Copper Tubing Jacket Question

[*MALICE*]

So I was looking at some different threads here and on Corbin's website about making bullet jacket from hard copper tubing.
One thing that I was curious about is how do you know how long to cut your copper tubing?

I'm going to use .308 as the reference for this.

Would you start off using the same length of tubing for a 170gr that you would for a 150gr and then trim it? OR Is it a case of doing a couple test pieces and then adjusting the length of tubing you cut after that?

On the Corbin's website it states that you want the tubing to be half a caliber longer than the punch (IIRC). Which leads me to believe that you'd either have to know how long you were going to cut the tubing to begin with (when you order the punch?), OR you'd have to trim the tubing to length after you closed the one end.

Please enlighten me

[Red River Rick]

Tubing jacket making dies are usually supplied to make one length of jacket, and are not adjustable. So, using a pre-determined length of tubing is the only way the dies will function properly.

By changing the external punch, you would be able to form longer or shorter jackets, but you will have to cut your tubing to the correct lengths required for each new punch.

Best thing is, make a jacket long enough that will meet your needs for the heaviest bullet you'll make, if you need a shorter lighter jacket, trim them to length.

If your wanting to make .30 cal jackets, 3/8" and or 5/16" rigid copper tubing will work.

RRR

[*MALICE*]

Ok, so how do you know how long a jacket you need for a certain weight? Is there a formula or calculation?

[Red River Rick]

Corbin has software that will do the calculations for you. Or, If you like exercising your brain, grab your calculator and do the math!

A certain jacket weight will be dependent on the correct amount of "Volume" of copper. An inch of 3/8" tubing with a 0.03" wall thickness will weight "X" number of grains. You can easily figure out the exact length of tubing required for each weight.

RRR

[DLCTEX]

Are you sure you want "hard" copper tubing for jackets? Hard copper is brittle and doesn't bend well. Coil copper tubing is what I would choose. It is softer and bendable.

[Red River Rick]

Yes! You want to use "Hard" or "Half Hard" drawn copper tubing. I've been making copper tubing jackets for almost 20 years....................and have always used rigid tubing.

When the maufactures refer to "Hard", they don't mean diamond hard or 62 RC. And no mattter how hard you think the copper tubing is, it is workable and will easily form into jackets.

If you want to make them soft after forming, anneal your jackets.

Read on: http://www.corbins.com/tubing.htm

RRR

[MT Gianni]

Are you sure you want "hard" copper tubing for jackets? Hard copper is brittle and doesn't bend well. Coil copper tubing is what I would choose. It is softer and bendable.

Hard copper as referred to in the plumbing industry is pipe lengths, soft is rolled tubing.

[MIBULLETS]

RedRiverRick has it right.

I make .358 jackets from 3/8" hard tubing. My jackets come out about .95 times the length of the original tubing length. This is only for my set though. How much larger the tubing is than the final bullet diameter, what shape point forming die and how much you close the base of the jacket all have a part in how long the final jacket is and then how heavy of a bullet you will make with it.

My advice would be to tell Corbin that you want to make an XXX gr bullet with the set and he will make the punch the right length for that. He does however sell a adjustable punch that screws in or out to make different lengths of tubing jackets with your set, but it does cost about 3X as a fixed length punch. Like I said, talk to him and explain what you want.

Dan

[*MALICE*]

I was planning on making the dies and punches myself. Looks like I'll be doing a little trial and error to see what works and what doesn't.

I've noticed that the end rounding dies are 'blind' with an ejector pin. Is there any reason (there probably is) you couldn't use a larger diameter punch (same diameter as die hole) that has a concave face to round the end? Seems like it would be easier to make the dies like that?

[MIBULLETS]

There is a lot of stress and the punch edges would need to meet the die wall which would make them very thin and easily breakable.

Somewhere here someone posted a picture of a 30 caliber tubing jacker maker. Maybe you could ask them about the punch lengths they are using and the resulting bullet weights.

Dan

[skeettx]

Hello MIBULLETS,
If you want to try something fun, for the 35 caliber bullet jacket, use a fired 30 cal carbine case.
For a 375 bullet use a fired 223 case cut off at the shoulder.
For a 458 bullet use a 35 Remington case cut off.
For a 470 bullet use a 22-250 or 308 Win fired case cut off.
For our 50 cal (510) bullets we have been using 7MM Rem Mag brass shortened and with the belts turned off.

OH, yes, you can use the seating dies for many of these cases for you point forming dies if you will turn a point/ejection plunger instead of the bullet seating stem.

What fun, what fun
Mike

[MIBULLETS]

Hello MIBULLETS,
If you want to try something fun, for the 35 caliber bullet jacket, use a fired 30 cal carbine case.
For a 375 bullet use a fired 223 case cut off at the shoulder.
For a 458 bullet use a 35 Remington case cut off.
For a 470 bullet use a 22-250 or 308 Win fired case cut off.
For our 50 cal (510) bullets we have been using 7MM Rem Mag brass shortened and with the belts turned off.

OH, yes, you can use the seating dies for many of these cases for you point forming dies if you will turn a point/ejection plunger instead of the bullet seating stem.

What fun, what fun
Mike

I have made 358 bullets from 30 Carbine, cut off 223, 9mm, and 30 Mauser cases and yes you are right it is fun.

[deerslayer]

Just curious, how are you guys cutting the tubing? And would this work in a swage o matic set up for the copper cups?