Corbin R-Type Boat Tail Punch Question

[Utah Shooter]

So I just picked up a set of Corbin .224 dies for wicked silly cheap. I have familiarized myself with how the process is done except for 1 punch. Is it even a boat tail punch?



Should I actually have a different die for doing this process? Maybe this punch was included with the set and it should not have been?

Also if you can see the top part with a bit of a lip on it? That prevents this punch from being able to even go into my de rimmed case. Should this be shaves off a bit be able to be inserted?

[frank martinez]

You know, I might ask that of Corbin direct. I showed the photo to a friend of mine who has been using Corbin stuff since before it was Corbin and he did not know.
Frank

[Utah Shooter]

Yeah I keep looking for a photo of one on their site and cannot find it.

[MIBULLETS]

It almost looks like a punch to make 243 jackets from 22 cases, but different than his normal punch for that.

[Spanners]

Likes like someone has had a hack on a lathe with it.
It appears there is a burr on it as if it was turned from the end back

[algunjunkie]

If you got it with a 224 kit what are the odds that it was made to swage primer pockets?

[martin]

Utah,

My guess is that this punch started out life as somthing else and was replaced by a new punch. I think algunjunkie is correct that it could be used to swage primer pockets. The only other possibility that I can see is that it could be a hollow pointing punch for pistol bullets but I kind of doubt it if the diameter is .224 and the fact that there is a burr which would preclude it from entering a die. Corbin heat treats and hardens their punches so the burr is likely the result of trying to machine it with a carbide cutter. You may not be able to remove the burr with a file in which case you would have to take it down with aluminum oxide sandpaper. If it were me, I would throw it in my junk can for a later project.

Martin

[Utah Shooter]

The following is a response from Dave. I do appreciate him taking the time.

"Thanks for your message.



If the diameter is about .224 inches on the main part of the punch, then this appears to be a base punch that someone modified for their own reasons. We only made one punch that looked like this, and it was a primer pocket swage, but it was polished, hardened, made of S-7 tool steel, and wasn't .224 diameter. We have not built primer pocket swages as a general rule because other manufacturers already have them, and they are satisfactory -- we generally don't make things that have been on the market with success because there are so many things for which there is a great need and no quality tools being offered. (No point sledge-hammering on the wall if there is an open door right next to it!)



One possible use, if the tip were polished, might be to make lead tip hollow points in a core seating die. If the punch will enter the core seat die without forcing it, then a long lead core that projects beyond the jacket or even is just about flush with the jacket, would probably seat and form a very big hollow cavity, which could then be wrapped around in the point forming die to make a large, blunt lead tip bullet with a smaller opening and deep HP cavity.



If the punch is hardened, then a ceramic bit would be needed to cut it properly. But if it is not hardened, we probably did not make it, and it could be cut with a cobalt tool steel bit or even just a HS steel bit. Aluminum oxide cloth would polish it either way.




D.R. Corbin, President
Corbin Mfg & Supply, Inc.
PO Box 2659, 600 Industrial Circle, White City, OR 97503



dave@corbins.com
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[danr]

this looks to be a cup forming punch of some sort.. the shelf on it looks to be a cutting surface for a die. the ledge of it looks to have been placed under allot of force.
though, the odd size of it, being .133 at the tip is odd..

utah mentioned this punch to me.. i thought about it, and also took some measurments of it from him.. i got enough information to reproduce the punch.. i was thinking of making one just so i could have it in my hands, and i could play with it in verious ways..

but right off hand, my thoughts are that it was used to form a 1/2 jacket cup from a flat.
i could be wrong though.. it wouldn't be the first time.


dan

[Hammer]

The base of this die looks exactly like the base of the die Mighty Thor discusses in his sticky on making 224 bullets from .22 cases. (less the yellow paint....) See the very first picture of the yellow jacket derim punch....

Only place I have seen a base on a punch with that much steel in it is in that sticky. I don't believe in coincidences... Seems to me someone used his sticky as a Template" for more punches.....

I am willing to go along with the primer pocket swage usage that someone adapted a Thor design punch to accomodate....

[MightyThor]

The size of the parts is critical here. It could very well be the expander to make the 243 cal jackets. You have to start the bell then expand with a separate punch with my old set. But if the diameter is smaller than .220 then It is likely something more like a pocket swage or such. It is most definitely not the punch for the boat tail. That forming is done on the outside of the bullet as the point is formed.

[Utah Shooter]

It is too long or high to have anything to do with a pocket swage punch. Not like I really need to have it for making projectiles but it wure would be nice to know what it goes to.

[michiganvet]

I just looked in one of my old Corbin booklets and that punch is indeed the accessory that opens up the mouth of the rf jacket so you can start a core for a .243 core seating die.

[danr]

I just looked in one of my old Corbin booklets and that punch is indeed the accessory that opens up the mouth of the rf jacket so you can start a core for a .243 core seating die.

odd, because the top part is .133 in size.. and 22 rimfire jackets are .200 to start with.

[michiganvet]

I think somebody has turned it down from the origional.

[MightyThor]

So could this be used to open a 17 cal. case?