what on earth is a 'gas check' cartridge?

[roscoe]

I have acquired a new .357 and was looking at Buffalo Bore's offerings. One is a heavy 'gas check' round with impressive characteristics. What exactly is that?

[Standing Wolf]

A gas check is a brass cup placed on the back end of a lead bullet before it's loaded in the cartridge case. It keeps extremely hot gases from cutting into the base of the bullet while it's traveling down the barrel; in theory, at least, it also helps reduce leading of the lands.

If you cast your own bullets of soft lead and/or push them to top velocity, gas checks help; if you use harder lead or load them more mildly, they're generally not necessary.

[Brasso]

For hot loaded lead bullets, the copper plate (gas check) is capped on the base of the bullet and prevents the hot gases from "gas cutting" past the bullet as it travels down the bore. Gas cutting can cause loss of presser, bullet deformation, bad accuracy, and most of all sever leading of the bore. It's usually recommended for use with soft lead bullets and velocities in excess of 1000fps. Some of the hard cast lead bullets don't usually require them unless pushed very hard such as in a .357mag or .44mag at max velocities.

I don't need them for full power 158gr .357mag loads when using commercial hard cast lead bullets with a bhn of 25 or higher. I have used them for wheel weight made .44mag bullets of about 18 bhn however. A good lube helps a lot to reduce leading as well.

[P95Carry]

You have your answers ... and well too.

I'll add tho one caveat - which is purely my own thinking. I use checks on my .357's in particular, and also on home cast rifle bullets (not pushed above much more than 1900). I have the feeling that apart from protecting the bullet bases from hot gas problems, they do as they engrave the rifling, actually ''scour'' some of the lead that may be left behind by the lead ahead of them. Much same I guess as saying what SW did but - thinking a bit differently.

Extra expense, but worth it IMO - very little leading when I use them, and don't have too much real hard alloy for casting plain base in huge quantities.

[Fumbler]

Very good info.

I think the two main reasons for gas checks are to prevent heavy leading and to maintain accuracy.
One of the largest factors in accuracy is how uniformly the bullet exits the muzzle. If the rear of the bullet isn't consistent then the gases do not exit the muzzle consistently. If gases exit one part first it will "push" the bullet a tiny bit off center and it doesn't go straight then.

[Powderman]

I don't need them for full power 158gr .357mag loads when using commercial hard cast lead bullets with a bhn of 25 or higher.

Yipe! That's a HARD cast round! Do you cast your own, and if so, out of what alloy?

home cast rifle bullets (not pushed above much more than 1900).

Just out of curiosity, what do you cast your rifle bullets out of? Also, what would your recommended weight be for a 30-06 load? Any recommendations for molds?

[P95Carry]

Powderman ....... I currently cast just two ... a .309 and a .314 . the former for .308 the latter for .303, tho it is unfortunately for my bore still a thou smaller than I'd like. The .309 of course would suit 30-06 just the same as the .308 Win.

The moulds are Lee and if wanted later I can check out the exact numbers, tho if you go to Lee site - http://www.leeprecision.com/ you can browse the moulds and probably spot the ones I mean. IIRC the .303 is 180 grain .... the .308 ... hmmm .. I'd have to check.

I use recovered alloy ... mostly stuff I dug out of berm, some a long time ago ... but when melting down I have sometimes added a small amount of extra tin and ... once the ingot is cast I check hardness, before re-melting and using. My ''best'' ingots have a very clear ''ring'' when hit by a steel object - those I know are good for the purpose. Not very scientific I know but over time this has worked for me!! An ''inferior'' ingot will be dull, or even have little or no ''ring''.

[Jim Keenan]

Just FYI, if using gas checks, the bullets used have to be made for them. A bullet cast for use with a gas check has a smaller diameter portion at the rear which fits into the gas check. The gas check is normally put on as part of the sizing-lubricating process.

Jim

[roscoe]

Wow - thanks! That's lot of good info, even if I don't reload.

[Paul "Fitz" Jones]

I have sold .30 125 grain bullet design molds with and without gas checks and simply put, gas checks are used to obtain higher velocities that would normally cause severe leading from the same bullets without them.
Fitz

[Vern Humphrey]

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Just out of curiosity, what do you cast your rifle bullets out of? Also, what would your recommended weight be for a 30-06 load? Any recommendations for molds?
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I'm lazy -- I pester the local tire stores for wheel weights and use that almost exclusively. Lubed with liquid alox, all my wheel weight bullets shoot very well.

In .357 Magnum, I have the Lyman 38430 -- this throws a 198 grain bullet, and I use it for my .35 Brown-Whelen (a custom '03 Springfield) as well. Again, I lube with liquid ALOX -- and no gas check.

I also load the Lee TL358-148-WC. This is a wadcutter design, and is best suited for mild loads. I load it in .38 Special and shoot it in both .38 Special and .357 Magnum revolvers for a practice/target load as well as for small game.

I load the Lee 452-255-RF in .45 Colt at velocities up to 1300 fps in my Ruger Blackhawk (and to around 1000 fps in my Colt New Service) and use no gas check

Rifle calibers are where gas checks are really needed. I like the Lee 160 grain .30 caliber mould (C309-160-R). Under the Lee numbering system, the "C" stands for "gas checked." I cast them out of wheel weights and use press-on gas checks (you can install them by hand) and lube with liquid alox. I like to lube the bullets, install the gas checks, then re-lube.

