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Discussion in 'General Handgun Discussion' started by Gulfcity, Feb 3, 2010.
Could someone explain the difference in polygonal and conventional rifling in a handgun barrel?
In conventionally rifled barrels the grooves are cut into the barrel. The drawback to polygonal barrels is that you can't (or shouldn't) shoot non-jacketed rounds...
Thanks NGIB, that's what I'm looking for. You had mentioned on another thread to me and suggested a Kahr PM9, and their specs on the barrel is a polygonal rifling. That's why I was asking. I didn't know the difference. Would you consider it to be a problem or concern?
Not unless you intend to shoot non-jacketed ammo. The Kahr PM9 is a great little carry gun, a tad pricey but nothing good is cheap...
end pics of conventional vs. polygonal rifling
Generally Polygon rifling is hammer forged into the barrel. Conventional rifling is cut from the barrel surface. Polygon rifling can allow higher velocity because of the lower friction. Polygon rifling is less disruptive to bullet jackets. It is also MUCH harder to compare bullets because of the minimal markings left on the bullet.
Is the thread officially killed yet.
Between you and crossfire, I'd say this one's toast...
Yep, its dead, you guys killed it. Thanks.
Wow and not one flame on glock, we're slipping!
** face palm **
They have the ghey. AWESOME.
How much increase?
I know that Glock has recommended against unjacketed bullets in their pistols, but HK doesn't warn against this, other than a comment (when asked) that lead MAY buildup quicker in Polygonal than standard rifling. I've shot a ton of cast lead through my HKs and never noticed any more buildup than any other rifled pistols I have--in fact, I would say that my polygonal barrels actually show less buildup and clean up easier than the rifled equivilants do. Does anyone have any actual experience with problems in their polygonal barrels with lead? I do clean my pistol barrels after every range visit--normally 200-500 rounds...
For many years I shot only hard cast lead bullets from my Glocks because they were cheap to load. I never had any problems. Lead builds up in barrels and should be cleaned out, but a few hundred rounds should not be a problem.
My method of cleaning out the lead buildup was always to fire 4 or 5 rds of jacketed bullets every couple hundred rds of lead.
I also shot plenty of lead through my Steyr GB. Steyr said not to do this because of the gas operation, but other than a really messy gun it all worked out fine.
I generally like to avoid doing things that fall under the "hypothetical problem" category, but lead bullets have never caused me any grief.
Dang, I failed at killing the thread so I will try again.
Glock specifically warns against using unjacketed bullets in their barrels. I cannot speak with authority about HK or the early SIG pistols. Theoretically the polygon rifling should gather less lead. For some reason glock "appears" to build up more lead.
The latest information I have heard is that the Glock problem may be related to the leade/free bore (the unrifled area immediately forward of the chamber).
Whatever the problem is (IF there is a problem) I would NEVER recommend shooting unjacketed ammo through a Glock unless the barrel was swapped out with a conventionally rifled aftermarket barrel.
Hmmmmm, i hadn't heard of this advantage before or considered it; thanks Robo!
"Advantage"? What are you up to, Orange?