What Glocks have polygonal rifling?

[Archie]

I have an H&K USP40. That pistol bore is indeed polygonal in cross section, that is, the circumference of the bore is a series of flat sides.

I keep hearing about Glocks and polygonal rifling. I sit here holding the barrel of my Glock 17, gazing down the bore. It is rifled in a more or less conventional manner. The only thing non conventional being the grooves are wider than the lands. (My impression is that lands and grooves are generally equal; I could be wrong.) At any rate, this barrel is not polygonal in cross section.

My Glock is a departmental issue. I must confess to not checking many other pistols, but the two or three I have seen (all from the same manufacturing run by serial number) are conventional. I do not understand how some would be rifled and some polygonal unless the barrels were made by different sub contractors?

Or does Glock have it's own definition of "polygonal"? (Like a liberal's definition of "progress".)

Trivia question: Does anyone know about "Lancaster" rifling and why it is so odd?

 

[Robb]

All Glocks are polygonal rifled with the exception of the .45's which are octagonal.
Robb

 

[Archie]

Uh, Robb....

Your response has two flaws.

1. Mine isn't. Not even close.

2. "Octagonal" means an eight sided polygon. "Polygon" means "many sided". So "octagonal" and "polygonal" are pretty much the same thing. A polygon might be "hexagonal", six sided.
(I love geometry!)

Allow me a question or two:

Have you looked down a Glock barrel? If so, which one, specifically the model?
Too much bad information gets repeated simply because no analysis is performed.

 

[glockten]

FWIW, neither my G20 nor my G29 have polygonal rifling.

 

[Gonzo_308]

If the bbl is polygonal does it even HAVE rifling? I thought that was the point. The inside of the bbl twists but doesn't have lands and grooves.

 

[Robb]

Have you looked down a Glock barrel? If so, which one, specifically the model?

Yes, examined many Glock pistols (including the models 17, 19, 20, 21, 22, 23, 26, 27, 33).

My personal Glock 17 (first generation) had well over 20,000 rounds through it when I sold it.
I also shot the Glock 18 along with many other weapons at the FBI Academy and on Range 7 on Quantico MCCDC in the late 80's. My father was the Program Manager at Ground Weapons (the USMC Development Center for small arms ranging from 9mm to 40mm). They've since moved buildings but it was in a small building near the boat dock in Quantico town.

If you want to get really technical GLOCK, INC. calls it Hexagonal and the .45 Octagonal, their terms not mine so take that up with Gaston Glock if you don't like it. I was just trying to say yes that Glocks DO NOT have conventional rifling in as few words as possible.

Robb

 

[Ben]

All Glocks are claimed to have polygonal rifling... there are many aftermarket barrels that do NOT however. Call Glock: 770 - 432 1202

or

http://www.glock.com

Ben

 

[PreserveFreedom]

The key is, do all Glocks have polygonal rifling from the factory? They should.

 

[George Helser]

PreserveFreedom,

I have a G26. The manual says it has a hexagonal bore and it does have 6 lands/grooves. The lands/grooves look like they were made on exactly the same tooling as my 1974 S&W Model 39 9mm. Under a magnifying glass, both have identical rifling.
The S&W has traditional lands/grooves so I would say my G26 does also.

One could claim that my old S&W and my new G26 both have polygonal rifling because the rifling has more than one side. However, it is easy to see the rifling in my G26 looks
NOTHING like my HKs (P7 & Mk23) with POLYGONAL rifling. The G26 has very distinct lands/grooves. My HKs have what looks like a wavy smooth bore without distinct transitions between land and groove. Please compare yourself or tell me how to post
pictures and I will post them.

So, what is the practical difference? POLYGONAL barrels have less friction so you get higher velocity/power from this more expensive tube. When I clock the rounds from my G26, I get the velocity expected from a barrel with traditional rifling. When I clock rounds from an HK POLYGONAL barrel I get velocity greater than from a traditional barrel.

I love my G26 but it is what it is. Why do some Glock owners make ridiculous claims about their arms? Are they misinformed or insecure?

Regards,
George
In sunny Arizona

 

[Tom B]

Your poll doesn't list the correct answer! See Robbs post above.

 

[Gonzo_308]

I"m in the sad position of arguing a point against peopleand a company I don't know. If the bbl has lands and grooves it is NOT polygonal!

Regardless of what any website says! Take a micrometer and guage the damn things for your self.

A polygon, in this case a hexagon or octagon depending on caliber must have six or eight defined sides with corners at either 60 or 45 degree angles. To put lands and grooves in the bbl would defeat the purpose of having the polygonal bbl wouldn't it?

And if I'm wrong the first selection of the poll would still be a correct answer. A polygon is a multisided object regardless of the size and number of the sides.

 

[johnwill]

I just checked four Glocks, a G17, G21, G26, & G30. Anyone that thinks that is conventional rifling needs to make a quick appointment at their eye doctor.

I won't debate whether the Glock rifling is polygonal, since there seems to be multiple definitions in just a few messages. I don't have an HK to compare to, so I don't really know if the rifling is similar. I will claim that it isn't conventional cut rifling like I see in my 1911's and Browning HP pistols.

