Slamfire Shotgun Build On AR15 Receivers.

[arakboss]

I picked up a 3/4 inch diameter grade 8 bolt today and a tiny 3/32 x 1/4 tension pin. I will grind the bolt to fit the reducer tonight and then figure out the firing pin this weekend. The hex head on the bolt must be a 1/2 inch thick and should make for a very solid breech face if I can get it to sit flat in the reducer. Pics of progress coming tomorrow.

 

[arakboss]

I want to order a chamber adapter that will allow me to fire 20ga shells in this set up. I also want a rifled adapter that will let me shoot a pistol caliber.

Looking at these but my shopping list is getting a little long these days, might have to wait on the adapters.

12GA to 20GA Shotgun Adapter - Stainless Steel - Free Shipping! | eBay

This adapter gives your 12 Gauge single or double shot break open shotgun the ability to fire 20GA ammunition. This adapter is precision machined from high quality stainless steel to the OD specifications of a 2 3/4 12GA shell.

www.ebay.com

12GA to 357 Magnum & 38SPL RIFLED Shotgun Adapter - Chamber Reducer - Stainless | eBay

This adapter gives your 12 Gauge single or double shot break open shotgun the ability to fire a 357 Magnum or 38 Special ammunition. It will easily fit into your break open shotgun barrel and accept any357 Magnum or 38 Special ammunition.

www.ebay.com

 

[arakboss]

Here is mock up photo of slam fire 12ga assy on AR receivers.




I need to work on the barrel to make it fit smoothly in 360 degree rotation. Trying to line up one orientation where it slides freely won't work. I believe the barrel pipe is not perfectly straight so I need to take the die grinder to it and rub off any spots where it hangs up in the 1" pipe.

 

[Yarome]

Here is mock up photo of slam fire 12ga assy on AR receivers.

The 1" looks quite long. It seems like kind of an awkward reach to slam any smoke(?)

 

[arakboss]

The 1" looks quite long. It seems like kind of an awkward reach to slam any smoke(?)

It does feel a little long at 12 inches. I think I am going to get a new shorter (maybe 8 to 10 inches) pipe for the shotgun set up and save the 12 inch pipe for the muzzleloader assy.

The 3/4 pipe that runs through the AR upper receiver needs an index pin like an AR barrel extension has. That way I can easily unscrew the reducer. I will have one reducer with shorter pipe for shotgun and the existing reducer with 12" pipe for muzzleloader assy.

I will need to drill a touch hole through the reducer for the muzzleloader assy. It is going to be very tricky to find a good spot to drill for the touch hole and end up just in front of the muzzleloading barrel's breech plug.
.

 

[It-That]

This is an affront to God. I think your build needs a playdate with my polymer AK

 

[arakboss]

This is an affront to God. I think your build needs a playdate with my polymer AK

A slam fire 410 build could be in my future if I can find a pipe with .700ish inside diameter.





Edit: A 3/4 piece of pipe might work if I was to put a thick coat of powder on the exterior of the 3/8 pipe (barrel portion in photo) and also apply a thick coat of powder to the inside of a 3/4 pipe (receiver portion). It is generally difficult to apply powder coat to the inside of small pipe but I had this idea of dipping the heated pipe into a fluidized bed of powder. The powder should instantly melt and stick to the pipe. I guess I will pick up another piece of 3/8 pipe nipple and another piece of 3/4 pipe to try it out. It would be less effort to just buy a 12ga to 410 chamber adapter but that would be too easy

 

[It-That]

A slam fire 410 build could be in my future if I can find a pipe with .700ish inside diameter.


