Gunsmithing Anyone here who can EDM holes into a barrel?

[sirhrmechanic]

Looking to have c. 16 1/8” holes EDM cut into barrels (two) for Delisle project.

I’d rather not drill and get burrs, though can “start drill”’the holes and leave blind for final breakthrough to be done with EDM. Though suspect that is not needed.

I can send blueprints...

Sirhr

 

[GH41]

Does this have anything to do with an integrated silencer??

 

[hangunnr]

You might give Mag-na-Port a call and see if they are capable of doing what you want done. The barrels I’ve had them do came back perfect.

 

[Adam B]

Mag-na-Port does great work!

 

[natdscott]

That, or if you have a good mill/drill, you can drive a lead slug to the point in the barrel where you need to drill, and drill into the slug, then drive it out.

No burr.

But sometimes, burrs matter a lot less than it seems like burrs should matter.

 

[sirhrmechanic]

Does this have anything to do with an integrated silencer??

Exactly

 

[sirhrmechanic]

So a search of some machinist sites is showing me another option... which is to machine and then Finish with a 2-flute ball-nose end mill running a bit bigger than drilled hole.

going to practice on some scrap barrel... but I think I can do at home.

Sirhr

 

[GH41]

Do you live in a country where this is legal?

 

[natdscott]

Do you live in a country where this is legal?

It’s legal here in the US.

 

[lariat]

So a search of some machinist sites is showing me another option... which is to machine and then Finish with a 2-flute ball-nose end mill running a bit bigger than drilled hole.

going to practice on some scrap barrel... but I think I can do at home.

Sirhr

This can work, done it before. Slow the speed for no chatter since it will be cutting for the entire flute length, not just in the edges of the ball that begin to contact the wall unless you use a lollipop. It’s spring passing but it will still cut. Chatter will blow the hole. Have you thought about reaming? Lead plug is a good idea no matter what.

 

[GH41]

It’s legal here in the US.

Right after you register the device, and submit to a background check before construction begins.

 

[BigBlue&Goldie]

There's always that one guy.....

 

[ajwcotton]

Drill then ream. How do you think gas ports get into ar barrels and they shoot pretty damn good with a nice cut rifled barrel.

 

[sirhrmechanic]

Drill then ream. How do you think gas ports get into ar barrels and they shoot pretty damn good with a nice cut rifled barrel.

My bet is that AR barrels are final bored and/ or rifled after the gas port holes are cut....

But I understand there are ways. But working with a home mill is different from an armory-grade machining setup for barrel port drilling.

Cheers, Sirhr

 

[ajwcotton]

Anyone who builds an ar from a barrel blank, ie all custom ar builders known for using high quality cut rifled blanks would drill them after.

 

[GH41]

Are you sure the ports are drilled through the rifling? This is the closest thing I can find to a drawing. It almost looks like the piece forward of the barrel is a sleeve threaded onto the end of the barrel with the ports in it. I have no way the scale it but the actual barrel doesn't look to more than 5-6 inches long. Plenty long enough for 45ACP.

 

[sirhrmechanic]

Definitely through the barrel. Into the rifling. All the Delisles were made with US Thompson barrels, modified for the purpose.

The barrels you see in the print were not long, and were ported and then a shroud was fitted over the ports to direct gas backwards.

I have a set of MoD prints... very clear.

Cheers, Sirhr

 

[GH41]

I see... One thing for sure... They didn't have EDM back then.