Gang case trimmer

[gjemba]

This is a gang trimmer that I made for cutting the bases and trimming the case to length. I used a 27/64" bit as the final dimension but spaced the metal with some aluminum flashing while machining. When I was complete with the machining I removed the flashing. That allowed good clamping since it tightened the holes .001. I can cut 28 cases at a time. After I remove the bases, I put them mouth up and cut them to the proper length for whatever length jacket I need. I have the .40 unit done. I am waiting on a Q size bit to make the .32 acp gang trimmer for making 9mm/.38/.357 jackets.

I cut the bases off with an end mill so I have a nice flat jacket. They are trimmed to length with a slitting saw. I ordered the blades and do not have them yet so Ihave not trimmed any cases to length.

Gary

[gjemba]

This is a pic with the jig loaded prior to milling the bases.

Gary

[BT Sniper]

Year ago I thought this would be the perfect set up but never got around to putting one together. Glad to see it now in use. Looks Perfect! Of course you know we got to see some bullets now made from these cases.

Thanks for sharing your project. Think I may just have to make one now too. Great work!

BT

[Southern Son]

That is fantastic.

[jixxerbill]

freekin ingenious !!!!!!! good job man, way to use that nogin.. lol... i would definatly like to see some of the bullets made with these casses...thanks for the idea...bill

[gjemba]

This is how the clamp was laid out and started. I sandwiched 3 pieces of 1/2" x 2" with a piece of aluminum flashing in between each piece. I faced off each edge so they were identical in width. I drilled each hole probably with 4 different size drills to help maintain center. I was careful to have the depth stop set so all of the holes are exactly the same depth. It woulld be a real pain to have to worry about maintaining an equal height of the brass if you ended up with holes of varying depth. I'll make some bullets this weekend. I will need to make some .45 since CH4D is out of .44 sets. They told me 4 to 6 months for delivery.

[BT Sniper]

PM me! I may have a set of the 44 dies you seek :) . I hate waiting for CH, as do a bunch of you guys I'm sure. I hope it is only 4 months but they ran out of the 40 cal in July I think it was and still havn't seen any sence.

Great work on the trimmer set up. I had tought a simple slide clamp in the extracter grove would have set the hight of all the brass the same at teh same time had the holes not been drilled perfect depth.

[BT Sniper]

Can we get a close up of the finished jacket side and bottom view?

[gjemba]

I will post some finished case pictures tonight.

[mold maker]

What is the advantage of milling off the extractor grove? I consider it only cosmetic and will be hidden on the loaded round.
I have seen some fired cases that are slightly different lengths, but the same weight. By machining off part of the head aren't you introducing another variable in weight? Doesn't this leave the primerless hole open for lead to have to extrude to fill ?
What am I missing?

[BT Sniper]

You guessed it, mostly cosmetic IMO, but I see an advantage in the 9mms used for 40 cal bullets. The ability to make a bullet under 185 grains is rather limited by simple means. With the rim removed I can still use the cheap and avialble Lee 125 grain mold for a core and all of a sudden a 185 grain bullet becomes a 165-170 grain bullet. Same is true for the 44 cal, a 255 grain bullet becomes a 235-240 grain bullet.

It also makes a bullet that is nearly the same length for given weight of compairable commerical bullets. May just be easier to form the bullet too as the rim is the last thng to expand. Only the flash hole will remain, the primmer hole will be completly removed. But again it is adding another step in making a bullet from a piece of brass that is allready pretty easy to make with great proven results.

Then there is a few that don't like the look of the rim on the bullets yet they buy Montana Gold and Rem gold sabor bullets so maybe a potential commercial advantage if one was to make a business out of these bullets. Ofcourse then you loose the "cool" factor without the head stamp on the base of your bulets.

All just another somthing to tinker with I guess.

BT

[gjemba]

I do it for cosmetic reasons and to get some of the weight out of the jacket. In my mind, getting rid of the rim provides a better balance and lower center of gravity with the lead extending clear to the base of the jacket. In doing so accuracy should be at its best level. True or not, I don't know.

[BT Sniper]

Rearward CG, I can agree to that. Only one way to find out about the accuracy but the theory sounds good.

BT

[MIBULLETS]

It can also be much easier on your press since you don't have to expand the solid brass part of the jacket.

[MakeMineA10mm]

I set my cannelure location according to how much of the nose needs to stick out to get to proper OAL for the round. So, when I seat to the cannelure with a swaged bullet with the head trimmed off, I get a lot more space in the powder area of the case. In the 44 Mag. this isn't an issue of fitting the powder in, but in any cartridge this has the effect of enlarging the case capacity, which reduces pressures. We will get higher velocities at same pressure or same velocities at lower pressures by getting rid of the rims.

[Doby45]

I would think that you would put them all in base first, trim to length to get all the cases the exact length, THEN flip them over and move the mill down to remove the neck. If you removed the neck first the neck removal depth can be affected by the different lengths of the brass. Atleast, that is how I see it.

[jonblack]

I was careful to have the depth stop set so all of the holes are exactly the same depth. It woulld be a real pain to have to worry about maintaining an equal height of the brass if you ended up with holes of varying depth.

I am no machinist, so please forgive me if I step on any toes. However, it seems to me that it would have been much easier to get uniform depth by drilling all the way through and then using a solid piece as the base.

How this approach have made your fixture easier to construct or am I missing something in the design of the fixture?

Thanks
jonblack

[gjemba]

I am no machinist, so please forgive me if I step on any toes. However, it seems to me that it would have been much easier to get uniform depth by drilling all the way through and then using a solid piece as the base.

How this approach have made your fixture easier to construct or am I missing something in the design of the fixture?

Thanks
jonblack

There are as many methods as people who come up with them. Anything we do is an experiment that gets fine tuned as the prototypes evolve. I could have added adjustable screws to the bottom to raise or lower the brass. With a flat base, the metal clamps would need to be trimmed to the correct dimension for the brass to be exposed for trimming. At the time, this seemed be be the best method compared to the time that I wanted to spend on it. I am satisfied with the results but I know that I will remake it in the near future as my ideas change.

Thanks for your input.