Slamfire Shotgun Build On AR15 Receivers.

[arakboss]

I thought I had started a build thread for this project previoulsy but couldn't find it.

I am beginning this project this weekend because it's "Merica". You can hold my beer when I complete it and fire it. I decided to go all out and make it 12ga. Chamber adapters will be used later on and a 12ga chamber will give me the largest adapter options.

The goal for this weekend is to buy and fit the upper receiver black pipe parts.

Basically I will be running a length of 3/4" ID pipe through an upper receiver with enough overhang on the rear to mount a 3/4" coupling. Another piece of pipe or tube will be fitted to the rear of that coupling to mount A2 style rifle stock. There will be a small amount of overhang in the front to mount a 3/4x1" reducer. A firing pin and breech face will be rigged up in the reducer. Then a short length of 1" ID pipe will be attached to the reducer. Later I will select a piece of pipe for the barrel, probably 20".

Operation will be like any other slamfire shotgun. To remove the pipe running through the upper receiver, the coupling on the rear will need to be unthreaded, then the rest of the pipe can be removed through the front of the receiver. The lower will serve as a base for the upper to mount on and the pistol grip will provide a spot to grip. The trigger, safety, etc will not be used. I will likely only install a grip and the take down pins in the lower I use.

Hopefully I will have pics of the receiver portion of this monstrosity by Monday evening.


If you are unfamiliar with slamfire shotguns this video will clue you in.

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[arakboss]

I am off to do some pipe shopping. I'm going to pick up a few extra fittings to use for muzzle devices. It won't hurt to have the extra weight. This thing is going to be a beast to shoot with 12ga.

 

[arakboss]

Took three stops to find somebody who could cut and thread pipe to my requested lengths. Ended up at George Morlan and man are the threads and cuts rough. I am going to have a lot of filing and fitting to do this weekend. Installing the breech face and firing pin in the reducer is going to be trickier than I thought. I may regret not just using an end cap design like everybody else does?

 

[arakboss]

This was a quick mock up to show overall length. The length will be about the same as a 20" AR15 upper. The weight will be more.





The largest pipe is currently at 12" but I will probably need to shorten that a bit for ergonomics. The pipe that will sit inside the AR upper receiver will need to be taken down from 1.05 inches to around .990 inches. The barrel will need work before a shell well fit in there. The 1" pipe will need work before the barrel will fit inside it.

The reducer will need to be fitted with breech face and firing pin. If you have any ideas for that, please share them.

 

[arakboss]

Assuming I can make this work and it doesn't blow up during first shots, I think I will run a 20ga chamber adapter for most of the shooting. That should reduce the stress on the pipe and make for a slightly safer and longer lasting firearm. I might try some of the other chamber adapters to.

12GA to 20GA Shotgun Adapter - Stainless Steel

www.theshootersbox.com

Goal for tonight is to make a shell fit in barrel and make 3/4" pipe barrel fit in 1" outer pipe (secondary chamber?). I am taking a break from filing, since the neighbor has buyers looking at another car right outside my garage door. I can't believe how many darn cars that guy sells.

 

[arakboss]

Hi brass shell fits barrel after a bunch of filing.

 

[arakboss]

Barrel fits in one position. It's going to take some work to make it fit 360 degrees. Not sure if I should carve on the outside of the 3/4" barrel or on the inside of the 1 inch pipe, what say you?

 

[bradsteen]

I would avoid carving on any pressure-bearing components if possible.

 

[arakboss]

I would avoid carving on any pressure-bearing components if possible.

I decided to just live with it fitting in one position. Once I have it all installed, I will put a makeshift bead on the top muzzle end of the barrel so I know which way to orient the barrel. The second barrel piece doesn't fit well at all. If I do this type of thing again I will take the advice of another slamfire shotgun builder and hand select pieces that fit well together in the store. This project ain't getting close to being done this weekend. Hopefully I will have it complete by next weekend. The wife and I are going shooting tomorrow and trying out the latest single shot AR upper I put together. We will also be putting some brass cased 7.62x39 rounds through the optics planet special upper. That upper is still in semi-auto configuration but I will be bypassing the gas system on that one soon. My decible meter arrived yesterday so maybe we will try it out at the range.

