Currious about gas checks

[cs86]

I've never used gas checks, but would consider them in a rifle if I ever decide to cast for one. I'd like to know how they are put on. Are they pushed on by finger, crimped on, and is there a special machine for them. I also wondered if they come off when the bullet is in flight?

[Larry Gibson]

Lyman's Cast Bullet Handbooks (3rd & 4th editions) give an excellent explanation to your questions.

Simple answers are; Are they pushed on by finger (initially but a "seater" is sometimes also used), crimped on(yes if they are the crimp on type, there are commercial and home made non crimp ons also), and is there a special machine for them (yes, either a lubrasizer with sizing dies or a push through sizer will crimp them on.. I also wondered if they come off when the bullet is in flight? (crimp ons should not come off in flight and slip ons many times don't either.

Larry Gibson

[ukrifleman]

I've never used gas checks, but would consider them in a rifle if I ever decide to cast for one. I'd like to know how they are put on. Are they pushed on by finger, crimped on, and is there a special machine for them. I also wondered if they come off when the bullet is in flight?

First off, you need to use a cast bullet that is designed to take a gas check. Check out Lee Precision for their range of bullet moulds for example.
The simplest and cheapest way to seat a gas check is with a Lee bullet sizing die of the appropriate size or, if you wish to use them unsized as cast, I have found the ideal way is fix them to the base of the bullet with Lok-Tite before I lube the bullets with Lee liquid Alox.
ukrifleman.

[Nickle]

Not that many years ago, there were no significant tools for seating gas checks, but most folks lubed with a Lyman 45 or equivalent. I've never heard of gas checks coming off myself, but I suppose it's probably happened. Not exactly a common thing.

Folks used to be led to believe a gas check reduced leading, but that's been debunked many times. It does seem they do protect the base of the boolit from powder combustion gases. I am of the opinion they aren't needed until your velocity gets up near the 2000 fps or over range.