Home Forums Hunting & Shooting Handguns Glock Smiles....

...doesn't get any closer to blowing a web than this....

Fired eight rounds of 10mm Underwood 140 penetrator ammo with the Lehigh solid copper bullet. Listed velocity from a 6" barrel is supposed to be 1560 fps... The first round from a Glock 40 was 1702. The three shot average was 1686 and one round out of a Glock 20 was 1640.

Four of the 6 recovered cases show excessive case bulge...two looked normal.










Sent these pics to Underwood yesterday but have not heard back from them...I'm a little hesitant to shoot the rest of this ammo. I have a two 1911s coming with supported chamber barrels but not sure I want to chance a blowout in those guns either...

Bob

Would a Wolfe barrel prevent that or is that ammo just to hot?

It's running 100+ fps over factory spec, which is already pretty hot.... A LW barrel I'm sure would help but I think this lot of ammo is a "little" warm. Factory ammo needs to be safe to fire in any 10mm chambered firearm...

Bob

At which point did you notice the first cracks...and did you keep shooting it afterward?

https://www.youtube.com/watch?v=WDvzul3rvTk

In this video the velocity from a 5" was right on the money...1507 fps...

https://www.youtube.com/watch?v=S2LKZy5-y64

I didn't notice the case bulge until I got home and emptied my shooting bag. As the ammo is fairly expensive I just shot 4 rounds over the chrono and then 4 rounds at a target 15 yards away to make sure the the rounds were hitting POA and how the group was...accuracy was excellent....

I was shooting some of my own reloads and had no case bulge at all...that said the 15.0 grains of AAC-9 with a 155 that was supposed to be going in the 1400 fps area from a 6" were only running 1130...

Bob

You can get 1130 with a 155 out of a .45 acp at standard pressure.

In my own limited experience with a G20, the Lone Wolf barrel I began with was MUCH worse in this respect than the Glock factory barrel I ended up with.

There's a chance the velocity measurement is actually the shock wave ahead of the bullet. I've seen that before with loads that have a lot of blast and are supersonic. The numbers are always in the range of what you're getting. Most often .357 Mag, but those loads are plenty hot enough. The solution might be to move the chronograph farther out, but I don't think I'd want to fire another of those rounds to find out.

Usually when this happens to me it's at an indoor range where the chronograph has to be pushed into position with a broom.

thank you for that, it might explain some readings i was getting with 44magnum over a chrony a few years ago, just set to close to the gun.

Chrono was fine...8' from the muzzle... Also chronoed .38 Super and .32 H&R Mag. that day and got expected readings including loads that hd been run over the same chrono in the past...

I don't think i would be firing any more of that stuff supported chamber or not.
i've never had that happen with my reloads in a glock 20 or a ruger blackhawk.
and in the blackhawk it was chronying to aound 1500fps.

13gr of AA#7, under a 155, in a standard Colt barrel (Hornady now recommends 12.7 max). It was running 1425 fps.



I've sold my S&W 610 revo, but still have the 10mm Kimber, which has a fully supported barrel. It will take pretty darn warm loads.

You need a lot heavier recoil spring before you fire any more of that. That should hold it in battery a tad longer, hopefully enough for the pressure to drop to a safer level.

A heavier recoil spring isn't enough there. You need a barrel with more chamber support before running any more of those loads. From personal experience, I recommend skipping the Lone Wolf and go straight to KKM if they make one yet.

Underwood does tend to load their 10mm a little warm for my comfort sometimes.

That's exactly what motivated me to let my Glock 20 go on a trade.

I was using PMC ammo.

Received a reply from Underwood to not shoot any more of the ammo and asked for the Lot Number....

Bob

The only time I've had any of my loads show "smiles" was when using less than maximum loads with AA#2.... Since then, Accurate Arms has dropped any 10mm loads using AA#2. In ortherwords, even some of the loading data can be pretty hot.
I've noticed that the "10" can do quite well with less than over SAAMI loads. And it can be very accurate. E

This.

Underwood is sending a UPS return label for the rest of the ammo and empties...they want to run the ammo in their Glock 40 and then will be sending me new ammo...

