doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com I read it in a magazine...

So according to all you train drivers, there's no possibility that duration of a traumatic event could put it below the threshold of neural response? And old Garwood is full of it because he didn't check whether there were both apples and oranges (differing charge wgts) in the ol scientific barrel? So be it. But if I'm to have my head off I'd rather have it off by guillotine than by hacksaw!

jack

Doesn't surprise me at all. His idea that a few thousands of extra headspace, because the rim cut was too deep for the rim thickness of the shells being used, caused significant extra recoil is about as silly as anything I've ever read, here, or elsewhere. The only gun I've ever had that had excessive rim cut depth was a Crescent .410. The result was primer setback, not increased recoil. The shells stayed forward, as they gripped the chamber wall. This is what shells normally do! They didn't come slamming back against the standing breech, as Guffie implied in his ridiculous theory. He probably didn't even know there was a recoil formula, or what the factors involved were.

I had an early 12 ga. NID which was off the face enuf to give a light transmitting breech. Shells rattled when closed. Kicked hard with 1 oz target loads--to the shoulder not the face. Another fellow who shot it commented the same without prompting. Didn't notice protruding primers in the empties; maybe I didn't look. I should have put those little foil washers on the breech wall and run a (subjective) comparison but I didn't so I can't claim that the "cure" proves the existence of the "disease". Maybe there will be an occasion in my first 74 (Coming soon!) to find out for myself in conditions of reasonable scientific rigor.

jack

Well Jim . . . while headspace may not be the problem in all cases, apparently it is in at least SOME cases, and Thomas even provides a "finding out for myself" example:

"In the first case, the cause of the violent recoil was diagnosed as excessive headspace by a gunsmith. I confirmed the reasonableness of this diagnosis and suggested that the shooter should test it by preparing some cartridges with metal-foil discs stuck on their heads so as to fill the headspace. He did this and duly reported, 'I stuck two discs of foil on the ends of ten cartridges with a standard load. The gun shut comfortably. I shot off all these cartridges in five minutes. I did not notice the recoil at all, and shot without any discomfort. Your prescription was perfect.'" Of course we're talking the "sensation" of felt recoil, so I suppose it could have all been in the shooter's head, but there it is. Sometimes a "tinfoil hat" really works.

I have read this before and am immediately struck by the "I did not notice the recoil at all". Went from "violent" to unnoticeable. WOW! That's scientific proof enough for me. I do agree that a tinfoil hat is appropriate.

Using a weight ratio of 100oz gun and 1oz load, the shotgun has moved about one-quarter inch in recoil as the load exits the muzzle (28" barrel). After that the recoil velocity of the gun is what is left for the shooter to deal with. For a given recoil speed, any differences in recoil perception would have to occur within that initial quarter inch of movement.

Never having used a muzzle brake, I take on faith that they work. Savage has a switchable brake on the Long Range Hunter, so it could be tried both ways. The effect of the brake depends on the gun having just got up to full recoil speed as the bullet exits, but not having moved very far.

A gas auto gets a few ounces of internal parts moving backward faster than the overall gun is moving, which exaggerates their momentum compared with the rigid part of the gun. This allows the total momentum of the gun to be the same with the rigid parts moving slower than a fixed breech gun. This apparently happens soon enough during recoil that it is perceived by many shooters of gas guns as easing the bite.

The effect of a muzzle brake is caused by allowing some of the jet gasses to expand angled away from the bore axis. This is a true reduction in recoil. Shotgun porting has the same effect, but to a very small percentage compared to a rifle.

A gas automatic spreads the recoil force out along the time axis. The action does not come unlocked until the shot charge has left the muzzle and pressure is bled off to zero or near zero. The action is then 'floated' momentarily, spreading the recoil out in time. There is also some gas venting which has the same effect as a muzzle brake, and an unavoidable slight loss of muzzle velocity due to the energy tapped off to work the action. Nice explanation with graphs in Butler 'The American Shotgun' Winchester Press.

