Slam Fire Documentation

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PostPosted: Sun Jul 03, 2016 12:12 pm
ravengunsmith wrote:I still have to wonder if it was intentional

And *I* still can't understand how adding extra parts - that could do nothing except release the hammer when the slide locked up - could be *un*intentional. On the other hand, it could be that "trench-clearing mode" *is* a side effect of what I think the aim really was.

impala59 wrote:A shot in the dark, so to speak, perhaps to achieve, with a manual action, (known reliability) parity in respect of rates of fire with the emerging self- loaders.....?

I don't think so.

I've used my M37 for several years now, nearly always for PSG. I *did* have a "serious" go at trying to engage steels in "slam-fire" mode and, with a bit of practice, I reckon that it *could* be done. However, it's not as easy as one would expect.

No, I reckon that the *real* justification was *much* more important...

Even shootin' nothing more serious than PSG, I know that a little pressure (nothing but a running timer, in this case) can make one "go to pot". You end up making mistakes. I can think of few things that'd apply more pressure than being in a gunfight. In a gunfight, there's not much more important than your gun going "bang!" when you expect it to. And *that's* what I think the extra sear is for.

So, let's set a scenario: you want to cycle the action - maybe after a shot has been fired or to take the gun from "cruiser ready" - in order to fire a shot. What happens if you squeeze the trigger *slightly* too early, before the bolt is in battery?

On a "normal" gun, as I understand it, for whatever reason you will *not* get a round fired. I do *have* pumpers that are *not* Ithacas, but I rarely use them, so I'm not that familiar with what actually happens. I don't know whether the action will be free (for you to rack in a new round) or whether you just have to let go of the trigger and pull it again. Either way, any sort of problem is *not* going to help matters.

However, if you're using an Ithaca with two sears, it doesn't matter; if the hammer is cocked, when you push the forend forwards, no matter *what* order you do things in, you'll get the expected "bang!". Now, to me, that seems a *much* better system in a gun intended for military use.

So, waddya fink of m'theory? Does it make sense to y'all?

Regards,

Mark.

P.S. Sorry, guys - I seem to have been a bit tardy with my reply...
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PostPosted: Sun Jul 03, 2016 2:56 pm
still not convinced slam fire was military driven.
I still think it was somehow a cog in brownings automatic and semi automatic gun design evolution.

think about it,,,
with the exception of the manually driven slide the is nothing to prevent a 37 from being full auto.
if you mechanized the slide action it would be classified full auto
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PostPosted: Sun Jul 03, 2016 10:26 pm
on a side note
after thinking this over I picked up my 41R that is slam fire capable
and my 82 ultra fleatherlight that cannot slam fire.

the difference between the 2 as we know it the disconnector .it mechanically keeps the hammer from being cocked, and there is a difference between that and keeping the hammer from being released.
I bring thing up because the result is having to rack the slide ,ejecting an unfired shell and loading a new one in without needing to manually press the slide release vs the ability to release the trigger and then squeeze it again to fire is a key point

nothing really new,,

then I got to thinking and took my 41R ,depressed the slide stop and pulled the trigger ,click!
now i'm not dumb enough to try it , but I can pretty much figure out what will happen if I fired the gun without the bolt being locked down by the slide stop.
the recoil will force the bolt and boltslide back into the receiver ejecting the shell.

there is half of the full auto cycle.i'm willing to bet if you put the right kind of coil spring between your forend slide and the receiver body you could get a full auto cycle.
either that or the gun explodes. and in either scenario I don't think the gun will last long

I don't recommend trying it ,and the act of doing it in my mind would be scary as hell
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PostPosted: Mon Jul 04, 2016 12:05 am
twistedoak wrote:and my 82 ultra fleatherlight that cannot slam fire.

the difference between the 2 as we know it the disconnector

Can I just confirm what you're saying, here?

You have an M37 Ultralight, made in 1982, that has a *disconnector*? Is that right? (I have to come clean here - I've no idea what a disconnector would look like...)

As I may have said, my 1975 M37's hammer stub has been removed (or never been fitted - I must take a closer look at the side of that hammer the next time that I get it out of the cabinet) to stop it slam-firing. I've never looked close enough at the trigger pack to see if anything *else* changed in the later guns.

