Wednesday, April 26, 2017

Glock K-boom, Rebuilding and testing

When I rebuilt my Glock after blowing it up, my original plan was to take it up to the range as soon as I got done with the Dentist. This plan didn't include breaking my wrist. It's now been about 4 weeks and the doc says I have 3 more weeks in the cast to go. Impatience won though and I tried out the new parts today. Here's what I learned:

1. Pulling the slide back with a left hand in a cast is very difficult.

2. I used to be able to shoot strong hand only passibly well. Now it seems I need some more practice. Shooting 2-handed borders on impossible, and weak hand, let's face it, isn't there.

3. The new barrel from Lone Wolf is very nice. It's also much fussier about the ammo I'm trying to feed it. I'm getting lots of failures to feed which I didn't get before. The cause I originally traced to insufficient final crimp, which seems to be back with the tighter barrel. I guess I get to re-crimp all my ammo.

4. I had been seeing some light strikes before, but much more now and noticeably off center so it looks like I need a new firing pin. I was beginning to suspect that problem before so I can't say I'm terribly surprised.

5. Trying to eject a lightly struck round from a tight-fitting barrel with a cast on your left hand is a waste of time. Change to an empty mag, use the rubber edge of the table against the side of the slide, and push. The stuck round pops right out.

6. Disassembling the gun with the fingers poking out of a cast and with limited flexure seems to be surprisingly difficult. I may need to make a tool to help pull the disassembly buttons down.

Gives me something to do during the impending snow storm. Mighty mountains from tiny molehills grow.


tsquared said...

One handed racking can be accomplished on the edge of your workbench. Barrel pointed down catch the slide on the edge of the bench and push down making sure the barrel clears the edge of the workbench.

Anonymous said...

some Glock slide pull assists available

Rock Your Glock



Brass Stacker

Billll said...

I was trying to avoid inadvertently using the front sight as an improvised charging handle. Once I get the cast off, things go back to normal.

Will said...

After your wrist heals, consider taking Judo lessons for 4-6 months. Make sure the class spends at least 1/3 of it's time learning and practicing falling techniques. Spend enough time learning how to do this, and you will be a LOT less likely to get hurt when you fall. That training will stay with you for decades, even without further practice. BTDT.

BTW, one of the causes, or amplifiers, of K-booms! is bullet setback. Glocks require a very tight crimp to resist this. The .40sw seems to be very sensitive to crimp and case tempering. Never re-chamber a cartridge using slide cycling. Better to hand drop it into the GLOCK chamber, lower the slide, and then bump the back of the slide to snap the extractor over the rim (NEVER do this on a 1911).
My G27 will shorten even new factory ammo, nearly every time a round is chambered. Reloads, even by re-manufacturers, can be scary in how much bullet movement there can be. This problem is suspected to be the primary cause of Glock K-booms!, especially in the forties. It plays hell with accuracy, due to the resultant variable pressure spike.

Since you reload, you may want to test cycle a round from each batch you build. Load from a mag, and measure OAL to check bullet movement. I've seen over 60thousands on re-man ammo. Scary stuff.

Billll said...

Good stuff to know. Thanks.

Roger said...

One of the most common problem with 9mm match barrels is that their chambers are much tighter than the original Glock caverns. Most reloading re-sizing dies do not go down the 9mm case far enough to remove the Glock bulge at the cartridge case base.
This bulge will cause the case to stick when it is most of the way into the chamber yielding the exact problem you complain about.
There are tools made to remove the bulge from "Glocked" brass. Meanwhile, you can
get a SAAMI cartridge gauge, which is nothing but a SAAMI 9mm chamber only, used to test fit reloaded ammo. If it fits in the cartridge gauge, it will fit in you Lone Wolf chamber. Finally, you are taper crimping all your autoloader ammo aren't you?

Roger said...

One more thought.
When a case has a glock bulge, it will commonly chamber almost all the way in, stopping a few thousandths of an inch before full chambering.
This can and does cause the barrel to fail to go up completely into battery,
This commonly causes misfires and off center (low) primer strikes because the case / barrel are not all the way up in full battery and alignment with the firing pin.

Billll said...

I had noticed the variation in primer dent locations and had wondered what might be causing that. My gun is .40 but the Glock bulge is present on a lot of the brass I use. I try to size the stuff as far down as I can get the press to go, but there often seems to be just a bit of bulge left over. Building a dedicated press just for this seems like a lot of work, but if it solves the "light, off center strike" issue than I guess it needs to be done.

Watch this blog for a post on an automated Glock-sizing machine. Just don't expect it right away.

Billll said...

O.K. it's not exactly automated, but pushing the cases through the Lee factory crimp die with the internals removed will remove the Glock bulge. Lee even sells a "bulge buster" kit that eases pushing the cases up and includes a cup to catch the finished brass as it pops out the top of the die. The effort required to do this to a case that's already been sized and decapped is modest to the point that a smaller piece of brass in the case holder can be used as a pusher, this in a single stage press.

Anonymous said...

Pachmayr RACK-IT Pistol Slide Racking Assist Tool

Billll said...

Judging by the number of gadgets out there to assist slide racking I would have to guess that there are a LOT of people with this problem for one reason or another. On the same page is the
Chambermax TA-1 which snaps into a Glock and adds some "knobs" to the slide making it easier to grip without getting in the way of anything else.
At the other extreme there's the P3, which looks like a variation on old-fashioned ice tongs.
The Handi Racker looks like it would work fine as a bench fixture for a target shooter It occurs to me that this one could be fitted with a "glove" to attach it to the back side of the weak hand if you wanted something to help shoot action pistol.

The Chambermax looks like the best all-purpose gadget to me at least, and would probably help most ordinary folk as well. My CZ, for example, has a 20 lb recoil spring and would benefit from something like this.

Getting injured is unfortunate, but you usually recover from it eventually. Getting old just plain sucks. We need a cure for that.

Will said...

Pay attention to rehab after the wrist cast comes off. It appears somewhat common to lose mobility in the wrist after fractures are repaired there. This can be due to the type and severity of damage, and efforts to regain what has been lost while immobilized. In most cases, 100% of original movement should be attainable.

Billll said...

Based on how it felt when the old cast came off, I'm anticipating a LOT of rehab work. (Grumble)