Cardboard checks?

[JDL]

I have a Lyman 457193 plain base that suffers from gas cutting in my .45-70. I cut some .015" card disks, put one in the mouth, and used the boolit to push them down. Now, I'm questioning my thought process. I know if the disk is against the powder and there is an airspace, chamber ringing can occur. There is about .2" space between the powder and boolit. I'm reasonably sure the disk is against the boolit base, but can't be for certain. Has anyone else done this, or do I need to pull them? -JDL

[mooman76]

Try shaking it. I did the same with disks cut from styrophoam like what meat comes on. If you don't think it quite does it use an extra piece to fill the gap!

[44man]

What kind of powder? Gas cutting is from a boolit too small and gas is getting around it. A wad will not correct it. If it is black powder you don't want more then .020" between the boolit and powder although the schuetzen (Spelling?) guys use a large gap. There is a lot of conflict as to whether the boolit must contact the powder.
As long as you are sure the wad is against the boolit, you will be OK. I would worry if it falls down against the powder.

[JDL]

44man, The powder was IMR-4198 (36 grains). Wheelweight boolit is a good bit oversized at .460", which is the diameter of the throat, but the groove is just .4575".
I called it gas cutting as I'm getting some leading, but it is just on the base band. On the driving edge of the groove there is a tiny "V" shape gouge and the edge of the base, is kind of jagged, reminicent of metal cut free hand with a torch. -JDL

[44man]

I would try a different alloy to see if the leading goes away. Every single gun that I shoot straight WW's from develops leading. By adding a little tin it goes away in some guns and for my others I even add some antimony.
I have never understood this. I shoot .460 to .461 boolits out of my Browning. I use 20 to 1 mix most of the time and have shot hard alloys with zero leading but all I have to do is shoot a few WW boolits and I clean out lead for an hour. All of my revolvers do the same thing.
The only luck I have with straight WW metal is with an annealed gas check.
Maybe adding some pure lead would help too, I never tried it much to say one way or the other.
I never read where anyone else has experienced this but it has been a problem for me for years. I shoot a lot of WW for light loads because it is cheap and I put up with the cleaning.
You can also try another powder like 3031 to see if it helps. I don't like 4198 in my revolver. I get wild pressure excursions where most cases fall out but several expand so much I have to remove the cylinder and poke them out with a stick. I never tried it in my Browning to see what it does in a rifle.
Let me know what you find.

[Bass Ackward]

JDL,

How many rounds you got down the pipe?

[45 2.1]

I have a Lyman 457193 plain base that suffers from gas cutting in my .45-70. I cut some .015" card disks, put one in the mouth, and used the boolit to push them down. Now, I'm questioning my thought process. I know if the disk is against the powder and there is an airspace, chamber ringing can occur. There is about .2" space between the powder and boolit. I'm reasonably sure the disk is against the boolit base, but can't be for certain. Has anyone else done this, or do I need to pull them? -JDL

You can take those cardboard wads and apply elmers glue to one side and set your boolit on it until dry. That should give you a cardboard gas check. This will help if your boolit isn't undersize (thats 0.459" and under, thats from measureing about 30 different 4570 rifle chambers and throats). Most problems come from too hard and undersize boolits in the 4570.

[JDL]

JDL,

How many rounds you got down the pipe?

That's anyone's guess! I got the B-78 new in 1976, before I started keeping detailed data, and have fired hundreds down range and quite a few in the field, mostly cast and paper-patched. -JDL

That's an idea 45 2.1. After having a night to think about it, I'm thinking maybe I should use a 100% capacity charge of slower burning powder, so there's no chance of an OH NO. Or maybe just forget the whole business and get an RCBS 45-400 and sell the Lyman. -JDL

[Leftoverdj]

It's safe enough if you cut the disks fatter than the ID of the case. I never had any success with cardboard, though. You need a better seal than cardboard will give. Similar disks cut from a discarded offset printing blanket (cloth reinforced sheet rubber) have shown some promise. They'll never match a proper GC, but they seem to make PB bullets usable at velocities 150-200 fps higher than usual.

There's also an outfit selling pre-made plastic wads for the same purpose. Haven't tried them, just heard they are available.

[GooseGestapo]

44man;

I've had similar problems to what you describe with W/W. I've decided that it has to do with size of the lube grooves, placement of said grooves, and amount and type of lube.

I've gotten splendid accuracy with the .459-405HB bullet and SPG at .458" up to 1,800fps and Slow powders in .45/70 (IMR 4064). the 405gr .458 (casts ).4595-.460), sized to .458 will lead and loose accuracy with either SPG or 50/50 at over 1,450fps.

I've also seen this situation with .358" handgun bullets in .357mag.
I guess it's just a w/w metal thing !!

[Bass Ackward]

JDL,

Well .... there are many possibilities here, but your wad solution might just work. I am always fascinated by gas cutting in a rifle because I myself have never seen it. I even shot rock hard 311284s at low pressure in my 06s that are outta round from .3076 to 3085. I just can't produce it.

Lots of time in handguns where poor ignition would not bump a bullet up, but never in rifles.



Goosey and 44 man,

ACWW (hardness) often finds itself in a bad pressure range for operation. Even if it is OK in the breech area, ACWW can often be too hard to continue to expand at pressures as they drop down a bore. And it is not hard enough to have the springback qualities of harder lead. That is why ACWW is the ideal hardness for fire lapping. Once it sizes down, it never cuts again. Thus you can actually just cut out a constriction or go as far as to lap in a taper. If you use hard lead, you will just lap in the same imperfections. Soft lead expands too much under pressure and will enlarge begining dmensions.

So what I am saying is that if you have a barrel / alignment (in a handgun) that is not .... absolutlly dimensionally perfect, ACWW is a poor choice to shoot. That's why some guys can do well with the soft lead and some guys claim that harder is the way to go. Especially in pistols. With ACWW conditions have to be just about perfect or you do get gas cutting / leading / outta balance fliers, wtc.

[44man]

Bass, I understand what you are saying. I use water dropped most of the time because it is easier for me. The strange thing about WW is it doesn't matter what size boolit I shoot, whether I air cool or water drop. An alloy each side of it reduces or eliminates leading. It could be a strange alloy used in this part of the country too. I am thinking it doesn't have enough tin to bond the antimony or has been recycled and mixed so much there is no way to tell what is actually in them.
A thought for all of you is the companies that recycle them into new weights will melt everything including zinc into one batch. And we worry about one or two zinc weights getting into our melt!