Bump/swaging dies for cast boolits

[PAT303]

On the boolit lube thread bumping boolits to a final size was mentioned,can I have some info on what bumping a boolit is exactly. Thanks Pat

[Bloodman14]

'Bumping' a boolit is the reverse of sizing a boolit down; the diameter is made larger by shortening the boolit with a special die. You would need a punch to fit/support the nose while smashing the boolit down in the die to make it larger.

[Eutectic]

Gunnerd is right in saying the most common terminology of 'bump' die would be for a die to increase the diameter of a softer lead boolit. The ones I've seen mostly are for paper patch boolits as diameter is important especially in smokeless loads and diameter of a chosen boolit may be smaller and need 'bumped' up. Also no lube grooves to contend with in this case. I have seen and also have done jacketed bumps in increased bullet diameter using point forming swaging dies. I have used more swaging type or dimension uniforming type dies personally and I tend to call them 'bump' dies as it is simpler language. Cast bullets are not perfect and a die to achieve correct diameters both body and nose wise and fix any misalignment of the same can make a more perfect boolit as long as cost isn't the object. Swaging type dies can change point/base configuration as well. Some handgun boolits with short bearing surfaces I have lengthened the main body length by swaging a hollow base into the boolit. I made most of mine when I had access to the machinery necessary.

Eutectic

[W.R.Buchanan]

Yes a simple die made from a piece of steel about 1/2-5/8 thick with a hole in it a few thou larger than the boolits.

You would place the boolit in the hole nose first and then a ball bearing in behind it.

Then squish it in an arbor press.

Now obviously this is only going to work for flat nosed boolits unless you make a plug for the other end that is shaped like the nose of your boolit. Another obvious point is that you have to make the die so that the ball is centered in the base of the boolit. No telling where your boolits would go with an off center dimple in the base? Rather than using a ball one could make a ram with a radius on the end so you didn't have to chase around after the ball on the floor.

Also you will need to set up some kind of stop on the press so all of the boolits come out the same size, and then I would recommend you run them thru a regular sizing die and lube them so they are consistant in size.

Alot more work than just getting a proper mould and sizing the resulting boolits accordingly.

Randy

[shooter93]

They are very common with the benchrest crowd Pat and there are several makers of the dies. The goal ofcourse is the infamous perfect fit for a given chamber.

[NSP64]

I made a bump die from my 44mag seating die(dont have a 44 at the time)
Made .451 230gr acp rn boolits from WDWW and then smashed them up to.459 with a FP.
Shot them from a 45-70
Dont have the 45-70 any more either.

[Idaho Sharpshooter]

Generally, the most severe reforming of a cast boolit. The CBA allowed minor swaging, ie sizing of a boolit. They set no limitations. Now, the serious shooters take a boolit and completely reshape it, often retaining only the grease groove or grooves.

1. buy a good boolit mold, and cast a bunch. Hone a sizer die out to just fit the boolit, and use
it to lube. No sizing at this stage.

2. buy a "bump" die to "perfect the as cast boolit, or slightly to completely reshape it. You
can reshape it to the point that no one can tell what mold it came from. The boolits WILL
be as close to identical as it is possible to be.

3. buy a custom chambering reamer, complete with that reshaped boolit throat shape, and cut
your chamber.

4. the loaded round will often have .001" or a fraction less clearance in the chamber. I got to
shoot two, and there was an almost hydraulic cylinder feel to the round being chambered.

The case never needs to be resized, which is wonderful for brass life. If your recreational life centers around shooting in cast boolit matches, all you need is a Savage 12-BV-SS in .308 Win and a Bench Rest Rifle chambered in some variant of the 308 x 1.5" Winchester case.

I met a gentleman shooting Schuetzen, bench only, who could cast a run of 500-600 230gr .32 caliber semi-spitzer boolits and hold .2 maximum lightest to heaviest in a day.
He had a Blackmon press and bump die, and he would show up at a match with 200-300 bumped boolits that all weighed exactly the same. He did rather well.

Rich

[.22-10-45]

Hello, Pat303. These dies can be quite simple..back in the mid to late 19th century, "pound dies" were made for muzzleloading match rifles..I have made these on a lathe myself..no real need to harden for light use with soft lead. They are 3 piece dies..body...which has hole dia. of finished bullet, base..which supports/forms bullet base. punch for this can be flat, cupped, or made to form hollw-base. & the nose-punch.
The one I made was for increasing the dia. of .58 minnie bullets for a .577 Snider. I used a fine thread base plug for adjustment.die was used in arbor press..top punch bottomed out on body die for repeatablity.
I also use a Corbin reloading-press type swaging die for re-forming nose shapes & squaring up bullet body to base..this one is .226 dia.