 

[arakboss]

The wife had a choice of going shooting or dragging me along for her hidden bottle hunt. She picked the bottle hunt. We failed to find it but we were in the vicinity. Somebody found it this morning, it was down by the river at Memorial Park.

 

[Yarome]

....her hidden bottle hunt. She picked the bottle hunt. We failed to find it but we were in the vicinity. Somebody found it this morning, it was down by the river at Memorial Park.

Is that like an Anti-AA event thing? (new to me) Personally, I completely appreciate the merit of hiding bottles, but usually only around the house or within stumbling distance. I dunno about where you guys live but LE in our area have gotten real picky about the whole "drinking and driving" thing lately.

Just sayin....

 

[arakboss]

Is that like an Anti-AA event thing? (new to me) Personally, I completely appreciate the merit of hiding bottles, but usually only around the house or within stumbling distance. I dunno about where you guys live but LE in our area have gotten real picky about the whole "drinking and driving" thing lately.

Just sayin....

I wish but it was this hunt.

Hidden Bottle Hunt - BottleDrop

www.bottledropcenters.com

 

[TTSX]

Took three stops to find somebody who could cut and thread pipe to my requested lengths.

I'm very surprised you don't have the means to cut and thread pipe yourself. Just go buy some dies and a $20 corded angle grinder and you can have all the custom "barrels" you want

 

[arakboss]

I'm very surprised you don't have the means to cut and thread pipe yourself. Just go buy some dies and a $20 corded angle grinder and you can have all the custom "barrels" you want

I have a very limited area for my tools and firearm stuff. This is the first time I have had a need for iron pipe in my personal life. The iron pipe we use at work is all used in 10ft lengths as we purchase it.

 

[arakboss]

I hope my slam fire build works better than the first one this guy shoots.

 

[salmon creek gary]

I hope my slam fire build works better than the first one this guy shoots.

I read "American Guerilla in the Philippines" about 5 times between age 10 and 19 That book was one of the few in Dad's library that wasn't about organic gardening. I recall stuff about improvising powder and cutting up brass rod for projectiles, but nothing about slam-fire shotguns. (Ebay is now sending me a used copy so I can read about Richardson's adventure/ordeal at least one more time.)

 

[arakboss]

I finally finished fitting the receiver mounting pipe. That is the piece that fits inside the AR15 upper receiver. It took forever to grind it down. A lathe would have made a much quicker job of it.

The next hardest task will be to figure out the breech face. I am thinking about buying a Grade 8 bolt with 3/4" diameter shank. Than grind the hex head portion to fit snug in my 1"x3/4" reducer. Once it is fitted, I need to mount some type of point in the middle of the hex head to function as a firing pin. Perhaps just a tiny ball bearing or a tiny round head screw. Ideally I could drill through the 3/4" bolt all the way through to the bottom of the shank and put an adjustable firing pin in it. That sounds like way to much work.

I am already losing interest in the this project so I need to finish it up quick before the parts get stuffed in a box.

I will post a new mock up by noon Friday.

 

[Yarome]

If you wanna go shmancy with a firing pin you might could grind down a drill bit. Drill partially into your breech face to seat the tail end round. That might make it semi adjustable either hot swapping the pin or allowing you to remove or add material into the "pin cup". That would give you the ability to play around with pin head profiles as well.

More work than I would wanna do with a slam fire, but I'm just full of time and effort wasting ideas!

To quote my grandpap, "If it were easy, I would do it myself!"

 

[arakboss]

If you wanna go shmancy with a firing pin you might could grind down a drill bit. Drill partially into your breech face to seat the tail end round. That might make it semi adjustable either hot swapping the pin or allowing you to remove or add material into the "pin cup". That would give you the ability to play around with pin head profiles as well.

More work than I would wanna do with a slam fire, but I'm just full of time and effort wasting ideas!

To quote my grandpap, "If it were easy, I would do it myself!"

For some reason your idea inspired this idea. I could drill a tiny shallow hole and install a 1/8" tension pin. After it's installed massage the end sticking out with a file and voila, firing pin done. If it ever needs to be replaced I should be able to pull it out and install a new one. Thanks for the inspiration.

 

[Yarome]

If it ever needs to be replaced I should be able to pull it out and install a new one.

That'll work. Maybe a coiled(?) More stability and less likely the head might deform(?)