Gas checks not staying on after sizing

[BobinIL]

I am having trouble getting my gas checks to stay on my bullets I am using the RCBS 405 FNGC bullet for 45-70 and hornady gas checks. I am sizing using an RCBS lube sizer and .458 sizer die. After running them throught the lube sizer the checks will sometimes stick to the sizer die plunger instead of the bullet. what can I do to remedy this? thinking I might try beagling my mold to make the bullet a little thicker

[Ben]

That may help ?
The Beagling isn't permanent and the tape can be removed at any time.

Another one is to do some trail and error with a piece of 400 grit sand paper on a tight fitting wood dowel ( that has a saw cut about 3/8 " deep in the end of the dowel ) in the gas check shank area of the mold.

You can remove .002 and it may make a huge difference in how your g/cs crimp in place. Go slow and cast a few and check things with your mic. Once you've taken too much metal out , you're in trouble...........GO SLOW !

[swheeler]

Try annealing a few gas checks

[bangerjim]

I also use Hornady Cu checks on everthing up thru 45 cal and they just do not come off. You may have a problem with the mold dropping under-sized GC shanks. Annealing as mentioned may help as that softens them a bit and allows them to form easier.

I have never had any luck with those home-brew checks. They always come off.

You can also enlarge the GC shank area by using PC......it adds about .002 to the diameter and they should snap on much harder and make it thru the die. Mine sure do! And you will no longer need grease lube.

banger

[454PB]

Are you sure the checks are pressed fully onto the rebated area before their trip into the sizer? I sometimes have to press the checks onto the shank beforehand, or they begin to "crimp" before they are fully seated resulting in the same problem you're having.

[masscaster]

I use the top Punch and Sizing Die to prep the GC for seating.
Place the GC in the Die, then gently bring the Top Punch down until it touches. A small amount of pressure and you'll feel a small pop. Now place the boolit on the GC and slowly bring the Punch down to square it.
Turning the boolit slightly as you increase pressure. Pull down adding firm pressure at the end of the stroke as normal.
If you place the GC and lightly seat it and the boolit falls in with no resistance it means the Shank is too small. If it's not too bad this method will still work.
I've seated millions of GC's over the years this way with no ill effects. The only problems occur when the Shank is too large.

Give it a try. ; )
Jeff