View Full Version : H & R 12 Guage Single Shot

December 30, 2010, 03:44 PM
I recently inherited an HR Single Shot 12 Guage and wanted to try it out. Does anyone know what casing lenght I can use? Any tips? I have only shot pump action shotguns.

December 30, 2010, 04:13 PM
It should be marked on the barrel. If it's really old and not marked it's probably 2 1/2"

December 30, 2010, 04:28 PM
We will lump it in the really old category then. Will there likely be any catastrophic repercussions if I use a longer shell? Sorry, I am a pistol guy so this shell length thing is weird to me.

December 30, 2010, 04:38 PM
You can probably measure it, from where the barrel starts and the chamber ends out to the back end. So basically measure from the back of the barrel inside the chamber to where the primer would be at the back. Should be either 2 3/4, 3, or 3.5". Newer ones are 3 inch but check it out to make sure. If you use the wrong size the shell wont sit up in the barrel right and I dont know what will happen if anything but lets not try it

December 30, 2010, 04:40 PM

Do NOT fire any modern ammunitiion in that gun. I inherited one 20 years ago and bought some ammo about 15 years ago. Fortunately, I never tried to fire it as I was sold 2 3/4" Winchester magum double ought buck. Had I fire it may have shot the firing pin back out in my face!

Just becasue the 2 3/4" inchers fit the chamber does NOT mean it is designed for them and especially ones with heavier loads. A gunsmith can measure the chamber and tell you if it is desighed for 2 3/4 or 2 1/2, but I have been advised until mine is checked out not to fire anything more thatn 2 1/2 inch shells AND ONLY ones desighed for older guns.

Here is that thread which is only a few days old. I think someone there suggests shells for older guns.

December 30, 2010, 04:42 PM
If it's not marked on the barrel, get a gunsmith to check it. Or, you can check it yourself with a fired hull.

Shotguns are chambered differently than other firearms. A shotgun chamber is long enough for the shell to completely open while in the chamber. The forcing cone is beyond that position, then the bore. At the very end of the barrel is a constriction called the choke.

So, if a fired 2 3/4 shell will chamber easily, then the gun is likely chambered for that shell, but only a gunsmith will be able to tell you with any authority.

Will there likely be any catastrophic repercussions if I use a longer shell?

Probably not, but then again, if it's an old shotgun... who knows? You might get a KA-Boom, you might not. It's safer to have it checked.

December 30, 2010, 04:57 PM
Thanks everyone for the info. I'll see if can find a gunsmith here in town that can tell me what size.

December 30, 2010, 04:58 PM

It is a quite possibly a 2 1/2" chamber but definitely is not a 3" or more. I cannot get a real good measurement on mine as I don't hve the eqipment, but it the end of the chamber, if I am looking at it correctly, is no more than 2 3/4" from the breech. As I can't get a good straigt measurement, it may only be 2/12.

Besides the size of the shell, don't we also have to consider the pressure generated by modern "magnum" loads versus what the breech and barrel were desighed for?

December 30, 2010, 05:03 PM
PawPaw is correct. I forgot that the chamber has to be longer than the shell in order for the the fired shell to open up. If yours is as old as mine, and it is the large frame model, it is desighed for a 2 1/2" shell. Regardless, it would be smart to have a smith check it out.

December 30, 2010, 05:16 PM
Besides the size of the shell, don't we also have to consider the pressure generated by modern "magnum" loads versus what the breech and barrel were desighed for?
if it's a 2 1/2" chamber loads must be kept moderate. If it's a 2 3/4" bout anything goes. The only thing is older 2 3/4 chambers have a different slant on the forcing cone and it may not pattern well. Older guns used rolled crimps instead of the modern star crimp.

December 30, 2010, 08:36 PM
The thing is at least 40 years old... at least. Stopped by to see if Walmart had any 12 guage in 2 1/2. No luck. I will definitely take it to the smith before firing.

32 Magnum
December 30, 2010, 10:15 PM
The FIRST H&R shotgun chambered for 2 3/4" cartridges was the upgraded Model 1908 - Variation 2 - which was introduced in 1921 or '22. Up to that date/year - all the older H&Rs were chambered for 2 1/2" 12 ga.
This variation will have a "long", slim fore stock. The 1st picture is a 1st Variation. The second picture is a later variation with 2 3/4" chamber.


