crest117
Member
For a given weight rifle, will the amount of recoil be directly proportional to the muzzle energy or do other factors affect the recoil? I don't mean felt recoil but actual recoil.
Question about recoil
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Reloadron
Contributing Member
Free Recoil Energy is what you are getting at. Hatcher's notes has a section on it but the linked SAAMI pdf is pretty good. You can see how the formula works out and what weighs in more heavily.
Ron
Ron
crest117
Member
Thanks, I am aware of Newton's third law of motion but I was wondering if other things would affect the recoil such as the burning speed of the powder or the weight of the powder charge.
Without special equipment or certain software you can only estimate that. Speed of powder gases is most often taken as 4000 or 4700 ft/s (2000 for black powder) or 1.5-1.75 times the muzzle velocity.
Reloadron
Contributing Member
Yes, did you read the link I posted with the formula? You may also want to read this about Hatcher's notes. Additionally note what Goosey mentions:
Look at the formula and you will see how much the weight of different factors contributes.
Ron
VoodooMountain
Member
Weight of gun
Powder charge
Weight of bullet
Velocity
Those account for the physical energy and there are calculators to do the math.
Adding a pound to the rifle reduces physical recoil by about 1lb., generally.
For felt recoil, which is subjective, the fit of the stock, barrel length, speed of powder, and muzzle blast can all have an effect.
Powder charge
Weight of bullet
Velocity
Those account for the physical energy and there are calculators to do the math.
Adding a pound to the rifle reduces physical recoil by about 1lb., generally.
For felt recoil, which is subjective, the fit of the stock, barrel length, speed of powder, and muzzle blast can all have an effect.
rcmodel
Member in memoriam
This answer is the best so far.
Stock design and fit play a very large part in felt recoil.
Take two 30-06 rifles of the same weight.
One stock fits you, with a straight cheek-piece sloping away from your face.
The other has too much drop, and a cheek-piece shaped to slap you in the face.
They both reduce the same energy, and recoil exactly the same in Ft/lb free recoil.
But one will hurt you, and the other one won't.
rc
Free recoil is affected by-
- Velocity of the bullet
- Bullet mass
- Mass of the propellant
- Mass of the firearm
- Velocity of the gas, which is a constant. I believe the velocity of the gas for smokeless powder is roughly 5700 fps.
Free recoil is also affected by muzzle devices that change the direction and/or velocity of the gas as it exits
- Velocity of the bullet
- Bullet mass
- Mass of the propellant
- Mass of the firearm
- Velocity of the gas, which is a constant. I believe the velocity of the gas for smokeless powder is roughly 5700 fps.
Free recoil is also affected by muzzle devices that change the direction and/or velocity of the gas as it exits
lysanderxiii
Member
Type of action and internal dynamics (if any) also have a lot to do with felt recoil.
Take a bolt that has exactly one cartridge length travel and slams in to the back of the receiver, stopping it short versus a bolt that has has sufficient travel the only be stopped by the action of the main spring, or a recoil operated weapon with a very large recoiling mass and a very short throw versus one with less recoiling mass and a long throw.
WelshShooter
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Lets make it simple and assume it's a bolt action rifle you're talking about.
The physical recoil, is basically conservation of momentum. The momentum of the gun (reoicl) is equal to the momentum of the bullet as it leaves the muzzle, which is calculated as mass times velocity. The lighter a stock becomes the more recoil you feel (because the velocity of the rifle increases).
However, in terms of "felt" recoil, rcmodel has this covered pretty well. If you have a rifle stock that has been made to fit you, or adjusted in any way for the shooter, you will feel less recoil than the exact same rifle with no customisation. The butt of the stock also makes a big difference, having a nice rubber recoil pad or shoulder pad will reduce the felt recoil quite drastically. Ever tried shooting a milsurp rifle with a steel/brass butt pad? That steel butt pad does not absorb any recoil (the rubber will compress and absorb some recoil) and therefore transfers all the recoil to the shooter.
This is the answer.
If you want to see how each of these factors can have an effect on recoil go to this site and play around with each of the variables.
http://www.handloads.com/calc/recoil.asp
Change any one factor just slightly and you can see a noticeable change in recoil. The one factor that most don't consider is the weight of the powder charge. If you can find a way to keep all other factors the same and get the same speed using less powder you'll see a noticeable recoil reduction without giving up performance.
This is why newer short action cartridges are becoming so popular. If you compare 308 vs 30-06, 7mm-08 /260 vs 280/270, or even 300 WSM vs 300 WM you'll see the shorter cartridges using considerably less powder, but giving 97-99% of the speed. You'll get about 20% less recoil and better accuracy from the shorter cartridges while only giving up 1-3% bullet speed.
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