A good load for these bullets in .30-06 is the suggested starting load for the .30-30 in just about any powder -- 3031, H4350, H414, and so on. This gives a moderate velocity (about 200 fps less in the .30-06 than it would in the .30-30) and enough powder in the case so the load is not position-sensitive.

[R.H. Lee]

I have an old 1903A3 Smith Corona with a 2 groove barrel that shoots gas checked cast bullets great.

[Vern Humphrey]

I have two '03A3s -- a Smith-Corona and a Remington, both in about 90% condition. I shoot a lot of cast bullets in those rifles -- and they shoot them very well, indeed.

Just walking in the woods (I have 185 acres, mostly wooded and access to about 2,000 more) I am apt to sling one of those rifles over my shoulder and they have accounted for more than one coyote -- and several crows, and an occasional squirrel. (But DON'T shoot a squirrel out of a tree -- those long lead bullets will go a LONG way.)

[Paul "Fitz" Jones]

When I was the distributor for the California Saeco co. all our cast rifle bullet designs were gas checked with the exception of the 45/70 designs. The Saeco luber had a gas check seating function that was handy and in selling the molds when linotype was common, I recommended experimenting starting with a 50/50 mixture of tire weights and Lino depending on the velocity and any bullet expansion desired. Some fellows just used tire weights with the gas checks.

I still have my 6mm mold for varmints on the ranch.

Calif Saeco had two .30 caliber designs the 196 grain for mainly 30/06 competition and the 120 grain for the M1 carbine and as a plinker for all other .30 caliber rifles. A number of fellows used them in their 30/30's for varmints. I recommended 4895 and 3031 for the large 30/06 and 8mm.
Most rifle mold customers wanted a 2 cavity mold but I talked them into a 4 cavity mold instead. There are a lot more powders to choose from now.

[Vern Humphrey]

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I recommended 4895 and 3031 for the large 30/06 and 8mm.
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For a while there, I was the only guy I knew who used rifle powders with cast bullets in rifles. Everyone thought I was wierd (maybe they were right, but my cast bullet loads shot well and weren't position-sensitive.)

[Paul "Fitz" Jones]

I have shot about 4 dozen coyotes on the family ranch with my Ca/Saeco 6mm 76 grain gas check tire weights lead bullets. A son wanted a mountain man costume so my cast bullet loads did not damage the pelts like the jacketed loads that would take off an other side leg and a lot of hide with it.

My favorite rifle is a Remington 700 Bdl 6mm with a Bushnell 4X9mm scope and it will take anything that I care to shoot. My local bears leave me alone and I do the same for them.

Our weapons are very versatile and there are a lot of fellows here on this list willing to share helpful information with new members.

[Powderman]

For a while there, I was the only guy I knew who used rifle powders with cast bullets in rifles. Everyone thought I was wierd (maybe they were right, but my cast bullet loads shot well and weren't position-sensitive.)

What loads do you use for your cast bullets?

[Vern Humphrey]

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What loads do you use for your cast bullets?
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For rifles, I like the starting load for a similar, but smaller cartridge -- for example, the starting load for the .30-30 in .30-06, and for .35 Remington in .35 Brown-Whelen.

That works out to about 28 or 29 grains of either IMR 4895 or 3031 behind a 160-grain cast bullet in the .30-06. For the approximately 200 grain Lyman in my .35 Brown-Whelen, I like 40 to 43 grains of the same powders.

In the .38 Special 148 grain wadcutter loads, I like 2.7 grains of Bullseye. This is a mild, minimum load and dead accurate in all my .357 and .38 Special revolvers.

For the heavy .358 bullet (the same on I use in the .35 B-W) I like around 12 grains of H4227.

For the 230 grain roundnose in .45 ACP, I like 4.5 to 5.0 grains of Bullseye -- with a 20 lb recoil spring and matching firing pin return spring.

In the .45 Colt, with the 255 grain bullet, I like 19 grains of H4227, and for really heavy loads in the Blackhawk, I go with Hodgdon's suggested max for Li'l Gun heavy loads -- but I don't shoot a lot of those.

[P95Carry]

Not to pre-empt Fitz (sorry, Vern) ... but a coupla loads I use are .... rifle - 180 grain .314 Lee with gascheck, in .303 ... 21.5 grns SR4759 ... a very handy powder because it bulks well and so does not leave case overly empty. This is quite a slow load but does group surprisingly well.

With .357 mag - use a 158 cast swc gascheck, by Lyman - superb bullet. That is over 14 grns N-110.

Those loads are not recommendations ... just mention that as a disclaimer but - you'll find data to support them in manuals.

[Brasso]

Most of the commercial cast bullets are very hard at around 25bhn. Wheel weight bullets can run from around 12 to 20 depending on whether you water quench or not and some other methods too involved for me to try.

I use old wheel weights scrounged from tire shops. I have about 500lbs sitting in my garage right now. I add about 2ft of 50/50 lead/tin soldering wire and water quench. Right now I only cast for .44mag using an NEI 270gr Keith style mould which drops out bullets of 285gr.