How is the Nosler Partition bullet made. Could that same type of bullet be made by the home enthusiast? Does it involve melting lead?

Let me start by saying that I do NOT know how the factory makes the current jackets.

As I understand it, the original brass jacketed "partition" bullets were made by boring holes in each end of a piece of brass stock. Then cut lead cores were inserted, one at a time, into each end of the brass stock. Then the two ends were swaged to shape, probably simultaneously. Finally, the "relief "belt' (groove) was machined around approximately the middle.

Nowadays the jacket is not the same brass material it was originally, and there is no "relief" cut around the middle. Whether the ends are still both finally swaged the same way, I don't know, but I suspect the jackets are made by using simultaneous forming punches rather than any sort of drilling.

Still, it would be relatively easy, though slow, to make bullets just like the originals at home.

As you likely know, P.O. Ackley used to make a somewhat similar controlled expansion bullet, but he left one end of the brass stock solid and just put a core in (and swaged) the other end of the bullet. He ended up with something very much like a Barnes "X" bullet for the rear half, and like a conventional lead-core bullet for the front half.

It still did pretty much what the Nosler Partition does...expanded rapidly on the front end, and hung together and penetrated all the way through with the back half. It would be even easier to make at home.

P.S., Corbin sells lead "core moulds" so a person can cast their cores at the correct length/diameter, rather than cut them from lead wire, if they prefer.

I believe I read that currently the Nosler partition bullets are made with jackets that are formed from copper wire, big copper wire. Holes are hammered (forged by drop hammer) into each end and then the lead inserted and crimped in place.

Mr. Corbin has been mentioned and in his writings, many available for download free on his web site(s) eg corbins.com, he compares the partition concept to the bonded core concept where the lead is soldered to the jacket. Cores come apart from partition bullets, in fact advertising had the nose lead "blowing off," ... the soldered core stays with the copper however it gets mangled. Mr. C. prefers this. Your call. happy trails.

Nosler states that their current jackets are made by impact extrusion.... whatever that is.

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Cartridge cases are made by 'back extrusion'. A brass slug [cylinder] is put in a female die and a male die is then inserted and the brass flows up between the male and female dies and the brass cup shaped case is formed. The Noslers are formed in a similar way ,the dies move by impact instead of just pressure.

impact extrusion... sounds like cold forming with a big punch into a bigger die, by a bigger hammer

quote:

Originally posted by Allan DeGroot:
Nosler states that their current jackets are made by impact extrusion.... whatever that is.

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Allan - I believe that is a term for what is similar to old fashioned "drop forging".

Basically, it is slamming a punch into a brass "blank",forcing the blank into a "female" die hard enough to make it flow longitudinally around the punch.

After the jacket is basically formed, then it is trimmed, filled with the core material (at each end, when making Partitions), then swaged to final shape and closure.

Corbin's have a type of partition bullet outlined in their writings. What they do is seat a core in a small jacket, invert it and insert it into the jacket of the bullet you are making. Another core is put on top of the inverted jacket and the final swaging pass is made.

I'm currently working on a design of my own that includes a gas check inserted into the middle of the bullet, but I'm only in the initial stages.

Rick,
I did this bck in the late 70's using copper tubing, lead and guilding metal outer jacket. It was difficult to get accurately made bullets and more difficult to get them to shoot accurately. It gave me real respect for the folks who make premium grade bullets. It worked better for handgun ammo but it is just as expensive to make a good bullet as it is to but good bullets. It takes less time to buy them.

Think I read about another way, whereby you swage your jacket ID from top and bottom, too big for the die so that copper is forced into the middle, making the partition. A small hole is left usually, but in effect you have an "A-Frame" jacket, which you can then fill with a core on each end, then point-form.
Never tried it though.

quote:

Originally posted by Alberta Canuck:


As I understand it, the original brass jacketed "partition" bullets were made by boring holes in each end of a piece of brass stock. Then cut lead cores were inserted, one at a time, into each end of the brass stock. Then the two ends were swaged to shape, probably simultaneously. Finally, the "relief "belt' (groove) was machined around approximately the middle.

AC interesting post, thanks, but, I'm not so sure about the early ones, I have some 200 gr 30 cal NPs from the olden days with the relief groove spun around them, they're much more of a semi round nose than todays spitzer jobbies. Anyway, when I sectioned one of these I found that in fact the partition did not totally join in the middle but there was a small hole right thru, the partition was more like as very extreme internal belt. I kind of figured they started with a tube & then bumped it to squeeze it together in the middle. Interestingly, some 416 A-frames that I did likewise too looked as though they were made in a similar way except in their case the hole in the partition was sealed off by a rivet of the same material as the case.
Left to right..416 cal 400 gr Swift A-frame, sectioned, whole & half case showing rivet between fore & aft sections, I had to melt the foreend lead out;.30 cal 200 gr Nosler partition(old style) whole & sectioned showing hole between fore & aft sections.;.375 cal. 300 gr current style partition, whole & sectioned


Now if only Nosler could figure out how to bond their fore end they'd be onto a winner, bet they're working on it,
Steve.

Sure, why not go bonded?? Huh??

The partition has been the Gold standard of premium bullets for over 50 years. It does exactly what it was designed to do. Expand easily, loose roughly 1/3 of its weight (pieces form secondary projectiles that can do damage far from the primary wound channel) then the remaining 2/3 of the bullet penetrates deeply.

Bonding would only serve to increase retained weight, which is not all it's cracked up to be.
better to have that 1/3 do the damage on the inside.

Very nice picture. Excellent cross sections.

Just a humble opinion from a former Nosler Tooling Engineer, ballistics manager and customer service technician.

Joe

The old-style Nos - that's what I was referring to. Interesting idea using a plug to swage into the hole left.

quote:

Originally posted by jcunclejoe:
Sure, why not go bonded?? Huh??

The partition has been the Gold standard of premium bullets for over 50 years. It does exactly what it was designed to do. Expand easily, loose roughly 1/3 of its weight (pieces form secondary projectiles that can do damage far from the primary wound channel) then the remaining 2/3 of the bullet penetrates deeply.

Bonding would only serve to increase retained weight, which is not all it's cracked up to be.
better to have that 1/3 do the damage on the inside.

Very nice picture. Excellent cross sections.

Just a humble opinion from a former Nosler Tooling Engineer, ballistics manager and customer service technician.

Joe

Joe, it was meant to be a tongue in cheek comment hence the wink smilie face. Your points are totally valid, but it amuses me how in reading the various forums (forae?)that the old Gold Standard is sometimes now seen as no longer cutting the mustard compared to the modern crop of bonded, partitioned & monolithic expanding projectiles. I still reckon if I do my bit the NP will do its bit, even my old 30cal 200 grainers. I'd love to have the in depth knowledge your background must give you.
Thanks for the compliment re the X sections, amazing what you can do with a hacksaw, vice, file & too much time on your hands.
Steve

You are quite welcome Steve, the compliment was indeed sincere. That is exactly the way it's still done at Nosler, sometimes they use a milling machine then file and sandpaper.

It is kinda funny how nowdays it has to be partitioned, bonded, plastic tipped, boattailed and have a BC of over .6 to even have a chance at killing a critter.

I'll bet every critter ever killed with Corelokt, silvertip or banana peel bullets are rolling over in their graves thinking they went down waaaaay too easy.

Hmmm maybe the critters these days are just that much tougher.

Then again it's amazing what can be done with a well placed shot and any reasonable bullet.
Take care and shoot well.
Joe