Reaming a chamber into a revolver barrel

[Hobbja]

So, I finally have all of the simple tools for my first real home build. I've been looking at barrels, blanks, and liners online and they can get a bit pricey.
I have found however that a lot of revolver barrels are inexpensive and readily available.
If I were to purchase say, a .38 special barrel, could I ream a chamber into it? Looking at a simple break barrel pistol design for plinking.
If its a stupid idea, just tell me. But know that I am not just going to go out and buy a .22 for plinking. I really want to put together a sturdy build that is my own. I currently don't own a bunch of guns. I sold most off and only last year did I purchase my first bp revolver. First gun I have owned since 2010, but no indoor ranges will let me plink with it for safety reasons I imagine ( unburnt powder on the floor walls and ceiling I presume could ignite)
So I came to this idea. Single shot break barrel pistol chambered in a rimmed handgun round, but not a .22, that I can take to the range and just shoot all day long.
Peace

 

[4v50 Gary]

Yes, it can be done, but you need to make an action (break open?) and fit the barrel to it first. Is it going to be like an H&R break open?

 

[MachIVshooter]

Yes, it can be done, but you need to make an action (break open?) and fit the barrel to it first. Is it going to be like an H&R break open?

Not necessarily. Just need to be able to set headspace one way or another.

 

[4v50 Gary]

Yeah, you're right, but I would want a solid lockup first before even putting a chambering reamer into the barrel.

 

[Hobbja]

Yeah, I plan on mounting a lug on the underside of the barrel so it pins to the receiver and pivots open. The locking lug will also be located there.
I'm not entirely sure i want to go the revolver barrel route, I really just wanted to know about the reaming so i can keep my barrel options open...
I would be going for a real tight lockup right off the bat. Head spacing (from what i understand) shouldn't be too difficult with a rimmed cartridge in a break barrel setup.

 

[BBBBill]

...I plan on mounting a lug on the underside of the barrel so it pins to the receiver and pivots open. The locking lug will also be located there...

The locking lug will work far better if it is 180 degrees from the pivot point. Locking on the same side as the pivot is inherently weak and subject to springing the action from firing pressures and breach thrust. Were I doing that I would machine a block to pivot on the bottom attach point and lock on the top with a threaded hole for the barrel to screw into.

 

[FROGO207]

I would be concerned that there was enough "meat" left for the chamber walls after reaming it out especially in 38 SPL barrel or such. To make one with an old .22 barrel of either a cut down rifle or a pistol would work I would think as there would be plenty of additional metal around the chamber area. I would think of making a side swiveling barrel with a stop and a lock to hold it securely to the receiver as the most expedient way while being somewhat strong. Design the firing pin to be spring loaded, pulled back with a cocking piece and the trigger locks it in cocked position. At one time I was going to build a .22 single shot with the old 10-22 barrel I had utilizing the precut chamber end and cutting off the bent section for a 10 inch barrel.

 

[Varminterror]

I would be concerned that there was enough "meat" left for the chamber walls after reaming it out especially in 38 SPL barrel or such.

There will be more "meat" left around a chamber reamed into a revolver barrel than there was in the cylinder it was originally firing from. The cylinder chamber walls are their thinnest at the locking notch, followed by the exterior wall, then wall between cylinders... You're talking about a LOT more material present in the barrel than in the cylinder. For straightwall cartridges, you're not talking about a significant change to the bore diameter anyway.

What is your strategy for modifying the revolver barrel to mate to your action? It might not be a terrible idea to retain the threaded tenon, fed into an "action block," which itself could then be situated for the pivot and lock, rather than machining into the barrel itself. Otherwise, you'll be losing quite a bit of barrel to remove the barrel tenon. I expect you'll be starting with a single action barrel, so you don't have to worry about ejector shrouds or ribs, just round barrel stock. A Redhawk contoured barrel with the ejector shroud removed, threaded into an action block on a break action might be interesting - and with some clever engineering could be made to run as a switch barrel rig for multiple calibers, if you were so inclined.

 

[Hobbja]

I do like the idea of keeping the threads and not machining the barrel, other than reaming.
With a proper "action block",a robust receiver and breech block, would it be safer to load +p /or chamber for .357 magnum? Safety is the whole reason that I have so many questions. It would be nice to have at least two caliber options.
Hmm, I bet it would be easier to install a simple extractor into this action block as well. I'm going to draw some things up, see if i'm inspired. Hmm again at multibarrel frame

 

[Carl N. Brown]

no indoor ranges will let me plink with it for safety reasons I imagine

The local indoor range told me they did not allow Black Powder because the BP smoke overwelms the ventilation system.
The indoor fan system is adequate to keep smokeless powder smoke moving down range and out the building.

On the outdoor range at the club on a cool, humid, windless day, during Black Powder cartridge match rapid fire pistol event, by the time we get off two strings of five shots each, it looks like a smoke screen.

