moooose102
Member
so what is the deal with the polygonal barrels. i have seen this mentioned several times before. i do not know what they are, and how they make for a better gun. or do they? or is it just another ploy to sell guns.
polygonal barrels
- Thread starter moooose102
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probably
more expensive to produce. no more accurate, supposed to be an increase in velocity with a polygonal bbl, how much is another thing. Have to be careful shooting lead out of one though, needs to be throughly cleaned. Glock does not recommend it, kahr also does not recommend lead. Normally a polygonal rifled barrel is a more quality type barrel also.
more expensive to produce. no more accurate, supposed to be an increase in velocity with a polygonal bbl, how much is another thing. Have to be careful shooting lead out of one though, needs to be throughly cleaned. Glock does not recommend it, kahr also does not recommend lead. Normally a polygonal rifled barrel is a more quality type barrel also.
Glock OEM barrels are 'hexagonal', same idea, similiar execution, H&K uses them, IMI/Magnum Research Baby Eagles, not sure who else uses them.
They supposedly give a boost to velocity and accuracy potential because of the increased bullet to bore contact, but I'm not sure how big the gain is.
They supposedly give a boost to velocity and accuracy potential because of the increased bullet to bore contact, but I'm not sure how big the gain is.
possum
Member
glock, h&k, also kahr iirc.
stay away from using kead loads in these types of barrels, or just insure that you clean them really well and remove all the lead fouling when you clean.
stay away from using kead loads in these types of barrels, or just insure that you clean them really well and remove all the lead fouling when you clean.
atblis
Member
Polygonal
Tanfoglio seems to use them sporadically.
CZ uses them on occassion (CZ82)
Tanfoglio seems to use them sporadically.
CZ uses them on occassion (CZ82)
Not necessarily. The equipment itself is expensive, but if you're producing enough barrels, it is very economical for cranking out mass quantities (like Glock).
gaowlpoop
Member
Jim Watson
Member
As to manufacturing cost, I suspect a hammer forge mandrel with gentle curves will last longer than one with sharp corners. All the stuff about higher velocity and longer barrel life is a case of making a virtue out of necessity.
Shadow1198
Member
Here's an example of polygonal rifling:
Technically, it does actually increase the velocity of the bullet as true polygonal rifling does not use lands and grooves and provides a better gas seal. It's not some drastic difference or anything but, it definitely does make one. Not to mention, generally it's easier to clean a true polygonal rifled barrel as there aren't lands and grooves so it is much easier to scrub everything off with a bore brush. The whole issue with not being able to shoot lead bullets through polygonal barrels is entirely due to the increased fouling present with lead bullets. I don't fully understand it but, apparently it's easier for fouling to build up with a polygonal barrel. If there is too much build up it can lead to severely increased muzzle pressure, which could in turn cause a kB.
Technically, it does actually increase the velocity of the bullet as true polygonal rifling does not use lands and grooves and provides a better gas seal. It's not some drastic difference or anything but, it definitely does make one. Not to mention, generally it's easier to clean a true polygonal rifled barrel as there aren't lands and grooves so it is much easier to scrub everything off with a bore brush. The whole issue with not being able to shoot lead bullets through polygonal barrels is entirely due to the increased fouling present with lead bullets. I don't fully understand it but, apparently it's easier for fouling to build up with a polygonal barrel. If there is too much build up it can lead to severely increased muzzle pressure, which could in turn cause a kB.
Glock .45's are octagonal, everything else is hexagonal, and both types are polygonal (I.E. hexagons and octagons are both polygons A.F.A.I.K.)! I like it, especially to make up for some lost velocity in compacts and subcompacts (I.E. kahr)! But it's not as big a factor for me in a full size.
DWARREN123
Member
My GLOCK barrels seem to stay cleaner with jacketed or plated bullets and they are pretty accurate. I don't know if they really do make a lot of difference but they work as good as regular rifling.
downside
Other than they all say stay away from lead bullets. i see no downside to the polygonal barrel. If its better, I like it. My little 3" kahr pm9 barrel can use all the extra git-up and go with a polygonal bbl, and that is fine with me. the theory sure sounds reasonable.
Other than they all say stay away from lead bullets. i see no downside to the polygonal barrel. If its better, I like it. My little 3" kahr pm9 barrel can use all the extra git-up and go with a polygonal bbl, and that is fine with me. the theory sure sounds reasonable.
usp9
Member
Here's a great shot of a polygonal barrel, (can you name the firearm 
)
Personally I don't think they are "better', just a different way of spinning the bullet. The main advantage, if there is one, may be in the increased velocity and longer life of the barrel. Accuracy may be a wash as well as ease of cleaning, IMO
)Personally I don't think they are "better', just a different way of spinning the bullet. The main advantage, if there is one, may be in the increased velocity and longer life of the barrel. Accuracy may be a wash as well as ease of cleaning, IMO
schmidtundveßon
Member
to usp9:
H&K P7?
H&K P7?
atblis
Member
Steyr
Steyr GB
Steyr GB
Rex B
Member
American Arms Escort .380
Shadow1198
Member
That is most definitely a P7 barrel. 
usp9
Member
schmidtundveßon,
None other.
None other.
moooose102
Member
so, if i am seeing correctly, instead of having grooves and lands, it is a barrel with, kind of flat or raised sections that are twisted. for lack of a better explanation. it almost looks a little like a microgroove barrel from marlin. so why do they want you to stay away from lead bullets? not enough engaugement?
usp9
Member
The bullet to barrel fit is tighter than the more open lands and grooves, therefore the additional fouling from an unjacketed lead bullet increases the pressure over time. In other words, there is no place for the added material to go. Jacketed rounds leave far less material behind in the barrel. At what point it becomes an issue... I don't know.
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