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Ithaca Mod. 37 Malfunction

8K views 20 replies 9 participants last post by  drcook 
#1 ·
This malfunction occurred in my Model 37 Featherlight 12 Ga., early 1960's Mfr., in perfect condition (or was). Ammunition was new (Remington 2 3/4 target loads). While doing some clay shooting, a shell in the magazine discharged upon slide retraction following a normal firing of the chambered shell. Fortunately the live shell ahead of the errant shell in the magazine did not discharge as well, or there might have been some serious damage. Upon the discharge of the shell in the magazine, it recoiled into the carrier, piercing the shell head, and the primer blew out of the shell, thus releasing additional pressure to prevent rupture of the hull. I recovered the primer with a metal detector and found that it had an indentation which is a perfect match for the rim of a 12 Ga. shell. This suggests that, upon slide retraction, the rim of the ejected shell from the chamber somehow struck the primer of the shell in the magazine causing that shell to discharge. Human error regarding gun handling and loading can be ruled out here. I have never seen this happen before nor heard of it happening. If anyone has had a similar experience or some pertinent information to share, I'd be interested to know of it.

Photo link=http://img109.imageshack.us/img109/4853/model37041.jpg
Primer photo (Note the primer separated from the battery cup)=http://img594.imageshack.us/img594/5329/iphone112712085.jpg
 
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#2 ·
It happened to me with a 37 I bought new in about 1973. This gun also had the annoying habit of sometimes dumping shells on the ground instead of bringing them up into the chamber. I found out 25 years later that there is a small spring that needed replacing. I also found out that a friend who was in Viet Nam said no one wanted an Ithaca because of the hull dumping problem. I fixed mine by selling it and getting an 870 Remington.
 
#3 ·
Shell dumping is caused either by worn spring/gunked up right hand shell stop or the right hand shell stop needing to be "timed" by it's end being bent over more to the left. It's a well known problem with an easy fix, inherent in the design. Such a problem is entirely and completely different of an ejected shell hitting the primer on a shell in the magazine and causing a discharge.

Here's the sequence. Shell in chamber, shell in magazine, hammer drops and shell goes boom down the barrel. Carrier has two steel fingers which are up in a recess on top of the action. User racks slide back, which pulls fired shell past those two steel fingers and when the metal end of the shell hits the back of the action the two steel fingers drop to guide the plastic front of the shell out and down towards the ground. Normally, those steel guide fingers would keep the metal shell cap from getting anywhere near the primer of the next shell in the magazine.

But it happened. Twice at least. So the next theory is that there is a timing failure that allows the shell in the magazine to dump and it dumps just exactly in the correct split second to meet the falling steel fingers, which tip the live shell up to meet the falling end of the fired hull,,,and kaboom!!!

This needs to go on I love my Ithaca, so that Les Hovencamp and Walt can weigh in on this one. I've heard of shells dumping, but never a shell coming out of the magazine meeting the head of an ejected shell.

Another real possibility could be misaligned "fingers" that don't properly catch the ejected hull and "hold" the fired hull behind the live shell. Then as the properly timed live shell releases, the magazine spring slams the shell back towards the rim of the "held" fired hull and Kaboom.

But I can't see how that the head of the ejected shell can ever get past those steel carrier fingers to hit the primer of a shell that's still completely in the magazine. And, if that shell was completely in the magazine when it went kaboom,,,it would have just wrecked the gun. The shells here are firing off in an unconfined state or else we'd have lots of mayhem and destruction.
 
#4 ·
SuperXOne said:
The shells here are firing off in an unconfined state or else we'd have lots of mayhem and destruction.
The only damage I recall is the wooden magazine plug was partially split and the spring was stuck into the end of it. But, it's been 25 or 30 years and I've slept since then. Without having a bolt face behind the shell, it lets the primer fly out, relieving pressure pretty fast, I suppose.
 
#8 ·
Where was the shells that in fact was in the barrel chamber go? Did you find it?

Where did the payload of the Kaboom shell in the magazine go?

What did the face of the shell ahead of the Kaboom shell up in the magazine look like?

Was there any damage to anything?

Could you please post a photo of the primer of the Kaboom shell.

This is extraordinary. Let's try scenario number three. Fired shell goes boom, slide racked, incorrect sequence for ejection of fired hull, fired hull is somehow stuck and brought back up to meet the head of the shell in the magazine.

I wish you'd post this over in I Love my Ithaca. I just buy these things ,,,I'm not a real expert at all.
 
#10 ·
My incident was quite awhile back, way before digital cameras, so I'm a little fuzzy on details, but I'm quite interested to hear Cogents replies. From what I remember, here's what mine did.
SuperXOne said:
Where was the shells that in fact was in the barrel chamber go? Did you find it? On the ground, as normal.

Where did the payload of the Kaboom shell in the magazine go? In the magazine tube, seems like the crimp was just partially opened.

What did the face of the shell ahead of the Kaboom shell up in the magazine look like? I think I only had the one shell in the magazine.

Was there any damage to anything? Partially split wooden magazine plug.
 
