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Any manufacturer offer a 10/22 polygonal barrel?

2373 Views 20 Replies 13 Participants Last post by  Vincent
Thread title says it all really.

In case anybody doesn't know what it is, it's a smooth polygon shaped bore that twists like rifling, but has no sharp lands or deep grooves. It offers, improved accuracy, less friction, higher velocity, less heat buildup, and less fouling, but the barrel will cost more.

Anyone know any manufacturers that are producing one for the 10/22?
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Is my hammer forged "T" barrel polygonal?

Is my hammer forged "T" barrel polygonal?

daajr

The text below is quoted from:
http://www.firearmsid.com/A_bulletIDrifling.htm

Hammer Forged Rifling

The newest mechanical method of rifling barrels is accomplished through a process called hammer forging. Hammer forging produces a type of rifling called polygonal rifling. A hardened steel mandrel is produced with the shape of the rifling formed on its outer surface. The mandrel is inserted into a barrel blank and the outer surface of the barrel is machine hammered. The hammering forces the barrel material down against the mandrel and the inner surface of the barrel takes on the shape of the mandrel. The mandrel is then removed from the barrel and the outer surface of the barrel is cleaned up. Just as in the other types of rifling, polygonal rifling can have different patterns. The most common polygonal patterns are 6/right and 8/right.

Polygonal rifling on the other hand is very different from conventional rifling. There are no distinct transitions between the lands and the grooves.

Polygonal rifling takes on a shape that is sometimes referred to as "hills and valleys.
 

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My Kahr also has polygonal rifling. It is not restricted to handguns however. I remember in the 70's several rifles, mainly HK's had poly rifling. Not sure about lead bullets, have to dig out my Kahr book but I vaguely remember them not being recommended.

For some reason this has always seemed to be slightly more popular with European firearms.

Most poly rifles barrels are hammerforged but buy far most hammerforged barrels have traditional rifling (Ruger,Sako etc.)
 

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Pdwight said:
Because you have a hammer forged barrel does not mean it has polygonal rifeling.

Apples and Macintosh's

Dwight P
That is correct. And 10/22Ts DO NOT use polygonal rifling.

Glocks DO NOT use Polygonal rifling since you can see lands inside the barrel. Glock Marketing people can call it what they want, but they certainly exaggerated. Glocks use a modified hammer forged rifling.

Take a look at a HK 91 or P7 if you want to see a true Polygonal barrel. There IS NO LANDS. The shape of the interior of the barrel resembles that of a polygon there is no conventional rifling at all. HK patented and perfected the real Polygonal rifling. You can use lead bullets in a true Polygonal barrel. I've done it.
 

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That is how the Kahr is as well. Nothing that resembles rifling at all. The bore is just not round but a polygon in shape and that polygonal shape just twists around the axis of the bore for it's full length which is also how the HK is.
 

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Discussion Starter · #9 ·
Well, I do know that all the "elite" match barrel makers are mostly small shops, sometimes even one man operations, and don't make a polygonal barrel because the costs for tooling up are immensely expensive. The machinery used to make them (usually a hammer forging process, but not always) isn't cheap. And at the price they would have to offer them at, without there being much of a market there, it would be a bad business decision.

HK has no patent on polygonal rifling.

As for testing whether or not they are or aren't less accurate, there isn't really hasn't been much testing. There are plenty of makers of high-grade super-match type barrels for cut rifling (the most labor intensive, but least expensive machine cost), and button/broach rifling (easy to make, but expensive machine cost), and hammer forging (immensely expensive), but there haven't been any head-to-head comparisons using the different rifling types made from the same steel stock and the same action type that I could find anywhere.

Anyways, still on the search for a polygonal 10/22 barrel.
 

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I really think the advantage of the polygonal barrel is lower cost compared to rifling when the manufactor is using hammer forging anyway. In other words I don't think polygonal " rifling" offers anything over traditional rifling. Competition shooters who use Glocks usually go to an aftermarket rifled barrel for increased accuracy and the ability to use lead bullets if wanted. Maybe the polygonal system might last longer when abused in a machine gun but how would you tell it's worn out? :rolleyes:

Ross
 

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Polygonal rifling is not really new. I believe that the Whitworth muzzle-loading rifle, used in the mid 1800's, had a polygonal (hexagonal) bore. It definitely used lead bullets. The American Rifleman tested one of the Whitworths a few years ago and found that it was as accurate as many modern rifles. If I remember correctly, the bullets were also made hexagonal.

