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View Full Version : Polygonal rifling and lead bullets?



Waldog
02-12-2007, 03:58 AM
I just read on another handloader website that it is not recommended to load/shoot lead cast bullets in pistols with polygonal rifling. Is this a true or is it bunk?

Wayne Smith
02-12-2007, 08:38 AM
It's bunk. Polygonal rifling was used in muzzleloaders (well, actually hexagonal, but what's another angle among friends?) with lead bullets. Many a lead round has been shot out of polygonal barrels, and generally with reports of less leading.

Scrounger
02-12-2007, 09:05 AM
It's bunk. Polygonal rifling was used in muzzleloaders (well, actually hexagonal, but what's another angle among friends?) with lead bullets. Many a lead round has been shot out of polygonal barrels, and generally with reports of less leading.

The 'poly' in polygonal just means there is more than one side, it doesn't specify the number as 'hexagonal' does. 'Poly' is the same as 'multi'. I assume the current rifling you are referring to is 'pentagonal', having 5 sides.

44man
02-12-2007, 09:36 AM
I have never had anything with that rifling but it seems to me that it would be easier on a boolit then regular rifling. I sure would not hesitate using lead.

Char-Gar
02-12-2007, 11:47 AM
You are talking Glock and the like are you not. The common wisdom was these barrels didn't do well with cast at all. However, common wisdom is not always correct, nor is wisdom all that common.

I really don't know, but would like to hear from someone who have shot cast through such a barrel and not a dictionary. Anybody have any hands on experience with this subject.

NVcurmudgeon
02-12-2007, 11:53 AM
Whitworth.

Springfield
02-12-2007, 12:29 PM
I shot quite a few 9mm and 41 AE bullets through my Jericho pistol back when I was an Armored Truck driver. Very easy to clean, no sharp edges. I mean like we practiced every Wednesday, for 6 years, as I was the Range Master. I have heard the same thing, especially about Glocks. The theory I have heard is there isn't as much room for expansion so if your barrel starts leading the pressure can go way up very quickly. Never had a problem with mine, and I was just loading your run of the mill commercial bullets. Didn't cast back then.

TDB9901
02-12-2007, 12:29 PM
Wasn't Deputy Al. or some one running a thread on this awhile back ,.......... shooting lead through some of his Glocks, and reporting good success??

Waldog
02-12-2007, 12:46 PM
I'm not shooting a Glock. I have an H&K USP .40 S&W that has similar polygonal rifling. I can't imagine that lead wouldn't work but, I thought I would ask other "experts". The only thing I have fired is jacketed bullets in the H&K. I'm at least going to try.

dbotos
02-12-2007, 01:42 PM
From what I understand, conventional rifling bites into the bullet a little more and keeps it at the twist rate of the barrel better. In a polygonal-rifled barrel, the rifling may not bite as much and if the bullet twists less than the rifling, the rifling acts like an oblique scraping tool on the bullet (rather than a parallel track), and that scraped-off lead gets left behind in the barrel and a wave of hot propellant gasses pass over it (as well as subsequent bullets) and there's your leading.

http://upload.wikimedia.org/wikipedia/en/f/f8/Polygonal_vs_normal_rifling.gif

I have heard of people shooting lead in their factory Glock barrels, but for what you save casting your own, you can just buy a conventionally-rifled barrel and not have to worry about it. Plus, a black Glock (or any other black gun) with a nice SS barrel looks really nice.

rigmarol
02-12-2007, 07:09 PM
I have a S&W .500 with a poly barrel. It shoots quite accurately and I've been very happy with it. If I drive it too fast I've noticed a small amount of leading but I've seen worse.

I imagine if driven fast enough, you COULD force a soft bullet through the barrel before the poly rifling could get a good enough hold on it to stabilize it, but I've not seen in my gun.

I Know it's not a glock or a bottom feeder but I hope the info helps.

gasboffer
02-12-2007, 11:05 PM
I'm on my second Glock, (9 mm). The rifleing isn't polygonal, it's six groove with rounded lands.
I've shot several thousand rounds of cast bullets, haven't had any problems, except some off-brand brass is really thick and wouldn't chamber all the way. This would happen with jacketed bullets as well as cast. I carefully check all my brass before sizing and toss the off-brand brass.
Glock warns against shooting ANY reloads in their guns, they don't specify cast or jacketed.
Clyde

trickyasafox
02-13-2007, 12:13 AM
i shoot lead in a 9mm g17 a g23 40sw and a g30 in 45acp

my only conclusion with lead so far, is 200gr LSWC feed about as well as a dyslexic in a spelling contest.

other than that no problems. that being said, i dont shoot more than 150-200 rounds per session. Clean up has proven no more difficult than with jacketed for me. i run some hoppes down the bore, let it sit while i clean the rest of the pistol, then hit it with a nylon brush and some dry patches.

also i use fairly light to medium data. i get all mine from speer manual or lee.

Ron
02-13-2007, 12:40 AM
I have posted this before but here it is again. I shoot my hard cast 129 TC boolits in my GLOCK 34 with never a problem. Just don't use HOT loads and clean after shooting & you shouldn't have a problem.

ELFEGO BACA
02-13-2007, 01:02 AM
Hard cast bullets have worked in my Glocks. I had a 21 that took cast without a problem. I have a 23 for over a dozen years that has rarely seen a jacketed bullet but 1,000s of cast! No problem yet!

