G48 stovepipe with live round?

[Bret]

I had the same problem with an H&K USP40, though it would happen at any point through the magazine. I sent it back three times to H&K. They replaced the magazines which didn't solve the problem. When they replaced the recoil spring, the problem went away. Personally, I'd try to duplicate it with and without the suspect magazine.

[ChazC93]

I've had this happen on my G19 Gen 5. At 10,500rds I encountered this malfunction. It was a magazine issue. You can send it back to Glock or just go cop a new one.

[Uni-Vibe]

My govt. Size 1911 in .45 started doing this. Not only stovepiping, it was ejecting live rounds. Cheap gun show GI type magazine. I threw them away and got Wilsons. Problem solved.

Although johnnyrem is right about an alternative cause. It could be a question of slide speed and timing.

[Circle_10]

My govt. Size 1911 in .45 started doing this. Not only stovepiping, it was ejecting live rounds. Cheap gun show GI type magazine. I threw them away and got Wilsons. Problem solved.

Although johnnyrem is right about an alternative cause. It could be a question of slide speed and timing.

Bret’s post above about his USP, and your post, remind me of a thread I found on Pistol Forum where a poster felt that his G48’s recoil spring didn’t seem to hold up well to a high volume of 147gr loads and he felt that sticking with 115s or 124s was a better choice for that gun. However he was having a different kind of function issue.
And....I should probably not lose sight of the fact that I’ve only had one malfunction with my 48 so far, so it’s pretty early in the game to start getting suspicious. It was just a malfunction that I’d never seen before.
I haven’t seen anyone else really echo the findings of the poster on Pistol Forum but it may be noteworthy that all I’ve shot through my 48 thus far has been 147 ball and HST, although I don’t think at 890 rounds I have anywhere near the round count that he had on his 48.
My usual ammo vendor was out of stock on 147gr ball anyway yesterday so I ordered some 124s to try, as it probably would be a good idea to try more than one bullet weight in this gun anyway.

[johnnyrem]

Springs do not get stronger over time and use, only weaker. A weaker recoil spring does not contribute to this particular issue, but a weak magazine spring certainly does. The logical fault is a magazine spring that took a weakened set.

As regards gun show “GI” magazines, most people could not tell a GI magazine from any other type and figure if it says GI it must be that. Having been to many gun shows I can tell you the vast majority aren’t even close in terms of materials and construction. Feed lips are wrong, followers are wrong, spring strength is wrong.

A real GI spec magazine feeds rounds with a straighter shot at the chamber than any other type, including the “brand names,”.

JMB specc’d a tapered lip, seven shot magazine with a good spring and a dimple on the follower to feed his 1911 for a reason.

[17K]

Don't forget the dimpled throat barrel. That goes along with the full tapered feedlips and the 230 grain round nose bullet.

[mark5pt56]

I found this looking around as I didn't know about the dimple on the follower.


Inertia! Just no way to get around Newton's Laws regarding motion.
Remember the old trick of jerking a tablecloth out from under a table setting? This is the principle at work here.

We have a round in the chamber and one round in the magazine.

Bang! The slide starts to move as the pistol torques up and back. The slide holds the last round slightly below the feeding position until it moves far enough to uncover it. Just as the magazine spring is struggling to move the round into position, the round is in a sort of "Limbo" while the pistol continues to move backward in recoil. The round obeys Newton, and stands still while the gun is moving away from it.

The magazine spring catches up, and gets the round up and into the underside of the feed lips, but because the pistol pulled backward away from it (Even though the pressure from the slide drags the round backward in the magazine)...it settles down forward of the feeding position. At this point, if the magazine spring is strong enough to keep it there, the slide pushes it ahead of the extractor. The pistol either fails to go to battery with the round fully chambered, and the front of the extractor rammed against the back of the rim. Extractor breakage is an eventuality.

If the spring isn't strong enough, the round is forward of optimum feeding position just as the slide smacks the impact surface in the frame, and triggers a second recoil impulse. The gun makes a short, hard jerk upward and backward...and the round is in limbo once more because the mass of the round has caused the magazine spring to compress slightly. The round...already too far forward in the magazine...jumps the follower, and is free of the magazine. The follower pushes the slidestop up as the slide moves forward, and the slide locks. If the magazine spring is weak enough, the next to last round will be ejected from the magazine, and the last round feeds. Ever found live ammo among your brass? Heeere's yer sign!

The problem is two-fold. One is the spring that has fewer coils to make room for the extra round. There is ample tension to feed until it gets to the last round...and tension is at a mimimum...but sometimes it can happen before the last round. Upping the spring rate helps, but doesn't address the other issue.

