doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com DGJ Article on Chamber Length/Pressure

Speaking of "recollections" . . . I recall quite clearly, prior to Bell's article on long shells in short chambers, that many people here still questioned the conclusions arrived at by both Burrard and Thomas. "Well, those were paper cases, not plastic." "Well, those were the old cork or fiber wads, not plastic." Bell's contribution, as I see it, was twofold: He used both paper and plastic hulls (and wads), and he used reloads. And he eventually came to the conclusion Burrard reached, which was that although the case itself is responsible for some increase in pressure (which Bell found to be slight), the contents of the case pose a far greater risk.

Bell does not get credit for "inventing the wheel" on this one, but to continue that analogy, he might deserve credit for tubeless tires (or radials), thus expanding upon what Burrard and Thomas had previously established.

That's what I said!!

You best re-read all your copies of Thomas, because that is EXACTLY what he did say. I no longer have access to the book it was in so can't quote you exact passage. Was offered first dibs on the book & if I didn't buy was going to E-Bay. It went to E-Bay.

When Burrard wrote this all the "True 2 3/4" cases were loaded to the higher intensity & also put up in roll crimp cases. What Sir Gerald was speaking of was the distinct possibility of the loaded shell being squeezed into the cone prior to firing, which even today I fell should not be recommended.
When the fold crimp was introduced extensive studies were done on putting the satandard 2½" load in a 2 3/4" case with the crimp closure. This made the loaded shell shorter & it did not extend into the cone until after opening upon firing. Burrard gave a full report on this at the time it was taking place. This was a report on a "New Condition" not a correction of "Wrong" data.

Neither Burard, Thomas nor Bell "Straightened Out" that issue. It was correct as written & still is to this day. There "IS" a potential of dangerous pressures being developed if a shell long enough to enter the cone prior to firing is used. This gives a very similar effect to an extra heavy crimp requiring much more force to open it. Pressure is rising at an astronomical rate as the powder begins to burn, but before the shot actually starts to move. Even a very, very short delay in that initial movement can prove catastrophic.
The propblem is "Both" Thomas & Bell took those statements of Burrard's (which were & are correct) totally out of their context & said He flatly condemned any use of the longer case in a shorter chamber. If you don't believe that my friend you just haven't understood what they said.

Miller, unlike you, I have my copy of Thomas--right in front of me. And an old Iowa farm boy like me can read every bit as well as a Redneck Hillbilly. Nowhere in Thomas' "Danger in Case Length" chapter does he say "Burrard should have said". Not there. Absent. Missing in action. Perhaps present in your recollection, but like I said, you need to reread it to refresh what you're incorrectly recollecting.

You're also misremembering what Burrard said about length. He wasn't talking about shells entering the cone "prior to firing". Here's what he says:

"The length of the loaded cartridge is EXACTLY THE SAME as that of the actual chamber and so, when turnover is opened on firing the mouth of the case is prevented from opening completely BY THE CHAMBER CONE;" (Emphasis mine.) Further: "The effect of the mouth of the case being held in BY THE CHAMBER CONE is much the same as that of giving the cartridge an exceptionally heavy turnover, and the effect on pressure will be obvious." (Emphasis again mine.)

As for Burrard and Thomas disagreeing . . . nope, not so. Eventually, after all the warnings about pressure increases from shells opening into the forcing cone, Burrard says the following:

"It will be realised, therefore, the the increase in pressure is the result of the longer LOADED CARTRIDGE rather than that of the longer UNLOADED CASE. But although these two factors causing an increase of pressure certainly do exist, the first is far greater than the second." (Emphasis Burrard's.)

Thomas repeats almost exactly the same thing: "But in the particular case cited by Burrard, the main danger arises, not from the constriction when the cartridge is fired, but from the fact that the longer-cased cartridges he had in mind invariably carried heavier loads;"

So, in summary, Bell was guilty of quoting Burrard out of context (although what Burrard wrote could have used better editing), but in fact proved that there is usually some increase in pressure when a case mouth opens into a forcing cone (which Burrard said, correctly, was the lesser of the two dangers). And Burrard and Thomas were in complete agreement on "the main danger": what's loaded in the shell, not how long it is. Which Thomas verified by posting the results of his tests with Eley shells.

Obfuscation and pettifoggery! It hurts my brain to try to read about two smart guys arguing over what somebody else might or might not have said. I know, I know, I don't have to read it...Geo

This might not settle anything but it will clarify what was and what was not said by Garwood.

