copper tubing jackets

[Danth]

Hello All: I've made some 257 Roberts bullets with copper tubing, but am unable to close the bottom end due to the thickness of the tubing. I've read that military bullets have open ends without issue. I've added a cannelure hoping to better secure the core. Do you see any issue? I've been thinking of making a die to produce a boat tail bullet which I'm thinking will further secure the core. What do you think? Best, Dan

[Valornor]

Usually military bullets with an open base do not have an open tip, and those with an open tip do not have a open base. Both style of bullets have jackets that are formed from copper strip.

With that said, bullets made from tubing do not need a completely close base to prevent a core from be shot out of the jacket. There will almost always be some hole left, I don’t mind seeing a hole from 1/32 to 1/16 in size.

With that being said, I don’t have an experience that shows a 1/16 hole being fine but a 3/32 hole results in core jacket separation.

A cannelure will help, but I wouldn’t rely on it to be the sole thing that retains the core.


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[Gew]

I've used 1/4" OD water pipe .020 wall thickness to test the consistency of the copper pipe before committing to a jacket forming set. The bottom was open and the tip was closed in an 8s die .243 caliber. I've heard the theory of the core being shot out and the core staying in the bore so after each shot I checked the bore and accuracy was great for what I was expecting, 1 inch at 100yards. One thing I was concerned about was the exit blast expanding the base. The target showed no evidence of a larger than .243 caliber. Try at your own risk for plinking and NOT hunting because they will not expand. thy shot fine for me from a .243 Winchester at 2 cents per bullet.

Another trick I've learned on here was to solder a 6.5mm gas check on the 1 inch tube and draw that jacket to .255 or .241. Works well and I would use that bullet for hunting. A touch of flux a bit of solder a torch and your done. Stand the check and tubing on a piece of tin or metal when heating. Doesn't take much for such a tiny piece of metal.

[Valornor]

The original Barnes Bullets were all made using copper tubing. Barnes still make them that way. They are a deep penetrating bullet, with extra thick jackets they do expand, Barnes Advertises 200% expansion.



Check out my website www.theballisticassistant.com

[swheeler]

The original Barnes Bullets were all made using copper tubing. Barnes still make them that way. They are a deep penetrating bullet, with extra thick jackets they do expand, Barnes Advertises 200% expansion.



Check out my website www.theballisticassistant.com

All you can see is the tiniest pin hole where they closed the tubing. I tried a picture of it but not clear, the 200 grain bullets use .032"IIRC and these 275 grain used .049" thick jacket.

[swheeler]

here you go..............

[Lead pot]

If you have a concern with the core coming loose you can always bond it. Flux the jacket inside and put the core in and melt it with a torch. Adding a little tin in the core is also a good thing doing this. This will do two things, bond the core to the jacket and also anneal the jacket.
The open base will not hurt a thing. I swage BT and rebated .308 BT and they both have open bases and HP point if I use tubing. If I want a FMJ I use a cup jacket. The .45 hard ball is swaged using a .45 cup also I use a lot of sweat caps for .44 and .45 jackets.
Attachment 251908

[Gew]

Nice work lead pot, that one bullet looks like a D46 clone.

[Lead pot]

Yes it does but it's a 200 gr and it was supposed to be a clone of the 168 gr Sierra match King that falls apart past 7-800 yards made a little heavier and a rebated BT added.