How does an Ithaca 37 eject?

**4V50 Gary** · April 6, 2022, 10:55 AM

I don't have one in front of me but it just dawned on me that I never thought about how they ejected. If I had one in front of me, I could figure it out myself but I turn to the audience.

I know they're bottom ejection.
I know they have dual extractors; with one top and one bottom

Pahoo · April 6, 2022, 01:19 PM

Gary,
If it helps, it's design features has it's roots in the Winchester-12 and Rem.-17. At one time, I remember and opperational animation, on YouTube. Perhaps this video link, might shed a tad on light, in the subject. .....

https://www.youtube.com/watch?v=IJYyjyB8Hjw
https://www.youtube.com/watch?v=jRYcxfU-yQo

Be Safe !!

HiBC · April 6, 2022, 01:59 PM

There are two fingers,a right and a left.Thay can spring out a bit to pass around the shell.
They multi task. When down low,as the cartridge stops release a shell from the mag tube,these fingers catch it.As the slide begins to move forward,they function as lifters.

As the forward motion of the slide continues,these fingers spread enough to pass around the diameter of the shell. Then they rest high in the receiver till the round is fired.
Then as the side is pulled to he rear,once the hull clears the chamber.these fingers sweep down,flinging the hull out the bottom of the receiver.

One modern problem that CAN show up with the I-37 has to do with modern ammo. he older shells had the case heads formed of brass,which was ductile enough to form a good,distinct rim with maybe a slightly larger diameter and a fairly sharp inside corner radius.

Today's plated steel case heads don't form as easily.The rims have a larger inside corner radius and the OD may be smaller. The Ithaca's dual hook extractors just don't have enough rim to grab.(In SOME cases!! Your I-37 may work fine!!)

When you have a failure to extract, the hull occupies the chamber. The shooter pulls the slide back,and another round feeds into the lifters.
Now that round cannot feed into the chamber, but the lifters prevent he new round from exiting the bottom. There is no side ejection port to shake it out of. And access to the hull in the chamber is a problem. Its a tie -up!!

In my experience,the immediate action is pretty easy and quick.

The bolt is already open,so the extractors are free of the extractor slots in the barrel. The barrel is easily removed by twisting the mag tube cap clockwise. That releases the underlug of the barrel from the mag tube . Twist the barrel 1/4 turn counter clockwise. The barrel has interrupted threads,so you will then be able to slide the barrel out of the receiver. The live round will shake out and the hull will flick out easily.

I love the I-37, its a favorite! But that weakness may be a consideration for an I-37 combat shotgun

FrankenMauser · April 6, 2022, 02:59 PM

Interesting that you've noted smaller rims on modern shells. That is not at all what I have observed, nor a people that I am working with.

As part of a shotgun evolution research project, a group of us discovered that quite a few turn-of-the-century designs -- especially for 20 ga guns -- cannot function with modern shells, because the rims on many steel bases are notably *larger* in diameter. (Also the different radius, but it only rarely matters, and only with some extractors.)

One now-forgotten brand (Union Firearms), in particular, has three 20 ga models that are completely incapable of feeding and functioning with modern bases (steel or brass), because the tolerances were so tight that even a 0.015" rim diameter increase causes a hard jam and binds the bolt.

I have seen some hiccups arise from these larger rims in guns made up until the early 1920s -- including with my own Remington 17, the design that the Ithaca 37 was based upon. However, the rim issue is most commonly encountered with repeaters made from about 1895 to 1905.

There is an ammunition historian in the group. Between them and the rest of us, we verified that most bases from the time period are a 0.015" to 0.020" smaller in diameter than modern shells -- pretty much anything made inter-war or newer.

It doesn't really apply to the rims at all. But while we are tangentially on the subject, many of those guns also will not run star/fold-crimped shells. They need the old style tapered roll crimp to function properly (for whichever shell length the chamber and action may have been designed to handle).

Dfariswheel · April 6, 2022, 03:37 PM

I'm not certain ejection is completely the same as the Model 37, but the Kel-Tec KSG and KS7 shotguns are modified John Browning Remington 17 and Ithaca Model 37 designs.

In these the ejectors are probably the simplest and most trouble free of any shotgun ever made.
The ejectors are nothing more then two recesses machined in the bottom side of the shell lifter.
When the slide is pulled back the bolt extracts the shell and pulls the case rim into these two cuts, ejecting the shell downward.
The lifter does not begin to move downward until after the shell is ejected by the ejectors.

Here's the shell lifter from a Kel-Tec KS7 showing the ejectors. John Browning simplicity at it's best ........

HiBC · April 6, 2022, 05:14 PM

Quote:

because the rims on many steel bases are notably *larger* in diameter. (Also the different radius, but it only rarely matters, and only with some extractors.)

