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Discussion Starter · #1 ·
I am working on a wild cat round that uses 308 brass for a base but will very likely have to have a lot of brass trimmed from the newly sized case neck. Is there a tool that I should use rather than a traditional case trimmer?
 

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A form-trim die from Redding. I would buy a 308 trim die from Midsouth and trim the bottom to shorten it. Redding will make a custom and I believe RCBS will make a custom.

Hornady has a lower cost trim die but it is not a form die. If you form your cases in your size die the Hornady trim die could be shortened at lower cost.
 

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Back a few years ago when I was first forming 30 Herrett cases from 30/30, I used my buddy's high-speed cutoff wheel, at his archery shop. You had to go a little slow until it was into the neck, but his unit had a little bracket on a pivot that made it pretty easy, once you got the hang of it. I used that to get them close, then the case trimmer to finish them off square. Chamfer, deburr and put together the fire-forming loads. :)

I'm curious about what wildcat you're making from the 308 that requires so much trimming. Give us the details! :D
 

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If you happen to have an extra .308 seater cut it to length then cut the top off so it will expose the amount of neck you want to trim slightly long, adjust your die in the press to give you say .010 to trim in your trimmer cut the excess off with a hack saw while in the press. Makes it fairly quick. I have done this just to make .308, .243 and .300, .250 Sav out of 06 brass. Milsurp brass and lots of was around when I done it and that stubby die has saved me many times for other projects.
 

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I use trim dies for all of my case trimming. You just remove the brass that sticks up out of the trim die. Normally this is done with a file, but if you have a lot of extra length, you can use a hacksaw followed by a file. The top of the trim die is hardened so a saw or file won't harm it.

I like trim dies because you never need to measure a case or set a trimmer. Adjust the die like a FL sizing die, and anything that sticks out of the top is trimmed off.
 

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Seattle,

If you are necking down very far, chances are you will have to run an inside reamer in to thin the brass (it won't all flow forward). Once you've done that and got a standard thickness neck, a motorized trimmer is probably going to go about as fast as anything else. Good excuse to acquire an expensive new toy on the basis of "need".
 

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I reform 223 to 221 Fireball and have a lot of neck to remove. I chuck it up in a drill and use a mini tubing cutter to get close. The cutter collapses the neck a bit so then I use a deburring tool to flare the case neck large enough to get the Lee trimmer inserted and then final trim it with a ball handle Lee trimmer. Sounds like a lot of work but they go pretty quick once you get into it.
 

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Discussion Starter · #9 ·
Thanks guys. That all looks like good advice. I may try several of your ideas. I have an arrow cut off saw so I may start using that.

Broom Jm, the cartridge is based on a 308W cartridge with the shoulder set back .100 and an AI profile and shoulder angle. I assumed that setting the shoulder back would extrude the brass somewhat causing the over all length to increase, hence the need for the trimming. The idea behind the cartridge is to increase the power potential of a Marlin 336 while reducing bolt thrust. I've fooled around with the 307W cartridge in Marlins for the last several years and the first limiting factor appears to be bolt thrust. Anyway, it is just an experiment. We are calling the cartridge the 30 Lever Maximum (I hope I'm not plagiarizing anyone else's nomenclature.)
 

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There are two different chamberings I load for that require considerable 'chopping' to get usable brass. My .221 fireball from .223 brass and my 6mm 30-30 AI for my Contender.
In both cases I made a small jig to hold the case and bought one of these mini chop saws from Harbor Freight. Its very fast and does a nice neat job. Takes about two seconds per cut.

http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=42307
 

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Thanks guys. That all looks like good advice. I may try several of your ideas. I have an arrow cut off saw so I may start using that.

Broom Jm, the cartridge is based on a 308W cartridge with the shoulder set back .100 and an AI profile and shoulder angle. I assumed that setting the shoulder back would extrude the brass somewhat causing the over all length to increase, hence the need for the trimming. The idea behind the cartridge is to increase the power potential of a Marlin 336 while reducing bolt thrust. I've fooled around with the 307W cartridge in Marlins for the last several years and the first limiting factor appears to be bolt thrust. Anyway, it is just an experiment. We are calling the cartridge the 30 Lever Maximum (I hope I'm not plagiarizing anyone else's nomenclature.)
Ok, so how much brass are you actually cutting, here? Are you talking .050", .300", or ? When I form 30 Herrett cases, I have to cut off almost .4", so a hand trimmer is out of the question. Also, due to ridiculous Indiana law, I'm considering a wildcat that would be based on the 356 case, shortened to 1.625", which would require a lot of neck to be cut/trimmed. As Uncle Nick said, be sure to look at your neck thickness and be prepared to ream cases to get proper neck tension. I have to do that on the Herrett, as well.
 

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Yes, many tests have been completed and it has pretty well been proven outside neck turning will produce better accuracy – in a rifle capable of producing the best level of accuracy.

Inside neck reaming is important when reducing the length or bullet diameter because a doughnut or ring of brass is often left at the base of the neck junction and a bullet which extends below the doughnut will bulge the case.
In the 1960’s some gunwriters wrote that if you were aware of where the bulge in the neck was you could use it as a seating stop – and I suppose you could.
When making 356 cases from 30-06 case inside reaming is a necessity. Making 25-35 from 30-30 is another case where it is a necessity to inside ream.
Seat a bullet and measure your outside neck diameter and you will know for certain. If you do not have a doughnut outside reaming works just as well. How do you think the guy on the Campfire would handle these picture?
 

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Slim,

Your second photo make me think there is a clear "need" to explore the question of whether a double or triple shouldered case might not have some hidden advantage?

I've seen a couple of illustrations of outside neck turning where the turning tool digs into the shoulder just far enough to even out brass thickness over the donut, so it blows out into the shoulder corner on firing. I don't see how you would know how far that needs to be without bisecting some or your cases with a saw, though.
 

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Nick,
It gets too far off topic but my father used this method when making 300 Whisper cases from 223 – that’s doing it the hard way. This was at a time when the 221 Fireball was in short supply.
Dad used a Forster outside neck turner and turned right down into the shoulder neck junction to eliminate the doughnut. It would have been much easier to use an inside reamer but at the time we did not have one.
We learned about sectioning cases with that project. We used a 2X4 with a hole drilled in it and a saw cut down to the hole. Shove the case into the hole and put the board in a vise which squeezes the case. Saw down through the cut and it is pretty easy to section a case. A sectioned case shows you a lot of things about forming cases.

It is fun to look at these double shoulder cases.
Wouldn’t it be fun to ream a chamber with double shoulder and have a Pressure Trace to compare the cartridge with a single shoulder.
 

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From his description, he is not shortening the case, nor changing the neck size. Based on his fuller description in his second post (would have been useful the first time around to stop all the red herrings charging around), he is concerned that the overall case length might increase.
From the sounds of the proposed wildcat, he simply needs to be able to trim all to a common length once sized down and fireformed. Any number of handheld trimmers will accomplish that.
The only secondary question is whether or not outside neck turning, or an inside neck ream, would be required due to the neck being a bit longer and using some of the old shoulder. In my experience, this should not be a problem, but he will only know once he makes a couple of cases and fireforms them. I personally use a Forster outside neck turner when I need to remove brass from the neck.
 

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Once I figured out my RCBS trimer (nonpowered) I took the handle off added a washer, 2 nuts and a 1 inch machine screw to the end of the spindle where the handle had been. I chucked that new little nub onto a powerdrill and voi-la Power trimmer. works like a charm. I put the drill on high speed don the safetey glasses and trim a whole batch of brass in no-time flat.
 
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