Troubles with Gas Checks

[mrblue]

So i've put on some test GC and have found that they tend to fall off with slight bumps or when i am test fiting them into the case. I am using a lee sizer and have tried it both ways with the boolit being put in either direction, top or bottom, they still seem loose. Any clues or hints to get a tighter fit, because i believe a few have already been lost into the case with the powder. thanks much

[Bad Water Bill]

Check the diameter of your boolit as dropped. Often the check area is smaller outside diameter than the inside diameter of the gas check.

Two answers that I know of.

1 open your mould a couple thousandths

2 Crazy glue the checks to the base of your boolits.

Now lets hear other suggestions.

[Blammer]

What type of GC are you using?
copper or homemade alum ones?

What bullet and what mould are you having these issues with?

sounds like your GC shank is a bit on the small side. May need to modify it a bit.

[Sensai]

There are two things that you need to check:

The most important is to either pull the boolits on the rounds that you suspect of losing the gas checks inside or check for barrel obstruction after each shot when firing them. A loose gas check inside the powder may or may not clear the barrel. A loose gas check in the barrel is not good!

The second, if the check and boolit shank are the appropriate size, is to check that you're actually getting the check onto the boolit shank before you size/crimp it on. I normally whack (technical term) the base with check installed on the bench then stand the boolit on the base before sizing/crimping. If it's not all the way on it will show and if it's on crooked the boolit will lean when sitting on the base.

Hope this helps.

[Tatume]

Veral Smith has this to say:

By contrast, the other sizers (other than Star) crimp the GC on before any of the bullet enters the die, so if the check shank has any deformities, or if the check shaves lead a bit on one side when pressed on, the check, being far stronger than lead, will force the bullet to size out of balance at the base end.

That’s not a problem with LBT moulds because we guarantee a slip on gas check fit, which prevents checks from shaving and going off center at all, and unlike cherried moulds, our check shanks are perfectly concentric to the bullet.

At any rate, this tiny, and probably invisible bit of press formed precision can shrink groups from 2-3 inched down to tack holes! DO NOT OVER LOOK IT!

In my experience, LBT bullets always have slightly loose gas checks. They are not crimped to the heel, but after sizing they remain a slip fit. This does not cause a problem, and I have fired many tens of thousands of them.

Take care, Tom

[blackthorn]

You may be getting a bit of "spring-back" of the check as the bullet clears the check seating die. If this is the case, annealing the checks before installation may help.

[Tatume]

Any clues or hints to get a tighter fit, because i believe a few have already been lost into the case with the powder. thanks much

Are you loading a straight-sided case, like 45 Colt or 45-70? If so, they are held in place by case tension. If you are loading a bottlenecked case you have two choices. Adjust the seating depth so the gas check remains in the case neck, or load a compressed charge. Either will ensure that the gas check does not fall off in the case.

[caseyboy]

Let's not forget the use of a dacron filler to hold the check against the boolit base.