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AR15.COM
12/10/2005 11:43:59 AM EDT
i've heard that a polygonal barrel can actually increase the velocity of a bullet as there are no grooves to allow escaping gas past the bullet...

How true is this?
How does their accuracy compare to a traditional rifled barrel?
If it's a good idea does anybody make one for the sig 226?
12/10/2005 12:45:38 PM EDT
[#1]
There is no advantage or disadvantage to either type of rifling when it comes to accuracy.  Polygonal rifling is forged into the barrel at the time of manufacture along with the twist rate. H&K is the only major manufacturer to use it on their firearms, although the Swiss K-31 uses it as well. I have target rifles with traditional cut rifling that are as accurate as any of my  polygonal rifled guns. The one thing you really can't do with polygonal rifling is shoot lead bullets. Glock and H&K both warn about this practice so it's best to stay with some kind of jacketed bullet if you want to keep your gun in one piece.
12/10/2005 1:02:04 PM EDT
[#2]
the desert eagle  uses polygonal rifling.  the baby eagles used to but they changed that in the past year or 2.  i didn't realize the k31 used it.  that is very interesting.  
12/10/2005 1:10:12 PM EDT
[#3]

Quoted:
There is no advantage or disadvantage to either type of rifling when it comes to accuracy.  Polygonal rifling is forged into the barrel at the time of manufacture along with the twist rate. H&K is the only major manufacturer to use it on their firearms, although the Swiss K-31 uses it as well. I have target rifles with traditional cut rifling that are as accurate as any of my  polygonal rifled guns. The one thing you really can't do with polygonal rifling is shoot lead bullets. Glock and H&K both warn about this practice so it's best to stay with some kind of jacketed bullet if you want to keep your gun in one piece.

What exactly is the warning about these dreaded lead bullets?
12/10/2005 2:06:41 PM EDT
[#4]
Because polygonal rifling has no groves, there is no place for powder or bullet fouling to go. This isn't a problem with jacketed bullets, but lead slowly builds up just in front of the chamber and eventually causes pressure issues that usually result in a kb. The same thing happens if you feed a stedy diet of .38 wadcutter ammo through a revolver. You get the lead ring buildup that has to be removed before you can fire .357's.


Quoted:
What exactly is the warning about these dreaded lead bullets?

12/10/2005 2:18:47 PM EDT
[#5]
Are copper plated (Ranier) lead bullets OK to fire in an HK?  I sure hope so, I just bought 1000 of them to load up for my USP .45.
12/10/2005 2:23:14 PM EDT
[#6]
My baby eagle has polygonal. I have never seen one without. Shoots like a champ, makes it somewhat easier to get clean too.

-Foxxz
12/10/2005 3:36:19 PM EDT
[#7]
I think the problem is with bare cast lead. There are a few companies out there that make lead bullets with either a metal plate or a polymer barrier that should be safe in polygonal barrels. I would contact Ranier and ask them if they recommend their bullets for your gun. You may also want to check out Precision Bullets.

precisionbullets.com/


Quoted:
Are copper plated (Ranier) lead bullets OK to fire in an HK?  I sure hope so, I just bought 1000 of them to load up for my USP .45.

12/10/2005 4:01:45 PM EDT
[#8]

Quoted:
My baby eagle has polygonal. I have never seen one without. Shoots like a champ, makes it somewhat easier to get clean too.

-Foxxz



apparently the new ones have conventional rifling.  their website used to say polygonal but it doesn't anymore.  and the new ones i saw at a gun show a couple months ago lacked the polygonal rifling.  its a real shame because i was thinking of buying one due in part to that feature.
12/10/2005 4:10:57 PM EDT
[#9]

Quoted:
Are copper plated (Ranier) lead bullets OK to fire in an HK?  I sure hope so, I just bought 1000 of them to load up for my USP .45.



There was a thread about this! I dont think that is recommended. I recall it saying not to use copper washed opr plated bullets.
12/10/2005 4:43:16 PM EDT
[#10]

Quoted:

Quoted:
Are copper plated (Ranier) lead bullets OK to fire in an HK?  I sure hope so, I just bought 1000 of them to load up for my USP .45.



There was a thread about this! I dont think that is recommended. I recall it saying not to use copper washed opr plated bullets.



Just my luck.  Do you happen to remember the thread title or author so I can search for it?