Gas Check Design for Current Molds

[DonMountain]

Over the years I have been casting lead projectiles from several different mold makers. Of course since I use them for hunting, deer mostly, but other animals as well, I buy most of my molds with gas checks. Some low speed, low pressure pistols I use unchecked designs. It seems like some gas checks are designed differently or are formed differently than others. I have gravitated to the Hornady gas checks because they seem to stay on better and crimp tighter for these high speed rifle bullets I cast for all the old military rifles. Including 45-70. The older Lyman gas checks seemed to be able to slip off after they had been sized in my RCBS LAM-II. And some of those formed by some of the smaller companies also slip off in flight. Maybe causing some inaccuracies? So, whats the difference in the basic design of these gas checks and why aren't they all made the same to crimp onto the bullet properly? And which makes are well designed and manufactured for current molds?

[gwpercle]

The two most common are Lyman and Hornady. Lyman are smooth on the inside and rely on friction to stay on . But Hornady have a raised ridge on the inside and when seated form a mechanical lock onto the boolit . Lyman can come off if there is not a tight fit between boolit base and inside of check .
Hornady checks can grip onto a base without having a perfect fit and when crimped on are a bear to get off a boolit base .

I prefer Hornady checks because they can be crimped tightly on the base and stay put.

Lyman more than likely started making the simple cup gas check first and Hornady improved on the design when people complained of checks coming off in flight .

When Lyman made both the mould and the check you could expect a reasonable fit.
Now dozens of companies make boolit moulds and dozens of different companies make checks it's a wonder any of them match up .

I keep checks from Lyman , Hornady and Bullet Swaging & Supply and between those three check makers can usually find a check to fit any given mould .

As to why they aren't all made the same ???? Have no freaking idea...just the way it is !

Gary

[Dapaki]

Have you tried Sage's gas checks yet? I ran low on Lyman checks earlier this year and nearly choked on my coffee when I saw the price (it's been a while, folks) and looked for other vendors. Sage's Outdoors came up and I found the aluminum checks for 1/4 the price so I tried a bag. No, they don't have the rim that locks on like Lyman checks but curiously, they don't spring back and don't cock or cant like the Lymans did from time to time.

I do size all my boolits after they get gas checks, base up through the LEE sizer die then PC and resized once more. I have not lost one gas check yet and of the few boolits I have found the bases of (I shoot steel) the GC was still on the base. That in itself is very unusual and I attribute it to the PC.

[DHDeal]

"As to why they aren't all made the same ???? Have no freaking idea...just the way it is !"

That's one of the best answers I've heard about the issue yet.