Stupid question about recoil: 1 cartridge vs another

[rookie7]

Alright - don't throw stuff at me, but... I searched to find the "stupid marksmanship" forum without success.

My gut is saying yes to my question, but I'm defering to the experts here on the Hide.

So here goes:

Will recoil be equal in 2 different cartridges/calibers if:

1. The rifle is exactly the same - stock, weight, etc.
2. The same powder and charge is used: example H4350 44.2 grains
3. The same bullet weight is used with roughly the same desgin - i.e. eld vs eld or Nosler BT etc.

Example:

6.5 creed shooting 130 vs 270 shooting 130 - using H4350 at 42 grains - won't they both have equal recoil energy?

6.5 creed shooting 100gr vs 6 creed shooting 100gr - using H4350 42 grains - same recoil?

So, what I'm getting at - within reason - bore diameter aside recoil will be equal as long as bullet weight and charge are the same.

Thanks

 

[Newbie2020]

Should be too close to matter

after I got addicted to the low recoil on my 6cm I started loading lighter bullets in my 6.5cm and it definitely made a noticeable difference

 

[huntnh]

Should be the same as long as the guns are the same weight and same muzzle device/ brake

 

[iceng]

Velocity is part of the recoil factor, as is the length of barrel required to get that velo. A 16" barrel and launching a 130gr @2850fps will be different that a 26" barrel for the same result.

A car wanting to get to 60km/h. You can put the pedal down and do it as fast as possible, or you can ease it on over 1/4 mile strip and do it really softly.

Also look into case capacity. There was discussion on a thread previously about velocity change via seating depth. The tiny change that the seating depth can produce to initial start pressure, will effect down range (end of barrel) performance.

Summary is: yes, but the average shooter can not feel it. It does take lots of experience of a variety of cartridges to "feel" such things. Most people can't even feel the difference between 130 and 140gr in a creedmoor, or a soft load with a 100fps drop in velo from a dud powder charge.

 

[hlee]

Enjoy

https://saami.org/wp-content/uploads/2018/07/Gun-Recoil-Formulae-2018-07-9-1.pdf

 

[Snuby642]

I thought I read something to do with shoulder angle effecting recoil?

My feather weight 270 has a hard recoil impulse with 135g bullets.
It carries nicely.

 

[alamo5000]

I thought I read something to do with shoulder angle effecting recoil?

This was my first thought too. Take a water hose for example. If you turn the hose on there will be a reaction when water shoots out the end of the hose. Now if you put a jet nozzle on the end of the hose, even if you turn the water to where the exact same volume of water is flowing the effect will be different.

Which one will be more or less is up for discussion, but I definitely think cartridge design will make a difference.

Whether or not that difference will be significant in the way of recoil is also to be determined.

 

[Supersubes]

No. The resulting pressures in those combos dont produce equal velocities, therefore recoil would be way off. For example, the 270 will be making very little pressure with 42 grains in that large combustion space. It’ll be dog slow. The 6.5 creedmoor will be making a good bit more pressure, as well as velocity and recoil.

In your 6/6.5 example, the 6mm should make more pressure, be faster, and have more recoil. In this example you cant simply set “bore diameter aside”, because the actual bore area between them greatly affects how pressure builds. Theres also the competing issue with the added bore area of the 6.5. If pressures were equal, the 6.5 would be faster, and have more recoil. This comparison is much closer, and I think the shooter would have a hard time telling the difference.

 

[chevy_man]

I thought I read something to do with shoulder angle effecting recoil?

My feather weight 270 has a hard recoil impulse with 135g bullets.
It carries nicely.

Total recoil, or felt recoil?


I've shot stupid guns with way too much drop in way to large a caliber that wanted to lift the barrel to the moon and drive you down. They felt stupid, and weren't fun to shoot at all.
Similar calibers in a well designed chassis that pushes straight back doesn't feel nearly as bad. Still moves you, but isn't trying to pivot at the wrist and rip you around with it.

The recoil energy is there, but how it feels can be wildly different between different stocks.

 

[Snuby642]

Standard winchester m 70 feather weight with a pencil barrel and lamminent stock.

It's good for 2 shots on a dime then walks. It kicks hard for a 270.
It's doing the job it was bought for my sons use it when they need to climb up steep stuff.

I'm to old for that crap and don't really care about trophies much.
Content to drop culls in easy access spots with milder cartridge.

 

[trident512789]

No they will not be the same. Recoil is not instantaneous. Since different cartridges produce different pressure 'waves' if you will and the powder charge is stacked differently (270 being more like 30-06--long narrow, 6.5 being more stumpy) the force to the bullet is different, and the force back on you will be different.

I don't know if it is enough to be felt, but the recoil will be different.

But your point about 'within reason' is tough to quantify.

Myself cannot tell the difference between different calibers like 308 and 6.5. Nor shooting a 175 gr vs shooting 220 grain in 300 Win Mag. Other people have said they can feel the heavier bullets.

I cannot tell 9 mm from 45 in (fullsize) handguns, but that begs the question 'What would a reasonable person feel'?

I know people who prefer 380 over 9 mm, but to me a 380 is more 'snappy' due to blowback design. (different cartitrides, different designs). It all way too subjective about what someone 'feels'

 

[Marine52]

Rifle recoil inputs: rifle weight; bullet weight; charge weight; muzzle velocity

JBM - Calculations - Recoil

www.jbmballistics.com

 

[gunsnjeeps]

Alright - don't throw stuff at me, but... I searched to find the "stupid marksmanship" forum without success.

