So...over the last few weekends I have cast a shoebox full of 358156s and have begun seating gas checks. I've got a number of Lyman gas checks, which are what I've always used, but I'll run out of them soon and will have to start applying Hornady gas checks. I expect them to be every bit as good as the Lyman, but I have never shot a single bullet with the Hornady gas check. Can I expect any difference at all? I can easily segregate the finished bullets but I'm curious as to whether that would even be necessary. Will there be any discernable performance difference?

What's the consensus?

I would segregate them, but only because I'm anal that way. I would expect zero difference in performance.

No performance but I have encountered issues related to fit. Not all Hornady checks slip on Lyman bullets easily. They will fit, but in some cases it takes a bit of extra effort.

The Lymans are a straight on fit while the Hornadys are a bit thicker around the lip to provide a crimping effect when seated and run through a sizer. At least that was the situation several years ago. Also, Hornadys are a lot cheaper the last time I looked.

Finally, and I have no way to verify this, but I read that Lyman checks are made by Hornady anyway...

Oh, you haven't lived until you encountered older Saeco designs (and some others) that utilized a tapered gas check shank. Whyinhell they did that I'll never know. The upshot is that I made a hardened tapered punch to fit in my arbor press with which I laboriously re-shape checks to fit on those shanks, both in .30 and .22 caliber. I've used that selfsame punch to alter the checks for use on other bullets too when fit was an issue. The tapered gas check straightens right out as it passes through the sizing die, yet allows for easy bottoming out against the bullet base for a flat/square fit. (And make no mistake, the base of a bullet- the steering end as it were- absolutely must be flat, and square to the sides of the bullet.)

You mess with this stuff long enough and god knows what for bizarre gas check scenarios you'll encounter.

Thanks for the input, gents.

Jim, my Lyman gas checks are probably 35 years old. I think I bought the Hornady GCs in about 2006 or so. There is a pronounced visible difference in color, and the rim of the Hornady GCs are a little bit thicker at the edge as I would expect based on marketing material I have seen (or maybe a magazine article).

Looking at an image of gas checks on Lyman's website, they do appear to have a thicker edge than they used to, and look a lot like Hornady gas checks. I noticed there is no longer a Lyman .41 caliber gas check offered. I have some Hornady .416"s to use for .41 mag casting because someone told me a long time ago the .416s would work. If it doesn't, I guess I'll retire my 410610 mold and just cast the RCBS .41-210-SWC. I kinda want to get away from using gas checks anyway and I'm trying to use them up. I have about 4500 .357 and about 1800 .41s to be used up.

New lyman checks are made by hornady

Sage Outdoors has the Lyman check for the 410610 .397 shank

Thanks Chisos.

I sell GC's that are good, they are copper and they are cheap.

I have all 3 types of 41 cal GC's. sounds like you need the 416 one's

shoot me a PM and i'll get you some prices, just tell me what cal you want.


but to your question, you should not expect any difference with the Horn from the Lyman GC's.

I haven't bought a Lyman mold for years although I have more than my share... All GC molds now are ordered from "Accurate" and use the Sage "Gators" ...This combination is flawless.

I’ve never been a big fan of the Lyman’s, always had better luck with the Hornady’s. Sometimes the Lyman’s would come off of the bullet base..".never had a problem with the Hornady’s. memtb

NOE makes a tool that helps seat gas checks straight. It's on my wish list. Powdercoating only makes it harder to seat them on older .348 RCBS, Lyman, NEI, and Saeco bullets.

Thanks, Dinny

One of my first bullet molds was a double cavity Lyman 358156 that I bought for a Ruger .357 Blackhawk that I bought at a pawn shop in Lawton, OK when I was stationed at Ft Sill in the early '70s. Being new to bullet casting and because it was a Lyman mold, I bought Lyman gas checks. I quickly found that the Lyman gas checks were prone to fall off, and switched to Hornady's which were said to crimp on to the bullet. Since then I've only used Hornady gas checks for all of my pistol and rifle gas checked bullets.

Exactly what I experienced.....went to Hornady’s, and never looked back! memtb

I understand the desire to seat a gas check as straight as possible...it just seems like the thing to do. But I've been thinking about that some. I could be wrong, but it seems to me that the little 30000 psi jolt the bullet gets would pretty much iron out any existing gas check seating deficiency in very short order. Is there evidence that this does not happen, or that there are deleterious effects on accuracy when it does happen?

BTW, I have decided my 358429s shoot just as well as my 358156s. Once I run out of gas checks, I'll just retire the mold and go with the 358429. Same plan for my .41 Mag (currently using 410610), once I get around to casting some checkless bullets to try out. I avoided the GC route altogether when I started casting for .44 Mag and .45 Colt.