22lr Pinch Trimming

[HtNRun]

For those of you that pinch trim 22lr for shorter cases, what is your preference?

1 - Trim before annealing
2 - Trim after annealing

What seems to get your best results?


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[pertnear]

What is pinch trimming?

[Mauser 98K]

Pinch trimming is the process of trimming jackets that consist of a lower die that supports the jacket and a tapered trimming punch that pinches the jacket between it and the die thus cutting the jacket and allowing one to remove the excess jacket...

[HtNRun]

Shortening a 22lr to roughly the length of a 22short for lighter grain bullets. Pictured is a 22lr, trimmed, a 32 gr core, point formed to a 40 gr hp, next to a 40gr hornady v-max.




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[Zbench]

Here is the money shot that others have described.

[Bills Shed]

When I used a pinch trim die,( for 22lr cases) I trimed before annealing. If I trim after annealing the case just crumples under the pressure and the waste metal does not peel away from the top punch. Also after pinch trimming with the brass still hard, the waste metal tends to break off cleanly from the remaining jacket.
That said I think it is a slow and not tidy process when it comes to trimming jackets. When I first got into trimming jackets I built a heavy base with a inverted Forster collet bullet puller to hold the jacket. It worked very well, was accurate and could do any calibre with a change of the collet. I thought it was quite slow though when doing a 1000 in a run. I forked out a got a Corbin ET-2 pinch trim die. It did a very average job to say the least. I have had my die sharpened up and it now cuts pretty neat. Some waste just falls off but there is usually some of the waste metal that needs to be removed by some means. I throw them all in a tumbler with large nuts and beat them to death. Time Saving was better but I did not think it was as neat or as accurate as the end mill. Ended up putting a pneumatic actuator on my collet set up to open / close the collet and a small ejector as well to push the case out of the collet when it was open. All I have to do is feed the collet and lower the end mill.
My collet setup and a end mill in a drill press is now quicker, neater and accurate to the .001"-.002" You can also do annealed cases in a this setup. The trim takes about 3 seconds from start to finish.

17 cal jackets are annealed and then I use a draw / pinch trim, semi push through, bottom ejection, system from Corbin. This DIE works very well, ( The ejection system was ****). Built an auto ejection actuator for this and it now works a treat if a bit bulky. The only problem with this type of setup is the punch only makes one length of jacket. Extra punches are not expensive though and Dave Corbin was easy to deal with. Using an end mill setup you can make any jacket length you like for the one off cost of a collet. ($12.00)

Bill

[MUSTANG]

ZBench - Who makes the pinch prime die and press in your picture?

I use a pinch trim die on my 22WMR and 17HMR cases in a RCBS press, it is more of a cone than what is in your picture. Use a Corbin press for my swaging operations.

[BlackoutBuilder]

I think Corbin does.

[HtNRun]

Thank you Bill. Your experience has been mine as well, and I was looking for validation. I had a batch I annealed for 55gr and didn’t have any fresh brass, so I did about a 1000. They all seemed to crumple or bunch in my Corbin ET-2. Great die, I don’t think it’s any more or less tedious than other methods described, so I roll with it.

I do have a new batch of 22 that I need to derim, and was going to try trimming before annealing.

Thanks again for the input!


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[Zbench]

That is a magnum pinch trim die made by Corbin using his Hydro CHP-1 press. Takes about 900 psi to trim those thick walled jackets.

[Bills Shed]

Thank you Bill. Your experience has been mine as well, and I was looking for validation. I had a batch I annealed for 55gr and didn’t have any fresh brass, so I did about a 1000. They all seemed to crumple or bunch in my Corbin ET-2. Great die, I don’t think it’s any more or less tedious than other methods described, so I roll with it.

I do have a new batch of 22 that I need to derim, and was going to try trimming before annealing.

Thanks again for the input!


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If you are just trimming off .150" ish I think you may get away with an annealed case but I am making jackets for 35gn soft points so most of the jacket is waste. The cone on my top punch puts a lot of pressure on the jacket so un-annealed is the only option, and even then some crumple. D Corbins web site shows a long taper on the top punch but the one he sold me has a angle of about 120deg. Very blunt shaped.

