Homebuilt shotgun

[BillyDa59]

I've recently decided that it's high-time I build myself a shotgun. I'm fairly deadset on building either a break action or falling block, just for simplicity's sake. 12 GA of course. I believe my biggest obstacle is going to be finding a proper piece of steel for the chamber and breach block.

That being said, what sort of steel do I need to use, 4140? How much chamber pressure can a 3 1/2" magnum shell generate?

Additionally, how much would it cost to bring my piece of steel to a machine shop and have them bore it out and trim it down to a set of specs I give them? I sure as heck don't own a lathe.

Thanks in advance.

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[BillM]

Finding the piece of steel is no problem. Try Pacific Machinery and Tool Steel in Portland Oregon.

Your problem is you have no idea what you need or how to do what you want to do. Hit the library or online bookstores.
Read and research evereything you can find on firearms manufacture. IIRC there are book out there specifically on
building single shot arms in the home shop. Far more complex arms have been made with simple hand tools--but you
have to have the skills. You won't get them overnight or from a book. Start out by rebuilding a couple of cheap beat up
guns. Maybe build a couple of kits. If you just HAVE TO "build your own shotgun"---and you are going to have others
do the work for you---bring a big checkbook.

 

[DoesItMatter]

You may want to contact the user "hubel458" in this forum:

<broken link removed>

He is doing some crazy shotgun action stuff!

Looks like his name is Ed Hubel - read the whole thread - he's got some youtube vids also!

 

[The Cheese]

I've recently decided that it's high-time I build myself a shotgun. I'm fairly deadset on building either a break action or falling block, just for simplicity's sake. 12 GA of course. I believe my biggest obstacle is going to be finding a proper piece of steel for the chamber and breach block.

That being said, what sort of steel do I need to use, 4140? How much chamber pressure can a 3 1/2" magnum shell generate?

Additionally, how much would it cost to bring my piece of steel to a machine shop and have them bore it out and trim it down to a set of specs I give them? I sure as heck don't own a lathe.

Thanks in advance.

If you don't have a lathe and a mill or access to them, this is going to be freaking expensive (think several thousand dollars or more). A cheap machine shop will charge $60/hr most are closer to $100. Then there's the set up time, and the fact that you are doing a one off. If you were to do a production run of say 200, most might play ball. One offs are not something a lot of shops want to do, or else they will ream you for it. If you can find a prototype shop i think they could do it, but again you will bend over to pay for it. Frankly, you could invest in a small harbor freight mill, tool it up and buy a used lathe and tool it up for probably close to what its going to cost you to have someone else do it. Then you have the tools for future projects.

 

[Velzey]

Most shops will not touch it, as its a huge liability if it goes kaboom! You can buy 12 ga bbl blanks from Numrich and make it into what you want.

 

[BillyDa59]

Alright, so for the sake of appeasing some of the more picky individuals, I've decided to do all the work myself with the limited tools I have, and I'll even forgo using a barrel blank. The books I found on home built guns all suggest surplus barrels or barrel blanks. The few exceptions to this is books on making pistols (short barrels) where a drill is used to create the barrel and chamber. I assume that won't work for a 30" barrel that I'm wanting (do they make 30" drill bits?). That being said, can anyone tell me how to go about putting a perfectly centered hole in a steel bar 30" long?

 

[BillM]

Check out the forum here: Garage Gunsmithing

Interesting article here on building guns with a lot of knowledge and very few tools: Guns from Afghanistan- helpful info for prospective buyers

Maybe a field trip to Darra would be in order?

 

[Mark W.]

I would assume that since the receiver is the firearm that NO machine shop that didn't have a proper License would even do the rough work for you.

As to a 30" drill bit No problem just weld a rod to it that is how Muzzle loader guys drill ramrod holes. Now ask what it would take to drill a .7290" hole 30" deep into steel and have it come out close to straight. You will have to shape the outside of the barrel around the resulting bore then work to straighten it. Your going to need something a LOT bigger then a 18V Makita to drill that hole. the hole would first need to be drilled under sized then reamed then lapped to it's final internal diameter.

To give you an Idea from McMaster Carr (HUGE on line machine shop supply co)

a .7031 drill bit would sell for $28 to 90.00 depending on the lenght none would be longer then 18" I would assume you would need a min of three of them to drill a hole 30" deep. So your looking at a min of $84.00

a .727 reamer (allowing the last .001 of radius to be removed by lapping) would cost you ???? as it would be a custom order item the closest stocked size to .729 is either .700 or 23/32" or .7185 leaving you 0.0105 to lap out. cost for a 23/32" spiral reamer $47.00

Now allow for having someone jig up and weld the longer tang on them and the gallon of cutting oil you will need..

This will require a very good 1/2" drive drill motor and HOURS of time MANY Hours. You will be able to remove only about 1/2" of material at a time before you need to withdraw the bit and clean the chips reoil it and start over.

Then if you get a nice straight hole you would have to center the tube in a lathe or filing jig and shape the outside of the blank to your external conture. If you don't have a lathe you can add a bunch more money. If you do it by grinder and file well I hope you have plenty of time. Oh and add money for a number of high quality files.

You might do better to learn blacksmithing and to weld up your tube over a mandrell. SHould we go into the costs of a small Propane forge that can handle a 30" long piece of material

I could easily see it costing $400.00+ to scratch machine a 12ga barrel. If your buying all the tooling and paying to have work done you done have the equipment for.

Buy your barrel.

 

[marty8587]

Wow! that Afgani gunsmith piece is really something>

 

[irequiem]

I admire the desire or the hutzpah, I would start with books and hanging out at the garage gunsmithing web site. They are crazy over there. Good luck,don't blow anything you need off,