Firearm & Gun Forum - FireArmsTalk.com

Firearm & Gun Forum - FireArmsTalk.com (http://www.firearmstalk.com/forums/)
-   Gunsmithing Forum (http://www.firearmstalk.com/forums/f33/)
-   -   polygonal vs traditional riflling (http://www.firearmstalk.com/forums/f33/polygonal-vs-traditional-riflling-99137/)

kuntreebouy 10-19-2013 06:19 AM

polygonal vs traditional riflling
 
ok, I know from what ive read that polygonal barrels have higher vel. readings due to less gas escaping and they last longer, but I couldn't find a str8 forward answer on which is more accurate in a rifle, I figured some seasoned guys on here can probly give me the str8 forward answer im lookin for,, which barrel would make a rifle more accurate??????????

DrumJunkie 10-19-2013 06:47 AM

The only thing I have found that polygonal rifled barrels have that the others do not is the lack of ability of using lead slugs. I've seen no added accuracy. In fact the biggest user of such rifeling is used in Combat handguns that are not known to be tack drivers.

danf_fl 10-19-2013 09:42 AM

It makes me wonder why Marlin added the Micro-Groove to their rifles?

http://www.leverguns.com/articles/fryxell/microgrove-barrels.htm

Mercator 10-19-2013 11:16 AM

Quote:

Originally Posted by kuntreebouy (Post 1406208)
ok, I know from what ive read that polygonal barrels have higher vel. readings due to less gas escaping and they last longer, but I couldn't find a str8 forward answer on which is more accurate in a rifle, I figured some seasoned guys on here can probly give me the str8 forward answer im lookin for,, which barrel would make a rifle more accurate??????????

I have not encountered a long gun with polygonal rifling, only handguns. I don't think accuracy is the main point of PR. A PR bore is easier to maintain. There are no grooves to hide the dirt, or to wear off and shorten the barrel life. Companies play with long gun rifling every now and then. I don't think Marlin has been able to prove that its micro rifling beats others. Back to PR, it is a nice feature but for most of us not a game changer.

hiwall 10-19-2013 12:03 PM

It is like saying Chevy motors are better than Ford or Dodge. They are just different.
Marlin is kinda funny, they made their reputation with Ballard rifling then switched to 'micro groove'.
Just like anything else you can likely find those that swear by it and those that swear at it.

JonM 10-19-2013 02:30 PM

I find it hilarious people jump all over themselves fighting to get a pre remington marlin with the microgroove. The ballard style works muuuuuch better with the 405 bullets and is the same as a microgroove with the 300-350 bullets.

Marlin switched to microgroove as a cost saver which led to decreased sales due to poor accuracy with most 45-70 loads. When freeeom got em they retooled to ballard style in the old old marlin way producing superior barrels...

The new marlin 45-70 is what i consider a sleeper gun that a lottttt of folks are cutting off their nose to avoid.

The problem with polygon rifling is it creates very very high pressures in a normally safe cartridge. Thats why glocks go kaboom more often than other handguns when a oopsie cartridge makes it through inspection. Glocks that convert to standard rifling dont have a kaboom issue.

When you step up the pressures to rifle cartridges you start turning firearms into grenades. Thats why you dont see much poly rifling.

Mercator 10-19-2013 02:38 PM

Quote:

The problem with polygon rifling is it creates very very high pressures in a normally safe cartridge. Thats why glocks go kaboom more often than other handguns when a oopsie cartridge makes it through inspection. Glocks that convert to standard rifling dont have a kaboom issue.
I think it is overstated. If the Kahrs and the HK's went kaboom because of their polygonal rifling, I've never heard of it.

KG7IL 10-19-2013 05:23 PM

My AR pistol has a BHW poly barrel. Can't say that I have tried to wring out the accuracy of that 7" barrel. I will tho' . . . all in good time.

I like the idea of a good gas seal and it's easy on the plated bullets.


Black Hole can be found at http://blackholeweaponry.com/

My pistol build is at http://www.firearmstalk.com/forums/f20/ar-picture-thread-83/index77.html#post1310243

JonM 10-19-2013 08:13 PM

Quote:

Originally Posted by Mercator (Post 1406387)
I think it is overstated. If the Kahrs and the HK's went kaboom because of their polygonal rifling, I've never heard of it.

they dont have unsupported chambers coupled with the poly rifling. mot handguns can take a lot of pressure with proper design. my point is poly rifling increases pressure and isnt normally a issue in handgun rounds

kbd512 10-19-2013 08:33 PM

HK's have gone kB!, but polygonal rifling didn't have anything to do with it.

If you have a gun with a high pressure cartridge and an unsupported case head, sooner or later it's gonna cause problems, even with underloaded factory ammo.

Most kB! are improperly loaded hand loads and a lot of them are way over pressure specs, which is why hand loading requires a lot more effort than most people put into it for it to be as consistent and reliable as factory ammo.

Yes, because the engraving process produces more force in polygonally rifled bores, the pressure is a little higher. It's still not that high. As for increased velocity, any velocity increase, like the pressure increase, will be marginal at best.

The quality of the barrel, and most importantly its heat treatment, has a lot more to do with the longevity of a rifled bore than anything else. The best barrel steel in the world is relatively easy to ruin with a poor quality heat treatment.

There's no significant difference in bore erosion between polygonal and land/groove rifled barrels. Almost all barrels that are worn out will have worn out throats and muzzles before erosion of the bore is a significant factor in the accuracy of the gun.

Basically, either is just fine for general purpose shooting. Most competitive target shooters I know or have encountered use conventionally rifled pistols and rifles. There's no reason why either form of rifling could not produce superb accuracy, but the cost of polygonal rifling generally prohibits all but the largest manufacturers from using it and it is mostly used for applications where cost is a major factor, like production of military/law enforcement pistols and rifles is concerned. They produce a lot of barrels, so the cold hammer forging machines are the way to go.


All times are GMT. The time now is 02:08 PM.

Copyright ©2000 - 2015, Jelsoft Enterprises Ltd.