 

[TN-popo]

Unless my Factory Glock Armorer instructors (Mike Blount/Joe Leineman(?)) are wrong, Robb is exactly right. All factory barrels are polygonal, except .45.

 

[johnwill]

My .45 Glocks seem to have similar rifling to the 9mm ones, no .40's to compare. There are more "swirls" in the .45 barrel... It sure isn't conventional rifling!

 

[Archie]

Back to geometry.

Absent all the manufacturers claims, (Brylcreem said the gals would all pursue me, they didn't!) what is polygonal rifling?

From basic geometry, a polygon is a closed form with "many" sides, composed of (straight) lines. Usually, polygons are more than five sided... a pentagon.
Hexagons are six sided, Septagons are seven sided, Octagons are eight sided, and so on. In geometry all are lumped into the larger catagory of polygons. A "regular polygon" has "many" sides and all are the same length and have the same angle connecting. To say that one shape is a polygon and another is an octagon is meaningless.
We all agree that a bore must be a regular polygon? Can't have one side of the bore one size and the opposite side a different size. At least not for normal purposes.... Okay.

A normal rifled barrel does not meet the geometry definition because the many sides are composed of arcs, or curved lines.

I went to the Glock webpage and read their statement that all their pistols have polygonal rifling. The instruction booklet with my G17 says the 17's bore has six surfaces, and the 45 models have eight surfaces. So, hexagons and octagons... The use of the term "surface" implies a polygon, but the booklet does not use the term polygon.

However, as I mentioned, my G17 has conventional rifling. Lands and grooves. The markings on the barrel match the markings on the rest of the gun. I was issued the pistol in the original case with factory papers and such. Unless the department replaced the barrels with aftermarket barrels and matched the serial number marks with EXACTLY the same style stamps (everyone agree that would be odd?), this is a Glock barrel.
This barrel has lands and grooves.

Now. Robb seems to be adequately qualified to differentiate lands and grooves from polygonal cross section. His G17 (identified as first generation, maybe something in that) has polygonal rifling. Not going to question that further. Robb, pray accept my apology for any implied or inferred insult.

(My Glock was issued to me this year, 2001. Presumably manufactured recently.)

Mr. Helser's observations seem to agree with mine. His Glock has lands and grooves identical to a Smith & Wesson he has. Mr. Helser has a couple of H&K's with polygonal rifling and they are substantially different in appearance. I won't question that observation further, either.
Just for the record, George: Have those barrels been replaced?

I have a USP40 with polygonal rifling. The interior of the bore has eight distinct sides and no grooves in the traditional sense. Absolutely not the same type as my Glock.

Johnwill reports finding four different models with polygonal rifling. Or at least, not conventional rifling.

Factory trained Armorers will repeat what the Factory trainer told them. Moreover, the type of rifling used is immaterial to the normal work an armorer does. Unless they look down a bore, their testimony is hearsay. This is not a judgement of their ability, just an objection to this particular bit of testimony. It is already established that Glock claims polygonal rifling.

So...
Could it be that Glocks originally were polygonal, and have changed along the way, without comment?

Could it be that Glock subcontracts barrels? Some are made one way, some another?

I think the possiblity of a mis-definition has been ruled out. Competent observers report finding polygonal rifling. To believe that all Glocks have polygonal rifling is also impossible.

I've thought about contacting the factory, but my email is not cooperating right now.

I am really curious. I will confess this question will not keep me up at night, nor is SA Fox Mulder working on it, but I am curious. Any other thoughts?

 

[ether]

How about this....

The first Glock 17 barrels were made using standard rifling. Glock later started using polygonal rifling in all their barrels. The .45's are octagonal, and the rest are hexagonal.

 

[Halo]

I have a Glock 17, 26, and a HK USP9. All of them have the same style of rifling, and all are noticeably different from the rifling in my SIG P220. I always assumed polygonal rifling referred to the shape of the lands, contrasting with the sharp-shoulder type of lands seen in a conventional barrel. If the Glock doesn't have polygonal rifling, I don't know what it is then, but mine are definitely distinguishable from conventional rifling.

 

[Ruben Nasser]

Glock barrels ARE NOT polygonal. HK barrels do have a "true" rounded polygonal cross section that twists. OTOH, Glock barrels don't have conventional rifling either. They are made by the cold hammering method (...easy to see because of the mirror finish, and because this shape of bore can not be cut normally), and have a round cross section with rounded lands and very wide grooves, 8 grooves in 45, 6 in all other calibers. I think they use the term "polygonal" to diferentiate from normal barrels, and they do claim the same advantages of a "true" polygon barrel: better sealing, more velocity, less wear. They have the same disadvantage as well: their rounded profile doesn't grab ead bullets very well and thus leading occurs very easily. You can shoot lead bullets with good results, but have to clean often.

 

[George Helser]

Archie,

For the record, the barrels in my pistols are all original. I bought them all new. The HK manuals state the arms have a polygonal barrel and the Glock manual states the G26 has a hexagonal manual. The manuals agree with my observations.

Maybe some pictures in this thread would go a long ways to clearing up this confusion!

Regards,
George
In sunny Arizona