Larry;
When it comes to advertizing its not for me to determine "WHY" but to simply state the facts. I quoted to you Verbatim from Alliant's own publication where the promoted AS as giving better patterns & reduced recoil than a "Typical Fast Burning Powder", which Larry was Red Dot. In fact I quoted to you from the same publication where they stated RD had produced more 100 straights than all other powders combined. As to why they felt they needed another powder sandwiched in between RD & GD I have no idea not having ESP. The fact is they indeed introduced one. Undoubtably they had invested considerable time & $$$ in that development & wanted to re-coup that investment. What better way to insure acceptable sales than a ""REDUCED RECOIL"" promotion. Further "I DID NOT SAY" that Aliant had any notion of discontinuing sales of RD. I have no idea if they even considered it or not, but they ABSOLUTELY DID ADVERTISE AMERICAN SELECT AS GIVING LESS ""FELT"" RECOIL. The Burma Shave reference was just a non-shooting reference. From 1929-1963 American roadsides were dotted with there catchy litte signs, many of which promoted, their Cream as being "VASTLY SUPERIOR" to the old traditional soap & brush method. Yet during that same exact time frame they also sold sets consisting of a mug, brush & cake of soap, items they vigorously promoted as being totally obsoleted by their Superior product. You have made a large number of very good an educated posts on this forum Larry, but none of them I can think of were related to things of a mechanical nature, but history, models etc such as the one just recently on the French Guild gun.
As to Thomas if he had no more details on the IMI test than he gave to his readers, the best he could have done would have been to kept his mouth shut about it. "IF" on the otherhand he knew them but didn't reveal them that is total "DISHONESTY".
There was a reduction in recoil when going first from BP to bulk smokeless which equiv charge weighed about half as much & again when switching from the bilk to dense smokeless which again cut powder wt by approx half. The were reductions which couold be both "Felt" & "Measured" but the reduction was not so much speed of burn related as it was wt of charge. Over those 50+ years of reading ballistic related items the method of reducing "Felt Recoil" has always been stated to go to a "Slower" burm rate ""ALWAYS"" except for "You & Your Idol". Can you quote any other source which agrees with that stance, & don't try Alliant again, I have already shown their stance takes the opposite tack. Your remarks on their advertizing shows you either have no understanding of ad techniques either or are just too stubborn & hard headed to admit them.

Well Miller, you always quote your machine shop background. Me, I spent a few years in the propaganda business, which is a whole lot like advertising. You don't target YOUR OWN products with an ad; you target the other guy's. If IMI were testing two of its own powders, no reason--from a "bottom line" advantage standpoint--to "prove" that powder A recoils less than powder B, unless they're trying to REPLACE powder B with powder A. I look at it as providing valuable information to the shooter. Do you want to go with the old standby, more 100 straights (was that as a percentage, or was that because so many more shooters reloaded with Red Dot?), or with the new kid on the block that gives less recoil? As for Burma Shave, maybe more profit margin in the canned stuff than the brush etc? Or maybe they wanted to play CYA, providing something for both markets--until the brush etc became obsolete? But I think that's a harder case to make for powder . . . especially in the case of Alliant, since it's clear they had absolutely no intention to dump Red Dot in favor of powders producing less recoil. (So demonstrated, most recently, by the new and cleaner burning Red Dot.)

As for the burn rate of powders . . . you being one of the guys who believes pretty much strictly in what can be MEASURED, not what one "feels" (which, admittedly, is quite subjective) . . . explain this, if you can: If you look at any Alliant book, you will often find a choice of the 3 powders we've been discussing--RD, AS, GD--with all other components exactly the same: hull, primer, wad, listed velocity. So why is it, then, that Alliant lists loads exactly the same, the only difference being the type and amount of powder, that the supposed "reduced recoil" AS and GD loads ALWAYS require more powder? 2 grains more of either AS or GD is quite typical; I can find one GD load requiring 3.5 grains more than the same load using RD. So . . . that much difference should surely show itself in MEASURABLE recoil, should it not? So why does Alliant promote powders requiring a heavier charge as having less felt recoil? Does not compute, if you're working strictly from the math in the formula.

[quote=that much difference should surely show itself in MEASURABLE recoil, should it not?[/quote]

no larry it won't necessarly show itself in measurable recoil for a couple of reasons. first, 3.5 grains out of the total mass of ejecta (say one ounce of shot plus the powder which is miniscule in comparison) would run the calucalable recoil ENERGY up by something less than one foot lb. and that's using a velocity for the powder of 4700 fps which is typical but if anyone referred to the a-squared manual as i suggested about 11 pages back they'd find that value can be anywhere from 2k fps for low velocity/low pressure loads to 7k fps or more for large belted magnum rifles. if you back off that assumed 4700 fps to something more realistic for a shotgun that less than 1ftlb drops to way less than one foot pound.

and second, if the powder has a different and more progressive burn curve and accelerates the shot charge more slowly down the length of the barrel the FORCE generated is much less. that was also pointed out 11 pages back but for some reason third grade math requiring the multiplication of 2 numbers to come up with a third number seems beyond the grasp of many. everyone resorts to comparing recoil by kinetic energy which is no more valid for recoil than it is for killing effectiveness of projectiles. until everyone can get "kinetic energy of recoil" out of their heads, they're never going to get what's going on when a gun recoils.

and if you don't believe acceleration matters, next time you need to stop your car, drive it into a brick wall instead of using your brakes. same amount of energy is expended but one is going to feel a lot worse (and yes i know that's decelleration but the math is the same, just the sign is reversed).

using kinetic energy for comparing recoil is simplistic, rudimentary, and an inaccurate indicator of what's happening but since that's what everybody has read somewhere in a magazine that seems to be all that sticks.