MtGun44
02-13-2007, 01:32 AM
When my friend called Glock after blowing up his Glock .40 with lead
bullet loads, they said basically "drop dead, we get 10 blowups per
week and they are all due to lead bullets and we tell you not to shoot
lead bullets, so go fish for any help"

I don't have one and Glocks aren't of interest to me, but this is his
story and he has loaded for rifles and handguns for 35 yrs and never
damaged anything else.

Bill

Ricochet
02-13-2007, 04:23 PM
I've never blown up a gun yet in 35 years of handloading, either. But handloaders do blow up guns all the time, from things like powder bridging in measures, giving a partial charge followed by an overload. I've seen it happen with my gear, but caught it before I loaded and shot it. (Knocking on wood.) Double charges are easy to get with small charges of fast burning powders, too.

9.3X62AL
02-13-2007, 08:33 PM
I responded in the Wheelguns/Handcannons area--summed up, SIZE MATTERS.

DaveInFloweryBranchGA
02-13-2007, 08:39 PM
I've shot Glocks several times and while I know they're light and easy to fix if broken, I've never understood why anybody would want one. I've had softball bats that had a better grip angle.

Seems to me like the XD-45 is the way to go these days.

Dave

GW_45ACP
02-14-2007, 01:18 AM
Glock's problem is the combination of leading with their barrel rifling design and a chamber design the doesn't fully support the case. I know that many people have no problem shooting the right cast lead boolits thru their Glocks. I also know that kB!'s are not unheard of, even with factory ammo. I have a friend that shoots cast lead through his .40 and 10mm Glocks without any leading problems. I would suspect that kB's have more to do with excessive case pressure caused by bullet seating depth and double powder charges than cast lead boolits. I even heard in one case that law enforcement practice ammo was chambered and removed from the gun over and over, eventually causing the factory loaded bullet to push into the case, resulting in excessively high case pressure and a kB! in a Glock. They are also able to fire with the slide slightly out of battery. http://www.thegunzone.com/glock/glock-kb-faq.html The leading of the barrel may contribute, but I'm skeptical.

BAGTIC
02-18-2007, 02:11 AM
When my friend called Glock after blowing up his Glock .40 with lead
bullet loads, they said basically "drop dead, we get 10 blowups per
week and they are all due to lead bullets and we tell you not to shoot
lead bullets, so go fish for any help"

I don't have one and Glocks aren't of interest to me, but this is his
story and he has loaded for rifles and handguns for 35 yrs and never
damaged anything else.

Bill

I suspect that is because most lead bullets fired are probably handloads and overloads are not unknown among overzealous handloaders. That isalso probably why most gun manufacturers include a disclaimer that the warranty is voided by use of handloads, lead or jacketed.

MtGun44
02-18-2007, 02:23 AM
I have no doubt that overloads happen. I have seen a letter passed
to me by our chief firearms instructor of our security force at work that
was from a big Federal agency asking why they were blowing up so
many Glock 40s with factory ammo and what was Glock going to do
about it? I have never seen the reply or heard any more about it,
but the letter was definitely real. Makes my wonder if Glock is using
the lead bullet thing to cover a real problem. Apparently all the
kabooms are with .40 caliber guns, altho I have no proof of this.

Don't like the Glock grip shape or angle, hate the triggers, my right
hand has been permanently formed into a 1911 grip shape, and I
love it. Besides the only time I shot a Glock 40 it hit me in the face
with the brass about 1/3 of the time. You can have all of my Glocks
that I didn't buy.

I do tell my students that if they use a Glock it will be very likely to be
reliable and reasonably accurate, so I try to keep my 1911 bias toned
down a bit in class.

Bill

TAWILDCATT
02-20-2007, 07:09 PM
i HAVE A HI-POINT IN 9 MM.FACTORY OR JAC BULLETS ARE VERY ACCR.HOW EVER LEAD HARDLY HITS TARGET AT 50 FT AND KEYHOLES.THAT GUN HAS POLY RIFLING AND I CALLED DISTRIB AND HE STATED NOT TO SHOOT LEAD BECAUSE THE RIFLING WOULD NOT GRIP BULLET.YOU CAN SHOOT LEAD IF BULLET IS HARD.THATS WHY GLOCKS BLOW UP.LEAD BUILT UP IN BORE.
WILDCATT

mooman76
02-21-2007, 12:36 PM
I have noticed that the barrel twist on the Glock is almost twice (something like 9 compared to about 16)as much as other barrels of same caliber even match barrels. I can't help but wonder if this has anything to do with the leading issue!

ebner glocken
02-21-2007, 08:53 PM
I load for my glock 19 using ww231, lead and no problems yet. When loading for my glock 20 it's lead and 800x with no problems at all. All loads are medium pressure, fired around 200 rounds per session, and cleaned afterwords. I've been doing this several years with no mishaps yet. Fortunatly I didn't hear about no using lead in glocks until I'de been shooting lead in them for a few thousand rounds.

Sundogg1911
02-21-2007, 10:01 PM
i cast .40's for a friend to shoot out of his USP. he hasn't had an issue with it.

9.3X62AL
02-22-2007, 02:43 AM
Mooman brings up a point of special irritation for me with the 9mm and 40 S&W--the twist rates in barrels of these calibers. The rates often run around 1-10", and this is twice as fast as necessary for the short fat bullets used in these calibers. Most aftermarket barrels use a more sane 1-16" pitch. That alone justifies use of an aftermarket barrel in a 9mm or 40 S&W for cast boolits.