View attachment 1240766


Edit: A 3/4 piece of pipe might work if I was to put a thick coat of powder on the exterior of the 3/8 pipe (barrel portion in photo) and also apply a thick coat of powder to the inside of a 3/4 pipe (receiver portion). It is generally difficult to apply powder coat to the inside of small pipe but I had this idea of dipping the heated pipe into a fluidized bed of powder. The powder should instantly melt and stick to the pipe. I guess I will pick up another piece of 3/8 pipe nipple and another piece of 3/4 pipe to try it out. It would be less effort to just buy a 12ga to 410 chamber adapter but that would be too easy

Oh this one I actually have a solution for. Get a section of pvc big enough to slide the pipe into, and cap it at one end. Drill a hole in the cap to slide some aquarium tubing into and out an air stone on that end and then the air pump or just compressed air into the other. I use this method for removing galvanization before I weld. Except you'll use powder and I use muriatic acid.

 

[arakboss]

The 1" looks quite long. It seems like kind of an awkward reach to slam any smoke(?)

I wacked a few inches off the 1" barrel and finally got the breech face fitted to the reducer. Firing pin is next. I will post some progress pics later this morning. I have done more bench grinding in the past week or two than I have done in the last 10 years.

 

[arakboss]

A slam fire 410 build could be in my future if I can find a pipe with .700ish inside diameter.


View attachment 1240766


Edit: A 3/4 piece of pipe might work if I was to put a thick coat of powder on the exterior of the 3/8 pipe (barrel portion in photo) and also apply a thick coat of powder to the inside of a 3/4 pipe (receiver portion). It is generally difficult to apply powder coat to the inside of small pipe but I had this idea of dipping the heated pipe into a fluidized bed of powder. The powder should instantly melt and stick to the pipe. I guess I will pick up another piece of 3/8 pipe nipple and another piece of 3/4 pipe to try it out. It would be less effort to just buy a 12ga to 410 chamber adapter but that would be too easy

A 410 build is not in my future, these things are way to much work. I may buy a 12ga to 410 ch chamber adapter so I can run 410 in my 12ga slam fire shotgun.

 

[arakboss]

Here are some progress pics of my slam fire project. I am going to try and pop a primer this week. I set the firing pin a little on the high side so it might puncture the primer. You can always file something down but you can't build it back up, so I will bring a file and a few primed hulls to test.

 

[arakboss]

Houston we have ignition. It is not perfectly centered but good enough. It did not puncture so all is well. It is ready for final assy and testing with loaded shells. I am going to put a box or two of various loads through it before taking it apart and putting some type of finish on the metal. This build is going to be launching pad for all sorts of configurations. Chamber adapters, blanks, muzzleloading, etc.

 

[Spec.-K]

I just used seamless 3/4" pipe with a piece of seamless 1" as the receiver.
I welded a disc on the end if the 1" pipe and center drilled it.
Tapped it to take a small screw that I rounded the tip off of, and I was in business.
Only problem was the loose chamber would cause the brass to flare out and you'd sometimes need a ramrod to clear the chamber.
But it worked!

 

[arakboss]

This feller tested the limitations of black pipe by making a 9mm barrel out of it.

 

[Spec.-K]

@arakboss combine the 12ga pipe barrel with your break action AR concept, and I think you're on to something

 

[arakboss]

@arakboss combine the 12ga pipe barrel with your break action AR concept, and I think you're on to something

That's funny, but in case you were being serious it won't work with my slam fire design. My set up requires pulling the barrel to load it.

 

[arakboss]

I am taking my slam fire shotgun parts with me on next trip to cabin property. Priority will be to clean up the mess the thieves left behind and secure what they didn't take. I should be able to set aside a few minutes of free time to partially assemble the shotgun and fire a shell or two.

 

[Pnwbrrt]

Do you have an update? I know it's an old thread but I'm super intrigued.

 

[arakboss]

Do you have an update? I know it's an old thread but I'm super intrigued.

The update is, all the pipe is sitting in bags in my trunk collecting surface rust. I have had tunnel vision problems with cabin security issues, measure 114, blah, blah, blah. I have had zero interest in working on any firearm projects lately and honestly don't expect that will change before the nicer weather returns in the Spring/Summer. Sorry.