Gas checks on bigger bullets?

Beagle333 · August 22, 2013, 09:29 PM

I have never owned a gas checked mold before.

But recently I had some questions and I'm having trouble finding the answer just by searching... so here are my two questions.The numbers are purely for the example. It could be any size bullet that is bigger than the gas checked base. Let's assume I have a rifle that needs a .460 bullet to fit the barrel. So I get a .45-70 mold that drops at .460. The gas checked base on the bullet is still going to cast for a .458 check, if I'm not mistaken.

#1. How do I seat a gas check on the base of a HP bullet that is sized to .460? Don't all .45-70 gas checked molds have a check groove that is designed for a .458 check? Obviously my .460 Lee sizer die wouldn't touch it, and my .458 die would muss up the bullet diameter. I had considered pressing it just barely into the .458 die, base first, and then tap it back out.... but I might muss up the HP nose. There's gotta be a better way.

And #2. If I did get it seated.... how would a .458 gc protect a bullet that is bigger than the check? Wouldn't the gasses just blow around the check?

I could easily see this scenario again when I'd need a .360 bullet (according to slugging the barrel) but I have to use the .358 checks on it. I actually have several molds that will cast .360, but they are all plain based, however if I had the GC version of those molds, they would still have a gas check groove that would only accommodate a .358 check.

I got a lot to learn about this new area of casting.

dahermit · August 23, 2013, 08:04 AM

Quote:

#1. How do I seat a gas check on the base of a HP bullet that is sized to .460? Don't all .45-70 gas checked molds have a check groove that is designed for a .458 check? Obviously my .460 Lee sizer die wouldn't touch it, and my .458 die would muss up the bullet diameter

The base of a gas check bullet is rebated to accept the inside diameter of the check. The outside diameter of the modern, crimp-on, unsized check is larger than the bullet itself and is always large enough that it will be sized smaller when pushed through a bullet sizing die. When you apply the gas check to your unsized, .460 diameter bullet, you will notice that it sticks out, beyond the bullet until it is sized.
Back in the day of the Lyman non-crimped on checks and Lyman molds that were way-oversize, that problem you envision may have existed, but with only .002 diameter from nominal size bullet and the thickness of crimp-on gas checks, I doubt if you will have any problems.

Beagle333 · August 23, 2013, 12:18 PM

Quote:

The outside diameter of the modern, crimp-on, unsized check is larger than the bullet itself and is always large enough that it will be sized smaller when pushed through a bullet sizing die.

I see the point. Thanks for the reply. Perhaps it will work perfectly. The rebated part is .428, but I was just curious that if the outside dia of the check is .458 and I shove it through a .460 die... it isn't going to crimp any.
But if you are right about it being larger than the finished check dia (.458), then it would touch the die and be crimped some.

Rangefinder · August 23, 2013, 03:45 PM

Just to varify, my .30 Caliber checks actually measure .3175 before the size/crimp. So they'd essentially be effective up to an over-sized bore/boolit to .317 and still have a crimp-on fitting. A .318 would simply step to a .32 Cal check which measures .329 (or there-abouts) before the sizing die squeezes it on down to the correct size. You are literally swagging the check to fit. I think I have a few somewhere, but I think a .35 Cal check (357 and 9mm) actually measures about .365 before sizing.

Mike / Tx · August 23, 2013, 05:17 PM

Buy ya books and send ya to school and all ya do is drool over the teachers....

Ok I know we are somewhat alike simply due to the info we have passed back and forth. So I am pretty cheap if I do say so myself, so I picked up the Lee sizers for my GC bullets.

If your looking to start throwing pennies away with each shot, pick out the proper Lee sizing die and you will be good to go. That is as long as your GC's are the proper size for your bullets. I would check with Blammer over at CB's for the proper size for the bullets your looking to check,

Also you might look here, (and does this sound familiar,) Clicky for tha Linky

Personally I only have a half dozen or so molds for GC'ed bullets. I think most of those are Lee with possibly a Lyman or two thrown in. I run most them through a .452 Lee sizing die and use Hornady 45 Cal checks. I have never mic'ed any of them nor even thought about it. I just shove them on the bases and shove them through the sizer. Ok I DO tumble lube them first, and then again after, but only because that is the lube I use for those bullets. I did try some on my new 4500, but in all honesty, the Lee was much easier and faster to boot. If they are a bit tight I just slam them down on my bench till they look seated on the base then shove them through.

I have recovered a LOT of them from my wood pile and some out of my dirt filled buckets and other than when I shoot one in on top of the other most if not all still have the checks in place.

Beagle333 · August 23, 2013, 06:42 PM

Quote:

If your looking to start throwing pennies away with each shot, pick out the proper Lee sizing die and you will be good to go.

