KAHR barrel difference regular vs polygonal rifling.

[medic579]

So the 4.0 barrel for the cw9 has the port, the added length and tge polygonal rifling. How much difference can the rifling make on a barrel this short?


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I am here: http://maps.google.com/maps?ll=30.447453,-84.262391

[Bawanna]

The CW has standard rifling. The average person or even above for that matter would never be able to tell the difference from shooting.

The plus to the standard rifling is you can shoot lead without worry. Not recommended with polygonal barrels.

[medic579]

Really, I didn't know that.


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I am here: http://maps.google.com/maps?ll=30.454035,-84.265181

[kahrlover123]

The CW has standard rifling. The average person or even above for that matter would never be able to tell the difference from shooting.

The plus to the standard rifling is you can shoot lead without worry. Not recommended with polygonal barrels.
Well, I'm not a pro shooter but I notice the difference in accuracy at 25 and 30 yards between the CM9 (standard) and PM9 (polygonal). I used +P ammo for this test.

[Thunder71]

Higher velocity is another benefit polygonal has over conventional.

[medic579]

Well who's shooting plain lead anyway. All I shoot is fmj and Speer gold dot + p

[medic579]

As long as it's jacketed right?

[OldLincoln]

Rifling comes up a lot here with Kahr having both styles. I found what I think is an excellent article (http://en.wikipedia.org/wiki/Polygonal_rifling) to educate all of us on the matter.

Poly rifling:
http://www.nij.gov/training/firearms-training/module10/images/fir_m10_t09_01.1_large.png

Traditional Rifling: (75mm WWII)

http://www.nij.gov/training/firearms-training/module04/images/fir_m04_t06_05.jpg

[medic579]

I've read that several times. Sounds like the barrels are stronger. I don't see why it would be a problem. Do we know the twist rate of the polygonal vs standard on this barrel?

[CJB]

This much I know:

Its easier to hammer forge polygonal rifling in a barrel than the impression of cut rifling. Hammer forging the sharp edges is a chore. Its done, but its more work, harder to hold precise than polygons.

Remember hammer forging starts with a short fat barrel with a hole in it, thats HAMMERED into a long thin barrel which is formed around a mandrel with a positive image of the rifling on it. Because of that, polygons - with no sharp edges to hold sharp - are much easier to form.

Traditional land/groove rifling as we know it today is whats called "button rifled", whereby a positive shape "button" or plug, is pushed through the barrel blank under high pressure, effectively "ironing" the rifling image into the bore.

Cut rifling for lands and grooves is still done, but on a much smaller scale, mostly for custom barrels and small lot production. Thats because the gang-broach is much cheaper to produce than carbide plugs or mandrels. So for high production, you invest in the tooling for button rifling or hammer forging.

As to the difference between one and the other in a short barrel... personally I think you'd have to chrony a bunch of loads, thru a bunch of barrels before any conclusion could be drawn.

[jocko]

sorry, this ol timer just ain't buying any accuracy difference in the two barrels in a kahr. Either one will shoot them in the same hole, just that 99.99% of the shooters with these small guns CAN'T.:banplease:

[JFootin]

Well, I'm not a pro shooter but I notice the difference in accuracy at 25 and 30 yards between the CM9 (standard) and PM9 (polygonal). I used +P ammo for this test.

Which was better? :rolleyes:

[JFootin]

Higher velocity is another benefit polygonal has over conventional.

I read a post here where a CW9 had more velocity than a P9 with the same ammo.

[ripley16]

I like polygonal barrels mainly because they are easier to clean.

FWIW I've shot lead through some of my Poly barrels with no ill effects at all.

[Mr. Zero]

I like polygonal barrels mainly because they are easier to clean.

+1 and they do generally offer a higher velocity due to a more complete gas seal of the bullet to the bore.

-Z-

[Bawanna]

Well, I'm not a pro shooter but I notice the difference in accuracy at 25 and 30 yards between the CM9 (standard) and PM9 (polygonal). I used +P ammo for this test.

25 and 30 yards is rifle territory for this deadeye. Thats a stretch with me and a handgun. Any hit would be an accident.

[beatlesfan]

I've noticed when I'm cleaning the barrel I'll hold it up so that the light shines through it, it is a lot prettier looking than standard rifling in my opinion. That's $200 right there right? :D

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[Thunder71]

Barrel, machining, extra mag, sites, to me it all adds up to $200 in value in my book.

Posted from my Thunderbolt using Tapatalk.

[beatlesfan]

Barrel, machining, extra mag, sites, to me it all adds up to $200 in value in my book.

Posted from my Thunderbolt using Tapatalk.

I'm sorry. I didn't mean it like that. I was just cracking a joke. I've got a T9 with the polygonal rifling and love it. I also want to pick up a PM9 in black w/ night sights. I've always believed in going big or going home. If I were to "settle" for a cheaper version of something, I'd always have that nagging in my head asking me why I didn't just spend a bit more to be 100% satisfied. No offense to the standard rifled Kahrs, that's just how I am lol.

P.S. Yay for Tapatalk!


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[Thunder71]

Haha, didn't really mean it toward you - your post just reminded me. :)

I'm the same way though. Got tired of buying, selling for a loss and buying what I wanted in the first place.

