new G40

will965 · December 05 2015 04:43:20 PM MST

Guys,
Got a new glock 40 coming in tomorrow or Monday... Comes with a 6 inch barrel. Got lots a good ammo but I also have about 500 200g lead bullets....I know I can use powder coated but the lead is a different story. Anyone used a 6 inch replacement barrel for this...will a kkm or wolf barrel fit this glock 40? And most importantly_does it need it?

sqlbullet · December 05 2015 05:16:54 PM MST

My understanding is the same barrels that fit a Glock 20 would fit the Glock 40, provided they are long enough.

As far as lead and the Glock. They would need to be sized .402"+ and have a good lube. I would certainly try them in a factory barrel. I have pushed a good bit of lead through mine. But the trick is if they are already sized .401", which would be standard, then they will almost certainly lead up the bore.

will965 · December 05 2015 08:40:30 PM MST

Just calipered.bout 20.....ummm all .399 $:-\$ ....what does that mean?

fltbed · December 06 2015 05:59:03 AM MST

Quote from: will965 on December 05 2015 08:40:30 PM MST
Just calipered.bout 20.....ummm all .399 $:-\$ ....what does that mean?

That means you'll most likely get moderate to severe leading. You could try powder coating them.

As to the question of, do you need a different barrel for shooting lead, you have to understand how the rifling reacts to leading.

In a conventional land and groove barrel, the grooves fill up with lead till it will no longer spin the bullet to stabilize it. Your bullets start going everywhere and you have a heck of a cleanup ahead of you scrubbing all the lead out of the bore.

In a Glock polygonal rifled barrel, the leading builds up evenly around the bore, slightly reducing it's diameter a few microns at a time, and increasing the chamber pressures as the bullet is forced down an ever shrinking bore. You won't realize you have an issue till the gun does a rapid disassembly in your face. (aka KaBoom)

A good bullet caster will keep tabs on how quickly leading builds up in the bore and clean it out before it becomes an issue and experiment with different alloys, diameters and lubes till the bullet produces no leading in the bore.

There are many shooters out there and several on here, that have never had an issue shooting lead out of a factory Glock barrel and probably never will, because they understand little nuances of what makes a cast bullet work.

Hope this helps

Jeff

will965 · December 06 2015 12:27:54 PM MST

Thank you...but I was asking if the 399 will even work in the 10mm...I'm thinking they are sized too small

tommac919 · December 06 2015 03:01:46 PM MST

This is one time SIZE does matter... and how hard it is !!

fltbed · December 06 2015 03:34:07 PM MST

Quote from: will965 on December 06 2015 12:27:54 PM MST
Thank you...but I was asking if the 399 will even work in the 10mm...I'm thinking they are sized too small

Will they work? More than likely.
Will they lead up your barrel? Almost certainly.

As a general rule, you want your lead bullets to be .001-.002 larger than your bore diameter, so the bullet seals the bore. Undersize bullets, (especially harder bullets) tend to lead more due to gas blow by around the bullet as it's traveling down the bore.
That's why I suggested powder coating them. The PC will normally add .002-.003 to the diameter of the bullet.

Jeff

will965 · December 06 2015 06:52:30 PM MST

Pisses me off cause I already loaded 50 w/o measuring them...think I might take them back to the gun show guy and ask for an exchanged since they are undersized...bought a box of 500...

sqlbullet · December 07 2015 08:08:09 AM MST

Those would likely shoot without much leading in my Para P16-40/10mm as it slugs out at .399". Ideally they would be .400, but as long as they aren't linotype hard they should bump up and seal.

The best bet for these in a Glock would be to remove any bullet lube and powder coat them.

10mm bore diameter by spec is .392-.394" as I recall. Bullet diameter by spec is .400, but the noslers on my desk also measure .399.

The real issue with these is you will get some gas blow by. That will act like a plasma cutter. Powder coat will add a couple thousandths and they will be fine. Check out the tumble method using Harbor Freight red. Easy peasy.

The_Shadow · December 07 2015 11:15:02 AM MST

Glad I'm not the only one seeing 0.3990" - 0.3995" on the Nosler bullets ${$default_huh_smiley}$

sqlbullet · December 07 2015 11:54:28 AM MST

I have to throw one on the micrometer today when I get home. But the calipers read .399"

sep · December 07 2015 12:12:06 PM MST

I too have a G40. The KKM G20 and G40 take the exact same barrel. No difference between em according to KKM. I handload 200 grain WFNGC bullets from both Beartooth and Doubletap in my 6 inch KKM barrel sized to .401 and there is very little leading and it cleans up easily.

I haven't tried these loads in my stock Glock barrel as most of the posters on various web sites believe the aftermarket barrels shoot a little more accurately. I don't know if they do or don't but I do know the chamber on my KKM is both shorter and tighter than my stock Glock barrel. You can somewhat measure the difference with a dial caliper. A chamber cast would probably be more accurate but there is a definite difference in chamber dimensions between the two barrels. I have no interest in using the stock Glock barrel since the KKM works so well.

will965 · December 08 2015 06:46:55 PM MST

happy day happy day... I actually got my glock 40 last night and took her to the range today for some reliability test. I didn't shoot bullseyes but I did shoot a lot of steel. I ran through about 7 mags of the following.

2 mags 200g rnfp copper jacket (8.5g long shot)
2 mags 200g xtp HP(8.5 long shot)
1 mag 180g Buffalo bore HP..
2 mags ppu HP

Gun ran like a sewing machine even with the different loads...very impressed, no jams all day! Well, it ran like a glock.next time out I will shoot her for a accuracy but she sure smashed some steels! Love it so far.