So I'm working on a franked-rifle project because I find that sort of thing fun. In this case, we're starting with an orphan M1909 Argentine Mauser barrel that had a bulged muzzle. Someone clearly removed this barrel and re-purposed the action, I have no idea if it got the ringed muzzle in service or through abuse here in Canada. The bore is otherwise pretty good. For a project, I'm going to build a German Kar98k pattern rifle that externally will look like an issue K98k, but that will be chambered in 7.65x53 Argentine. Why? Well, because I can, and I like the caliber. I have dies, brass, etc. already as well. I also have most of the parts on-hand.
I have a take off K98k 8mm barrel with a poor bore that I'm using for reference. By poor, I mean heavily pitted, counter-bored, and generally awful, but that's OK, we're just pulling dimensions off it.
So right away, there are some things that we need to fix:
1) An Argentine 1909 barrel is 29.13" long while a K98k barrel is only 23.62" long.
2) A K98k Barrel has a .900" journal ahead of the chamber that the rear sight base is soldered to. An argentine barrel, on the other hand, is 0.760" in the same area as the argentine sight base is smaller in diameter.
3) The end of the chamber area on a K98k is a sharp corner, on an argentine barrel, it's radiused.
4) The Argentine barrel necks down less quickly, so near the muzzle we will need to reduce the diameter to match a K98k barrel contour.
Here's an example comparing the rear sight area of both barrels after the sights are sweated off (Argentine on top):
Note that the argentine barrel is thinner. I've already cleaned the ruling off in prep to solder on a collar to increase the diameter. Also, I already turned the the front of the chamber area at the step to get rid of the radius there. The sleeve will now fit flush and we can re-machine a nice, sharp step like a K98k barrel.
In this photo, you'll see an old piece of shotgun 12 gauge barrel I've already bored out to .76" inner diameter. I took this photo before machining off the radius at the barrel step, you can sorta make it out:
Next, I re-tinned the argentine journal. It was not tinned in many areas, just where the rear sight base made contact. I also tinned it over a longer surface.
I also tinned the inner diameter of the sleeve. You'll notice the sleeve is now machined down closer to final dimension. It's still about 10 thou too big everywhere and will be machined to final size on the barrel, in case it solders on slightly off centre.
Now it's soldered on and needs to cool. If you do this project, the sleeve should not go on all the way when cold once tinned. If it does, you machined the ID too big. It should start on, but it should only slide home once you heat it enough that the two tinned surfaces liquify. Use a thin coat of flux on the barrel shank to help the two surfaces fuse. I add more lead solder to the top until I see it come out the seam at the bottom. I then let the bottom cool a little and add a bit more at the top to fill any remaining joint gaps. It will get cleaned up later when we machine the sleeve to final dimension.
Set up for soldering:
You'll notice the sleeve heat blued. No big deal. These barrels are not hardened anyhow and the germans heated them with Oxo Acetylene to install the rear sight bases at the factory. It will be in the white again once we turn it to size.
It's cooling now, more photos when I'm further along
I have a take off K98k 8mm barrel with a poor bore that I'm using for reference. By poor, I mean heavily pitted, counter-bored, and generally awful, but that's OK, we're just pulling dimensions off it.
So right away, there are some things that we need to fix:
1) An Argentine 1909 barrel is 29.13" long while a K98k barrel is only 23.62" long.
2) A K98k Barrel has a .900" journal ahead of the chamber that the rear sight base is soldered to. An argentine barrel, on the other hand, is 0.760" in the same area as the argentine sight base is smaller in diameter.
3) The end of the chamber area on a K98k is a sharp corner, on an argentine barrel, it's radiused.
4) The Argentine barrel necks down less quickly, so near the muzzle we will need to reduce the diameter to match a K98k barrel contour.
Here's an example comparing the rear sight area of both barrels after the sights are sweated off (Argentine on top):
Note that the argentine barrel is thinner. I've already cleaned the ruling off in prep to solder on a collar to increase the diameter. Also, I already turned the the front of the chamber area at the step to get rid of the radius there. The sleeve will now fit flush and we can re-machine a nice, sharp step like a K98k barrel.
In this photo, you'll see an old piece of shotgun 12 gauge barrel I've already bored out to .76" inner diameter. I took this photo before machining off the radius at the barrel step, you can sorta make it out:
Next, I re-tinned the argentine journal. It was not tinned in many areas, just where the rear sight base made contact. I also tinned it over a longer surface.
I also tinned the inner diameter of the sleeve. You'll notice the sleeve is now machined down closer to final dimension. It's still about 10 thou too big everywhere and will be machined to final size on the barrel, in case it solders on slightly off centre.
Now it's soldered on and needs to cool. If you do this project, the sleeve should not go on all the way when cold once tinned. If it does, you machined the ID too big. It should start on, but it should only slide home once you heat it enough that the two tinned surfaces liquify. Use a thin coat of flux on the barrel shank to help the two surfaces fuse. I add more lead solder to the top until I see it come out the seam at the bottom. I then let the bottom cool a little and add a bit more at the top to fill any remaining joint gaps. It will get cleaned up later when we machine the sleeve to final dimension.
Set up for soldering:
You'll notice the sleeve heat blued. No big deal. These barrels are not hardened anyhow and the germans heated them with Oxo Acetylene to install the rear sight bases at the factory. It will be in the white again once we turn it to size.
It's cooling now, more photos when I'm further along
