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Gas Checks
#1
Just getting started in reloading so I wanted to ask about gas checks.

What is their purpose?
Are they used on both rifle and pistol ammo?
Are they used on lead, jacketed, or both?

Anything you can provide about them is appreciated.

God bless!!

PPP
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#2
I'm hoping we can get some good information on this subject because I would really like to know too Big Grin
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#3
With exposed lead in the base of the bullet the heat and pressure can melt lead, causing a build up of lea in the barrel.

Not commonly used except on cast or staged bullets.

Especially in higher velocities like .44 mag and the like.
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#4
Gas checks are used on cast lead bullets. You really only need to be concerned with using them if you cast your own bullets. If you buy commercially available lead bullets that require gas checks they will already have them.
Their purpose is to prevent the hot gasses of the burning powder from eroding and deforming the base and sides of the lead bullet.
If you want to shoot cast lead bullets you'll need to determine whether you need gas checked bullets or not. For shooting low pressure rounds, as in cowboy action shooting, you won't need gas checked bullets because the loads are light, pressures are low and deformity isn't an issue. If you want to shoot cast lead bullets in high pressure rounds like .357 Magnum or .44 Magnum you will have bullet deformity problems unless you load light or use checked bullets.
Reloading manuals may or may not specify checked bullets. I highly recommend the Lyman Cast Bullet Handbook if you have an interest in casting OR loading with cast lead bullets.

A great source of information without buying a book is:
http://castboolits.gunloads.com/forumdis...Gas-Checks

If you have any interest in casting your own bullets I strongly recommend looking at their entire site rather than just the gas check forum.
http://castboolits.gunloads.com/forum.ph...8e6848ccf7
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#5
+1 on what mauser said especially about the castboolits site. To add to it generally a gas check is not needed up to 1400 fps. Some say 1300 fps. Using a gas check velocity up to 2000 fps and above with the proper cast mix is obtainable. The mold for gas checked bullets will be cut so the check can fit onto the cast. The other cuts are plain base that are flat and there is a bevel cut that helps start the seating process similar to a boat tail in jacketed bullets. Utilization of cast boolits requires a try and see how it does approach. My high end .357 mag employs a gas check while my .44 mag 245 gr SWC with a healthy dose of 2400 does not. It's a fascinating art to study and play around with.
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#6
Connal;47523 Wrote:With exposed lead in the base of the bullet the heat and pressure can melt lead, causing a build up of lea in the barrel.

Not commonly used except on cast or staged bullets.

Especially in higher velocities like .44 mag and the like.

My understanding as well. Jacketed bullets are far more resistant to leaving deposits in the barrel due to hardness and higher melting temperature. Lead melts around 600°F or so, pure copper is 1500°F-ish. Combustion temperature is around 3000°F, but only for a fraction of a second.

I think of the "gas check" as just enough jacketing to prevent lead fouling.
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#7
So, is this a common rule, gas checks for lead cast over 1300 FPS, that is to held for all calibers?

Reason I ask is since rifle calibers often range 2000 to 3000 then if using lead cast bullets a gas check is necessary.
That makes sense.
This since I plan to reload .223, .243, .30-30, and 7.62x39.
I would think for the .223 I would us jacketed bullets but I was not sure with the other calibers.

Thanks.

God bless!!

PPP
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#8
Pistol Packin Preacher;48152 Wrote:So, is this a common rule, gas checks for lead cast over 1300 FPS, that is to held for all calibers?
...


No, I don't think there's a hard number. Lead with a higher percentage of hardening alloys is harder and thus more resistant to fouling. The guideline I recall was subsonic = plain lead OK, supersonic (1100-1200 f/s)=gas check. 2000 f/s and up is gas check for certain, tho.

I recall some shooters also patched bullets in lieu of a gas check.

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#9
Yep, the 1400 fps is a general rule. Cited in past literature that plum escapes me but currently printed in Lee"s reloading manual. However I do think each firearm, load, mix is unique to itself. Checks may be needed or not. More about it than I know: http://castboolits.gunloads.com/showthre...velocities Have to ask but what is it you want to do with cast? Don't usually give advice but rather share my experience, but will go out on a limb here. It seems from your posts you're relatively new to the reloading game. I would suggest to stay with jacketed for a few thousand rounds to get some experience under your belt. This way all the variables will be known, and any abnormality can probably be easily rectified. If you do wish to continue with cast I recommend one caliber to start with. A pistol round would be good. Trying your luck with reduced loads in the 30/30 would probably prove to be allot of fun. If you were closer I'd be happy to show you some of what I've found out along the way. Good luck.
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#10
Pistol Packin Preacher;48152 Wrote:So, is this a common rule, gas checks for lead cast over 1300 FPS, that is to held for all calibers?

Reason I ask is since rifle calibers often range 2000 to 3000 then if using lead cast bullets a gas check is necessary.
That makes sense.
This since I plan to reload .223, .243, .30-30, and 7.62x39.
I would think for the .223 I would us jacketed bullets but I was not sure with the other calibers.

Thanks.

God bless!!

PPP

Since you're new to reloading I'll suggest that you stay away from cast bullets altogether, stick with jacketed. If you want to plink with a .38 Special or .45 Colt using low pressure loads go for cast but otherwise stay with jacketed. Reloading for rifle you'll have to know where to look to find lead bullets, (or cast them yourself), and that's not what I think you;re looking for. Most anything you buy is going to be copper jacketed and not in need of gas checks so I'd say have at it and don't worry about it unless you want to go out of your way to shoot lead.
Now to clarify a point here, most commercially available bullets are lead core with a copper jacket. They don't need a gas check. Solid copper bullets, as in Barnes, don't need a gas check. If you want to shoot non jacketed lead bullets the box will say "lead" "cast" "Hard cast" or something similar. They're less expensive and are most common in cowboy calibers. Most shops will have a separate section for them and if I'm reading your intent correctly I don't think that's what you're looking for at this stage of the game unless you're looking for cheaper plinking ammo for a handgun.[Image: hsunwm.jpg]

ETA picture of cast bullet box.
There are three types of people in the world:
Those who make things happen,
Those who watch things happen,
And those who wonder what happened.
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