polygonal?
what does this term mean? how is it different from reg rifleing?thanks don
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quote:Instead of the rifling being square and hanging down in the bore so that
it can engrave a square notch in the bullet it has flats where the
rifling would be. The bullet is not upset much. Instead of having 6 or
8 sharp knotches it will have small flats that are very unnoticeable.
This makes the bullet fly better in the wind because there is no sharp
edges to bite into a cross wind. The bullet jacket is not deformed as
much so the chances of loose cores are much less. Since there is no
sharp corners to burn off the barrel life is much longer and is
dependent on heat checking alone to end its life. That is one major
reason most barrel makers are not interested in them. It would decrease
their business by half. They are more difficult to make than regular
rifled barrels for a couple of reasons one being they are difficult to
lap and give a cut barrel maker more problems due to tooling.
Gale McMillan
Guns kill people like spoons made Rosie O'Donnell fat0 -
Maybe this will help visualize the shapes. 
Credit for these illustrations belongs to: http://www.firearmsid.com/0 -
Hello I believe the English FERGERSON was one of the first to use it then The NEWTON rifle co in BUFFALO NY. Now I know H&K use this type in the P9 as well as others.the people that use it make it sound like the greatest thing since sliced bread but I have never known any records on any match guns of any kind to use this type of rifleing. NONONSENSE YOUR PICS ARE GREEAAT first class and as they say a pic is worth 1000 words.
"PRAISE THE HARDBALL GUN"0 -
A number of upper end European companies use polygonal rifleing...Peter Stahls, Desert Eagles, H&K amoung others. 0 -
I have heard not to use lead bullets as the barrel leads easily?
[:)]
When a worm wants to relax,does he go fishing?
ATF,Eagle Guns0 -
Here's what Magnum Research has on their web site regarding polygonal rifleing in the Desert Eagle....
"Why can I not see the rifling in my barrel?
The Desert Eagle features the innovative polygon rifling system. To the uniformed eye used to seeing the sharp edges of the land and grooves of typical rifling, the Desert Eagle pistols bore does look almost smooth and featureless. The polygonal rifling reduces gas leakage and bullet distortion and promotes higher velocity; longer bore life and easier cleaning. Accuracy is typically as good or better than conventional rifling, which is probably why many Desert Eagle owners claim that it is the most accurate pistol they've ever shot."
http://www.magnumresearch.com/FAQ_deserteagle.asp0 -
ATF,
I have shot lead bullets in both the Glock and Desert Eagle and yes, they do lead but I didn't notice that it was significantly more than with a conventionally rifled barrel. My barrel cleaning habits are pretty good so the shot number didn't get to be huge before I cleaned either one of the barrels. The supposed increase in leading is attributed to the improved gas sealing of the polygonal bore, which increases pressure and therefore velocity, temperature and leading.
I thought that it might be productive to add, that there are barrel manufacturers who are producing the polygonal rifling form in the longer barrels for rifles, as well. Gary Schneider, Lothar Walther USA, Shilen (Ratchet RiflingT), Broughton 5C (canted land) and someone had mentioned that Pac-Nor was also but I can't find mention of it on their website. I have two of Gary's that I'm testing currently so I'll have some first hand observations from rifle length barrels also.
Here is a C&P from another site regarding leading and a photo to go along with the written portion. Well, the picture is protected so you'll have to use the website link: Screw the picture, it ruins the size of the board. If you'd like the link, use my profile and e-mail me and I'll e-mail it to you.
Can I shoot lead bullets in my Glock?
This has been debated on rec.guns and GlockTalk about 10,000 times. There are basically 2 schools of thought:
School #1: Don't Do It
Glock barrels use special polygonal rifling not found in most handguns. This rifling is one of the main reasons Glocks are extremely accurate guns. However, the same rifling can cause a high degree of leading when not using jacketed bullets. In other words some lead from the bullet sticks to the inside of the barrel when it is fired. Too much leading can quickly lead to high pressures which can cause the barrel and/or gun to break or even explode. Most people who weigh in on this subject fall into this category including Glock Inc.
School #2: Don't Worry About It
If you clean your barrel well and do it every time you shoot there will be no significant leading. Many, many people use lead bullets almost exclusively in their Glocks and do not have any problems whatsoever.
Additional notes from [Hoss]:
Not all lead is created equally. You can shoot lead in your Glock (probably) but you should use a hard lead from a reputable manufacturer. The homemade lead bullets made from wheel weights and other recycled lead should be avoided! Just becuase one type of lead bullet and load shoot fine in one glock does not mean it will be safe in others. Each barrel is different and must be carefully checked when first using lead.
Additional notes from [JT]:
You *can* shoot lead in a polygonal barrel, as many Glocksters do. But you need to be aware of some potential dangers in using lead bullets, not to mention voiding your Glock warranty if you use non-factory ammo.
First, if you decide to use lead bullets, use hardcast bullets at medium velocities for best results. This will reduce potential leading of the bore. Theoretically, polygonal rifling allows the bullet to seal the gases better than traditional land and groove rifling, thereby increasing velocities but also increasing potential problems with bore-leading-induced pressure spikes. Lead particles from the bullets have no where to hide in polygonal rifling as in the lands and grooves of conventional rifling and with better bullet-to-bore sealing, serious pressure spikes can develop when the bore is fouled.
However, note that some dismiss the purported velocity increases with polygonal rifling. Mike Orrick (GlockTalk's "BrokenArrows") has pointed out that his chronographed results of identical loads in conventionally-rifled barrels versus same-length polygonal barrels yielded higher velocities in some of the conventionally-rifled barrels.
Secondly, absolutely get all the lead out after at least every 200 rounds to avoid lead buildup, pressure spikes and potential corresponding kBs! With the tighter seal of the bullet, pressures can increase significantly in polygonal barrels. There have even been reports of Ranier-type bullets shedding bits of copper jacket in polygonal barrels, causing the same pressure spikes that are caused by excessive leading. Just be sure to use hard-cast lead bullets or good-quality jacketed bullets and keep the velocities down to earth.
Thirdly, polygonal rifling doesn't get the same grip on the bullet as conventional rifling. This may affect accuracy with some loads, especially hot ones. Even with using copper-jacketed bullets, some LEAs have reportedly banned the use of polygonal barrels in duty guns because of the potential difficulty in forensically identifying the rifling patterns on a bullet shot from a polygonal barrel. IOW, it's sometimes impossible to identify which polygonal barrel a particular bullet was shot from. Who shot whom?
Another recommendation is to moly-coat your lead bullets and/or treat your barrel with one of the spaceage lubricants, such as TW25B spray from Kleen-Bore. This will definitely help the cleaning process and may even increase velocities slightly and help with accuracy.
Last, but not least, most experts recommend getting a conventionally-rifled barrel from replacement barrelmakers such as Jarvis or Bar-Sto if you shoot a lot of lead. These barrels generally offer more case support than stock Glock barrels as a bonus. Use your replacement barrel for practice and the stock barrel for carry.0
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