Gas check 101

[Lennyjoe]

Lets talk gas check for a bit.

Since I'm new to the revolver/lead reloading arena I have noticed alot of talk about gas checking loads with lead. I've been reloading for autoloaders and rifle but with jacketed bullets for the most part. Just started reloading lead for .45 ACP recently as well.

Reason I ask is cause I'm fixing to start reloading 240gr Meister hard cast bullets for my .44 mag.

So educate those of us that are un-aware on the reason for gas checks and how/what they do as far as reloading is concerned.

Standing by for the first lesson

 

[Father Knows Best]

A gas check is just a metal (typically copper) cap that goes on the base of the bullet. It protects the base of the bullet from getting burned/melted and causing leading. To use a gas check, you start with a bullet mold that is designed to produce gas-checked bullets. They will be flat base with a step around the outside where the lip of the gas check fits over the base. The gas checks are purchased separately and are generally installed on the bullet at the sizing step (your sizer presses on the gas check as you force the bullet through the sizing die).

 

[Father Knows Best]

I should've mentioned that you can also buy lead bullets with the gas checks already installed. They cost a little more than non-checked cast bullets, of course. Here's a picture of one with the gas check clearly visible on the base:

 

[Lennyjoe]

Thanks for the info.

BTW, the image isn't showing up. At least on the current computer I'm using.

 

[LHB1]

Hey Lenny,
Be aware that gas checks will raise the pressure of cast bullet loads. The same load WITH gas check supposedly gave 5,000 more psi than without the gas check as reported many years ago. Not sure whether I read this in Handloader mag, Lyman cast bullet manual, American Rifleman, or other pub. It's OK to use gas checks IF the bullet was made for them (rebated heels) and the load is developed properly but DON'T just substitute a gas checked bullet for regular cast bullet in MAX load without reducing powder charge.

Good shooting and be safe.
LB

ps: I recently threw away about 7-8,000 gas checks of various sizes that were 30-35 years old. That tells you how much I used them.

 

[Father Knows Best]

Thanks for the info.

BTW, the image isn't showing up. At least on the current computer I'm using.

Strange. It shows up on mine just fine. Here's the link: http://www.midwayusa.com/mediasvr.dll/image?saleitemid=827283

It's from Midway USA's online catalog, item number 827283, a 180 grain .358 diameter gas checked bullet from Cast Performance.

 

[Lennyjoe]

Picture showed up on this computer. Must of been the one at work.

 

[longhorngunman]

At what velocity should one start using gas checks? Or is it not needed at all if your using the proper bullet size for your bore?

 

[dmftoy1]

I think the general rule of thumb is to consider them when you exceed 1000fps and to definately use them if you're exceeding 1200fps. At least that's what sticks in my mind from a Shooting Times article I read about 20 years ago.

 

[P95Carry]

Lenny -

I prefer gas check bullets for faster loads but - I do think plain bases can be sent way faster with acceptably minimal leading... as long as bullets not undersize and with slower powders. Certainly big bullets like 45 cal.

I generally try and cast gas check bullets proper from choice, using the specific moulds but did find the following interesting article from American Rifleman April 1971 - giving some ideas re applying gas checks to already plain base bullets. I have yet to try this out but hope to as I got a load of thin copper sheet some while back.

Two pages - but beware each is about 350k - kept that size so they'll print out reasonably OK.-

Page 1
Page 2

 

[MCgunner]

Basically, if you're shooting .45ACP, you don't need no stinkin' gas checks. If you're shooting a magnum caliber, you probably do if you're shooting cast bullets. If you're getting leading, the gas check bullet will probably solve it up to rifle velocities. I think around 2200 fps range is about the limit of usability before you're forced to use jacketed bullets. Some big bores are paper patched for the same reasons, avoiding leading, basically a paper jacket.

I fire .357 158 grain lead SWC gas checked bullets to 1900 fps in my .357 carbine with no problems. Very accurate round in that gun. It's kinda neat being able to use cast, home made bullets in your rifle. That's one of the things I like about the .357 carbine.

 

[Lennyjoe]

See, we all can learn a thing or two here

I'm loading Meister hard cast 240gr bullets for my .44 Mag and was wondering if I need to use gas checks on them. I'm guessing not.