Bandsaw Case Trimming
Make time and do a better, more precise job trimming cases with a bandsaw than conventional case trimmers when shortening cases for reforming
Lopping off substantial excess case length making shorter cases is a snap with a holder such as this one pictured.Lopping off substantial excess case length making shorter cases is a snap with a holder such as this one pictured.
It is for shortening 1.6" .357 Max. brass necked down to .300 Whisp-R Improved, ending up with a precise 1.4" case length.
I make up similar fixtures for a variety of cases such as my 1.4" .30 Bellm made from 2.200" .444 Marlin brass and the traditional .30 and .357 Herrett rounds from .30/30 brass.
This one is made from a scrap piece of gun barrel, drilled out with conventional drill bits and the rim counterbore lathe turned. After the internal work the barrel piece is milled rectangular and the slot milled into it for the actual case length. You can forgo the rim counter bore if you like, and the slot can be sawed. In other words, you do not have to have a lathe and mill to make these yourself.
Go from this:
to this in seconds, more like 1 second:
(Note: The marring of the finish on this fired and annealed reformed .357 Max. case is not from the fixture. It is from resizing and reforming. Very little case marring results if the inside of the fixture is relatively smooth.)
Steel fixture holds the case for it to spin against a bandsaw blade.
End of fixture to the slot milled in it equals the desired case length and puts the band saw blade in the correct location every time.
End of fixture is counterbored same depth as the case rim is thick.
This is so you can feel that the case head is flush with the end of the fixture.
Length of the case is actually referenced from the front side of the case rim, and case rims do vary by a few thous.
Thus final case length will also vary by the amount of variance in case rim thickness. Drill the fixture large enough to let the case spin without binding, both in the body and the neck areas. Ie, you need two drill sizes.
One large enough for the case web and one for the neck.
For rimmed cases, make the body area long enough to not touch the shoulder. For rimless, depth of drilled hole for the case body must be precise since the shoulder becomes the reference point. Or, cut the slot referenced from the shoulder and rely on the neck area only to support the case while spinning.
Side of bandsaw blade rests against and is guided by the side of the slot.
Notice I am holding the fixture grasping it with thumb and forefinger while my middle finger presses against the case head, holding it against the bottom of the rim counterbore in the fixture.
Life of the fixture dimensions is surprisingly long. Hint: A slightly dull blade with less set in the teeth is better than a new, sharp blade, both for function and for the life of the fixture.
In operation, the case is brought slowly to the blade so the blade will spin the case in the fixture.
As it spins, the case neck is scored/grooved on the outside. And since it is spinning, the cut is perfectly square to the case body.
The case is scored before the blade actually cuts it off.
If you look closely you can see the blade started into the neck before I backed it away quickly enough to show just the grooving effect.
With the case neck scored like this, no outside deburring is necessary.
Safety is another big issue.
If you make the fixture large enough so that you can hold onto it with both hands guiding the fixture into the blade with fingers at a safe distance from the blade it is quite safe to use
The above is being shared to help the shooting fraternity past one of the problem areas involved in making wildcat cartridges and other case forming.
I am not offering to make these for others at this point, preferring to stay more focused on barrel work rather than general machine work.
As quick and easy as these fixtures make the job, there is little excuse for not shooting all those .30 and .357 Herretts floating around!
It is faster and easier than routine case trimming with conventional case trimmers!