Gas checking a mold???

[Steve E]

Wasn't there a thread here about someone that altered plain base molds to cast gas checks style bullets?

Steve E.........

[crabo]

It's the other way around. You would have to add metal to be able to use gas checks.

[Steve E]

I'm aware of that, I thought there was a thread about someone that altered molds by ADDING a small ring(split for each mold half) of metal somehow(and I don't know how)so you could cast bullets that would use gas checks. Maybe it was someone just talkingabout it.

Steve E............

[bobk]

The way I read about was to punch a hole in the center of the GC, insert in the mold, and pour through that hole. Think I'd invest in a set of snap ring pliers, if I ever figure out how to punch the holes in the center of the GC.

Bob K

[Larry Gibson]

You can face off the top of the mould blocks removing the bottom driving band. The lube groove then becomes the GC shank. The bullet is correspondingly lighter. Seems it would be easier and less expensive to just buy another mould made for GC bullets.

Larry Gibson

[beagle]

Pretty hard to do that. It has been done by silver soldering split rings in the mould base but it's a pretty precise operation due to the tolerances of GCs involved.

As has been pointed out, it's cheaper to buy a GC mould. Adding a GC shank would almost be alabor of love and very expensive and might not work correctly./beagle

[Steve E]

Thanks beagle, that was the info I was looking for. Now I have to see who has a GC type mold for a bullet like the RCBS 270 Gr. SAA bullet. Thanks again guys.

Steve E.........

[mooman76]

You could try soft checks. They go on any mould. There are also alternatives like fillerin the case that sort of act like a check by protecting the base.

[GP100man]

i`ve tried a metered amount of COW to protect the base , it worked to a degree but measuring powder then COW was just a little bit too much for me .

GP100man:castmine:

[JIMinPHX]

I suppose that you could build up the top of the cavities with a little braising rod & then machine it back down to the necessary shape. The craftsmanship involved would probably cost you more than a new mold though.

[Bret4207]

There's also the option of having a swage die made the forms a GC shank on the cast boolit. $$$$$ and picky work to do I imagine. Didn't someone try using a foil disc that was applied during the sizing process? IIRC it was something like .003 foil with a sticky adhesive and the disc was just "ironed" onto the boolit as you sized. I don't recall any more specifics.

[Charlie Sometimes]

There was an article in the first Handloaders' Bullet Making Annual (1990) by Dave Scovill about using the gas check with a hole through it and placing them in the driving bands in the mold and then pouring the bullet- the title of the article was The Wilk Gas Check (Ed Wilk- deceased at that time).
He placed one on the front band and the last band (where the gas check belongs). There was a set of dies that fit your reloading press and a taper sizer that could size them to the appropriate caliber bullet mold.

I tried it one time using a sheet metal hand punch on 30 caliber bullets and results weren't too bad, but it was labor intensive that way (my fingers were too big and the mold is HOT).

It is a very interesting article- it claims to have destroyed the cast bullet velocity barrier with this technique.

[crazy mark]

If you have a lathe it isn't too hard to make a die for a Lyman or RCBS sizer to put a GC shank on a bullet. It does take time and patience. The die upper dia has to be the max size you want your bullet to be and the TP has to match the nose really good. I have done this for myself and it did take a while to get it polished to the proper sizes.

[Frank46]

Hey I know lets get Buckshot (aka mikey) to do it, he'll do anything with metal in it.
Sorry Rick couldn't resist. Frank

[MakeMineA10mm]

If you're talking making thousands of boolits, my idea wouldn't work, and what I'd suggest is simply taking a cast 45-270-SAA boolit and sending it to Lee with the instruction that you want a GC base, and they'll make you a custom mould for that.

Now, before doing that, if you want to test them to see how they work, I'd suggest chucking the boolits in a lathe and carefully turning off a little metal off the base to form a GC shank. Doing 10-12 boolits would let you fire them with an already-proven load with the plain-base version to see if the accuracy, lack of leading, etc., was meeting the hypothesis of why you want the GC version. Then you'd know if it was worth it to do the custom one.

[Bret4207]

Thanks beagle, that was the info I was looking for. Now I have to see who has a GC type mold for a bullet like the RCBS 270 Gr. SAA bullet. Thanks again guys.

Steve E.........