My gut is saying yes to my question, but I'm defering to the experts here on the Hide.

So here goes:

Will recoil be equal in 2 different cartridges/calibers if:

1. The rifle is exactly the same - stock, weight, etc.
2. The same powder and charge is used: example H4350 44.2 grains
3. The same bullet weight is used with roughly the same desgin - i.e. eld vs eld or Nosler BT etc.

Example:

6.5 creed shooting 130 vs 270 shooting 130 - using H4350 at 42 grains - won't they both have equal recoil energy?

6.5 creed shooting 100gr vs 6 creed shooting 100gr - using H4350 42 grains - same recoil?

So, what I'm getting at - within reason - bore diameter aside recoil will be equal as long as bullet weight and charge are the same.

Thanks

After reading your post I would say no. Free recoil uses the variables mentioned by Marine52. With equal weight rifles, bullets, charges, and velocities the recoil is the same. In your examples the bullets will have different velocities due to having the same weight but different bore diameters, which changes velocity due to pressure changes.

6.0 CM 107 gn HPBT 35.7 gn Varget 2950 FPS
6.5 CM 107 gn HPBT 35.8 gn Varget 2700 FPS

In your first example the 6.5 CM and .270-08 are fairly close to each other with a 130 grain bullet. The .270 may be 100 fps faster but uses more powder, both variables would give it more recoil.

PS: I had to guess on a .270 case, .270-08 is the closest. The .270-08 can drive the .277 bullet faster than the 6.5 drives a .264. The .308 case has about a 4 grain volume difference. Using the 6.5 CM charge in the .270-08 case may result in the .270 being slower.

 

[Badmonkey]

Necromancing this thread because I have question along the same lines. I'm looking to mitigate recoil for PRS rig and am in the process of choosing cartridges for a gas gun, and a bolt gun.

Say you have a 6mm rifle with the same barrel length shooting 105s at 2850fps. Would a 6BR running a higher pressure with 30ish grains of Varget produce more or less felt recoil that a mild load in .243 Win with 44ish grains of H1000?

I can rationalize a case for both being the milder recoiling setup. The case for the BR would be less powder, quicker recoil pulse, but maybe a bit more jumpy. For the .243, a lower pressure charge and a longer, but smoother recoil pulse. I can also see how the difference woudn't amount to a hill of beans, as 2850fps is 2850fps.

Any and all opinions, anecdotes, or imperical evidence welcome.

 

[hlee]

Recoil velocity is a function of the velocity and mass of “ejecta” (bullet + powder), and the rifle weight. More powder will equal more recoil velocity. Heavier rifle will equal lower recoil velocity. If you were to hold the rifle weight, bullet weight, and muzzle velocity constant, the cartridge with more powder will have more recoil velocity. In the above example, I’d expect the 6br to have about 9% lower velocity than the 243.

 

[Snuby642]

I can't see any difference using the same projectile at the same speed and same type firearm.

I have read things about different shoulders on the brass effecting it but don't believe it.

Equal velocity shoving equal weight seems to warrant equal reaction (recoil).

There is a lot of stuff on the market to help mitigate felt recoil at reasonable prices and then there is hyped up crap as well.

Muzzle devices and recoil pads work, adding weight works.

Most of the rest is crap with added hype and if brand fanboy hype weighed anything some of it would work but that's not happening.

I like E C Tuner Brake for my applications. The aggressive brake portion seems to work better than the cheap to mid price stuff I've had since it mitigates rearward blast and the tuner is making me a happy guy.

One of the very few fanboy things I own in life.

 

[vh20]

Recoil velocity is a function of the velocity and mass of “ejecta” (bullet + powder), and the rifle weight.

This is the age-old formula I’ve always been told is correct. I’ve never studied it to prove it right or wrong, but have read a few articles by “knowledgeable” people who have, and their conclusions were that it is correct, ie change anything in the formula, but still end up with the same velocity and mass of ejecta (bullet + powder) and you end up with the same recoil.
Me, I don’t claim to know, but it makes a fair amount of sense, and seems to be fairly accurate based on my totally anecdotal perceptions behind the rifle.

 

[Badmonkey]

Recoil velocity is a function of the velocity and mass of “ejecta” (bullet + powder), and the rifle weight. More powder will equal more recoil velocity. Heavier rifle will equal lower recoil velocity. If you were to hold the rifle weight, bullet weight, and muzzle velocity constant, the cartridge with more powder will have more recoil velocity. In the above example, I’d expect the 6br to have about 9% lower velocity than the 243.

So does this essentially mean that in the example I gave the .243 win would recoil similarly to a 6br with a 119grain bullet (if there were such a thing)?

 

[Sheldon N]

I can rationalize a case for both being the milder recoiling setup. The case for the BR would be less powder, quicker recoil pulse, but maybe a bit more jumpy. For the .243, a lower pressure charge and a longer, but smoother recoil pulse. I can also see how the difference woudn't amount to a hill of beans, as 2850fps is 2850fps.

As noted above, the amount of powder also adds to the recoil. Some of the initial ignition energy goes towards launching the powder column forward, adding to the total recoil.

There is something to be said for shorter duration recoil. The sooner the recoil is over, the sooner you can start to see what's happening downrange.