The other part of the problem is the smooth follower. Browning knew how
inertia would affect things, and he put a small dimple on the top of the magazine follower. The dimple's function is two-fold. It adds a small amount of height to the follower in order to give it a "Leg Up"...and it stops the forward movement of the round. More accurately, it keeps the pistol from moving out from under the round in recoil. In this function, it's basically a back-up for the spring as it fatigues, and provides a better opportunity for the round to stay in position to be stripped from the magazine by the slide instead of being pushed ahead of it...or... in the extreme cases, escaping from the magazine completely.

John Moses designed a 7-round magazine and he put a dimple on the follower for very good reasons. Whenever we try to change things in order to "improve" the gun...we very often cause problems. There just ain't no such thing as a free lunch, I'm 'fraid.

[1168]

I found this looking around as I didn't know about the dimple on the follower.


Inertia! Just no way to get around Newton's Laws regarding motion.
Remember the old trick of jerking a tablecloth out from under a table setting? This is the principle at work here.

We have a round in the chamber and one round in the magazine.

Bang! The slide starts to move as the pistol torques up and back. The slide holds the last round slightly below the feeding position until it moves far enough to uncover it. Just as the magazine spring is struggling to move the round into position, the round is in a sort of "Limbo" while the pistol continues to move backward in recoil. The round obeys Newton, and stands still while the gun is moving away from it.

The magazine spring catches up, and gets the round up and into the underside of the feed lips, but because the pistol pulled backward away from it (Even though the pressure from the slide drags the round backward in the magazine)...it settles down forward of the feeding position. At this point, if the magazine spring is strong enough to keep it there, the slide pushes it ahead of the extractor. The pistol either fails to go to battery with the round fully chambered, and the front of the extractor rammed against the back of the rim. Extractor breakage is an eventuality.

If the spring isn't strong enough, the round is forward of optimum feeding position just as the slide smacks the impact surface in the frame, and triggers a second recoil impulse. The gun makes a short, hard jerk upward and backward...and the round is in limbo once more because the mass of the round has caused the magazine spring to compress slightly. The round...already too far forward in the magazine...jumps the follower, and is free of the magazine. The follower pushes the slidestop up as the slide moves forward, and the slide locks. If the magazine spring is weak enough, the next to last round will be ejected from the magazine, and the last round feeds. Ever found live ammo among your brass? Heeere's yer sign!

The problem is two-fold. One is the spring that has fewer coils to make room for the extra round. There is ample tension to feed until it gets to the last round...and tension is at a mimimum...but sometimes it can happen before the last round. Upping the spring rate helps, but doesn't address the other issue.

The other part of the problem is the smooth follower. Browning knew how
inertia would affect things, and he put a small dimple on the top of the magazine follower. The dimple's function is two-fold. It adds a small amount of height to the follower in order to give it a "Leg Up"...and it stops the forward movement of the round. More accurately, it keeps the pistol from moving out from under the round in recoil. In this function, it's basically a back-up for the spring as it fatigues, and provides a better opportunity for the round to stay in position to be stripped from the magazine by the slide instead of being pushed ahead of it...or... in the extreme cases, escaping from the magazine completely.

John Moses designed a 7-round magazine and he put a dimple on the follower for very good reasons. Whenever we try to change things in order to "improve" the gun...we very often cause problems. There just ain't no such thing as a free lunch, I'm 'fraid.

Thanks

[johnnyrem]

The GI pistols had what was a narrow relief on what would now be considered an unthroated barrel. This is considered a “hardball throat” and was all that was needed to feed a ball round with a curved front end and a curved ogive. SWC target ammo does not work with this type of barrel throat, which is really a clearance and not any type of feed ramp. The frame is the feed ramp.

The long commentary above in post 17 was a critique of eight round flush fit magazines without a dimple. Less room for spring in that space which means it is a weak spring. Not good. No dimple on the follower so there is no redundancy to make up for the weak spring. Not good.

The short leg on the follower to make it fit an extra round in the normal seven shot space make the follower less stable. Among other things this makes the slide lock less reliable and more apt for the follower to pitch forward after the last shot and ding aluminum frames. Not good. A less stable follower could not even have a dimple because the round would nosedive if it snagged the dimple. Not good.

The GI magazine has a decent spring plus a backup for the spring with the dimple. Redundancy is design genius, and he was.

[Circle_10]

So back to my Glock 48, does this look like a mag issue too?

0817B47F-8B13-47F8-A7E4-EC4C1C35B316.jpg

As far as I can tell, the slide got hung up on the round while going forward, with the round failing to strip out of the magazine. Looks like the slide almost overrode the round actually but hung up the bullet and left a pretty good mark on it. Once again it was the last round in the mag, but a different magazine this time. Ammo was Blazer 147gr. Round count now 950.

EDIT: I’m kind of thinking this one might have been more of a Circle_10 malfunction than the gun or mag actually. It kind of seems like this might have been some kind of short stroke. This could be caused by “limpwristing” the gun couldn’t it?