Underwood ammo Glock Barrel Question

[Masonlaw1]

So the G40 on the bottom took a nice deer last year. I used Federal 190 grain JHP duty ammo that was probably 20+ years old. With the SRO I can shoot a group at 50 that my hand can cover, couple of inches at 25 off a modified rest simulating field conditions. On the off season I ordered some Underwood 200 grain flat nose black cherry hard cast to hunt with this year.
I went out today, shot ten rounds of the 190 grain at 25 to confirm zero and then went back to 50. I shot from a solid bench off a solid rest. The first five rounds of Underwood were all over the place, I mean 16 inch spread. Shot five more, same thing. Loaded five rounds of the old JHP, and sub 4 inch group, dead in the diamond.
What gives? I’ve never read anything bad about Underwood and everything says hard cast shoot fine from a Glock. Bad batch? Next week im going to take the M&P 10 with the RMR, which I just zeroed, and try the ammo through it. The experience was disheartening.

 

[StrykerByte.45]

No, no one said hardcast shoots fine in Glock barrels. They said its safe to shoot in them, and better if poly coated. I suggest that you get a KKM precision barrel, that would be your best option. They are also much more accurate than Glock barrels.

 

[jmr40]

I've never used Underwood. But I have used heavy for caliber hardcast bullets made by Buffalo Bore and DoubleTap in 9mm (147gr), 45 ACP (255 gr) and 10mm (200gr) and have found it to be very accurate in Glock, S&W and Sig pistols.

 

[StrykerByte.45]

I've never used Underwood. But I have used heavy for caliber hardcast bullets made by Buffalo Bore and DoubleTap in 9mm (147gr), 45 ACP (255 gr) and 10mm (200gr) and have found it to be very accurate in Glock, S&W and Sig pistols.

Oh, okay. I misunderstood. I wonder what the difference is. Were either coated a certain way? Underwood uses a "Hi-Tek" coating now. I know they recently changed. BB, I'm not sure, I think they are just lubed somehow. Those things can make a difference and they might work with one gun and not the other and vise versa with the other rounds. This is why you should always buy extra ammo and test it in the gun. You expect to use it and it's range for you. Put it to actual use. You can't just use another manufacturer's ammo even though it's similar and call it "good to go" like these mindless new shooters like to do.

 

[JTQ]

I’ve never read anything bad about Underwood and everything says hard cast shoot fine from a Glock.

No, no one said hardcast shoots fine in Glock barrels.

In the "everything" world, I'd guess the Glock owners manual would be at the top of the "everything" list, and it probably specifically says not to do that.

 

[Lennyjoe]

My G40 shoots both the 200 and 220 gr Underwood loads just fine. No difference from them to my 200 gr XTP loads. All out of a factory barrel

 

[StrykerByte.45]

In the "everything" world, I'd guess the Glock owners manual would be at the top of the "everything" list, and it probably specifically says not to do that.

Don't confuse soft lead bullets with hardcast lead bullets. They are not the same thing. Hardcast lead bullets are safe to shoot in Glock barrels, though they might not be the most accurate. Keyword is might.

 

[Masonlaw1]

Thanks Lennyjoe for at least letting me know your experience is different versus telling me to read the owners manual or buy a different barrel. I’ll see what happens when I shoot the next ten rounds from the box through the S&W. Then I’ll check the next box.

 

[JTQ]

Delete

 

[Riomouse911]

Did you shoot another load at the same time to see if the sight hadn’t lost its zero? I’d hate to hear you bought a new barrel or spent money on something else, only to find out the sight went wonky.

Just an idea…

Stay safe.

 

[Masonlaw1]

Did you shoot another load at the same time to see if the sight hadn’t lost its zero? I’d hate to hear you bought a new barrel or spent money on something else, only to find out the sight went wonky.

Just an idea…

Stay safe.

Followed up the two underwood strings with a known ammo and it shot to zero. Strange.

 

[jjones45]

Not all guns like all ammo. That particular bullet the Glock barrel doesn’t seem to like. For self defense I like to keep stock barrels, but for hunting or target shooting I’d probably look at a kkm barrel and see what it does or just go with a different load all together.

 

[StrykerByte.45]

Did you say that the old ammo is JHP and the Underwood ammo is hardcast?

Did you chronograph?

180gr is very high sectional density and the limit of stability for a .40cal round. Anything past is really pushing it, and much more the higher weight and/or the faster you go. Polygonal barrels are much worse at stabilizing these rounds than standard barrels, specially the shorter the barrel is. Also, a hardcast bullet will be much harder to stabilize than a JHP, (an arrowhead has more weight at the rear of the projectile to ensure stability). A hardcast is balanced and requires more spin to stabilize it at higher speeds.
Like I said, high sectional density worsen these effects. Even if you get the .40 projectile to stabilize in trajectory, it will still have the high tendency to tumble upon impact, which is not good for penetration. It can be okay for hunting deer, but not to penetrate bear hide or bone for defense. This is one of the reasons I prefer the 255gr 45auto for defense, it will have straight line penetration more likely.

 

[welldoya]

This summer I bought a Glock 20 (10mm) to take to Alaska for bear protection while fishing. This was all new to me so I did a lot of reading.
Everything I read said to use hard cast for bears but I also read that it’s not good to use in Glocks due to the polygonal rifling. Apparently the leading can create dangerous pressures. I even contacted Glock and they said do not use hard cast in Glock barrels.
Of course, the rebels said they use hard cast in their Glocks with no problems and I’m sure a few rounds wouldn’t hurt.
One solution would be to buy an aftermarket barrel but I didn’t care to spend $700 on a gun and immediately buy a $200 barrel for it.
So, I looked around and found Federal Premium Solid Core for dangerous game. It’s a coated bullet similar to the Underwood and shot well in my Glock.
It was very hard to find and I’ve noticed that it’s even harder to find now. I don’t know if it’s been discontinued or what.

 

[Riomouse911]

Followed up the two underwood strings with a known ammo and it shot to zero. Strange.

Ya, that gun/barrel/ammo combo doesn’t seem to mesh. Sometimes that happens and it’s plan B time.

Hope you find a solution and can get back out there with your 10mm, that’s a great hunting auto for sure.

Stay safe.

 

[Lennyjoe]

Give KKM barrels a good look. My initial thought was to buy a KKM for my G40 like I did with my G20 but decided to hold off and shoot some rounds (reloads and factory). Needless to stay I’m sticking with the factory G40 barrel for now.

 

[StrykerByte.45]

Here's a document by Buffalo Bore about hardcasts in Glock barrels. It should answer all your questions.

Hard Cast Bullets in Polygonal Barrels

Hard Cast Bullets in Polygonal Barrels

www.buffalobore.com

But I'm the one that's wrong for saying hard cast are safe to shoot in Glocks. I'm always the one that's wrong.
I'm sure that I'm also wrong about how high sectional density bullets are more likely to tumble( in their trajectory or upon impact) and are harder to spin and require longer barrels and benefit from standard rifling barrels.

 

[SDGlock23]

I will say that hardcast may give "iffy" accuracy but I've found that Underwood 180gr XTP 10mm is very accurate in several guns.