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Quantitative Recoil Measurement?
Will14
Member Posts: 44 ✭✭
Is there a method or formula to come up with a value for felt recoil from a given rifle with a given load that would allow a person to compare the recoil from one rifle/caliber to another?
Thank you,
Will
Thank you,
Will
Comments
http://www.handloads.com/calc/recoil.asp
But you cannot calculate felt recoil by definition. The same load will feel different in guns of different stock styles. The same computed recoil will feel different when it is generated by a heavy bullet at low velocity or a light bullet at high velocity. You could probably get a good idea for comparison of loads not too far apart, like whether a Winchester Model 70 .270 will kick enough less than a Model 70 .30-06 to matter.
You have a good example of the difference in Newton's Law recoil and felt recoil. A friend of mine had a BLR .308 and we thought it was a noticeably harder kicker than other guns of similar power and weight. Something about the balance and stock shape, I think.
TC Encore, and a ton of barrels. I'm willing to sacrifice the labor if you'll provide the gun and ammo
Anyway, as stated you can do some math, but also as stated there are variables that you can't do the math on.
Is there a method or formula to come up with a value for felt recoil from a given rifle with a given load that would allow a person to compare the recoil from one rifle/caliber to another?
Thank you,
Will
The quick answer is that yes, there are formulas to do this.
Without getting into too much detail, the most important physical/mathematical measurement you need is the free recoil energy, which is effectively the kinetic energy of the recoiling gun. The higher that energy, the harsher the recoil.
Note that while the momentum of the BULLET and the momentum of the RIFLE are by necessity equal in magnitude but opposite in direction (per Newton's second and third laws of motion), the KINETIC ENERGY of the bullet and gun will NOT be the same. That's why heavier guns have less recoil than lighter ones. If you think about it for a moment, its also why you don't suffer the equivalent of a gunshot wound to the shoulder every time you fire a round!
Alternatively, if you just need a ballpark answer (ie how does a .243 compare to a 30/30; or whatever) you can look at published tables, like this one:
http://www.chuckhawks.com/recoil_table.htm
Amplifying what's already been said, most individuals don't really care about the mathematical definitions of recoil (eg how many foot pounds or whatever). That's a good first approximation, but it doesn't tell the whole story.
For the average shooter the definition of recoil is the SUBJECTIVE unpleasantness associated with firing a given gun.
That, of course, is going to depend on the load in question and mainly the WEIGHT of the gun in question, but its also going to depend on the shape of the stock (including its area and angle), the anatomy of the shooter, whether or not the gun has a buttpad, the CLOTHES the shooter is wearing, how the shooter is standing (or sitting) and a few other factors.
I can say from experience that the effects of recoil are cumulative.
I find that if I consistently use good form and stand up, I can take quite a bit of punishment. On the other hand, all it takes is *ONE* shot with a medium (or heavier) caliber rifle where you aren't holding the gun right to get a nice bruise on your shoulder. Once that happens, then EVERY other shot for the rest of the day will hurt!
Thank you for the help. The calculator and chart are what I was looking for. I currently have a Rem 700 in 7mm Rem Mag and a BLR in 308 for deer hunting. They are both overkill and I do not enjoy shooting either of them. I'm going to sell them at the end of this season and look for something a little, well, a lot, easier on the shoulder. It is difficult for me to shoot different rifles, but now I have a starting point for what caliber to go with.
Thank you again,
Will
Gentlemen,
Thank you for the help. The calculator and chart are what I was looking for. I currently have a Rem 700 in 7mm Rem Mag and a BLR in 308 for deer hunting. They are both overkill and I do not enjoy shooting either of them. I'm going to sell them at the end of this season and look for something a little, well, a lot, easier on the shoulder. It is difficult for me to shoot different rifles, but now I have a starting point for what caliber to go with.
Thank you again,
Will
If that is your goal, I think that Hornady makes a low recoil load for the 308.
Or, get a simple reloading press and make your own low recoil loads - think something like a 125grn bullet at 2300fps or so.
Or maybe just a better recoil pad...
Gentlemen,
Thank you for the help. The calculator and chart are what I was looking for. I currently have a Rem 700 in 7mm Rem Mag and a BLR in 308 for deer hunting. They are both overkill and I do not enjoy shooting either of them. I'm going to sell them at the end of this season and look for something a little, well, a lot, easier on the shoulder. It is difficult for me to shoot different rifles, but now I have a starting point for what caliber to go with.
Unless you need to hunt something VERY big from VERY far away, I'd toss the magnum.
On the .308, even that one can be a handful, especially if the gun doesn't fit you right.
But before you start swapping guns, have you tried a recoil pad? In my experience a good one can take about 40% of the sting out of a shot and make all the difference. Much easier and cheaper than tossing the entire gun, I think, particularly if you otherwise like it.
Also, as mentioned, Remington makes a factory load called "managed recoil" which puts out a 125 grain bullet at 2600fps:
http://www.midwayusa.com/viewproduct/?productnumber=233209
If you figure a standard .308 puts out a 168 grain bullet at roughly the same velocity, this will give you a 26% reduction in recoil right off the bat. Looking at it a bit differently, the managed recoil load should give you similar ballistics as a 30/30 with lightweight bullets (though the .308 gun itself will probably be heavier, so recoil might be lighter yet). Only question is will the lighter load reliably cycle your auto gun.
Remington also does make a managed recoil 7mm magnum load, if you wanted to take a look at it. That one puts out a 140 grain bullet at 2700 fps, meaning it turns the 7mm magnum into something somewhat lighter than the .308.
On reloading, of course if you did that you could design any load any way you want, including making your own low-recoil loads. But unless you otherwise have the inclination to do it (eg you shoot a lot or would just enjoy it), this is probably not a good answer. Its not going to be cost or time-effective to buy a new reloading kit from scratch, learn how to use it, work up the loads, etc, if you're only expending a few boxes of ammo per year.