442-1 & polygonal rifling

[BruceM]

This is another example as to why you should never accept what you read on line as gospel. My Kahr MK9 Elite 98 has polygonal rifling, as do all Kahrs with the possible exception of their economy models. Kahr issues no warning about using lead bullets in their handguns.

Roger that. Seems to me that my Springfield Armory Omega 10mm with the Peter Stahl top half has polygonal rifling. I've had zero issues with that bore leading. All manufacturers warn not to use reloaded ammo because it's a variable that cannot be controlled to any extent in dealing with warranty issues. The same goes for cast bullets in polygonal rifled barrels. Polygonal rifled barrels make proper bullet sizing a bit more of a sporting proposition but no where near an impossible one. Now, if you're one of those folks which cleans and inspects your guns after every 500-600 rounds whether it needs it or not, then firing cast bullets thru barrels with non-standard rifling may not be in your best interests. For those who do proper load development and maintenance, cast bullet with Glocks or H&K should not present a problem.

Bruce

 

[DevilDog72]

yes and...

I just bought a new 442-1 and a new 642-1 yesterday. One has a late November 2011 date on the shell envelope and the other has a January 2012 date on the shell envelope. They are quietly making them both ways it would seem.

Here's the greater mystery to me: the 442-1 came in the same blue plastic box that we've all been used to seeing for years, but the 642-1 came in an old fashioned looking dark blue cardboard box! Serial numbers were factory correct and matched the gun on each box. What's up with that?[/QUOTE


My 19-8 came in a blue plastic box and years later I bought a NIB 642-1 nl and it came in a blue cardboard box. Curious....

 

[MajorD]

Don't mean to get off subject but Polygonal- type rifling, to my knowledge as a certified Glock armorer, is only used in Glock and H&K handguns. This type of rifling can NEVER be used with lead bullets as it can result in dangerous increases in pressure.

A oft repeated story that is terribly false! With properly loaded cast lead bullets for routine shooting lead bullets in glocks and similarly rifles barrels are NOT some clicking time bomb.
I and many friends have fired tens of thousands of cast bullets in glocks with no surprises. Run a dry brush and a few patches down the bore every couple hundred rounds and it will keep it sufficiently clean and safe.
The problems develop when:
1) in RARE cases an extremely soft lead bullet results in excess leading which is ignored by the shooter and creates a bore constriction
AND
2) they are trying to run hot loads or a sloppy handload results in an overloaded round ( which would have damaged the gun regardless of bullet construction anyway)
OR
3) a jacketed round which has less "give" to squeeze through a lead constricted bore is fired in a heavily leaded bore
#2 keep in mind no gun company I know of condones the use of reloads which is pretty much how you end up with a lead bullet auto pistol round anyway.

In summary have some glocks shooting lead bullets blown up?
Yes, but the lead bullet alone as an independent factor is not a sole cause- there is more at play

 

[patrickd]

Lead bullets overpressure??? No way. Lead bullets offer less friction, start easier and generate lower initial starting pressures than a jacketed bullet .
The only reason they say do not shoot cast in polygonal rifling is due to poor accuracy with the softer bullets. Polygonal rifling has rounded lands and soft cast bullets don't grip the lands like a jacketed would and therefore tend to not stabilize properly. At 10 yds you won't notice this, but as range increases you will. I shoot cast out of a G19 and they shoot fine, but I cast with a hard alloy beefed up with linotype for hardness.
Polygonal rifling was developed for one reason. That was to extend barrel service life.
Anyone who would let a barrel lead up to the point where it restricted enough to cause a safety issue deserves to blow himself up. Even in the worst case scenario, I'll bet you you wouldn't blow up a serviceable gun from barrel leading. Think about what happens when you fire a shotgun slug through a full choke. The same thing would happen to your pistol bullet. It would swage down to the ID of the bore just like that way oversized shotgun slug does.