[Deerbuster]

I was going to calculate the recoil energy of my 870 using slugs with a "max dram" charge. the calculator asks for a number, so I'm not sure what to put in there.

 

[RandyWakeman]

I was going to calculate the recoil energy of my 870 using slugs with a "max dram" charge. the calculator asks for a number, so I'm not sure what to put in there.

You can't, no max dram actually exists.

Dram is a unit of weight used to weigh ( :roll: ) blackpowder.

 

[Deerbuster]

I could swear I have seen some websites with slugs's recoil energy in footpounds that have max dram.... maybe the socalled dram equivalent could be calculated from the velocity? 1450 fps...

Oh yeah, I forgot to put in dram equivalent instead of dram. if theres a difference, then its what i meant.

 

[RandyWakeman]

According to physics, the momentum of a free recoiling firearm is equal and opposite in direction to the momentum of the ejecta and powder charge. The formula for free recoil of a firearm is:

Recoil Energy in ft. lbs. = (Bw Mv + 4700 Pw)2 / (64.348 Gw) where:
Gw= the weight of the gun in pounds
Bw = weight of the ejecta (shot and wad) in pounds
Pw = powder weight in pounds
Mv = muzzle velocity in feet per second

Example: Our shooter has an 8 lb. target gun with a load using 19.0 grs. of Clays, a wad weighing 33.0 gr., shot charge of 1 1/8 oz. and giving 1200 fps muzzle velocity. First we must convert the ejecta weight to lbs. (1 1/8 oz. = 492.0 gr.) Dividing grains by 7000 converts to pounds.
Gw = 8 lb.
Bw = (492.0 + 33.0)/7000 = 0.075 lb.
Pw = 18/7,000 = .003 lb.
Mv = 1200 fps

Substituting the numbers in the formula we find the recoil of the shooter's load = 21.05 ft. lbs.

(As published by Hodgdon, Lowry, et al.)

 

[Deerbuster]

So the only way would be for me to open up a shell and get a powder scale and see for myself?

 

[grimakis]

Doesnt the box say how much powder / shot is inside each shell? Convert ounces to pounds, weigh the whole shell, subtract the weight of an empty hull and the shot to get the weight of the wad. Or you could open it up...

 

[Deerbuster]

Well like I said, its slugs, and its a one ounce slug, and I'll check out the box for any fine print.

 

[Deerbuster]

I can't find the weight of the powder anywhere. I checked all six sides of the Remington Copper Solid box.

 

[Beginner Trap]

Comparing your Remington load to a Ballistically equal Federal load, the dram Eq. of your load is 3.98. In short, that means the gun's going to kick a lot. So, basically, get used to it. The only way to know how hard it kicks is to step out on the back porch and pop one off :lol:

BT

 

[Deerbuster]

Hm.... I wonder how legal it would be to do that. :lol: (i have neighbors)

And I've shot some before, just that I want some basis so I can know how much foot pounds I took to the shoulder

 

[RandyWakeman]

So the only way would be for me to open up a shell and get a powder scale and see for myself?

Not really. Calculated recoil is not important; felt recoil is what we all care about.

Pulling the trigger is the only way to experience that.

 

[SmokeAddict]

You could look up a reloading recipe from Hodgdon.com to get a charge weight in grains for an equal load.... Thanks Randy for that example!

 

[RandyWakeman]

The dram doctrine has gone on a long, long time; moreso with blackpowder and "volumetric equivalents":

http://www.chuckhawks.com/blackpowder_volumetric.htm Not all that fascinating, is it?

Okay, let's cut to to the chase.

For an 8 lb. gun, your load has approximately 28.7 ft. / lbs. of recoil energy.

 

[Deerbuster]

Thanks Randy,

I'll go see exactly how much this gun weighs at my mom's chiropractor (he's cool like that, he likes guns too). He has a medical scale thingy.

 

[claybreaker]

Point it at a deer and shoot it and you won't even notice the recoil. My deer rifle has a brutal kick at the rifle range but I didn't notice any kick at all taking an 8-point this afternoon.

 

[Beginner Trap]

I've got a Remington 7600 in .30-06 that has a 18.5" barrel. I shoot a 180 Gr. load and it kicks a lot and it will ring your ears. I shot a deer with it last weekend and I didn't hear the blast or feel the kick, most amazing :lol:

BT

 

[SmokeAddict]

And I doubt that an 870 with slug barrel weighs 8 lbs to boot, so you could add a little more to that! Claybreaker nailed it! It only kicks if you miss the deer!

 

[Deerbuster]

The rifled barrel is only 20 inch with rifle sights. Its definately lighter than the vent rib smoothbore

 

[Slick13]

I was going to calculate the recoil energy of my 870 using slugs with a "max dram" charge. the calculator asks for a number, so I'm not sure what to put in there.

Look up your load on its manufacturer's website, and it will give you actual velocity of the load.

As for the recoil energy.... it's a slug load. It's heavy and fast, and probably going to hurt.

~Michael