Confusion about powder burning rates vs recoil


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matt35750
August 9, 2013, 04:28 AM
If you put blackpowder and smokeless powder side by side and burn them the blackpowder burns much faster. However blackpowder has less recoil than smokeless. I called Remington who said there low recoil shotgun shells such as these http://www.brownells.com/ammunition/shotgun-ammo/remington-managed-recoil-sts-target-shotgun-ammunition-prod43449.aspx have the same shot weight and velocity as there regular shotgun shells they just use a slower burning powder. Can someone explain this to me as I don't get it.

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Deus Machina
August 9, 2013, 05:15 AM
This is in part because black powder has less stored energy overall, usually. It's done burning well before the bullet leaves the barrel and any further acceleration is just the gasses equalizing pressure, whereas smokeless is building pressure a good distance more. Even after the bullet's left, in many cases.

In general, a faster burn rate means harsher recoil because the build of pressure is faster. Black powder just doesn't get to a pressure as high.

Al Thompson
August 9, 2013, 07:33 AM
Lets see if the folks in reloading can help. :)

frankge
August 9, 2013, 08:15 AM
Not always. In uspsa we load a heavier bullet with a fast powder to make power factor which results in a snappier, lighter perceived recoil.

ATLDave
August 9, 2013, 11:06 AM
Percieved recoil is highly subjective. The total recoil momentum is easily calculated using the weight of the bullet and ejecta and their velocity. But some people will perceive a shorter recoil impulse as being lower than a longer impulse, even if the total momentum is the same. Or vice-versa.

Now, most of the best low-recoil rounds - your .38 wadcutters, for example - will have fast-burning powder. But they also are generally not achieving very high velocities, so the absolute momentum is lower. Fast-burning powders often work better at lower velocities than slower-burning powders. But a fast-burners versus a slower powder that are achieving the same velocity? That recoil difference will be pretty subjective. That's the beauty of reloading... you can play around with stuff and figure out which you prefer.

BTW, things get more complicated if you've got a compensator involved.

carbine85
August 9, 2013, 11:33 AM
Black powder doesn't burn as completely as smokeless powders. That's one of the reasons why it's so dirty and smokey.

SlamFire1
August 9, 2013, 11:37 AM
I agree perceived recoil is highly subjective.

I have shot hundreds of rounds of 510 grain 58 Cal Minie balls with 50 grains of black. In theory this amount of mass should recoil harder than a 150 grain bullet out of a 30-06. And yet, the recoil from the 30-06 is sharper and hurts more.

Grumulkin
August 9, 2013, 01:20 PM
Recoil is subjective BUT there is a difference between various types of powder. In my opinion, recoil with black powder for the same weight of projectile one would use in a gun using smokeless powder is more, not less. Part of the equation is burn rate and another part is the actual weight of the propellant.

ironworkerwill
August 9, 2013, 01:39 PM
I would assume the faster a projectile is accelerated the more perceived recoil it has. As I also assume the opposite is true.

For instance, shocks on an automobile will slow the travel of the chassis. If we were to shorten the time of travel the perceived Gravity would be greater. Also it's not the fall that kills you it's the sudded stop at the end.

I'd have to side with Deus Machina on this one.

Mr. Farknocker
August 9, 2013, 02:32 PM
Sounds more like a question of whether there is a correlation between a powder's burn rates and the energy it produce in a given period of time. A lot of reloaders rely on burn rate charts when determining the proper starting load for their particular bullet/powder combination. I was always puzzled by this since a powder's burn rate is but one factor in determining the amount of energy produced or released over a given period of time and that factor alone, is insufficient to draw conclusions about the amount of energy released and, hence, the similarity between two powders. Good 'ole Chuckie seems to agree with this this and goes as far saying in an article written by Randy Wakeman, "[p]rofessional ballisticians do not use them at all, simply because they have no particular meaning."

http://www.chuckhawks.com/powder_burn_rate.htm

243winxb
August 9, 2013, 04:51 PM
have the same shot weight and velocity as there regular shotgun shells 7/8 oz of shot at 1100 fps will produce low recoil. This is not a standard loading. If you study the loads here http://www.alliantpowder.com/reloaders/default.aspx 12-Gauge, 2 3/4 -in. Remington Plastic Shells (STS, Nitro 27, Premier RXP and Gun Club) 7/8 oz load at 1150 fps. Extra-Lite powder (Powder density allows use of standard available components (wads and cases) . They just reduce the amount of powder used. Less powder=less pressure=less recoil.

frankge
August 9, 2013, 06:54 PM
go over to brian enos reloading sections and see us argue about who has the bunnyfartyiest bunnyfart lol

243winxb
August 9, 2013, 08:13 PM
Red Dot vs Green Dot- Green Dot is listed as " Lower felt recoil " If we compare loads using the same velocity & shot weight, Green Dot produces 400 psi less pressure. Does less pressure, convert to less recoil? Compared 1150 fps -1oz-CB 1100-12 wad-Rem209P- Case 2 3/4-in. Remington Plastic Shells (STS, Nitro 27, Premier RXP and Gun Club)

sage5907
August 9, 2013, 11:19 PM
Quote: "Not always. In uspsa we load a heavier bullet with a fast powder to make power factor which results in a snappier, lighter perceived recoil."

frankge made a good point. I can load one 150 grain bullet for my 30-06 with IMR 4064 and another bullet with IMR 4350, both loads at the same velocity and the same point of impact at 200 yards, and the IMR 4064 load will have the least felt recoil. Acceleration of the bullet is happening faster with IMR 4064 although it is happening with both powders within the length of a 22 inch barrel.

flashhole
August 11, 2013, 05:49 PM
altdave had some good comments. Do you have energy per unit volume for the black powder. Burn rate plays a role in cartridge performance but black powder is typically lower energy than smokeless powder. Felt recoil is simply a matter of force. What energy (bullet and charge performance) is applied to what weight (gun and shooter).

brickeyee
August 12, 2013, 02:25 PM
The effect s of 'felt recoil' and gun design usually swamp most of the speed difference.


You can compute recoil impulse (instead of free energy) but it is more complicated and often the differences are swamped by other effects (bore axis height, but angle on long guns, grip angle, height in the hand, etc.).

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