Home Forums Hunting & Shooting Ask The Gunwriters gas checks

Because bullets are hard to find except a few cast bullets are showing up, I'm wondering about gas checks.

My questions:
1. must the cast bullet be molded specifically for a gas check?

2. What specific tooling should I have to install gas checks?

3. Can one drive a gas checked cast bullet as fast as a jacketed bullet?

any other advice you can offer.....

BTW, I'm shooting a .38 special//357 Magnum revolver.

Gas checks are usually applied during the sizing & lube operation. The bullet will be recessed for the gas check. A hard cast of 22 brinel cast be driven faster than a jacketed at near same pressure

1. Yes. There are exceptions involving hard grease wads under the bullet bases, and "gas checks" comprised of metal discs under bullet bases, but they're in the realm of "kind of work but not real well".

2. Usually done when sizing/lubricating in a dedicated tool. Can be installed also with a simple Lee push-through die.

3. As stated above, yes, with a hard-as-sin alloy bullet, and better still if powder coated. In all my attempts at such folderol over the last 50 years I never achieved nearly the same accuracy as with jacketed bullets. "Usable accuracy", yes, but not "bragging accuracy". Then there's the issue of whether said hard cast bullets expand on game. Generally at worst they'll behave like FMJ bullets, or at best will fragment to a degree (if bone is encountered) which means they're extremely dodgy at best. That's one lesson I learned the hard way and the animals suffered needlessly.

I'm a proponent of cast bullets. I shoot a lot more cast than jacketed in centerfire rifles and handguns. But, I'm content to play in the sub-2000 fps arena, experimenting and striving for ultimate accuracy within the limitations of the venue.* I keep the jacketed stuff in reserve for the occasions that demand them, and don't try to make one duplicate the other. If the "shortage" doesn't improve or gets worse I'll shoot jacketed stuff less and less and my shelves full of them will get pretty dusty - but my shooting won't decrease one bit as long as my lead stash (about a ton) holds out. Well, as long as the primers hold out I guess.


*A wise man told me once that a bullet only needs to travel fast enough to punch a hole in the paper.

Addendum: There's nothing wrong with shooting cast bullets designed for gas checks without their gas checks. Keep velocity down to around the sonic level (no more than around 1300-1400 fps or so) and cast them soft (bhn 8-10). Accuracy may or may not be of bragging quality but who cares as long as you're getting in some "trigger time".

I like them harder for 1300, 1400 FPS

When shooting lead alloy bullets that don't expand well do yourself major favor and place it so you drive through the vitals and break the far shoulder as well when exiting. MB

Addendum, II: I've been experimenting of late with cast bullets in an M1 Garand. I found a hard (bhn 18-20) gas checked bullet (regular lube, no powder coating), a spitzer shape weighing 170 grains, driven at a bit over 2000 fps with a reduced load of IMR-4895 both works the action and provides "usable" accuracy. The gun with its new Criterion barrel will provide 1.5MOA accuracy with 150 Sierra FMJBT bullets + 47gr. Varget - pretty decent for an as-issued M1. The cast loads provide a full MOA more which is certainly usable for any purpose an M1 will be put to. Lead buildup in the gas cylinder? Maybe a bit, but I clean the gas cylinder after every range session anyway, doesn't everybody? The big thing IMO is that throat erosion with such a load is non-existent or minimal, and brass lasts forever. (Not to mention cheap as dirt to load.)

That's why I said "no more than 1300-1400 fps".

Another one of my half baked opinions. I have a very short attention span, and it gets shorter with inaccurate plinking/practice shooting. For some reason, a character deficiency I guess, I need to be confident that if my sight picture is correct, trigger pull is correct, basic marksmanship principles are applied...that I will hit the goddam bullseye. Anything less than that is just noise, which bores me. tip: shoot low velocity plain base bullets when you can and/or shoot medium to standard velocity gas check bullets with checks applied when you can. Avoid bevel bases and unchecked gas check bullets, it's a recipe, generally, for disappointment for the cast bullet beginner. Powder coating? The debate rages on, and I am unqualified to opine.

LBT Blue is excellent for speeds up to 3000 FPS. Accuracy will increase with a hardness in the 30's

1. No. I know of at least one company that makes thin aluminum gas checks designed for plain-base bullets. https://www.sagesoutdoors.com/
2. I've found Lee push-through sizers to be the cheapest and easiest way to install checks.
3. For your revolver use, the right bullet (sized to match your cylinder throats) of the right alloy (sometimes harder, softer) will produce more velocity with top loads because of less inherent bore friction. Checks aren't necessarily required for this, but they can smooth over a lot of bumps. Powder coating is another "cheat" that solves many problems without much fuss.

To find out what is going to work best, it helps to try a lot of stuff. The results may surprise you. I've found, contrary to gnoahh, that cast bullets can beat the accuracy I get with jacketed bullets, within a specific yardage, say 100 yds. I've shot 5-shot groups with a 30-06 and cast bullets that are less than half the size of any jacketed bullet load. The difference is that I can't do that at 400 or 500yds with cast bullets. I consistently find that cast bullets are more accurate in various revolvers than jacketed bullets as well.