#11 ·
Thanks for your interest and input.
The shell which discharged normally in the chamber was on the ground, having ejected from the receiver. The rim of this shell had a flattend dent about 3/8" long along the radius of the rim and 1/8" in width. This dent looks like it was caused by impact with a flat metal surface rather than the primer of another shell (just to confuse the issue more). None of the other shells fired that day have any such damage. The plastic hull of this shell is scorched just ahead of the metal base. No scorching at this location was noted on any of the other shells fired in the Ithaca that day (a total of 39 shells were fired leading up to this malfunction).
The live shell ahead of the discharged shell in the magazine was compressed from end to end and sooty, but, fortunately, was not discharged. I do not have that shell at the present time, but will be in possession of it soon. There was loose #8 shot in the magazine. The follower nose, made of metal in my gun, was dented. The magazine spring was distorted along several of its coils. It is obvious that the shell in question discharged in the magazine, but is set back about an inch or so into the receiver, having recoiled into the carrier rails, the latter piercing the head of the shell. This has locked up the action, and I will leave it like that for now while I look into the cause of this. There was no apparent damage to the other parts of the gun, however I can't rule that out until the gun is fully disassembled and examined.
I'll look into "I Love My Ithaca". I'm assuming that is another Ithaca forum?
Photo of primer (primer separated from the battery cup and the two were recovered separately with a metal detector)=
http://img594.imageshack.us/img594/5329 ... 712085.jpg
 
#12 ·
The "flat metal surface" that shell hit was the discharged kaboom in the magazine coming back and whacking it, is my guess.

That primer was split because it fired and the pressure drove it back against the rim of the fired shell, is my guess, too.

This just had to be caused by the ejecting shell somehow getting it's base over and hitting just exactly center on the primer.

There's just no way to prevent that. Whatever can happen will happen, I suppose.

I'm wondering if there was any problem with ejection. I owned a 37 once that I had to bend the carrier fingers in order to get to eject correctly. If the fired shell in the process of ejection got sideways in the carrier, that's my best guess of how it could get over and hit the primer of a shell in the magazine.

Right now I'd almost rule out any "shell dumping" causing that. Which is bad, because "shell dumping" is well known and is an easy fix.
 
#13 ·
From the other posts it sounds as if the carrier forks slipped over the rim of the fired shell during the ejection cycle. The fired shell being caught in the forks is pointing mouth downward, the action completes the opening cycle and releases a fresh shell from the magazine, the fresh shell hits the rim of the spent shell and the primer fires. During this time the spent shell is hammered against the front part of the trigger plate. The primer is ejected and the resulting gas pressure/jet forces the spent shell out of the reciever. The gas jet also pushes the shell forward back into the magazine compressing/distorting the mag. spring. The spring forces the shells back to the rear and impaling the shell onto the carrier forks.

Just a thought.
 
#14 ·
I witnessed an Ithaca have a round set off by an out of alignment fork as described here. The gun was out of battery when the shell went off and the force was vented into partially open action. No injuries and only minor damage to the gun. I believe that the gun had had several dropped rounds just before this occurred.
 
#15 ·
Same thing happened to me. From April 2012.

So I had a out of battery detonation this weekend,....

While shooting skeet with family and friends, using a older police surplus M37 Ithaca I took the shotgun from my cousins fiance after she fired it, muzzle pointed up and ejection port pointed away, with one hand on the pump and one hand on the stock (no finger in trigger gaurd) I racked the slide. halfway back, something happened and I'm not real sure what. What I am sure of is the next round as it exited the mag tube fired. The round was primarily in the ejection port, the mag tube took some force with the majority blowing out the ejection port. The shell carrige was bent and jammed the action, we set it aside thanked God for the incredibly stong John Browning action and went back to shooting. When I got home I starting cleaning and taking apart, the expended shell was jamed above the shell carriage. I pulled it and recovered the primer it has a strange distinctive mark in it. Closest I can figure is the ejecting cartridge rim was leaving when the mag spring released this shell back maybe the primer struck the rim of the incoming shell,...? I have no Idea. There was no damage to the forged receiver or mag tube, The shell carigge was bent down pretty bad, thats what jammed the action, I straightened out the shell carriage and she seems fine, still strangest thing I've ever seen . Glad it wasn't a side ejecter with some one standing next to me,.....that would have been bad.

 
#17 ·
MyTWINCH said:
Same thing happened to me. From April 2012.

So I had a out of battery detonation this weekend,....

While shooting skeet with family and friends, using a older police surplus M37 Ithaca I took the shotgun from my cousins fiance after she fired it, muzzle pointed up and ejection port pointed away, with one hand on the pump and one hand on the stock (no finger in trigger gaurd) I racked the slide. halfway back, something happened and I'm not real sure what. What I am sure of is the next round as it exited the mag tube fired. The round was primarily in the ejection port, the mag tube took some force with the majority blowing out the ejection port. The shell carrige was bent and jammed the action, we set it aside thanked God for the incredibly stong John Browning action and went back to shooting. When I got home I starting cleaning and taking apart, the expended shell was jamed above the shell carriage. I pulled it and recovered the primer it has a strange distinctive mark in it. Closest I can figure is the ejecting cartridge rim was leaving when the mag spring released this shell back maybe the primer struck the rim of the incoming shell,...? I have no Idea. There was no damage to the forged receiver or mag tube, The shell carigge was bent down pretty bad, thats what jammed the action, I straightened out the shell carriage and she seems fine, still strangest thing I've ever seen . Glad it wasn't a side ejecter with some one standing next to me,.....that would have been bad.

In my opinion if it had been a side ejection shotgun, this malfunction would not have happened. A bottom ejection shotgun puts the spent shell in place for the next live round's primer to come in contact with it. A side ejection shotgun doesn't do this by design.
 
#21 ·
If any of you still have those shells, can you measure the rim diameters ? On the ones that seemed to cause the malfunction (ie: the fired, not the discharged ones) and some of the unfired ones?

What I am alluding to is to see if there were some shells that had a rim diameter, while being in design tolerance, was on the low side and the tolerance of the "fingers", could be towards the high side. While both were to spec, a tolerance stack up occurred.

This actually happens a lot in the manufacturing world, especially in the days of manual machining, and someone didn't build things "to print" but used the allowable tolerances.
 
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