Home Forums Hunting & Shooting Ask The Gunwriters polygonal rifling any advantages?

Yes Mom, I know; I took geometry a few hundred years ago. The important difference of the Whitworth is the way the bullet fits almost perfectly in the bore from the start rather than being engraved (or apparently swaged to fit as in your pic) like with other types. There were also one or more that had little wings on the bullet that matched grooves in the bore and did the same thing but weren't as practical.

Pappy, you said "hexagonal rather than polygonal". I don't need to argue with you, but your comment indicated you didn't understand what that meant. No need to get snarky about it, please. My comment had nothing to do with the Whitworth stuff.

Yup, that is a good point (the bit in bold). Some modern examples - HK uses (or did use anyway?) 6 flats in their 9mm hexagonal polygonal bores. Glock uses a series of flats and rounds (the flats are the "lands" in traditional rifling), and BHW uses Caudle rifling which has no flats but is shaped from 3 offset circles. All of them call their style "polygonal rifling".

Whitworths era did not have truly hard alloys in small arms available, so it's amazing in how his bullets worked. Most prevailing arms of the period all were bump and swell/patched or Minie designs.
The principles of full diameter, swaged bullets came along with cartridges.
The use of lead in them hasn't changed.

The 1917 Revolvers aren't so different to make run with cast as poly type barrels.

I've run cast through Glocks and Tangos without issue. Colt 1911s are also of the shallow land variety and running over groove and without care of "too hard" in those fixed chambers is easy, much easier than wheelguns.

I briefly considered calling you a condescending f*ck, but went with the "Mom" thing instead, since after all it was my error that started it. As a recovering spelling and grammar nazi, I understand the compulsion to confront ignorance wherever it's found. No offense taken (anymore) or intended.

Since you seem to know a bit about this, I have a question: Is there any evidence that the flats formed by the polygonal rifling have any slowing effect on the rotation of the bullet? I've read that the Whitworth slugs made a distinctive buzz or whir in flight, which means (I think) some energy is bleeding off making that sound.

Umm, Ross Seyfried had excellent accuracy using lead ROUND bullets in a Pedersoli Whitworth. Details in Rifle Mag. archives.

Not only Ross; Sam Fadala too IIRC, and maybe that capandball guy on YouTube.

Refresh my memory.

As I understand Ross Seyfrieds work, he had a Whitworth designed projectile mould for the Whitworth rifle he wrote about.

A minor point but bullets shot from poly rifled barrels have a very slightly better BC due to the added resistance of the rifling ingraving for metford riffling. It is so tiny you would need Doppler radar or some other very accurate equipment to measure it. It is like the ridged mono bullets, not enough difference to tell in the field but at least mathematically a slight difference in air resistance.

Polygon rifling imparts spin to stabilize the bullet; just like every other rifling form. The reason it has not taken over the gun world is because it doesn't work any better and may not work as well as conventional rifling. Back in the eighties, Shilen did indeed offer a barrel with polygonal rifling. I bought a few of them, 6mm and 30 cal. They shot OK but not great with jacketed bullets but the two I put on for cast bullet shooters worked very well. About ten years later, I got a couple of H-K blanks in 224 caliber. I chambered them for 22 BR and, again, they shot reasonably well but they were no Hart. One of the big problems with the Shilen polygon (called DGA rifling by Shilen) was that it didn't clean well because the brush wouldn't follow the rifling. The bottom line was, they just didn't shoot that well. I always felt that the deformation of the bullet jacket and potential loosening of the core would always limit accuracy with jacketed bullets in polygon bores.
One theory claimed they were a bit faster because they sealed the bore better. I never did any velocity testing simply because I didn't really care. My concern was with accuracy. If it wasn't there, I didn't care what the velocity was.
Anyway, the day I see polygon rifled barrels winning BR and "F" class matches is the day I'll start choosing them over conventional rifling forms.
The Shilen ratchet rifled barrels are a little different than a polygon and are, in fact, convemtional rifling with a funny shape. I have two on rifles of my own. The 6mm, which I bought when they first came out, is definitely different. When one looks from the muzzle, it's hard to see the rifling at all while from the breech, it looks pretty normal. It spins the brush just fine going from breech to muzzle but skips coming back. The second barrel is 6.5 mm and the ratchet form is much less marked. In fact, it looks fairly coventional from both ends. It spins the brush both ways. Both of these barrels shoot very well and clean easily.
Some liked polygon rifling for patched round ball rifles because they sealed well and cleaned well with loading. Some may remember the Whitworth replica produced by Parker Hale. These rifles were supplied with a mold for a conventional, grooved, lubricated, bullet. Loaded as recommended by the manufacturer, they shot very well through the hexagonal bore.
As far as the deformation of the bullet having any effect on rotation goes, I doubt it. GD
.

Black Hole Weaponry seems to have a good reputation in polygon rifled AR style barrels, but I have no personal experience with them.
They also make barrels for bolt actions.
Anyone use these?

https://columbiariverarms.com/rifiling-manufacturing-process/

Pac-Nor makes them available as a rifle barrel option, I appreciate your sharing of experience.
Thanks

As far as the deformation of the bullet having any effect on rotation goes, I doubt it. GD

Just an idle thought I had while mowing the lawn. The story about the sound made by the Whitworth bullets always intrigued me; similar to the distinctive rip of the German 88s, which my father has talked about, on a much smaller scale of course.

That ratchet thing is an old idea too. I wonder if anyone is playing with oval bores these days. Those should be easy to clean, but might run up pressures with jacketed bullets unless maybe sabotted (patched) to cut friction.

These are the Barrells David Tubb used to win several F Class Matches.http://schneiderriflebarrels.com/#rifling
They don't go into detail so these may be closer to 5R or Ratchet rifling than a true polygon.

Hawk 1

Seyfried's best results were with Lyman #457-121P. Same mold for both the Parker-Hale and Whitworth. He had both molds, the traditional hex mold came as an extra cost item sold with the rifle. I had one, cast Bhn 8 soft bullets in the Lyman BUT, I did use the hex wadcutter that came with the rifle for over-powder wads. It did everything it was reputed to do on 600 yard steel...but the recoil was brutal, and after the initial joy making hits with a muzzlestuffer at medium range I traded it off. The recoil was just not fun.

Thanks for the reply!

I have the magazine around here somewhere, and I can't find it now you have me looking for it!

Oh well.

Is polygonal rifling the same, similar to, or, completely different from the Metford rifling (found on the Lee-Metford rifles around the 1900's) (Charles Newton used his version/variation on his Newton rifles as well)?

Same, Metford is the radius ed type of polygonal rifling.

Here is an interesting article on the Newton-Pope Rifling which is a form of polygonal or oval rifling similar to the Metford.http://ps-2.kev009.com/ohlandl/Cast_Bullet/Vault/Newton-Pope_Rifling_Oval_Bore.html