Sounds like they're being standup about it and proceeding as one would expect.

8' is the absolute minimum and could be too close for a load with a lot of blast. Ken Oehler himself recommends shooting through a 'blast shield' (a piece of plywood with a hole in it) to prevent shock wave-induced errors and/or moving the chronograph out to 15'. It's a cheap check when something is looking screwy.

i should add that in the glock, it has a much heavier recoil spring and a KKM barrel.

I tried a Lone Wolf 6" slide mated to a 6" Lone Wolf barrel. The accuracy was the worst I have ever seen in any of my handguns. I've had questionable performance from Lone Wolf barrels in the past.

I went ahead and sprung for a Bar-Sto 6" barrel that will need to be fitted to the Glock/LW 6" slide. When I get my Glock back from Bar-Sto I'll try some of those Underwood rounds. I've shot a lot of Underwood ammo in the past out of an OEM Glock barrel and didn't notice anything wrong with the brass after being fired.

From what I have read, KKM barrels have more support than LW barrels. I've had three KKM barrels (one 45 Super & two 10mm Auto) and the support was good and smiley's were nonexistent. I've never had a LW barrel to compare the two.

Jerry

The ammo has been switched out but there were other interesting developments with the Glock 40.... While cleaning the gun I did some function testing and discovered that the trigger was not properly resetting to the safe position. If the finger was quickly removed from the trigger it would usually reset but if finger was slowly removed it would not...would have been very easy to holster the gun with the trigger in the ready to fire position.

Since I had never stripped down a Glock before I called a friend who has been doing his own work on them for a long time. Upon pulling the receiver down the previous owner apparently had replaced the factory disconnect and trigger return spring with Ghost aftermarket parts. The striker spring had also been replaced with an aftermarket spring that was significantly less in weight that stock spring in my Glock 19...apparently that is why the trigger was not resetting properly and misfires.

Emailed the Seller and told him what was going on and requested the original factory parts be sent. He wrote back stating he thought he had put them in the box... Just gotta love people who don't know what they are doing and then when they sell a gun don't even bother telling you its been altered...

Got the parts back and put them in...all problems cured...zero malfunctions...

Back to the ammo... I had sold one box of the original lot of ammo to a friend and was not able to get it back before shipping the ammo back to Underwood. They test fired the ammo in their Glock 40 and got 1580 fps with what they call a normal smilely as their ammo is hotter than most. But they said there is nothing out of spec with the returned ammo. They shipped me the replacement ammo from a brand new lot just made up...


Get the box of original ammo back from my friend and give him a new box. And we run the old box through the same chronograph as originally tested...

Glock 40.....1625 fps {original 1686}
Glock 20 w/LW barrel....1645 {original 1640}
PARA LS Hunter 6".....1572

New lot of ammo:

Glock 40.....1602
Glock 20.....1581
PARA 6"......1570

There were no smilies on any of the brass.

One question I have for you Glock guys...does the striker spring contribute to the overall poundage of the recoil spring. I am just wondering if the aftermarket striker spring was letting the slide come back faster and that is what was causing the smiles on the brass. Three rounds of the ammo was fired out of my friends gun in the original test. Two of the recovered rounds have no smiles...I am betting one of them was fired from his gun.

If that is the case...could it be that a lot of these Glock Booms are being caused by reduced poundage striker springs put in to lessen the trigger pull...

Thoughts...

Bob

I have no personal knowledge, but I thought your question was interesting, and I started Googling. It appears that the recoil spring and the striker spring both contribute to lock up on a Glock. I found one thread where this was discussed on Glock Talk. GT Link There are other links that did not seem to have as much info that went on for pages. I tried to find if the striker spring has an impact on slide velocity but have not found anything so far.

As for me, the concept of a “normal smilely” just doesn’t sit well with me.

In a 1911, you can tune the locking with a square bottom firing pin stop, along with the recoil spring. Not sure how the heck you adjust it in a Glock.

My Sig P220 Elite 10mm has a very stiff recoil spring, and a very stiff mag spring, too.