I doubt that this system used with a .22LR would improve on the accuracy of a good match grade barrel with traditional lands and grooves - but it would be interesting to try! :)

GHP
 

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One of the supposed virtues of polygonal rifling is that the base of the bullet is not as deformed as by tradional rifling, The Whitworths set cast bullet records that are still right in there with the best today. As most of you probably know the condition of the base or heel of the bullet is extremely important.

As to accuracy HK rifles have always been very accurate. I'm not just taking about the 91 series but they also made a sporting semis that were very accurate as well.

This idea has always intrigued me. When I bought my Kahr 9mm I did not realize they had this system and was really surprised to find it. One byproduct is that it is really easy to clean.
 

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HK is the predominant maker of polygonal barrels and we all know their reputation for accuracy in both rifle and hand guns...mass production guns at that. Polygonal rifleing is supposed to seal gases behind the projectile much better than other rifleing, hence the higher pressures. As for excess pressure in a leaded LR round. I don't think it would be excessive in the LR cartridge. IMHO ;) Mac
 

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Another in the now discontinued for importation series from HK is the HK300 in .22 Winchester Magnum Rimfire (WMR). With a hammer forged polygonal bore profile, the 300 has a V-Notch rear sight and conventional front sight. . It has either a five round or 15 round box magazine capacity and a straight blowback inertia bolt. None of these guns, with the exception of the SL6 and SL7 appears to still be manufactured. They are not represented on the official German HK website. I don't know with certainty though.

With the HK05 mount, a scope could be added. The 05 mount was made for commonality with all HK sporting rifles. The stock was made from European walnut.


Pac-nor makes a poly barrel in rimfire
http://www.pac-nor.com/barrels/
 

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I read somewhere that lead pistol caliber bullets didn't work so good in polygonal barrels because the lead being softer than the jacketed bullets didn't take the spin quite as well. I think it would be more of a problem short barrels such as found in pistols.
 

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No one outside of HK in Oberndorf Germany makes a true polygonal rifling on modern barrels that I know of. HK is the only manufacture to have perfected this type of rifling on a barrel making hammer forging machine. Unless HK get into the 10/22 aftermarket barrels your out of luck.

FWIW Most if not all all hammer forging barrel making machines come out of Germany. Ruger bought its 1st one in the early 90s and it cost more than 2 million dollars.

Kahr and some IMI guns baby Eagle for example do indeed have a true polygonal rifling. They bought their barrels from HK.

I see glock has created much confusion about this subject. They also got it wrong. A polygon is defined as a FLAT many sided geometric figure in the English language. There is nothing flat about glocks rifling.

In convention rifling lands join the grooves with a relatively sharp perpendicular edge.

Glock rifling is is unconventional in that lands do not join the groves with a sharp perpendicular edge. But rather a rifling that is basically radiusing the intersection between land and groove. Very much like 5R rifling that was popularized by Boots Obermeyer. I suspect the reason why glocks are allergic to lead bullets is they used way to much of a good thing (very large radius) creating to much surface area for friction and heat. Because 5R rifling is supposed to do very good with 22LR lead bullets.

There are other barrel makers producing and experimenting with this type of rifling. Obermeyer and the rest are using cut rifling. I don't think we will see button rifling used in this case because of to much tool pressure for successful process all the time.
 

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Smoky, you are incorrect about Kahr getting their barrels from HK. They get their barrels from Lothar Walther. If you go to the Kahr website and click on barrels it will take you to a page on how their barrels are made and it states clearly that the barrels are made by Lothar Walther, I have always heard of very good things about Lothar Walther barrels so I found that interesting.

Also if sometime up the road someone here looks at a Kahr and sees lands and grooves don't be too shocked. At least one model, the new CW9 polymer and stainless econo model ( if you can call well over $500 econo), has standard rifling but the rest still have polygonal.
 

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Vincent said:
Smoky, you are incorrect about Kahr getting their barrels from HK. They get their barrels from Lothar Walther. If you go to the Kahr website and click on barrels it will take you to a page on how their barrels are made and it states clearly that the barrels are made by Lothar Walther, I have always heard of very good things about Lothar Walther barrels so I found that interesting.
Was unable to find anything about how barrel are made barrels on Kahr website. But I will take your word for it. The German barrel maker of Lothar Walther definitely has the technology and facilities to make them.
 
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