length of 5/16" copper tubes for different weight .308 bullets?

[bigjake]

Wow! this swaging page is dead! come on gentlemen get this forum rolling!

Anyway, could someone tell me the cut lengths of the 5/16" tube for different weight .308 bullets.

[deltaenterprizes]

Measure a bullet the weight you want and add about .154” to allow for closing the base.

[bigjake]

So just basically wing it. because the jackets are thicker made with copper tubing. The lead by volume is less. in other words "experiment"

[nun2kute]

I believe Dave C. has a calculator to predict jacket/core weights ??? anybody got one ?

[MUSTANG]

Big Jake; there will be some dependency on your specific 5/16 copper tubing Jacket Making Dies. (i.e. Corbin, RCE, BTSniper, etc..). Also; how you cut your tubing (Mini-Chop Saw, Tubing Cutter, or) can have impact on length of tubing before shaping into a jacket of a specific length.

For MY BTSniper made 5/16 copper tubing jacket making dies; I cut my tubing with a 1/2 in. - 1 in. O.D. Pipe Size Corrugated Stainless Steel Tubing Cutter available at Home Depot.


I used to use a Harbor Freight Mini Saw; but found it difficult to get a consistent (good) nose point because the jacket was almost always left with a lip on one side when cut.

The tubing cutter creates a different problem to overcome; that is that some copper is extruded under the cutter; resulting in each end at the mouth being slightly less than the inside diameter of the reset of the cut tube/jacket. I am able to expand/true the diameter at the mouth when I insert the tube into the die; and expand/true the mouth through the force of the radiused punch when the Press is cycled. There is some level of force to push the punch through the lightly constricted mouth; but the press expands the inside of the mouth; and the outside is sized/trued when the press is cycled and the tubing is cycled inside the die.

Many find it difficult to get a consistent cut tubing length if a tubing cutter is used. I have avoided this problem by fabricating a "Length Gauge". My length gauge is created using an All Thread Coupler. I use a bolt, a nut screwed onto the bolt near the head of the bolt; then the bolt screwed into the All Thread Coupler. Setting the depth of the "Length Gauge" is as simple as screwing the Bolt in or out of the "Coupler" until the correct depth is accomplished - then the nut is screwed down to keep the bolt from shifting in or out of the coupler; keeping a constant length gauge when set. I insert the 5/16 tubing into the coupler, hold it firmly against the bolt face inside the coupler; then use a SHARP cheap paring knife to score a line into the copper tubing at the edge of the All Thread Coupler (about 25% around the tubing - do not need to score a circle into the tubing). The score allows me to set the circular cutting blade of the Tubing cutter into the score (like a small tracking groove) tighten slightly; then cut the tube by turning 360; tighten and turn 360 again, and repeat till the tubing is fully cut. Repeat as often as the number of Jackets you are going to make. I get fairly constant copper tubing lengths this way for making jackets.


NOW - your question was length. I mostly make 175 Grain .308 bullets (I use same jackets for the few 147/150 gr Bullets I make). I cut tubing as described to 1.145" (depth of the Length Gauge I described). After running through all the steps to make jackets in my BT Sniper dies; I have a .308 jacket with a length of 1.085 - Just the perfect length for a 175 Grain .308 bullet made in my Corbin 8s Nose Swage Dies.

[bigjake]

Excellent Mustang! I purchased that cutter the last time you gave me information on .308 bullets. It cuts great. Its the best tubing cutter ive ever used. What dia.core do you use?

thanks to those that replied with info.

[MUSTANG]

Excellent Mustang! I purchased that cutter the last time you gave me information on .308 bullets. It cuts great. Its the best tubing cutter ive ever used. What dia.core do you use?

thanks to those that replied with info.

I cast cores in a Corbin core mold at 0.218"


I then size/uniform my cores in a Corbin Core Swage Die at ~ 0.225 (Fits nicely in the thicker walled 5/16 Copper Tubing Jackets).

[MUSTANG]

I believe Dave C. has a calculator to predict jacket/core weights ??? anybody got one ?

The Corbin Jacket Length/Diameter/Weight Chart can be found here: http://www.corbins.com/corewts.htm