OK. I haven't had an I-37 for several years.I shoot an O/U double.
The rim size issue was a recollection from a discussion about the I-37 with a friend and shotgun mechanic several years ago. I may have mis-remembered.

IMO,there is something about the modern ammo that seems to be related to extraction problems.Regardless ,I did reasonably well describing thr cycle of oerstion to answer Gary's question,

And if you do get a failure to extract,the tie-up descrbed will happen,and the remedy I described is effective.

jaguarxk120 · April 6, 2022, 05:37 PM

On the Model 37 the shell lifter arms do not sweep the spent shell from the action.
When the spent shell is pulled from the chamber the extractors hold it in place,
at the spent shell head/rim strikes a notch cut in the underside of the lifter arms.
This action causes the spent shell to flip out of the loading port and downward.
This is a design from the World's greatest gun designer.

TRX · April 6, 2022, 07:51 PM

Shotgun shell dimensions weren't truly standardized (in the US, anyway) until the mid-1960s. Before that, they varied quite a bit by manufacturer.

**4V50 Gary** · April 6, 2022, 11:25 PM

Thanks everyone. It's hard to vusualize it from a parts diagram alone and you guys made it easier.

rc · April 7, 2022, 02:01 AM

Browning BPS and Ithaca 37 are very similar with the Browning being the cheaper design with more stamped parts and a thumb rather than cross bolt safety. The elevator fingers do help eject with force with an extractor on the bolt in these guns. You got to clear out the old shell before you can lift in a new one. There are arguments these guns are not as good for tactical use as mossbergs and Remingtons where you can change out the shell in the chamber but they are a super reliable design by JMB. You can't lose a shell from the system like you can at a high angle with side ejecting pumps and muck and rain doesn't just fall into the action through a side opening like typical pumps.

tango1niner · April 8, 2022, 12:48 PM

I was having extraction issues with my Ithaca M37. Closer examination showed the crappy low brass heads of the Winchester ammunition were expanding into the extractor cut-out. This reduced the amount of bite the extractor had. That coupled with tired extractor springs (pretty old M 37) compounded the problem. I sent ammo back to Win. who said it was
good ???

I put new springs in place and all seems ok. I will find out for sure this summer when we shoot a little trap...

April 6, 2022, 10:55 AM	#1
4V50 Gary Staff Join Date: November 2, 1998 Location: Colorado Posts: 21,831	How does an Ithaca 37 eject? I don't have one in front of me but it just dawned on me that I never thought about how they ejected. If I had one in front of me, I could figure it out myself but I turn to the audience. I know they're bottom ejection. I know they have dual extractors; with one top and one bottom __________________ Vigilantibus et non dormientibus jura subveniunt. *Molon Labe!*

April 6, 2022, 01:19 PM	#2
Pahoo Senior Member Join Date: February 16, 2006 Location: IOWA Posts: 8,783	Reference Winchester Model-12 Gary, If it helps, it's design features has it's roots in the Winchester-12 and Rem.-17. At one time, I remember and opperational animation, on YouTube. Perhaps this video link, might shed a tad on light, in the subject. ..... https://www.youtube.com/watch?v=IJYyjyB8Hjw https://www.youtube.com/watch?v=jRYcxfU-yQo Be Safe !! __________________ 'Fundamental truths' are easy to recognize because they are verified daily through simple observation and thus, require no testing.

April 6, 2022, 02:59 PM	#4
FrankenMauser Senior Member Join Date: August 25, 2008 Location: In the valley above the plain Posts: 13,424	Interesting that you've noted smaller rims on modern shells. That is not at all what I have observed, nor a people that I am working with. As part of a shotgun evolution research project, a group of us discovered that quite a few turn-of-the-century designs -- especially for 20 ga guns -- cannot function with modern shells, because the rims on many steel bases are notably larger in diameter. (Also the different radius, but it only rarely matters, and only with some extractors.) One now-forgotten brand (Union Firearms), in particular, has three 20 ga models that are completely incapable of feeding and functioning with modern bases (steel or brass), because the tolerances were so tight that even a 0.015" rim diameter increase causes a hard jam and binds the bolt. I have seen some hiccups arise from these larger rims in guns made up until the early 1920s -- including with my own Remington 17, the design that the Ithaca 37 was based upon. However, the rim issue is most commonly encountered with repeaters made from about 1895 to 1905. There is an ammunition historian in the group. Between them and the rest of us, we verified that most bases from the time period are a 0.015" to 0.020" smaller in diameter than modern shells -- pretty much anything made inter-war or newer. It doesn't really apply to the rims at all. But while we are tangentially on the subject, many of those guns also will not run star/fold-crimped shells. They need the old style tapered roll crimp to function properly (for whichever shell length the chamber and action may have been designed to handle). __________________ Don't even try it. It's even worse than the internet would lead you to believe.

