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View Full Version : Do I need a gas check



paul h
11-21-2013, 02:39 AM
Dare I suggest we create another sticky, but this is a frequent enough question that I think it deserves at least a thorough enough discussion as to why one might want to use one, and why one might not. The answer as with all things cast bullet is, it depends.

This also seems to be really two different questions.

1) I'm purchasing a new mold for my 300 eargasplittenloudenboomer, should that new mold be a gas check mold and hence the caster is fully planning on installing gc's on the boolits.

2) I've got a gas check mold and was wondering if I could use the bullets in my gun without gas checks.

Let's look into this a bit. Lead is a fairly soft metal, and we can play with that a bit with alloying and heat treating, but still pretty darn soft. We are kicking the base of the bullet with a 16,000- 40,000+ psi hammer. As most of us are aware, while the base is just a unglorious end of the bullet, it is critical to top accuracy. So protecting the bullets dairy air is a wise move.

Gas checks serve several purposes. The protect the critical base of the bullet, they act as a hardened (relative to the lead) socket that engages the rifling and helps resist the shearing force of the rifling, and they can scrape minute quantities of leading and fouling from the bore.

On the flip side, if you're paying $1/lb for lead, a copper gas check will tripple the cost of a nominal 170 gr bullet. They also add another step to turning lead into a shootable bullet.

Back to the original question, do you need them and hence are they worth the additional cost. The majority of my handgun molds are plainbase. The ones that are gc's are that way for a paticular reason. My .358" 200 gr WFN is a gc because I want to use it in both handguns and my 350 rem mag. I always place a gc on the bullet as I don't know for sure what gun I'll use it in when I cast it, and for volume shooting in handguns I'll use a lighter pb bullet. In my 480 ruger I have both a pb and gc 400 gr mold and my buddy designed the one with the gc and I've seen no reason to plainbase it. 1000 gas checks will last me a long time in that chambering. I also ordered my Mihec 400 gr hp mold as a gc because I wanted to be able to use softer alloys in the hp and still achieve top accuracy.

For rifle rounds I'd tend to go with gc's as I want everything to go in my favor to provide top accuracy at over 2000 fps. When you give a cast bullet a 40,000 + psi boot in the rear, and drive it out the muzzle at over 2000 fps, you might as well have everything in your favory, don't scrimp on that little bit of copper or aluminum. If you're looking for mild plinking rounds, go with a lighter plainbase design to save on lead and copper.

My 2 cents, or 1/2 a gascheck ;)

sthwestvictoria
11-21-2013, 05:08 AM
Part of the question - Can I shoot X GC mold without a GC - is already a sticky:
http://castboolits.gunloads.com/showthread.php?48857-Gas-Check-Boolits-without-Gas-checks
In the Classics and Stickies section:
http://castboolits.gunloads.com/forumdisplay.php?35-Classics-amp-Stickies

44man
11-21-2013, 09:50 AM
The big problem is the rate of twist and velocity needed for the length of the boolit, it seems to just fly out the window with cast shooters.
The gas check and what it is for has been explained but when leaving it off shortens the drive length, many think it can be shot out of twist rates.
The check is a skid stop and seal but there is a relation to lead hardness, velocity and twist. Shoot dead soft that skids and expect a check to stop it is a fallacy. Checks are not scrapers.
To take one twist and shoot 900 fps to 2200 fps with one boolit is a fallacy.
You take a GC boolit and find a load, then leave the check off and the gun turns to a shotgun and even see sideways boolits. You do not see the drive length and twist/velocity relationship.
Cast shooters are the worst for matching what is needed and revolver shooters the very worst.

ShooterAZ
11-21-2013, 09:56 AM
Even if it is a sticky, it is evident that the "want the answer right now" and the one post and you never hear from them again bunch will never read the stickies. For the record, the few times I have tried not using gas checks on a gas check design the results were less than acceptable for me.

Bret4207
11-21-2013, 09:58 AM
This issue has been discussed ad nauseum and the Gas Checks section was specifically created to catalog all the variations of the same question in one spot several years back.

44man
11-21-2013, 10:25 AM
This issue has been discussed ad nauseum and the Gas Checks section was specifically created to catalog all the variations of the same question in one spot several years back.
Exactly, but some think that you can do anything with cast that you can't do with jacketed.
Actually, my cast shooting is close to, at jacketed or over jacketed loads. Jacketed will in most cases need less powder.

quilbilly
11-21-2013, 01:50 PM
I just think that with rifle boolit molds, the gas check gives you so much more flexibility to experiment which is part of the fun for pathological tinkerers like me. That being said, I do find that I enjoy finding a load that a rifle will stabilize and doesn't require a gas check.

Harter66
11-21-2013, 04:00 PM
44,
I have several examples that would disagree w/less powder to meet or exceed jacketed plea.
I don't have a checked pistol mould,not for 9s,357,or 40 let alone 45s. I also shoot plain based 7mm, 30s and 32s . I don't remember whom or the exact wording ,but to the effect,'I believe GC's are a crutch and a compansation for a lack of knowledge and willingness to learn through trial. They are a temptation of instant gratification.'

I think that you reach a point in terms of caliber where the check is just so much baggage. That point does get adjusted by the case behind the caliber. Example. I worked a 32 Rem (win spcl) the plain based boolit exceeded Jacketed velocity and matched accuracy on nearly 4gr less powder. I don't think for 1 second I could expect the same from an 8mm-06' or 8mmRM. The 35s up to Whelen don't seem to care .Whelen and Wins I don't see much about them but I did get 2100 fps w/158 RNFP out of a 9x57. 30s seem to be more fickle some days I get 2000 no issues some days they are all over,and if I weren't such a cheapskate I would GC them and be over it. Again though the 200gr plain base works fine in the x39 and I expect 30-30 the 308 and up not so much. I will say above plinking the 7mm's must be checked or otherwise protected,even in small cases like a 7x6.8Rem and 7-30 Waters.

FWIW my .02

Jack Stanley
11-21-2013, 04:38 PM
I sorta figured if I was to fit the bullet and use the right powder for a moderate velocity I could get away with no gas check . I've never even been in the gas check pages so maybe one of these days I should see what I've been missing .... after I shoot up the cans full of ammo that's loaded .

Jack

1Shirt
11-21-2013, 04:47 PM
My opinion only, is that if you are driving a plain base blt at less than 1600 fps or preferably less, and the base of the bullet is sharp and clean, and not below the neck of the ctg, you don't need a gas check!
1Shirt!

paul h
11-21-2013, 06:19 PM
I sorta figured if I was to fit the bullet and use the right powder for a moderate velocity I could get away with no gas check . I've never even been in the gas check pages so maybe one of these days I should see what I've been missing .... after I shoot up the cans full of ammo that's loaded .

Jack

That was really my point in this thread is that under the cast bullet heading there should be a discussion of whether or not you need a gas check. Most people starting out aren't likely to look under the gas check forum.

Bret4207
11-21-2013, 07:00 PM
I think a sticky here in bold red lettering directing people to the Gas Check forum would be the best idea.