I've always had trouble with gas checks

[S.B.]

I don't think I own a mold(gas check design) that I've ever had checks stick properly while sizing? So, my plan is to cast some pure lead from these molds and a friend with a machine shop has agreed to put them in a lathe and drill a 1/8" hole in their noses to put an arbor(no. 8 screw with head removed and screwdriver slot cut on end), use some valve grinding compound and spin them to try and open up the gas check area of molds?
Steve

[blikseme300]

What gas checks and molds are you using? I typically use checks that are from Hornady and I learned that annealing the checks helps a lot. The spring-back of checks that have not been annealed could be causing what you are experiencing.

[marvelshooter]

Do you press them on as a separate operation before you size the boolit? I place a thin steel ruler over the sizing die and push hard against it and then they go through the sizer.

[S.B.]

I've tried Hornaday, home made aluminum and everything else I heard of, nothing seems to work my molds are LBT Lee Accurate Lyman irons etc. Yes apply checks in the same stroke of lubing press Lyman 450.
Steve

[GOPHER SLAYER]

I have many molds and lots of gas checks. Several years ago I bought a case of 30 caliber Hornady gas checks several years ago and found they do not work with some of the older Lyman molds. Fortunately I was able to buy several boxes of old Lyman gas checks.

[earlmck]

Do I understand you correctly that you own four different brands of moulds and they all produce gas checked boolets whose bases are too small to hold onto the check when pressed on with your fingers? So you just place the check on the die, the boolet base into the check and size? And the check bases of all these boolets are so undersized that the checks remain loose after the sizing?

If that is all correct than you do indeed need to hone out the base area a bit so the checks will grab on. But I gotta' say you are the unluckiest mould buyer I have ever heard of. I have over 20 gas check design moulds and of these there are two that won't reliably hold onto the check when pressed on with fingers. But even these two will hold the check nicely once they have gone through the sizer.

But if you are not seating the check squarely onto the base before sizing because you thought that was just a nuisance step, therein could be your problem. Get the checks seated square, maybe using the technique mentioned by marvelshooter. Size 'em after seating square and if they still won't stay firm you do need the honing.

[merlin101]

Ignorance must be bliss!( Me not the OP). When I started using checks my knowledge of them ended with 'they go on the bottom' and I've had little to no problems. Yeah I've had a few that weren't square but almost all clamp on tight and stay on. Usually I just start it on the base and then size away. With 4 molds and different brands of check I think the problem is procedure not all the molds.

[Rcmaveric]

I always run the bullets through a gas check seater before crimping. Ensures they are all the way on and square. Had some problems with 6.5 mm checks. If they are bit loose then a dot of super glue goes on the check then I seat the check in the bullet and crimp. Only happens every know and then.

[gwpercle]

If you use a lube/sizer try this method.
I have a Lyman 450 and a batch of gas checks that do not snap onto a particular 9mm boolit base snugly , the GC's tend to fall off while I'm putting them into the lube/sizer . The boolit base is slightly too small , half the GC's wont stay on.
So I stopped trying to put the GC's on the boolit base ....I place the GC into the sizer die hole, cup side up of course , then place the boolit base in the GC cup , make sure the nose is lined up with the top punch and pull down on the handle. The GC gets crimped onto the boolit base and stays put , the boolit lubed and we are done ! Don't even need a seprate gas check seater either.
I have a bad habit of always doing things the easy way ....others seem to want to do the most difficult fixes with lathes and turnings and altering moulds....maybe I'm to simple minded .
Gary

[robg]

Used Lee and rcbs molds, used hornaday and gator checks ,had no problems using Lee push though sizers .

[Walks]

Talk to the folks at SagesOutdoors.com. They make the GATOR gascheck and also special checks for undersized shanks. They helped me out and I'm HAPPY as a pig in ****. They have great Customer Service and are cheaper than LYMAN/HORNADY.

[toallmy]

Sages sells me nice checks to , talk to him . 256-492-5158

[Strtspdlx]

I would also consider annealing, I made a video on youtube on how someone explained it to me, and it worked wonderfully. but my problem was they where seating just enough to hold onto the base but theyd rotate back and forth on the base, if I tried with my thumb nail theyd pop back off. I annealed them and got rid of the spring back and they work perfectly now.

[Motor]

OP. If you have a machinist friend have him measure your bullets and the thickness of the material that your checks are made of. This isn't rocket science. When the check is squeezed down to whatever size the die is it's inside diameter should be smaller than the diameter of the bullet where it's supposed to go on.

Hornady 30 caliber checks are made with material that is around .014" thick. So that would be .028" total. So if you are using a .310" push through die the base of the bullet needs to be around .284" to have a .002" "crimp fit".

Many molds are designed for a material in this thickness range. So if you try soda cans or aluminium siding or something else that isn't in the .014" thickness range they are not going to be crimped on.

From my own personal experience I haven't had any issues with Hornady gas checks but I have had issues with aluminium gas checks even ones made of the correct thickness and annealed. Go figure.

Motor

[S.B.]

Motor, I took a little different approach with this. I use a small hole telescoping gauge (then measured with my Starlet mike)to insert into the gas check portion of one of my molds(a LBT that knew was for a Marlin 45/70 that used .458 sized bullets) the gas check area measures .425 and with gas checks measuring .018= .0443 means I need to open it up another .017". I was taught in machine shop that a press fit should be no more than .001 per inch of surface?
Steve

[Motor]

Motor, I took a little different approach with this. I use a small hole telescoping gauge (then measured with my Starlet mike)to insert into the gas check portion of one of my molds(a LBT that knew was for a Marlin 45/70 that used .458 sized bullets) the gas check area measures .425 and with gas checks measuring .018= .0443 means I need to open it up another .017". I was taught in machine shop that a press fit should be no more than .001 per inch of surface?
Steve

Steve. I've been a machinist all my life. (30+years) .001 fit on a gas check would very likely be fine. The point I was trying to make is there needs to be some interference fit of they are simply not going to hold.

I work with press fits almost daily. I assure you many are more than .001" but not much more, not enough to argue over.

Motor