Seems Tennessee Hillbilly's memory is better than Iowa Farmboy's reading comprehension. Why am I not surprised...

Seemed to me like friendly sparring in the style of the great debates. One is allowed to attack the weaknesses of an opponent's argument--premisory, factual, logical, chronological--to one's advantage and one's opponent may also, as a response, sharpen up his argument until it pierces the chaos of conditions no longer prevailing, the false simplicity of mono-causation, and the comforts of received "wisdom". However, the "log cabin" origins thing in which opponents take off their ties and roll up their shirtsleeves in an attempt to dwell in harmony with all us plowboys and sheepherds is probably only shameless pandering to the tip or reverse snobbery in such accomplished exegetes LOL.

jack

Larry;
The Statement that "Burrard Should Have Said" was from a book which was an assemblage of articles Thomas had written for, I believe "The Field". As I said I do not now have the book to cite you exact reference, But, He did in fact make the Statement. You will note that nowhere in the writing quoted by Snipe Hunter, does Thomas direct readers to the proper section of "The Modern Shotgun" where Burrard explained the exact things Thomas was covering. Burrard stated when the normal 2½" load was put up in a 2 3/4" case & closed with the fold crimp both pressure & velocity were for parctical purpose unchanged (paraphrased, not direct quote). Thomas' data shows this to be true, not arguing that. He did not However explain that the statements he quoted from Burrard applied to an altogether different shell & were as true in his day as they were when written. The "True 2 3/4" " shell mentioned was one carrying the heavier load designed for guns carrying 2 3/4" chambers. It was put up in a 2 3/4" case & closed with a roll crimp. Loaded length of this shell would have been about 2 5/8". The chamber depth of a nominal 2½" gun depending upon exact time of build & makers whims could be from an actual 2½ up to 2 5/8", thus from an exact shell length to an 1/8" short. Cones of the era were short & steep. Chambers of the day would have simply been marked 12C, so the "Average" owner would not likely have even known the exact length in his gun. Pushing a loaded shell 1/8" into a steep coned chamber can indeed increase the resistance it has against opening. Pressure rise could be dramatic.
My question boils down to If either Thomas or Bell were going to cite Burrard at all (Both Did) why did they cite only that part which was not applicable to their discussion & totally omit that which was. Again "WHY"??. Ego?? about all I can come up with, I don't think either were/are that ignorant.
Personally I find such actions simply inexcusable.

Nitro, must be your reading ability has been jolted by . . . well, too many 400 Nitros. Now that the Thomas article in question has been posted, please reread and see if you can find the quote "Burrard should have said"--which Miller credits him with saying. "EXACTLY", no less.

Miller, the article posted above is, I'm quite certain, the one you're thinking of. It's from Thomas' "Gun Book"--which is, indeed, a compilation of his articles (but from "Shooting Times", not "The Field").

From the article, it's obvious that Thomas' readers were confused by what Burrard wrote. (That's why I said that Burrard needed a better editor, because before he gets around to saying that the problem is the load and not the case, he goes on--at some length, some of which I quoted above--about the longer case resulting in increased pressure.) Thomas, in fact, makes a statement that can be interpreted the same way: "It cannot be too strongly emphasized that it is indeed dangerous, in general, to use cartridges whose unloaded case length exceeds that of the chambers of the gun." But he immediately explains that it's really the heavier load that causes the problem.

He certainly could have added, but didn't (or maybe it got edited out? Editors can do harm as well as good!) that Burrard came to the same conclusion. But both of them can be quoted out of context to make it sound as if the length of the case is the problem. In fact, the very title of Thomas' article--"Danger in Case Length"--would lead one to believe that there IS a danger in case length! A simple editorial change--"Danger in Case Length?"--would've made for a better and more appropriate title.

Given the number of times Thomas cites Burrard as an authority elsewhere in his books (along with quite a few other "gun gurus"), I don't think ego figured very much into Thomas' writing. Nor do I read that article as any claim by Thomas that he "invented the wheel" when it came to using longer shells (with appropriate loads) in shorter chambers. For that matter, credit doesn't go to Burrard on that score either. It was the Brit ammo manufacturers who figured it out. Both Burrard and Thomas were simply reassuring their readers that those PARTICULAR long shells were perfectly safe in their shorter-chambered guns.

And Bell added the reassurance that the same is true of reloads using modern components in longer cases. All made valuable contributions to our knowledge base.