April 6, 2022, 11:25 PM	#9
4V50 Gary Staff Join Date: November 2, 1998 Location: Colorado Posts: 21,831	Thanks everyone. It's hard to vusualize it from a parts diagram alone and you guys made it easier. __________________ Vigilantibus et non dormientibus jura subveniunt. *Molon Labe!*

April 6, 2022, 01:59 PM	#3
HiBC Senior Member Join Date: November 13, 2006 Posts: 8,283	There are two fingers,a right and a left.Thay can spring out a bit to pass around the shell. They multi task. When down low,as the cartridge stops release a shell from the mag tube,these fingers catch it.As the slide begins to move forward,they function as lifters. As the forward motion of the slide continues,these fingers spread enough to pass around the diameter of the shell. Then they rest high in the receiver till the round is fired. Then as the side is pulled to he rear,once the hull clears the chamber.these fingers sweep down,flinging the hull out the bottom of the receiver. One modern problem that CAN show up with the I-37 has to do with modern ammo. he older shells had the case heads formed of brass,which was ductile enough to form a good,distinct rim with maybe a slightly larger diameter and a fairly sharp inside corner radius. Today's plated steel case heads don't form as easily.The rims have a larger inside corner radius and the OD may be smaller. The Ithaca's dual hook extractors just don't have enough rim to grab.(In SOME cases!! Your I-37 may work fine!!) When you have a failure to extract, the hull occupies the chamber. The shooter pulls the slide back,and another round feeds into the lifters. Now that round cannot feed into the chamber, but the lifters prevent he new round from exiting the bottom. There is no side ejection port to shake it out of. And access to the hull in the chamber is a problem. Its a tie -up!! In my experience,the immediate action is pretty easy and quick. The bolt is already open,so the extractors are free of the extractor slots in the barrel. The barrel is easily removed by twisting the mag tube cap clockwise. That releases the underlug of the barrel from the mag tube . Twist the barrel 1/4 turn counter clockwise. The barrel has interrupted threads,so you will then be able to slide the barrel out of the receiver. The live round will shake out and the hull will flick out easily. I love the I-37, its a favorite! But that weakness may be a consideration for an I-37 combat shotgun

April 6, 2022, 03:37 PM	#5
Dfariswheel Senior Member Join Date: May 4, 2001 Posts: 7,478	I'm not certain ejection is completely the same as the Model 37, but the Kel-Tec KSG and KS7 shotguns are modified John Browning Remington 17 and Ithaca Model 37 designs. In these the ejectors are probably the simplest and most trouble free of any shotgun ever made. The ejectors are nothing more then two recesses machined in the bottom side of the shell lifter. When the slide is pulled back the bolt extracts the shell and pulls the case rim into these two cuts, ejecting the shell downward. The lifter does not begin to move downward until after the shell is ejected by the ejectors. Here's the shell lifter from a Kel-Tec KS7 showing the ejectors. John Browning simplicity at it's best ........

April 6, 2022, 05:37 PM	#7
jaguarxk120 Senior Member Join Date: February 28, 2008 Location: Michigan Posts: 2,619	On the Model 37 the shell lifter arms do not sweep the spent shell from the action. When the spent shell is pulled from the chamber the extractors hold it in place, at the spent shell head/rim strikes a notch cut in the underside of the lifter arms. This action causes the spent shell to flip out of the loading port and downward. This is a design from the World's greatest gun designer.

April 6, 2022, 07:51 PM	#8
TRX Senior Member Join Date: September 24, 2008 Location: central Arkansas Posts: 400	Shotgun shell dimensions weren't truly standardized (in the US, anyway) until the mid-1960s. Before that, they varied quite a bit by manufacturer.

April 7, 2022, 02:01 AM	#10
rc Senior Member Join Date: April 28, 2001 Location: CA Posts: 1,763	Browning BPS and Ithaca 37 are very similar with the Browning being the cheaper design with more stamped parts and a thumb rather than cross bolt safety. The elevator fingers do help eject with force with an extractor on the bolt in these guns. You got to clear out the old shell before you can lift in a new one. There are arguments these guns are not as good for tactical use as mossbergs and Remingtons where you can change out the shell in the chamber but they are a super reliable design by JMB. You can't lose a shell from the system like you can at a high angle with side ejecting pumps and muck and rain doesn't just fall into the action through a side opening like typical pumps.

April 8, 2022, 12:48 PM	#11
tango1niner Senior Member Join Date: March 5, 2009 Location: NY Posts: 317	I was having extraction issues with my Ithaca M37. Closer examination showed the crappy low brass heads of the Winchester ammunition were expanding into the extractor cut-out. This reduced the amount of bite the extractor had. That coupled with tired extractor springs (pretty old M 37) compounded the problem. I sent ammo back to Win. who said it was good ??? I put new springs in place and all seems ok. I will find out for sure this summer when we shoot a little trap...