 

[Varminterror]

I do like the idea of keeping the threads and not machining the barrel, other than reaming.
With a proper "action block",a robust receiver and breech block, would it be safer to load +p /or chamber for .357 magnum? Safety is the whole reason that I have so many questions. It would be nice to have at least two caliber options.
Hmm, I bet it would be easier to install a simple extractor into this action block as well. I'm going to draw some things up, see if i'm inspired. Hmm again at multibarrel frame

The calculations for barrel thickness required per pressure are out there on the web, no engineering degree required. If you consider the wall thickness in the cylinder, then consider minimum barrel thickness in large caliber single shot break action rifles, I think you'll be quite pleasantly surprised how much cartridge you can pack into your barrels. I might not choose a light weight model as my barrel donor, but recall - the peak pressure in these cartridges is happening when the bullet is in the barrel - so if you start with a 357mag capable revolver barrel, it'll remain so capable once the chamber is reamed.

Being lazy tonight - it's after 10pm afterall - and not deigning to pull out my calipers, here are a couple pictures to illustrate what I'm describing:

Here's a photo stolen from an ebay add for a Redhawk 44mag barrel:



Now compare against a cylinder from a 44mag Redhawk:



Remember, the thinnest point of the cylinder is actually the exterior wall, at the locking notch, but even ignoring that fact and considering the barrel tenon thickness compared to the wall between the cylinder, we're talking about plenty of meat.

In reconsidering the switch barrel option today while I was in the deer stand, I had the notion it would be best to NOT run it as a thread change, just make multiple action blocks fitted to the same receiver, easy peasy lemon squeezy.

 

[Hobbja]

That makes sense. Potentially I could end up with a lot of caliber options and no cross threading worries. Now with chamber reaming, are there any options other than a purpose built reamer? If it's not safe please just say so, I will buy a used one online somewhere.

 

[BBBBill]

There are at least a couple sites that rent reamers. Here's one - https://4drentals.com/products/shop/
Note that since you are doing this in a barrel instead of a cylinder you will need a separate throating reamer. Cylinder reamers don't have a leade/throat section to smooth the entrance into the rifling. You can ask if they have one for use in a rifle such as a lever action like a Marlin or Rossi. That would take care of the throat/leade.

 

[Varminterror]

After considering it, if you build a thread change break barrel, you'd have to ensure the threads of all of the barrels were indexed the same, which is an absolute pain in the butt for what it's worth. The threads would eventually wear and you'd end up with some makeshift method of reindexing. Whereas if you make interchangeable action blocks into which the barrels are threaded, then you'd be able to mate the threads as needed for each particular barrel independently, and the only headache is the extra work in making multiple blocks. Both can work, but the block method will be easier without machining equipment.

You will need to use purpose built reamers for this job. As mentioned above, there are multiple places to rent reamers. You will need a "roughing" or chambering reamer, and a finish reamer, both. I will also say, if the cost of the reamer purchase or rental is of concern, I'm then worried about your mindset into building your custom firearm. A break action can be built on the cheap, but it's not going to be free. If you're too motivated by money, you'll end up not pursuing the project, which isn't fun, OR you'll compromise the integrity of the project, which can be dangerous.

Another option would be to have the chamber reamed by a smith once you have everything else finished. It really can be a last step. It's usually cheaper to rent the reamer and do it yourself, BUT, if you don't own a lathe, it may make more sense to have the barrel chucked to ensure the chamber is cut concentrically, rather than relying completely upon the reamer pilot.

 

[Hobbja]

After considering it, if you build a thread change break barrel, you'd have to ensure the threads of all of the barrels were indexed the same, which is an absolute pain in the butt for what it's worth. The threads would eventually wear and you'd end up with some makeshift method of reindexing. Whereas if you make interchangeable action blocks into which the barrels are threaded, then you'd be able to mate the threads as needed for each particular barrel independently, and the only headache is the extra work in making multiple blocks. Both can work, but the block method will be easier without machining equipment.

You will need to use purpose built reamers for this job. As mentioned above, there are multiple places to rent reamers. You will need a "roughing" or chambering reamer, and a finish reamer, both. I will also say, if the cost of the reamer purchase or rental is of concern, I'm then worried about your mindset into building your custom firearm. A break action can be built on the cheap, but it's not going to be free. If you're too motivated by money, you'll end up not pursuing the project, which isn't fun, OR you'll compromise the integrity of the project, which can be dangerous.

Another option would be to have the chamber reamed by a smith once you have everything else finished. It really can be a last step. It's usually cheaper to rent the reamer and do it yourself, BUT, if you don't own a lathe, it may make more sense to have the barrel chucked to ensure the chamber is cut concentrically, rather than relying completely upon the reamer pilot.

I would not compromise my safety for savings. I have a lot of options for barrels including pre-chambered "blanks" that have plenty of material to cut threads or pin into the action block. The threaded revolver barrel being just one option, the option that appeared at the time to possibly be less expensive and very sturdy.
In all reality it may be safer for me to go with a pre-chambered blank for my first build. Pin it or thread it is the next decision, then caliber choice.
For practice Maybe I will pick up a cheap barrel, cut it into short pieces, buy a used reamer, and ream the pieces. also it will give me material to practice crowning.

 

[Hobbja]

Thank you everyone for your input. I have picked up a 1" outside diameter, 5" long 357/38spc chambered barrel "blank" from a reputable source. It was the safest option. Now I have to figure out the "action block", shouldn't be as difficult as deciding on a barrel. Get sum pics up when I get things more organized.