Question about felt recoil

[chevyman181]

How does a person calculate felt recoil?

Say all things are the same except the cartridge... 8 Pound rifle, 162 gr 7mm bullet, at say 2900fps, is the felt recoil the same no matter what cartridge is pushing the projectile?

7-08, 280ai, 7mag, 7saum, if they are all in an 8 Pound rifle shooting the same 162gr projectile at the same speed, will the felt recoil be that much different?

I know the 7rum uses way more powder than 7-08 just curious if the powder charge has any effect if it's pushing the same projectile at the same speed.

Thanks

 

[Fire_9]

There are calculators that do it. Of course the 7 RUM is going to have more recoil than the 7-08.

 

[noharleyyet]

The size, duration, and color of the bruise near the insertion of the anterior deltoid.

 

[BackofBeyond]

In what world would a 7HT and 7RUM be shooting the same projectile at the same velocity?

 

[Carl]

How does a person calculate felt recoil?

Say all things are the same except the cartridge... 8 Pound rifle, 162 gr 7mm bullet, at say 2900fps, is the felt recoil the same no matter what cartridge is pushing the projectile?

7-08, 280ai, 7mag, 7saum, 7 rum, if they are all in an 8 Pound rifle shooting the same 162gr projectile at the same speed, will the felt recoil be that much different?

I know the 7rum uses way more powder than 7-08 just curious if the powder charge has any effect if it's pushing the same projectile at the same speed.

Thanks

The powder charge weight also effects recoil as all the powder is pushed out of the barrel as well.

I often include recoil calculations when I'm bench racing options, I use JBM's calculator:

JBM - Calculations - Recoil

www.jbmballistics.com

Input looks like this:



Output looks like this:

 

[p_ham]

Powder charge does have an effect, velocity aside. Gasses do have weight. More gas equals more weight. You can calculate recoil energy. Felt recoil will vary by stock design and action type.

 

[Forkyfinder]

In what world would a 7HT and 7RUM be shooting the same projectile at the same velocity?

Maybe a 300 wsm and 300 win mag would be a better example.

 

[BackofBeyond]

Maybe a 300 wsm and 300 win mag would be a better example.

Absolutely, those two have a very similar case capacity. But to translate the original question to .30 caliber, what would recoil be like for a .308 and a .300 RUM pushing the same projectile at the same speed? We’re comparing volume (powder capacity) of a kumquat vs a watermelon.

 

[Forkyfinder]

Absolutely, those two have a very similar case capacity. But to translate the original question to .30 caliber, what would recoil be like for a .308 and a .300 RUM pushing the same projectile at the same speed? We’re comparing volume (powder capacity) of a kumquat vs a watermelon.

300 wsm has like 10% less capacity and has similar speed with light bullets from factory ammo. Or .30 tc to .30-06

I think the original question is an exaggerated example but you could compare it with other practical examples too.

 

[chevyman181]

Yeah, the rum was exaggerated. I edited the question. I'll play with the calculator posted.

I googled a couple of calculators and they didn't show much difference in recoil with change the size of the cartridge and all other factors staying the same. Weight of rifle and projectile, velocity, and so on. I was a little surprised.

Thanks for input.

 

[noharleyyet]

I've heard comments regarding 300WSM & 300WM...one that the short mag pushes rather than hits. IMO, not true, both crack ya about the same.

 

[EastTNHunter]

Yes, there is the physics aspect of mass and velocity, as well as weight of the gun, but as has also been mentioned there is what I have heard described as a “jet effect” that varies based upon powder charge. But there is also a geometry and fitment aspect that cannot be shown on recoil charts that will be very individual-shooter-dependent. Type and size of recoil pad also affects this.

 

[MTLabrador]

I've heard comments regarding 300WSM & 300WM...one that the short mag pushes rather than hits. IMO, not true, both crack ya about the same.

Rifle weight and stock design make the biggest difference for me. My .338 WM is heavy enough that even with the old hard Ruger pad it’s tolerable. The Finnlight .300 WM comes back hard, but the McMillan with a good pad tamed the bite a little.

 

[noharleyyet]

The WM is a Walnut Kimber Classic, fairly light with a decent pad....WSM is a 700 action in a Carbon Stocky with a thinner pad...I'd say they're comparable weight wise & only notice recoil on the bench.

Rifle weight and stock design make the biggest difference for me. My .338 WM is heavy enough that even with the old hard Ruger pad it’s tolerable. The Finnlight .300 WM comes back hard, but the McMillan with a good pad tamed the bite a little.

 

[ImBillT]

Mass and velocity of the projectile are part of it, and mass and velocity of the burned powder is the other part of it. Rifle weight is another part of the equation, but that’s not exactly dictated by cartel she selection.

A 7-08 might be using 40-45gr of powder, a 280AI could be somewhere around 58-63gr of powder and a 7mag could use over 90gr(I think).

Now you might be thinking that 20gr more powder in the 280AI would make the 280AI shooting a 168gr bullet kick like a 7-08 shooting a 188gr bullet, but you’d be wrong. When the bullet exits the muzzle, the powder in the barrel accelerates to a velocity that is higher than the bullet. The result is that 1gr more powder results in more increased recoil than 1gr more bullet.

The 280AI with a 168 generates more recoil than a 7-08 with a 190. There are some very handy calculators out there.

Stock design and fit definitely effect how the recoil effects you. I’ve had some stocks that resulted in a lot of muzzle rise that just flat beat the heck of me, while a harder recooking rifle that came straight back didn’t bother me nearly as much.

 

[Wind Gypsy]

A 7-08 might be using 40-45gr of powder, a 280AI could be somewhere around 58-63gr of powder and a 7mag could use over 90gr(I think).

Maybe in a rum you could use over 90 grains of powder. 7 RM is more in the 60s to low 70s.

 

[ImBillT]

Maybe in a rum you could use over 90 grains of powder. 7 RM is more in the 60s to low 70s.

My mistake. I was thinking a 7mag was bigger than that. That is the reason I put “I think” in parentheses. I don’t own one and didn’t have a manual around, or wifi.

 

[oxn939]

Powder charge does have an effect, velocity aside. Gasses do have weight. More gas equals more weight. You can calculate recoil energy. Felt recoil will vary by stock design and action type.

I also wonder about powder types, maybe something to do with burn rate. Was doing load development for a .30-06 a few years ago and noticed unusually light recoil with one powder. Pulled out three rounds of my next load and right back to feeling like an '06. Seen the same in several other calibers too

 

[p_ham]

I also wonder about powder types, maybe something to do with burn rate. Was doing load development for a .30-06 a few years ago and noticed unusually light recoil with one powder. Pulled out three rounds of my next load and right back to feeling like an '06. Seen the same in several other calibers too

Gas pressures and jet thrust at the muzzle could change the recoil amount, for a given velocity.

Powder A: faster burn rate, lower charge, full burn in the barrel.
Powder B: slower burn rate, higher charge, burnout after leaving the barrel.

Powder B would have higher recoil force due to the higher charge weight, gas volume, and muzzle pressure.

 

[std7mag]

Realistic answer is you can't calculate felt recoil.

There are formulas that calculate the energy that the gun will actually recoil.

But felt recoil is really to the individual.
Some people just handle recoil differently than others.