but the general public should NOT shoot lead bullets in a polygonal barrel. Period.

As I understand it -- but this may be incorrect -- polygonal barrels are very effective for a given diameter, but are less expensive to manufacture. Then too, the vast majority of handgun shooters buying new service pistols probably DON'T shoot lead. So a lower-cost alternative which does not suffer performance degradation, is arguably a good business decision.

One acquaintance, a master level (professional) shooter uses lead in his Glocks -- losts of rounds -- without problems. He says the secret is sizing the bullet to the barrel, as some barrels have overlarge dimensions -- and that extra space allows more hot gases to hit the lead and that causes leading.