Bill

[uncle dino]

Z.. If your using 900 psi.. The body of your pinch trim die needs to be sharpened.. I have quit using the hydro for pinch trim operations.. I now do it by hand. The problem with the hydro is.. Even when you set the ram at its max extension. Pinch trim dimension will change. And will dull the cutter.. The cause is heat. The hydro warms up and the ram will grow slightly and dull the cutting edge. It takes very little tool to tool contact to dull that edge. I sharpen my trim dies on the lathe with a tool post grinder. D

[uncle dino]

Bill.. The blunt shaped punch actually works better than the long taper punch.. Puts less pressure on the jacket as it is cut. The long punch may split the jacket easier, but all the pressure comes as the jacket is nipped off. The long punch causes greater weight variations in the trimmed jacket. D

[Zbench]

Dino,

Normally you would be right, but in the pictures shown, I am trimming super heavy duty jackets that are 0.065" thick.

I also don't rely on the position of the ram to determine when to stop. The way Corbin advocates, and what I do is to turn the pressure way down and advance the ram into the plug cutter with jacket loaded, while energizing the ram up, continue to adjust the pressure up just until the jacket is sheared away. In my experience, there is always a small bit that doesn't get trimmed which doesn't allow the cutter and the die body to make contact. Once that is set, turn the pressure up just a shade more, then use the pressure sensor and adjust the reverse valve to just below that pressure. It take s few jackets to get that pressure adjusted perfectly, but when you have it, you run in auto mode and not only does the cutter reverse immediately, because the dwell time at the top is exact each time, the trim length is 100% consistent. Mine vary by less than .1 gr. For a Jacket weighing 230 grains, that is pretty darn good.

Try it and see if you get similar results. The only way to trim these thick jackets is with the hydro, or with a collet in the lathe with a chucked end mill. I think the hydro is faster.

Zbench

[uncle dino]

Good info Z. I'll give that a try. D

[Zbench]

Next time I'm doing it I will get the wife to take a video and post it here...

[Zbench]

I was trimming some heavy jackets today and remembered my promise to show some video of the process. In this video the jackets are being trimmed at about 1000 pounds of pressure, but as soon as it reaches that pressure the auto reverse kicks in and retracts the ram. This process makes the length very accurate and after trimming thousands of jackets this way, the punch and die is still sharp. It's a little tricky to set up as you adjust the ram with enough pressure to get the jacket to shear, then you have to tweak it a little higher, then adjust the auto reverse pressure to be just under this set pressure. Sounds complicated, but it is pretty easy after you do it a few times.

To be fancy, I'm also using the load sensor to adjust the ram up some and stop to allow me to load a new jacket to be trimmed.

Not going to win any Academy Awards, but you can see it at: https://youtu.be/qMpjTyOtJEY

[Traffer]

Pinch trimming is the process of trimming jackets that consist of a lower die that supports the jacket and a tapered trimming punch that pinches the jacket between it and the die thus cutting the jacket and allowing one to remove the excess jacket...

I cannot get a picture of that process in my mind. I would like to find or develop a process for trimming 22lr cases down to 22 short size and 6mm Flobert size for reloading 22 short and 6mm Flobert. I have been meaning to start making these rounds but haven't gotten to it yet. Didn't know there was already a process developed for that.

[Hueyville]

Think I will start lining up my 22 magnum brass along the front of my bowling pin table and use my long slide pin gun to clip the extra off with 200 grain SWC cast boolits. If the bullet tip doesn't allow cases to clip off clean will get one of my 38 special wad cutter guns after them, bet clearing bowling pins will get easy after a few months of "clip trimming" all the 22 magnum cases I have. ;-)

It has given me an idea, going to machine a case holder for my mill. Chuck a 45° champhering bit in mill and set stops up so the champhering bit stops about a thousandth from contacting wall of the holding fixture and should take all the extra length off the long cases. 900 psi would be easy in either device. Could also machine a holder and punch for my arbor press or hydraulic press. Of course buying shipped to my door may be more cost efficient but could not find the ET-2-R Adjustable-Length Jacket Trim Dies on their price list. About what do they cost for the rimfire pinch trim die setup?

[Zbench]

http://www.swagedies.com/mm5/merchan...ory_Code=RDIES