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Just when I thought my latest bout of 'Clarence Darrow Syndrome' (a disease that afflicts many, is often embarassing, but almost never fatal) was over...

Well now that we have the Shuttle and flywheels and measurements of thrust from 2 or 3 grains of powder in the mixed discussion about guns, I'll toss in that I believe acceleration of a firearm in recoil is measureable...you can believe it or not. Accelerometers are common pieces of test equipment which my wife, a vibrations and accoustics test engineer, utilizes in her daily work. So plotting the acceleration curve over time is straight forward stuff.

You can always just lay the gun on a table and pull the trigger with a string and see what if any load makes it jump more.

Chuck, you are absolutely right. This would be the kind of data that could be compared to "felt" recoil by a panel of various size and sensitivity people. Possibly, you would be able to correlate curve characteristics to subjective "feelings." Perhaps you would find some shooters sensitive to recoil acceleration, some to recoil velocity, some to recoil displacement, and some to recoil force. And, there may be other factors.

If we had load by load time-pressure curves, I think we could calculate acceleration, velocity, displacement, and butt plate force. The shoulder contact area over which the recoil force is acting may also be important if we find that recoil pressure against the shoulder is important.

I suspect that G. Thomas's recoil study is accurate. It is unfortunate that he didn't include data so we could check this study. Unfortunately, he wrote for an audiance that generally didn't "peek at the works." Only recently have there been gatherings of "shotgun geeks" to slice and dice everything ever written, sift out the truth, preserve it, and then extend it.

...or stubbornly "disprove it". ;-)

JC

I mentioned in another post, That Diane brought back my "FE" Lefever from Bertrams yesterday. This morning, I shot 50 2 3/4" loads through it on my clays range, broke 48. Then walked up to the east pasture and killed 8 doves with same set up. I admit that without scientific data, that this is valueless. But I still have all my parts, so does the gun. I laid it out on the dining room table, loaded, with a string on the trigger to try the recoil thing but got caught and was forced to stop....

Guns and strings together are usually an indicator of sumpin not so good... or alcohol induced test engineering.

Don,
I think that outfit that makes the pressure trace has a unit that, together with the PT, would yield sufficient data.

Because Burrard and Thomas say so, Jim--Burrard indirectly, Thomas (and others) more directly?

Burrard says: "If the mouth of the cartridge is compressed by being held by the chamber cone, the resistance to the initial movement of the shot charge will be greater and the pressure will be increased." What happens to the increased pressure? If you increase the pressure without changing anything else, won't you also increase velocity--which increases recoil?

Thomas: "Again, the prevalent use of 2 3/4" cases, suitably loaded, for guns with 2 1/2" chambers may be perfectly satisfactory if the guns have normal cones, but not if the cones are exceptionally abrupt, as some are, when the use of the longer case may give rise to objectionable, or at least enhanced, pressures." He refers to a specific case: "This gun shoots the Impax cartridge, with its 2 1/2" case, very satisfactorily. But with cartridges with 2 3/4" cases, though designed for 2 1/2" chambers, it recoils unduly and makes his right arm numb. Three out of four crimps were shot right off . . . " Gun writer Charles Fergus reported precisely the same problem when shooting British shells in longer hulls (but designed for 2 1/2" chambered guns) in a pre-1900 Brit double: Significant increase in recoil, blown ends. No problems with true 2 1/2" cases. And no problems with either shell in a Brit gun from the 1930's, with 2 1/2" chambers but longer forcing cones. The excessive restriction caused by the design of the forcing cone certainly appears to be the culprit. That's why we can't really say that 2 3/4" shells, even if loaded to proper pressures, are a good choice in ALL 2 1/2" guns. If you're getting significantly increased recoil and blowing the ends off shells, you probably ought to stop.

Chuck, we hadnt gotten to the alchohol part yet, but aye the hour draws nigh...I didnt think the string test would hurt anything, it was aimed out the window, at one of the wifes cats...

Now, so far I note, no one has posted any Accelerometer results. I would most certainly love to see such input. I am quite willing to be "Proved" wrong. I will not however simply cave in to "Anecdotal" evidence in which the "Tester" cannot even verify at what velocity his loads left the bbl, other than to say "I took them out of the XXXX FPS block of the loading manual".
As to Thomas yes I understand he was an "Engineer" (So was Casey Jones & he Wrecked the Train) & I am just a low life machinist. Matter of fact "Mr ED" pointed out quite sufficiently my low grade status a while back. I don't however roll over & die quite that easy.
Now as I recall, correct me here if I am wrong Larry, This test which Thomas cited was not carried out at the time of his report. I do seem to recall him stating it was "Formerly" done. Now let me state this as simple as I know how; I have little doubt these tests were carried out & that the results were as stated. I am in no way calling Mr Thomas a liar. What I do find though is that "If" there were data available giving details of the types of powder used etc, & he failed to give full particulars, that was iresponsible reporting. If on the other hand no details were available; for him to publish it & create a cockeyed story as he did to substantiate it as he did was even more irresponsible. To paraphrase him "A shell loaded with fast powder will recoil less because the shooter doesn't have time to feel it". My friend "I Ain't That Thar Igorant Yet".
A few years back when Alliant Powder Co was introducing a new powder to their shotgun line, Select maybe, not sure & not worth hunting up the old manual, They alloted two full pages of their reloaders guide to explainging how this powder would "Reduce Recoil" for the target shooter in comparsion to a typical "Fast Powder". No doubt they were comparing it to their own Red Dot. The burn rate of this new powder fell between Red & Green Dots. The reason, according to them, for this reduced recoil was because it was "Slower", thus a lower pressure peak & slower acceleration. I feel absolutely certain there were people on the Alliant Team equally (or superiorly) qualified as was Thomas, yet their claims were diametrically opposed to those of Thomas. I personally feel that in spite of these folks qualifications, the statements they were making, while technically true, were of such a mi-nute' magnitude as to have no practical effect upon the shooter. They were after all trying to "Sell" a new powder & yes they were "Still" selling their old standby Red Dot. I also "Very Strongly" suspect the test cited by Thomas was performed using one of the older bulk powders in comparsion with a dense powder. No doubt the company promoting the tests was at the time selling shells loaded with both types. No doubt also it was during an era in which the dense powders were proving more economical for the amunition Co's to produce, load & handle etc. No doubt as well there were at the time "Old Die Hards" who desired to cling to the old. It is certainly a possibility this Co was desiring to phase out the bulk type powders, but were afraid of losing customers if they just went Cold Turkey, & that this was a promotion for the dense type of powders.
Now I realize you have already referred to this line of thinking as un-founded ignorance, but I never claimed to be overly smart, but have been made well aware over the years of many "Marketing Ploys".
Bottom line is "If" I were desiring to reduce the recoil generated by my current favorite shotshell powder Alliant Green Dot, I would really not know which way to go. You & Gough would indicate I should switch to Red Dot, but everyone else seems to be of the opinon Unique would be the direction to go. Guess I'll just endure the Green, I kinda like having my teeth Rattled.

This is totally out of context & a misapplication of any thing Burrard said on recoil. If you can prove otherwise cite Chapter & Page Please.

If I were blowing the ends off shells "I WOULD STOP Immediately" irregardless of whether it was accompanied by an increase in recoil or not. A condition causing the ends to be blown from an otherwise sound shell could very likely be a condition which could cause an increase in pressure generated. This might be, but would not automatically be, accompanied by an increase in the velocity. If it did not bring on an increase in velocity it likewise would not bring on increased recoil.