doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com A5 Felt Recoil Tester

an interesting feature of the browning a5 auto loading shotgun is its ability to cycle a variety of loads, which create different levels of felt recoil...this is accomplished by changing the positioning of friction rings in their relation to the action recoil spring...for those not familair with how the a5 works, see the link below...

https://www.thefirearmblog.com/blog...anding-auto-5-friction-ring-orientation/

sooo, what about using an a5 as a test platform to determine the suitabilty of shooting particular loads in old doublegons, that you wish to protect from heavy recoil?

for example, if a particular load will not even cycle an a5 set up for light loads, then is that load most likely suitable for shooting in your old doublegon?

Wowie, Fast Eddie. you finally posted something really interesting to me. Although I mainly shoot side-by-sidesd and Win M12's. I have owned a light 12 Belgian mfg. A-5 for over 40 years, 28" mod. VR barrel- not quite as heavy as a M-1 Garand (I was an armorer in the USMC) but solid and reliable. I use it for turkey with coppered lead loads, ducks and geese with steel shot, and sometimes for volume shooting with the 3-shot plug removed for crows and pigeons. Unlike the younger yuppie members of our DU chapter, who go ga-ga over all the synthetic stocked semi-autoloaders, mine has never failed to fire, early Sept. "bonus season on geese" to late Jan Goose season-like a Timex-- "takes a lickin', keeps on tickin. Great article. RWTF

Recoil is only part of the reasons I shoot low pressure loads in doubles. Low pressure/low velocity loads more correctly duplicate the loads these old guns were intended and designed to shoot. A 1300 plus fps load had not been invented yet or more correctly the powders for them had not been invented. Loads were 1100-1200 fps, one ounce to one and a quarter ounce, mostly towards the lower end on both.

Recoil is a function, or result if you want, of action of pushing shot down the barrel and reaction of the gun moving in the opposite direction. Nothing related to pressure at all. If you push a load down the barrel you get recoil. Total recoil generated has to be almost exactly the same if you do it at 1100 fps with a fast burning powder or a slow burning. You might get slightly more or less depending on powder burn rates but total recoil force has to be the same for our purposes.

Doubles were designed for the ammo of that time period. Barrels and wood were made to handle that ammo with safety. Now a hundred years of oil soaking wood does make it weaker but not hopelessly brittle. So as long as I use ammo it was capable of handling when designed it should be ok. I tell people it is not the height of the brass, not the velocity, not even the pressure alone that we must deal with. It is the combination of everything. If your load does what you need at substantially less pressure and recoil what more do you want? A dead bird or broken target is the goal.

c. 1900 standard loads were actually heavier than today's, with very similar pressures. The “standard” U.S. 12 gauge Field and Inanimate Target load was 1 1/4 oz. shot with 3 1/4 Dram (1220 fps) of Bulk (DuPont, “E.C.”, “Schultze”) Smokeless in a 2 5/8” or 2 3/4” case, with a modern transducer pressure of 8000 - 9500 psi.

Live Bird loads were usually 1 1/4 oz. 3 1/2 Dram Bulk Smokeless Powder in a 2 3/4” or 3” (for additional padding) case, with a pressure of 11,500 psi

Just before WWI: The “standard” U.S. 12g Field and Target load was 1 1/8 oz. shot with 3 Dr. Eq. (1200 fps) Dense (“Ballistite” or “Infallible”) Smokeless in a 2 3/4” case with a transducer pressure of 8,500 - 10,000 psi.

20g period reported pressures vary significantly but 7/8 oz. 2 1/2 Dram BULK Smokeless was 8000-10,000 psi.
7/8 oz. 2 1/2 Dr. Eq. DENSE Smokeless was 11,000 - 12,500 psi.

ed's suggestion fails to accommodate for the weight of the gun.
Lower recoil in a vintage double is wise, and it's not hard to pick a foot/pound target based on the recoil calculation
1 oz. at 1180 fps (2 3/4 Dram) in a 7.5 pound shotgun = 17.3 ft/lbs of free recoil.
17 ft/lbs seems like a good target no matter if a 20g, 16g or 12g. Or maybe 17 ft/lbs for a 12, 16 for a 16 and 15 for a 20?

I just bought another A5 for sea ducks. a 12 gauge magnum 3" version. It's pretty heavy but it won't be carried much if used for sea ducks.

try to focus here guys...

the question is, if a particular load does not generate enough recoil energy to cycle an a5 set up for light loads, could that load then be suitable for shooting in your old double gon?

there are three possible answers...

yes, maybe and no...

if no, then, why not?

You could say the same thing about any of the recoil operated shotguns. Franchi, Beretta, etc.
So, I’d say maybe.

You are just pushing against the spring, and the mass of the shotgun.

I suppose on an individual basis you could correlate for yourself.

Your A5 is not going to be very precise and only tell you one thing. Did it work or not? Are you going to say any load which works the A5 is automatically not usable in a double? If it worked, by how large an amount? If it did not by how much? And that assumes working an A5 has any correlation to being safe in a double.

You could use recoil calculations for a load as a better guide. Under 10 pounds ought to be safe, maybe 12 pounds. Velocity could be a general guide as well. 1100 fps on a one ounce load should be safe. But then you need to know pressures as well. There are one ounce load which generate higher pressures even with low velocity. A one ounce load, going 1200 fps that generates 11,000 + psi might be OK but I can find many better ones to load.

Give me known psi and velocity. I will pick a good one from there.

Pressure is not the same as recoil, ed. That has been discussed, at length, right here, prior to today.

I can change what loads cycle or don’t cycle your A5 with a drop of oil on the bronze bushing. Or, substituting a worn recoil spring for one that isn’t. Or a badly worn action spring.

Part of the genius of the A5 action is that the thing will cycle just about anything you stuff in it, provided it is somewhat clean and has most of the parts it was built with still installed.

Your question as to a design that measures pressure accurately has already been answered, with piezo devices, installed in barrels specifically to measure pressure.

Best,
Ted