Why not have Mountain Molds make one? You can design it online with his program and the quality is superb.

http://www.mountainmolds.com/

[leftiye]

Since ya cain't cut metal back on, the onliest ways I know to put gas checks on a plain base mold is to mill the bottom driving band off, and ream the next grease groove to correct diameter to hold a check. This really only works on a mold with many grease grooves, and a narrow bottom driving band as balance, and lube capacity suffer otherwse. The other way is to turn down your bottom driving band (on your boolits) to the correct diameter to take a gas check.

[leftiye]

I suppose that you could build up the top of the cavities with a little braising rod & then machine it back down to the necessary shape. The craftsmanship involved would probably cost you more than a new mold though. Jim in Phx

Or, maybe silver solder (1250 degree solder so the solder wouldn't melt at normal temps, keep Bryte on mold to stop scaling) a brass plate onto the top of the mold, and then mill flat and to correct thickness, and cut hole the correct diameter for gas check shank. Actually, the braising rod might be better.

[Cap'n Morgan]

Clamp the mold halves together, and mill/drill an over-size, flat-bottom pocket to the depth of the shank you want. Fire up the lathe and turn two disks the size of the pocket. Braze a disk in each mold part and mill (or hacksaw/file) the disk flat with the sides of the mold. Clamp the halves together, and bore the shank to size.

[docone31]

What would happen if....
Say a mandrel was ground, with an hole in an end that copper wire was inserted, then the wire was wound on the mandrel and cut to length.
A mold could be modified to accept the coil from the front driving band to the gas check.
The coil could be inserted into the mold, then the casting poured.
From this point, the wire jacketed boolitt, or whatever it would be called, is then sized to final size.
The Wilk check looks like a pain to stabilize the front modified check to use, whereas the coil could just be inserted and poured through. The coil would not have to be tinned as the bore would hold it in similiar to a gas check.
I paper patch with great results, perhaps the wire bearing surface could also duplicate the performance of the paper patch without the lengthy fabrication time needed for the patch to dry and besized.
Cutting the coils would be no issue, I do it in my jewelery business to make jump rings. The length of coil would be set in a guage and a jewelers saw could cut the single wire to shape.
This way, a person could make a supply of wire coils ahead, and cast away.
I might be reinventing the wheel, but it makes some sense to me.
One day, when finances allow, I just might get a mold body from Lee, and get the mold cut.
Cutting the coils is no biggee, I do it with much smaller coils for fixing earrings, neclaces, etc.
We have a guage similiar to what I am describing to cut lengths of coils. We cut them either across the top, or can cut off lengths.
Food for thought.

[leftiye]

Doc,
A smooth sided mold could possibly be threaded as you describe to hold the copper coil by using a round pionted cutting tool (not a problem as the width of the tool would be small). You might have to use a set of built up mold blocks - the bearing or straight part bored and threaded, and then bolted/fitted to an ojive part - on each block. This so the threading - which might require a number of cuts to be taken - can be ended without making a mess. A special tap might also be used to cut the thread.

[docone31]

The difficulty,
Most molds are hot! Alignment is a challenge no matter what.
I can see where threading would help maintain the size of the coil in the mold, aside from the cut length.
My thoughts on a straight sided mold cut out,
the coil could be dropped into the base of the mold, then the sprue plate shut and the mold filled.
I am just going to have to try it one day.
First would be to get the dimensions of the mandrel. For my .30cals, I would want the coil to project .310 to be sized down to .309. This would give a flattening of the coil, as well as sizing. The coil should be just short of the base so sizing would lock the coil in from the bottom as well as the indents formed by casting into the mold with the coil in place.
I normally run my molds real hot. It takes time for the sprue to shrink, and cool.
It would be like casting either solid signet ring, or filligree. The solid ring takes a cooler mold, about 600* to 800*. Filigree takes about 1000*. With the wire in the mold, it would have to run hotter to not pull away from the wire in the mold itself. The wire being wound into coils would have to be cleaned as it is wound. Enough oxides will form after wrapping.
I haven't fired jacketed loads in a long time but I have been watching the prices grow taller as we speak.
I do not see wrapping the boolitt after casting. Too many variables, spring back, tension, deformation of the casting itself.
Threading the mold, on the other hand, assures identical placement of the coil, and would insure spreading of the coil for the lead to grow out of.
In other words, place the coil in the mold, close the mold. The threading would interrupt the coil spaceing and slightly open it up.
Lots to think about here.
Reinventing the wheel is fun.