December 30, 2010, 11:52 PM
Hmmm, it looks like the second picture, but it has a 32" barrel. The serial number is 222703. I might check with H&R as well.

December 31, 2010, 12:41 AM
Mine is a little older, serial #36616. Instead of the snap on fore end, it has a screw to attach it and it also has the barrel pin with a hinged thumb piece. The width of the frame indicates to me that it is what is called a large frame Model 1900.

I read some other posts by 32 Magnum and have heard he is the go to guy on H&Rs.

32 Magnum. If you see this, do you know if in order to replace my firing pin spring I have to remove both the trigger and trigger guard, which are held by a small drift pin, and then remove a larger drift pin that retains the hammer. The later ones had firing pin screws inserted from the top of the reciever. Mine is inserted on the bottom of what I call the breech block. While the trigger pin was easy to drift out, the hammer pin doesn't want to budge. I am wondering if it was peened over to prevent the pin from coming loose.

Do you have any advice as to how to remove the triigger drift pin. I imagine I could try heating the reciever or drilling out the center of the pin while being careful not to enlarge the pin hole on that side of the reciever. Of course before screwing the pin up beyond use I would get one from NUMRICH.

The hammer pin for my large frame is still available for a wopping $1.75 from Numrich. Here is a link to the parts schematic. http://www.gunpartscorp.com/catalog/Products.aspx?catid=8079

December 31, 2010, 04:58 PM
As it turns out, I was at my son's house today and he has come into possession of an old Model 12 WInchester in 20 gauge. We took it down and measured the chamber. It's chambered for 2 1/2 inch shells.

So, on coming home, I did an internet search, and found some.

It's called Gamebore Ammunition and it's available in various shot sizes (http://www.midwayusa.com/viewProduct/default.aspx?productNumber=766772) in 12 and 20 gauge. I may have to order a case for my son's 20 gauge (http://www.midwayusa.com/viewProduct/default.aspx?productNumber=916525).

December 31, 2010, 05:53 PM

Thanks for the heads up. I will have to pick some of this up with my next order.


December 31, 2010, 09:27 PM
Edsal, Per oneounceload's suggestion on what I might try in my Model 1911 "look at Polywad or RST for low pressure "vintager" loads". The proglem with mine has to do with the firing pin not retracting into the breech block after taking as shot due to a broken firing pin spring. Is yours ok as far as that goes?

32 Magnum
January 2, 2011, 01:53 PM
Sorry for delay in responding - HOLIDAY stuff intervened. Also, thanks for the nice words - I try my best to help out with H&R stuff, to the limit of my knowledge - which is limited pretty much to the outsides. Looking at my examples of the Model 1900 - I don't see an easy way to remove the firing pin. There has to be a pin or screw somewhere that will release the spring mounted firing pin, but where that is, I can't determine.
Sorry I can't be of more help. Let us know how you make out - I'll make sure to file any info you provide - hopefully can help someone in the future.

January 2, 2011, 03:06 PM
Thanks 32 Magnum. I would post what I got from Numrich but it may be a copyright violation (not the free schematic). It provides that on some models the pin is internal and accessed by removing the tgrigger guard.

The trigger and trigger guard is easily removed bt tapping out a drift pin. Still, while I can see the head of the firing pin screw and I can get the blade of a screwdriver on it, I have been unable to get it to budge but I am being careful not to round off the slot for a common screwdriver blade.

I am going to try penetrting oil and modifying a basic screwdriver shank and then try to remove it. (This would be a cinch if it was on top of the breech.)

The better method might be to remove the hammer, which I attempted, as it impinges on access to the firing pin screw. What I thought is another drift pin, and it is clearly shown in the picture you provided, doesn't want to budge. I wonder if it isn't jusst pressed into place but if the ends are peened over. I have only tried tapping it out with a drift pin and it is possible it comes out with something like a gear puller.

Looking again at your picture, there is a difference between it and mine. They both have a barrel pin with hinged toggle that folds down into a recess cut in the side of the receiver. However, mine is circular while yours is more of a rectangle with rounded corners.

As for getting back to me quickly, don't be silly. I am asking you for help and expect you have other things to do with the holidays.