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On page 50 of Elmer Keith’s Gun Notes Volume II Elmer says the following: “A close relationship between cylinder throats and barrel groove diameter is mandatory for finest accuracy and absence of leading. Gas checks will keep bores clean but also raise pressures about 3000 psi in heavy loads, and induce gas cutting of the topstrap and cylinder junction. Gas checks are usually too hard to upset to fill the cylinder throats and permit gas to blow the lubricant out of the bullet grease grooves. I can see no useful purpose for gas checks in revolvers, though they are excellent in auto pistols and rifles, to prevent fusion of the bullet base as well as scraping the bore clean with each shot.”

I had not heard that gaschecks would raise pressures, nor had I known that they would cause gas cutting. I have a Ruger Bisley 45 Colt. The light 250 grain bullet loads that I shoot are with plain base bullets (no gas check) but the heavy loads that I shoot have all been using gas checks. I use the Cast Performance 335 and the Beartooth Bullets 345. I do not remember why I decided to use gas checked bullets for my heavy loads but I am wondering if I should switch to plain base bullets. Obviously Marshall must think that gas checks are fine since many of his 45 caliber bullets are only offered with them. I would appreciate some advice and thoughts on Elmer’s statements and whether or not I would be better off without the gaschecks. Thanks, Brian C.
 

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Brian,

ALthough Elmer is the undisputed dean of gunwriters in my estimation, on this one count I consider him to be not entirely up-to-speed.

As you have correctly observed, I do consider gas checks, especially on handgun bullets designed for high pressure, high velocity loads to be a great benefit. The gas-cutting of the topstrap he alludes to I've never witnessed, at least no more prevelant than when using jacketed bullets in revolvers, even after many thousands of rounds through single action revolvers at high velocity/pressure.

Also, the "obturation of the bullet to fit the chamber throats" isn't at all necessary if the bullet is correctly sized to fit the throat in the first place (the benefits of custom sizing). And in all instances, a cast bullet of the proper diameter to fully fill the cylinder throat dimensions will always shoot better than a bullet that is undersize for the cylinder throats, regardless of gas-checked, bevel-based or plain-based design.

As for the pressure increase of gas checked bullets, I can't quantitatively vouch for that statement one way or the other with hard numbers... not yet. I'm working on a tech note with that info one angle of the topic of consideration, and haven't yet obtained the pressure testing information from Hodgdon Labs at this time. Perhaps in the near future we can have a quantitative figure to back up or dispute this statement.

Also, keep in mind that the very best bullet lube that Elmer had used at the time he made those statements, was the Ideal Banana Lube which he so highly recommended. The bullet lubes we use today totally eclipse the performance of the lubricants he experienced, and thus many of the performance perameters have changed, due simply to this one element of cast bullet development.

I'm not going to say that very accurate and powerful cast bullet loads cannot be developed with plain based bullets, quite the contrary, I've got some superbly accurate loads using them. However, by-and-large, the most trouble-free loads, requiring the very least load development, and being the most impervious to climatic condition changes will be those employing gas-checked bullets in high pressure/velocity applications, provided as mentioned earlier, that the bullets are properly sized to the cylinder throats of the revolver to begin with.

We sell several plain based bullet designs for the various handgun calibers, and some of the bullets are virtually identical in design and weight, except for one is gas-checked and the other plain-based (.44-280g WFN PB & GC, also .45LC 300g WFN PB & GC). For the vast majority of our thousands of customers, if they have ordered both styles of bullet, most generally reorder the gas-checked design when they need more bullets. (at least if shooting high pressure/velocity loads) THere is a persistent minority of customers however who continue to use and love the plain based bullets of these selections, but they are generally using mild to moderate loads in their handloads.

Brian, I don't know if this fully answers your question. It's too bad we don't have Elmer around these days to test drive the new crop of heavy cast bullets that we now enjoy for our shooting and tinkering. I think he would have been pleased, and surprised at what we are now able to accomplish with our sixguns.

God Bless,

Marshall
 

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Discussion Starter #3
Thanks Marshall. Well put. I am not one of those who think that Elmer Keith is God. I was surprised by what he said based on what seems to be the norm nowdays as far as gaschecked bullets goes. I will continue to shoot gaschecked bullets and not worry about the concerns he raised. Brian.
 

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Hi, Gents:
Old Elmer used the H.P. White labs to check his pressures, so I wouldn't be surprized if that 3000 psi difference was real. The Hodgdon data should be interesting. Another thing. I've heard somewhere that too soft bullets can slug up in a revolver's throat and raise pressures. Elmer mostly used lead-tin alloys that aren't as hard as the high antimony heat-treated bullets we use now. That could confuse the issue. Just wondering. :confused:

Bye
Jack
 

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I haven't heard any recent evidence about gas checks raising pressures. Marshall, it will be interesting to see what you come up with. I have used lots of gaschecks on my pistols. I use a thin lubed cardboard wad in the 45 Colt pistol loads with plain based bullets. This reduces the build up of lead/lube on the frame when shooting lots of rounds. The loads are low pressure to start with and the wads are thin, so I believe any pressure increase is minimal.
 
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