Regards,

Mark.
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PostPosted: Mon Jul 04, 2016 8:38 am
the "stub" was removed and iirc the slide stop was altered to pevent the hammer from locking
aka disconnecting it
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PostPosted: Mon Sep 25, 2017 9:34 am
2nd Attempt here, first was wiped out during submission?
This has been a subject that has bugged me for a time now and so after a little research I now present what I feel is a definitive answer (maybe setting myself up for a fall there)
Firstly some (I won't call them facts as am sure to be reprimanded!) information, relevant to the subject

There are three different types of trigger for the model 37, the slam fire, the standard and the fire interrupter. The slam fire dates from the beginning 1937 up to circa 1975 and so may be also called the Original. The standard, introduced in around 1975 until current and the fire interrupter introduced around 1976 predominantly for LE use. I am somewhat vague with dates as production used up old parts and items on the shelf in stores were sometimes modified. Also the Ithaca Gun Co. was famous for oddities during production
1 Slam Fire (Original) trigger. When a shot is fired and the trigger held back during the reload cycle, the next round will fire as the bolt goes into battery, the slide will trip the hammer sear. If the trigger is released during the action cycle, the hammer will remain in the down/back position until the trigger is pulled again
2 Standard trigger. When a shot is fired and the trigger is held back during the cycle the hammer will not be retained by the sear and will follow or ride the bolt back into battery, it will have insufficient inertia to hit the firing pin and so will sit in the up/forward position behind a live round and the gun will not fire until the trigger is released and the action cycled again (live round ejected) If the trigger is released during the reload cycle the gun will fire as normal as the hammer will be retained by the sear awaiting another trigger pull.
3 Fire Interrupter trigger. When a shot is fired and the trigger is held back, the hammer will be retained by a second sear, and, as the action is cycled and another round loaded releasing and pulling the trigger will fire the next shot. Again, if the trigger is released during the action cycle, the second sear is redundant and the normal sear takes effect.

The Model 37 was developed from the Remington Model 17 and shares most of that guns design and features (JM Browning designed) In the early thirties Ithaca were looking at developing a pump gun and also seriously looked at the Winchester. How history could have been different! In the end patent expiry and the offer of manufacturing equipment from Remington (who had discontinued the M17 and were developing the M31) pointed the way. Now both of these potentials would 'slam fire', not as a feature but simply that was the way the mechanism worked.

The Model 37 has the fewest internal parts of any pump action shotgun, it is this simplicity that has seen the gun through the last 80 years.

Our grandfathers never saw the "danger of death" motto on every item that they purchased as we do today. They used common sense particularly with firearms. The so called 'slam fire ' was normal on many guns at that time.
Today, litigation is king and we are treated as though we cannot think for ourselves or take responsibility for our actions.

The military use of shot guns goes back way beyond the scope of this post, so I shall confine myself to the famous WW1 German demand for the banning of the trench gun (the also slam firing Winchester 1897) as a vile weapon when used by the doughboys for clearing trenches. How much worse than grenades, poison gas and artillery I can't imagine. One can imagine slamming your pump for all you were worth to clear a trench. The M37 was used in WW2 but it seems to have been most popular in Vietnam as a Platoon point weapon, where, using 00 buck, 72 9mm lead projectiles could be fired into the jungle in a few seconds using the slam fire. Additionally, a duck bill spreader was developed to improve the sideways spread. This formidable weapon was unsurpassed in this role.
I believe that US military trainers would take into account the performance and features of any given weapon and train their users appropriately, maybe some of the Veterans on this forum would know for sure and feel able to comment.

With Law Enforcement the issue is a little different. A LE officer who, using a slam fire trigger model 37 in a stressful situation, may keep his/her finger pressed on the trigger during an engagement or firefight and may well then encounter an Accidental/Negligent Discharge during the course of his or her duty. This, of course, the lawyers would jump all over. Like wise, using a standard trigger M37 in the same situation could find the officer with a dead gun in his or her hands with potentially fatal consequences. So was developed the 'fire interrupter' trigger which prevents both of these situations, albeit at the cost of some of the great simplicity of the M37 design.

For sportsmen, hunters, wing shooters, clay busters, IPSC competitors and the like, any of the triggers will be as usable and safe as any other. With a sound knowledge of your gun (and shouldn't we all have that as a matter of course?) all of these triggers are safe. I should mention here that early guns that are worn should not be slam fired as there is a possibility of the hammer striking before the bolt is locked, any gunsmith or the Ithaca Gun Co. itself would be able to check and rectify. I do not know if the 'Fire interrupter' trigger is available from the Gun Co., it is mainly LE but was apparently offered as an option to the civilian market. Over this side of the pond, most things Ithaca are rare and very few LE guns have made the crossing!

To finish I have satisfied myself that I understand how things were and are now, we all know that our M37's will always be referred to as that 'slam fire gun' I just think that we have firearms with a little more history than most and maybe that's why they seem to have more character than most.
The above is my opinion only and quoted information is from a number of publications, primarily the excellent books by Walter Snyder and by examination of my collection and also those of some of my shooting pals. If I have wrongly quoted anything regarding US Military or LE practice then I am happy to stand corrected

The original question from Mark (ChAoS) was about why have slam fire? I believe that in a different age it was simply why not? This was a tried and tested mechanism and, the gun would always fire and not fail when called upon, for defence or putting food on the table. All this achieved simply with few parts and the genius of JMB. Any documentation would be on the standard and fire interrupter trigger as these are the modifications from the original.
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