Polygonal Rifling?

[264Wins]

I know of some handguns with polygonal rifling and have read that you can eek a little more velocity out with them. Why is it not common in rifles? I have seen it offered by barrel manufacturers. What is gained or lost with it?

 

[Mikecr]

I don't know why it isn't more prevalent, but I can tell you that actual polygonal rifling is very rare from aftermarket barrel makers. You can get true polygonal, and taper bores, in Canada. But if you do business in Canada, you will get screwed.
Do not believe just anyone who says they offer it. What they're likely merchandising is a bore cut with a worn out broach, producing less defined rifling that is standard otherwise (Pacnor, Schneider).. And notice there are no cut rifled polygonal. The actual polygonal barrels(factory, H&K, Glock) are hammer forged.

 

[Deleted member 46119]

One thing to consider: the after market barrel makers serve and are involved in bench rest/high accuracy shooting. If the polygonal rifling worked from a speed and accuracy standpoint then barrels would be available in every flavor you could imagine.

As I understand it from others, polygonal rifling works with solid lead bullets, however copper/copper jacketed don't obturate to the bore well in rifles.

I have a pistol with a polygonal barrel and it is supposed to be the opposite. Jacketed not soft lead. Go figure? No way to get reliable data from the pistol. Never tested accuracy differences.

Maybe it has to do with bullet diameters. Solid lead rifle bullets are often .0005 to .002 over jacketed so there is plenty of material to close/seal (obturate) to the bore.

 

[264Wins]

Would that pistol happen to be a desert eagle? I have one which is what kind of got me thinking about the polygonal thing. Also I know it was done in an early rifled cannon but the rounds had to be preformed to the rifling. They were like a twisted hexagonal cylinder if memory serves me right. I wasn't sure if it never caught on because of the complicated manufacture, some kind of negative effect on B.C. of the bullet due to the exaggerated "corners" that polygonal rifling would form or what. I thought some folks on here might have some insight.

 

[marshal]

I don't know why it isn't more prevalent, but I can tell you that actual polygonal rifling is very rare from aftermarket barrel makers. You can get true polygonal, and taper bores, in Canada. But if you do business in Canada, you will get screwed.
Do not believe just anyone who says they offer it. What they're likely merchandising is a bore cut with a worn out broach, producing less defined rifling that is standard otherwise (Pacnor, Schneider).. And notice there are no cut rifled polygonal. The actual polygonal barrels(factory, H&K, Glock) are hammer forged.

Firstly why would you say such a thing, and secondly who in Canada makes polygon rifled barrels? and thirdly you'd be absolutely nuts not to shop in Canada
with the CAD being what it is.

 

[C.O. Shooter]

My H&K pistols have the Polygonal Rifling

 

[Mikecr]

Firstly why would you say such a thing,

I've had both the only aftermarket barrels I know of claimed to be polygonal, and neither are.

and secondly who in Canada makes polygon rifled barrels?

Don't remember,, don't care anymore.

and thirdly you'd be absolutely nuts not to shop in Canada

I have over $10,000 worth of gun components from two different gun builders hung up in a warehouse somewhere at the border(right near 10yrs now). From what I hear, there is no credible process to get my stuff. Only an importer could manage it(possibly). Neither gun builder put in the slightest effort in this regard.
Given this, I could not in good conscience recommend business with Canadians, no matter what they promise, and no matter what others think of them.

 

[marshal]

I've had both the only aftermarket barrels I know of claimed to be polygonal, and neither are.
Don't remember,, don't care anymore.
I have over $10,000 worth of gun components from two different gun builders hung up in a warehouse somewhere at the border(right near 10yrs now). From what I hear, there is no credible process to get my stuff. Only an importer could manage it(possibly). Neither gun builder put in the slightest effort in this regard.
Given this, I could not in good conscience recommend business with Canadians, no matter what they promise, and no matter what others think of them.

Care to mention the builders?

 

[marshal]

So you paint a whole country with the same brush because you had a bad experience? I would imagine there is more to the story other than "your side of it" but as you said - you don't care anymore.

 

[yorke-1]

Blackhole Weaponry makes polygonal barrels; I have one on a CZ 527 that I had converted to .264 LBC/6.5 Grendel. It shoots a touch under 1/2 MOA which is perfectly acceptable for this gun since it's just little carbine I had built for my son. I do get higher velocity from the poly barrel than I do from a conventional barrel of the same length, it's not significant enough to make me switch over all of my barrels to poly rifling. I know that polygonal rifled barrels are much more popular with ARs.

We did have problems with a polygonal rifled BHW barrel when we stepped up in speed though. A friend and I both had barrels chambered for a 6.5/338 RUM improved (similar to the 6.5 Allen Mag). Mine is a McGowan 1-8" twist 260 Rem barrel that I had rechambered and the other is a BHW 1-8" twist. My barrel shoots the Matrix 160 at 3430fps and groups in the .4 MOA range when I do my part. The polygon barrel keyholes the 160 gr bullets at 100 yards when shot at the same speed. The best answer we can come up with is that the poly rifling just doesn't grab the long, heavy bullet enough to get a good spin on it at those speeds and the bullet is essentially stripping through the rifling. 140gr bullets don't have this problem in that barrel.

Speaking of Matrix Ballistics, that alone is reason enough to do business with Canada. I don't know of any US companies making a comparable bullet!

Andrew

 

[Beng]

@Mikecr
Are your guns located at said warehouse due to import or export regulations of either the US or Canada?

 

[Mikecr]

Export -to USA. Well, this according to both builders who said they sent my stuff, but neither could make any guesses about border issues.
One of them was 'Prairie Gun Works' at the time(now PGW DEFENCE TECHNOLOGIES INC). Big order with them paid up front.
The other, Bill Leaper, I sent him custom actions, barrels, reamers, dies, etc for finishing. Work paid for. He had no reason to lie about finishing my work and sending out.
Both said they had, and internet chatter at the time implied border gun snatching by Canadian government.

Either way, I did my part in this twice in a row, and 'that side of the border' let me down twice in a row.

The two barrels I had(still have one) which were claimed to be polygonal, but were not at all, - Schneider, Pacnor. The Schneiders (3) were for a Tubb2000, 6XC. The Pacnor(1) is on my Browning in 6br.
True polygonal does not have raised lands, radiused, canted, wore out, or otherwise. If your barrel does, it's not polygonal, regardless of merchandising.