It's not going to be a LOT of shots. I'm wanting to do it for just a few. I'd like to be able to run really soft alloy HP's through the .45-70

But there's a lot to learn about the different sizes. If it was as easy as "snap on, and push-thru", that would be great.... but it's not for all of them. The .45-70 mold I'm wanting to shoot has a check shank of .428, but should be sized to .460. This confused me, due to my ignorance of these things.
I thought a ".458 GC" was the actual size.

Quote:

You are literally swagging the check to fit.

I can see that now that I have just got a bag of em in the mail from Blammer and miked em and they are .468 O.D., so I should be good, as long as I can flare them just a bit, since the I.D. is .426 on em. NOE does make a tool to just barely chamfer the base of the GC shank and it is supposed to make them easier to seat.

I guess my title of this thread was wrong..... it wasn't bigger bullets, it was just that I didn't know the checks were bigger to start with and were swaged down to fit, and both are the same size. I guess I better get out my dowel and sandpaper and take that .457 die up to .460

Thanks Guys!!!!

August 23, 2013, 03:45 PM	#4
Rangefinder Senior Member Join Date: August 4, 2005 Posts: 2,017	Just to varify, my .30 Caliber checks actually measure .3175 before the size/crimp. So they'd essentially be effective up to an over-sized bore/boolit to .317 and still have a crimp-on fitting. A .318 would simply step to a .32 Cal check which measures .329 (or there-abouts) before the sizing die squeezes it on down to the correct size. You are literally swagging the check to fit. I think I have a few somewhere, but I think a .35 Cal check (357 and 9mm) actually measures about .365 before sizing. __________________ "Why is is called Common Sense when it seems so few actually possess it?" Guns only have two enemies: Rust and Politicians.

August 23, 2013, 05:17 PM	#5
Mike / Tx Senior Member Join Date: April 8, 2000 Posts: 2,101	Buy ya books and send ya to school and all ya do is drool over the teachers.... Ok I know we are somewhat alike simply due to the info we have passed back and forth. So I am pretty cheap if I do say so myself, so I picked up the Lee sizers for my GC bullets. If your looking to start throwing pennies away with each shot, pick out the proper Lee sizing die and you will be good to go. That is as long as your GC's are the proper size for your bullets. I would check with Blammer over at CB's for the proper size for the bullets your looking to check, Also you might look here, (and does this sound familiar,) Clicky for tha Linky Personally I only have a half dozen or so molds for GC'ed bullets. I think most of those are Lee with possibly a Lyman or two thrown in. I run most them through a .452 Lee sizing die and use Hornady 45 Cal checks. I have never mic'ed any of them nor even thought about it. I just shove them on the bases and shove them through the sizer. Ok I DO tumble lube them first, and then again after, but only because that is the lube I use for those bullets. I did try some on my new 4500, but in all honesty, the Lee was much easier and faster to boot. If they are a bit tight I just slam them down on my bench till they look seated on the base then shove them through. I have recovered a LOT of them from my wood pile and some out of my dirt filled buckets and other than when I shoot one in on top of the other most if not all still have the checks in place. __________________ LAter, Mike / TX

August 22, 2013, 09:29 PM	#1
Beagle333 Senior Member Join Date: January 7, 2012 Location: Auburn, AL. Posts: 2,332	Gas checks on bigger bullets? I have never owned a gas checked mold before. But recently I had some questions and I'm having trouble finding the answer just by searching... so here are my two questions.The numbers are purely for the example. It could be any size bullet that is bigger than the gas checked base. Let's assume I have a rifle that needs a .460 bullet to fit the barrel. So I get a .45-70 mold that drops at .460. The gas checked base on the bullet is still going to cast for a .458 check, if I'm not mistaken. #1. How do I seat a gas check on the base of a HP bullet that is sized to .460? Don't all .45-70 gas checked molds have a check groove that is designed for a .458 check? Obviously my .460 Lee sizer die wouldn't touch it, and my .458 die would muss up the bullet diameter. I had considered pressing it just barely into the .458 die, base first, and then tap it back out.... but I might muss up the HP nose. There's gotta be a better way. And #2. If I did get it seated.... how would a .458 gc protect a bullet that is bigger than the check? Wouldn't the gasses just blow around the check? I could easily see this scenario again when I'd need a .360 bullet (according to slugging the barrel) but I have to use the .358 checks on it. I actually have several molds that will cast .360, but they are all plain based, however if I had the GC version of those molds, they would still have a gas check groove that would only accommodate a .358 check. I got a lot to learn about this new area of casting. __________________ . . . Have a Colt and a smile.