Granted, but I stick with good old NRA formula 50/50 lube. It's served me well since the late 60's for anything and everything. I'll concede there are better lubes today, but I cringe at the thought of changing lubes in my lubrisizer. Sub-MOA accuracy with "mild" alloys at mild velocities suits me just fine. Example: I get as good or better accuracy with a .22 Hornet than most fellas do with full-snot jacketed loads. So what if my loads aren't as fast if I'm not shooting at small critters way out there and merely punching holes in paper? If/when critter killing is called for then I load some 45 jacketed's at substantial velocity and sally forth.

As for extremely hard bullets, since I pretty much have lost all interest in playing at exteremely high velocity with cast bullets I prefer to husband my stash of monotype and linotype for the purpose of "sweetening" pure lead or nearly pure lead.

Yep. I too enjoy way below sub-MOA accuracy in most of my .30-06's, particularly with the ones I have dedicated to nothing but cast bullet shooting. (My ersatz M1903A1 USMC sniper with Unertl scope, and the M1903 Style T target rifle comes to mind. The 1954-vintage Model 70 is another.) Certainly in keeping with the accuracy they return with jacketed stuff, and often better. My Winchester M54 .30-30 will shoot factory equivalent jacketed stuff into 1.5-2MOA with the Lyman 48 sight. When I bolt on a Unertl/Fecker/Targetspot scope and unleash some pet cast loads it becomes a sub-MOA beast for ten shot groups, while the jacketed stuff still struggles to get down to around a MOA. Don't even get me started on the performance of my old .22 Lovell wildcats and Hornets!

As opportunities to shoot beyond 200 yards are nonexistent around here, I have zero interest in how well my loads perform at "to hell and gone" distances!

It's been so long since I fired a jacketed bullet out of any of my handguns I can't begin to comment there. 200gr. lead SWC's out of the 1911's and wadcutters out of my K-38 are about it for me these days. (A 1911 stuffed with state-of-the-art 230 jacketed HP's resides in my night stand, but I have only function tested them and don't care how accurate or inaccurate they are. Within 10 feet or so it really doesn't matter a whole lot.)

Thanks for the replies.....please keep them coming.

I find that without some fiddling, which is more difficult when buying lead bullets as opposed to casting your own, generic cast bullets usually won’t shoot as well as jacketed.

But, and it’s a big But. I’ve also found in my travels that what I’d estimate at a minimum of 97 percent of people cannot shoot a handgun well enough to realize that difference. In my opinion those folks will benefit more from the added trigger time using cheaper and available cast bullets more than they will from the slight accuracy advantage of jacketed bullets. Shoot enough to hone your skills to a degree where you can tell the difference and then worry about that last 1/2” or less.

I enjoy casting and fiddling with bullets, have a mold for almost every handgun caliber I own and several in some cases. I ironed out the diameters and hardness that work for my guns a while ago and now I just shoot. I could never afford to shoot jacketed bullets at the rate I shoot. Someday soon I plan to drag the rifle molds back out and start shooting more reduced load centerfire stuff.

Elmer didn't have any use for gas checks.

FWIW I shot lots of polymer coated bullets - no gas check - in my .357 revolver. Full throttle as well as milder loads. I had no problems at all with either, and good accuracy - certainly good enough for IPSC competition. I shot truckloads more in 9mm and a fair few in .45, but of course those weren't reaching the same velocities as the full-throttle .357 loads. They sell such bullets here, and they not only are inexpensive but you save all the work of casting, coating etc.

I also have used polymer coated bullets in my .45/70. For loads up to about 1600 fps or so I have not used gas checks, but I had a good number of 420 gn coated GC bullets, and loaded them to about 1800 fps. They worked well, though recoil was a bit brisk.

1. For the most part yes. I understand you can get special checks that will go on plain base bullets but I have never used them or seen the need.

2. A luber/sizer tool or one of the Lee style if you prefer.

3. In handguns yes, rifles not so much. I shoot a lot of cast bullets and cast my own more for fun shooting than anything else. I have used the .357 and .44 Mags to take deer with my home cast bullets. Except for self defense loads, none of my handguns get shot with jacketed bullets. Fankly, I'd just as soon use my cast bullet handloads for SD but here is that threat of an over zealous prosecutor using my handloads against me.

For .38 Spl. I run three different loads. deither 2.7 gr. Bullseye or 3.1 gr. W231/148 gr. wadcutter. 150 gr. plain base semiwadcutter and 5.0 gr. Bullseye or W231 and a 158 gr. gas checked Semiwadcutter over 5.0 gr. Unique. All three loads are accurate in my handguns. For the .357 mag. either the 150 gr or 158 gr. Semiwadcutter over 14.0 gr. of 2400. Bullet alloy is my own mix with a BHM level of 11.
Paul B.

And I've never used a gas check. In all my Smith 357's I use the 158 RNFP, or SWC, BHN 12 with 4.5gr Universal in 357 cases. More of a 38 really. Great plinker and I run this load in my 19/66's to the 27.


I'd like to learn more about cast loads in 30-06 and what's involved to follow up with jacketed.