Polygonal - What's The Point?

[Bill K]

So, reading here and on a number of other gun forums there seems to me a consensus that polygonal "rifling" doesn't amount to a dimes worth of difference in a handgun shot @ SD distances. Yet Kahr, Glock and several other manufactures offer handguns with or come standard with polygonal barrels. So what is the point? Why do they even bother?

Thanks,
Bill K.

[jocko]

I think prestige of a top quality barrel but ur rigfht at SD distance, proably no rifleing will suffice. the TRaurus Judge has oh so slight rifling in it just enough to quality it as a rifle barrel but it seems to shoot 45 long colts OK. that gun was meant to shoot shotshells and nothing else but to get around the law, they had to rifle that barrel, ..

[Bawanna]

Polygonal rifling (pronounced /pəˈlɪɡənəl/, US dict: pə·lĭg′·ə·nəl) is a type of gun barrel rifling wherein the traditional lands and grooves are replaced by "hills and valleys" in a rounded polygonal pattern, usually a hexagon or octagon.

Polygons with a larger number of edges provide a better gas seal in relatively large diameter polygonally rifled bores. In the Glock pistol, for instance, octagonal rifling is used in the large diameter .45 ACP bore, which has a 11.23 mm (0.442 in) diameter, since it resembles a circle more closely than the hexagonal rifling used in smaller diameter bores.

[Bawanna]

http://en.wikipedia.org/wiki/Polygonal_rifling

This link relates alot of the history, pros and cons to polygonal rifling. Some good information there to start with.

[ripley16]

Lasts longer, easier to clean, and some produce higher velocity... all good things.

[jocko]

I've got 31000+ rounds to prove longer lasting and easier to clean.in my trusty PM9, so u-all put that in ur pipe and smoke it!!

[Willieboy]

Golly Bawanna, you're quite cerebral this evening.

[kpm9]

Forensically, it is apparently harder to get a match from a bullet that traveled through a polygonal bore, than one that traveled through a rifled bore with std land and grooves.

Believe it, or don't.

[CJB]

I'm not convinced on the wear claim, for the following reason -

Take a look at the Kahr barrel's innards. It looks like rounded off lands. Thats the hills and valleys. So lets suppose you get a traditionally rifled bore, and shoot the piss out of it. Lets say it wears out all those fine edges. What are you left with? Rounded off hills and valleys......

I think you'd be hard pressed to say that either would remain accurate longer than the other. You might SEE wear in the traditionally rifled barrel, but would it actually effect performance?

[Bawanna]

Golly Bawanna, you're quite cerebral this evening.

Why thank you Willie,



I think. Gotta look up cerebral, is that a good thing?

[CJB]

Its good as long as its not used along with words like hemorrhage, anomaly, contusion, atrophy, etc.

Cerebral is much better when used along with the word "bourbon".

[MikeyKahr]

Another

Palsy, too.

[jocko]

I think I read where the bore diameter is smaller with polygonal rifled gun that standard rifled barrels, .. I think it was in that tutorial that bawanna posted about polygonal barrels..

[deadhead1971]

....nothing lasts forever...(well except jocko's PM9 maybe)...if it wears out, replace it.

I used to worry that my chrome-moly ar15 barrel would lose accuracy after 10,000 rds. But that will be 5-6 years from now, and new chrome-lined barrels are $200. So IF and when I wear it out, I'll just get a new one.

[Tilos]

Poly Rifling

The usual reason for ANY change is COST.

Engineers know Poly barrels are way CHEAPER to make...
And Marketing has convinced us Poly is BETTER.
YMMV
Tilos