Polygonal vs conventional rifling

19 March 2002, 04:39

As an interested amateur and journalist, I wonder if anyone would explain the difference in performance (accuracy, velocity etc) between conventionally rifled and polygonal barrels. Also, would today's ultra velocity be better served by going polygonal? Thanks, and if I sound like an ignoramus, I am an interested one.
Good shooting!
Mehul.

------------------
Mehul Kamdar

19 March 2002, 09:33

Bill Leeper

Though great claims have been made for polygon rifled barrels these claims have never been substantiated. If they had been more barrel makers would have switched to this type of rifling.
It is noteworthy that all the makers of benchrest quality barrels use more or less conventional rifling patterns. The lone exception is Shilen with their "ratchet rifling" which could be said to be a modified polygon and seems to be working as well as the conventional barrels.
Shilen's attempt at making a competitive polygon rifled barrel around 1980 was a failure. I never did see one that would deliver competitive benchrest accuracy. Regards, Bill.

19 March 2002, 12:27

Pyrotek

Polygonal rifling is said to be less affected by bore erosion(when the lands of rifling on conventional riflings wear, accuracy suffers), seal gas better and stress bullets less. H&K used to make guns with polygonal rifling, but recent products goes back ot conventional rifling.

20 March 2002, 04:58

mehulkamdar

Thanks for the info - I am aware of Heckler and Koch, but I also remember reading somewhere that some Israeli gunmaker had used polygonal rifling for pistol barrels. Were there many others who experimented with this? This is only for archival information and I would appreciate any further news you may have. Thanks once again - I am really grateful.

21 March 2002, 14:38

Rusty Gunn

quote:
Originally posted by mehulkamdar:
...I also remember reading somewhere that some Israeli gunmaker had used polygonal rifling for pistol barrels.

That was the Desert Eagle handguns, that used polygon rifling. My friends 44 mag has such. ~~~Suluuq

21 March 2002, 16:01

Pyrotek

I haven't heard much about gun makers practicing this concept except H&K and Magnum Research.

The legendary H&K PSG-1 is polygonal rifled too : http://hkpro.com/psg1.htm

21 March 2002, 22:23

mehulkamdar

Thank you friends - I shall also be e-mailing Mr Woody Woodall of Lothar Walther USA as suggested by Mr Wiliam Tompkins and shall post the reply here for whoever is interested.

22 March 2002, 05:21

<Dave King>

Pac Nor also makes polygonal rifled barrels and I believe most of these are used by Tac-Ord www.tac-ord.com . Visit their site and e-mail Jim Ryan about those barrels as I believe the buttons Pac-Nor uses/makes are made to Jim's specs.

I have several rifles with polygonal rifling, one has a Harris Gun Works barrel and the others use Pac-Nor.

There apparently is a "male" and a "female" form of this rifling and I don't understand enough about it to explain the difference.

I get good velocities from my rifles and they're quite accurate. My polygonal rifles rifles are a little fussy about shooting non-lead core bullets and I don't do that anymore.

22 March 2002, 05:46

mehulkamdar

Thanks again friends - I am reproducing the mail from Mr Woody Woodall at Lothar Walther for the benefit of all interested:

We do make both polygon and conventional rifling. Polygon is made to
operate in a more dirty environment and to be more durable. On average,
you will give up about 7-10% in accuracy. But, in tactical guns, we have
seen repeated groups that are between 3/8 and 1/2 moa. So, it is
accurate, but not so much as a benchrest barrel.

There are two types of polygon. What I call male and female. The male
type is like that which Glock uses. The female type is like that of H&K.
For a wide variety of bullets, the male type is better as it handles the
pressure spikes caused by the different bullets.

Velocities will tend to be slightly higher, but this will range from only a
slight increase to about 3%. But, way too many factors are coming into
play to guarantee any set amount of increase.

I hope that this answers your questions.

A special thanks to Mr Bill Tompkins for putting me through to Mr Woodall. I shall also mail Tac-Ord as suggested by Mr Dave King. Thanks, sir.