A couple years ago Brian Pearce published some 10mm loads in Handloader, that he developed in Kimbers with fully supported barrels. If you can find them they might give a good outline on what is the upper end of safety in a well supported barrel.

Thanks...

In addition to the recoil spring and having a square bottom firing pin stop, the 1911 mainspring also contributes to slowing down the initial slide opening.

Since buying the Glock 40, I've also purchased two 1911s in 10mm. The first was a RAI Combat Commander size gun the other a Para USA Elite LS Hunter. Both have proven to be exceptional shooters.

I belong to LoadData.com...they have all of Brian's loads over there...many smokin'...

If anyone is looking for 10mm bullets, Widner's is having a sale on them. Just bought some Speer 165 bonded HPs for $12.00 a hundred delivered. That is about what I paid for the Berry's plated..

I keep threatening to sell the Sig and the two 10mm 1911's, and then buy a really good 10mm, like a Nighthawk or a Dan Wesson Silverback.

Thanks to this thread decided to bring the ol' Gen 3 29 w LW 5-in. tube to the Ranch today.

Need to see how the DT 135s hit. Thinking bout going big off duty all Spring & Summer.

DT 135s should be moving out quite smartly from a 5" tube....

The "ka-boom" I had with my 10mm G20 came with a 6" Lone Wolf barrel. I switched to a 6" Glock "Hunter" barrel, and also changed to a SS recoil rod and a stronger recoil spring and had no more problems - including smiles.

Whose SS recoil rod and spring did you go to...I'm looking at changing mine out also....

i'm not mikewriter, but i went to wolf
https://www.gunsprings.com/GLOCK%20%C2%AE/cID1/mID5/dID116#121

but don't work in generation four guns.

RJM, I can't remember the manufacturer (don't have the gun anymore), but I bought them from the Glock Store. They have a large selection of both springs and rods of different materials.

This.

I modified a 30-30 case and shot it 15 years ago in a Glock 20 stock barrel.

Waste of time. I got a 10mm Bar Sto barrel [better case support] and got a lot more power in work ups before bulges.

I got a KKM 40sw barrel for the Glock 20 and it will go even higher as 40sw brass[small primer] is higher pressure than the 10mm brass [large primer]. Gotta remember to throat the chamber if I am gonna use 10mm OAL with 40sw hot handload work up in that barrel.

Ended up ordering a Lone Wolf stainless steel Gen4 guiderod and dual spring set...should be here next week. And while ordering took another look at their aftermarket barrels...ordered a 6" .357 SIG barrel.

Last week Wideners had 10mm bullets of sale. One of them was the 165 grain Speer Gold Dot HP that ended up being $12.00 a box delivered...that's less than the Berry's plated 155s I have been shooting.

Bob

The Lone Wolf barrel and recoil spring assembly came in Thursday...

All I can say about the recoil assembly is .... WOW! I paid the extra $10.00 for the high polished unit and it was so slippery I dropped it twice before I got it in the gun. With the factory unit in the gun brass from the 10mm would go about 12'...with the LW unit 6-8'. The extra weight and spring rate make a noticeable difference in recoil impulse and muzzle rise. Well worth the money.

The .357 SIG barrel dropped right in and ran 100%. Did two ten round groups, one at 10 yards and one at 30 that could be covered with my hand... Although there were no failures to cycle I can tell that the recoil spring assembly is a right at the point of malfunction as all the cases dropped right at my right foot. I should have thought to try the factory setup to see if the ejection pattern is different...

For a house gun the gun will be setup as a .357 SIG with Buffalo Bore 125 Gold Dot HPs. These are rated at 1430 fps from a 4" barrel...should push 1500 from a 6"... For travel/car will go back to the 10mm with Underwood 140s for penetration....

Bob

I kind of call my glock a 41mag light.
what is interesting is to fire that 10mm round out of a rugerblackhawk with the longer barrel.
It is smoking.

Marking

Why do you chrono 8' from the muzzle?
I have always used 10 ft.

Get the Bruin. 10mm wants the extra barrel length. Keep the Sig, though.

...as long as the blast was not effecting anything 8' has worked fine.