Posted from my Thunderbolt using Tapatalk.

[CJB]

sorry, this ol timer just ain't buying any accuracy difference in the two barrels in a kahr. Either one will shoot them in the same hole, just that 99.99% of the shooters with these small guns CAN'T.:banplease:

Jocko also knows that the fit of the barrel to the slide and frame and slidestop has more effect on overall accuracy than the type of rifling. Or at least I hope he knows that :p!!!!

Saying I have a CM and a PM, and the PM shoots tighter... is not a large enough sampling to smooth out the irregulars due to fitting variance.

Jocko's got it right.

[jocko]

Jocko also knows that the fit of the barrel to the slide and frame and slidestop has more effect on overall accuracy than the type of rifling. Or at least I hope he knows that :p!!!!

Saying I have a CM and a PM, and the PM shoots tighter... is not a large enough sampling to smooth out the irregulars due to fitting variance.

Jocko's got it right.

assuming all things are equal except the barrels, one will shoot no different. a cm9 and a pm9 should be identiucal in construction but as we all know, some are tighter than others out of the box. It is a moot point IMO anyway, one will never shoot the barrelk in his gun as good as the barrel can actualy do, especially in a small frame gun like kahrs. enjoy the barrel you have, shoot it like u stole it, wouldn't make a hill of beans to me if my PM9 had the conventional rifled barrel. I do not know either if kahrs lothar made barrels are only on the polygonal rifled guns or whether all kahr barrels are rifled by lothar. I think all lothar does is supply the 3 ft barrel blank rifled and then kahr does the final machiing of the barrel itself. But that being said CJB is right.

[jocko]

25 and 30 yards is rifle territory for this deadeye. Thats a stretch with me and a handgun. Any hit would be an accident.

got that right, 30 yards for this ol timer is 23 yards to far for me. I have been shooting at the same 6" paper plate for 3 years now at 30 yards with my trusty "deadly" PM9, and I can still eat off that plate with no dripping at all..:blah:

course on a scale of 1 to 10 formy gradng of my shooting I would put me in at about negative 4.

[kahrlover123]

25 and 30 yards is rifle territory for this deadeye. Thats a stretch with me and a handgun. Any hit would be an accident.
I agree that PM9 or CM9 is effectively for 10 yards or less and there is no difference between the two.
But my buddies and I went to the range and did some "comparision tests" between the two, strecthing out to 20, 25 and 30 yards. The results are obvious to me.

PM9 gives little more tighter group and little more accurate.

You do not to believe me. Just test it yourself when you have the chance and see the result.

[Bawanna]

I don't question your results, you've never lied to me have ya?, but I think the point is on any given day with another CM and another PM the results could be just the opposite.

The barrel slide fit, the trigger components fit, lots of factors play a part.

You could easily have a very good PM and a very bad CM. Could be the CM was newer and not broke in as much as the PM and will get better.

No matter really, they both are really good and I'd be happy with either one or preferably both. I know, I know I'm greedy but I want em all.

[kahrlover123]

You're probably right. I only sampled one PM9 vs another CM9 so maybe it's not a true test. Next time I go the range with my buddies, I see if I can get more samples and I will post the results :)

[HadEmAll]

My CW40 with conventional rifling always generated more velocity than my K40 with polygonal rifling.

With 155 grain JHP, and 165 grain FMJ's, the CW40 always had 10 - 20 more feet/second.

Bear in mind, the CW40 barrel is also .1" longer than the K40 barrel. Obviously enough to offset the supposed lower friction of the polygonal rifling. At least in my 2 pistols.

I can't comment on any potential accuracy difference. They were both minute of felon at 15 yards.

[jocko]

.1" as u know in some areas, is MASSIVE.

[JFootin]

.1" as u know in some areas, is MASSIVE.

LOL! It takes a dirty mind to get this one! http://i1230.photobucket.com/albums/ee486/John_England/laugh.gif

[jocko]

tarnished maybe!!1 u should get ur mind out of the gutter, course all ur kahr friends are down there...

[medic579]

I'd give any thing for an extra .1 on my "barrel".

[wyntrout]

Get what?? :confused:

Wynn:)

[Jim K]

I have pistols that have both types of rifling. I can't detect any difference in shooting precision between the two.

I think that the ratio between trigger pull and pistol mass has much more to do with the problem than any thing. Find a weapon that has the right balance of concealabilitity, fit, mass, and trigger pull. Practice often. Practice some more.

There is a BIG difference between marksmanship at the range and self defense.
I have seen the best officers in real world situations lay down fire like the spray pattern from a fire hose so remember the game is mostly mental.

BTW, buy a pistol that is 100% reliable. Pretty by it's self don't get it.

Jim K

[ripley16]

I'd give any thing for an extra .1 on my "barrel".

A 50% increase... that's a lot to wish for.;)

[earle8888]

I agree and ditto the last part of Jim k

[jocko]

A 50% increase... that's a lot to wish for.;)

really need to get a grip on urselves!!!!!!:cheer2:

[Bawanna]

Hickory, dickory, dock, I wanna big .......... speaking of which where the heck is Jfrebin lately. Been gone awhile.

[jocko]

oh my bawanna I am speach less. which is odd for me as u well know.