An aspect of physics, and how it relates to rifles

It is all in the PHysics but

The physics relate more to the MASS of the bullet than the mass of the powder.

Regarding the volume of the different cases consider Boyle's law which states that in a perfect closed system containing a gas, the volume and pressure will react inversely. That means the 30-06 case which has a larger volume so will have less a lower pressure.

If all the science is confusing do you test this way. Vary the powder charge with the same weight bullet in the same case. Then you will see increased recoil with a higher powder charge. Another alternative test is to shoot 2 different bullet weights with the same powder charge out of the same case and you will find that the lighter bullet will recoil less. If you do both tests, you will notice LESS difference between the varied powder charges than between the varied bullet weights.
 
Regarding the volume of the different cases consider Boyle's law which states that in a perfect closed system containing a gas, the volume and pressure will react inversely. That means the 30-06 case which has a larger volume so will have less a lower pressure.
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So a larger case volume = lower pressure. What affect exactly does pressure have on recoil?
 
Shredder, I would say it would be different because the pressure would be different. Without looking at a load chart I do not know if 40gr in the 30 06 would even work. I might fail to push the bullet out the barrel and thus create a dangerous over pressure.

I am no expert but in loading my .243 and .270 sometimes using the same powder, the grains of powder called for are not proportional to the bullet weight. A better example: on one load in the 270 a 130gr bullet takes more powder than a 150 gr bullet, but results nearly equal velocity, I think because the 150 gr seats deeper into the case, leaving less space for the powder to work in and therefore allowing equal or greater pressure to be created with less powder in the same .270 case. That is about the best I can explain it with my limited physics education.
 
Ya, after I posted the question you just answered- someone made a comment about how case volume causes different pressures. I won't ever be able to make a 30-06 kick like a .243 (with the rifles I have anyway- all gadgets aside) and that's kinda what I was trying to do in the first place. Thanks for your insight all:D
 
Don't make this too hard. It's not about pressures, or volume or powders except in how they affect the acceleration of the mass of stuff coming out the barrel. Because of one of those other pesky laws, mass cannot be destroyed, it can only be converted. So the mass of the powder whether it's in granulated form or gaseous form is the same.

It's about F=ma. The sum of the weight of the bullet and the weight of the powder charge converted to mass units, and how fast the mass is accelerated. Unequal bullet weights in the same caliber with identical charge weights will have different recoil values. ONLY because you have changed the mass being accelerated.

How you perceive recoil is another thing entirely.

If you need to calculate free recoil, just google it. There are plenty of on-line recoil calculators. This one is good as it allows you to change variables and compare outputs. Have Fun. :D

Http://www.handloads.com/calc/recoil.asp
 
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I agree with what Greg says, except the regarding powder there is another variable which is burn rate. So different type of powder having the same mass but different burn rates will perform differently as far as velocity and recoil.

I load bullets ranging form 55gr to 107gr in my
243 and the difference in recoil, while measurable, does not seem significant to me.
Same is true in my .270 Win when changing from 130 gr to 150gr.
 
If you want light recoil in a .30, use 2400 or equal burn rate powder. 20 grains in an '06 behind a 169-grain lead gas check give about 1,800 ft/sec. Seems to be about 2,000 with a 150-grain SP jacketed bullet.

That jacketed load works okay in a .30-30, .308 and a .30-40 Krag, although it's about max in a .30-30.
 
If you want light recoil in a .30, use 2400 or equal burn rate powder. 20 grains in an '06 behind a 169-grain lead gas check give about 1,800 ft/sec. Seems to be about 2,000 with a 150-grain SP jacketed bullet.

That jacketed load works okay in a .30-30, .308 and a .30-40 Krag, although it's about max in a .30-30.
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I'll have to get my hodgdon booklet out and look at burn rates again. I haven't studied some of the basic aspects of reloading since I first got started. Thanks for the reference:D
 
As for the influence of the powder, shoot a 168 gr .308 bullet at 3400 ft in front of nearly 100 gr powder with and without muzzle brake. In the first case, the impulse of the powder gets subtracted, in the second case added to the recoil impulse.
You will notice the difference.
 
The ONLY influence of burn rate on recoil is the fact that a faster powder tends to develop velocity with less mass.

(To be sure, there are some differences at the millisecond and shorter time frame, but our shoulders feel the bump at the 100-millisecond or .1 sec time scale.)
 
simply put, add charge of powder to bullet weight to get total grains of projected material, calculate MV (speed that bullet and powder leave muzzle) and this will give you the specific amount of impulse. this same amount of impulse is transferred to your weapon. half of the utilized energy goes out the barrel, half goes back to you.

You will, beyond a doubt, find various rounds with equal impulse that will still be totally dissimilar in felt recoil.

In reality, you should think about this. I once checked with a few people about my "low recoil" loads, and really, used the same loads, but gave them better hearing protectors.

They all felt the reduction in recoil, because muzzle blast and noise were reduced when they wore the better muffs.
 
JASmith said:
The ONLY influence of burn rate on recoil is the fact that a faster powder tends to develop velocity with less mass.
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A slow burning powder that develops the same velocity will do it with less peak pressure than a fast burning powder. The delayed burning means that the powder is less efficient so you must use more of it, but, since both powders delivered the same work to the bullet, the area under the pressure curve must be the same. This means that there is more pressure in the barrel at the moment the bullet leaves the barrel on the slow burning load and that means that the powder gasses will come out of the barrel faster as well as being heavier.

A good example is comparing a smokeless 3 dram equivilent shotgun load to shell actually loaded with 3 drams of black powder. (82 grains) That smokeless load will likely only need something like 20-22 grains of some suitable smokeless powder.
That smokeless load will likely develop a peak pressure of around 9700 to 11000 psi.
That black powder load's peak pressure will likely be somewhere in the 4900 psi range.
The smokeless load uses the first foot or so of the barrel to do the lion's share of the shot acceleration and then the pressure drops off dramatically as the shot nears the muzzle, the gun sounds like a normal shotgun due to that low muzzle pressure.
The black powder uses the entire barrel to accelerate the shot using a sustained moderate pressure instead of a rapidly decreasing high pressure. The high muzzle pressure makes the gun go BOOM!!! and people comment "what kind of a cannon were you shooting out there?"
That high muzzle pressure means that the black powder gasses come out of the barrel at a higher velocity as well as having more mass. That's why a 3 dram black powder load kicks more than a 3 dram equivilent smokeless load. More powder mass AND higher propellent gas velocity. In fact, you will be amazed at how much a black powder charge by itself (no shot) will make the gun kick.
 
Originally Posted by JASmith
The ONLY influence of burn rate on recoil is the fact that a faster powder tends to develop velocity with less mass.
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Originally Posted by B. L. E.A slow burning powder that develops the same velocity will do it with less peak pressure than a fast burning powder. The delayed burning means that the powder is less efficient so you must use more of it, but, since both powders delivered the same work to the bullet, the area under the pressure curve must be the same. This means that there is more pressure in the barrel at the moment the bullet leaves the barrel on the slow burning load and that means that the powder gasses will come out of the barrel faster as well as being heavier.
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A fair percentage of black powder combustion products are solids.

Also, I will agree that muzzle pressure, as the driver for gas acceleration after the bullet departs the muzzle, has some influence on recoil.

I still maintain that the principal drivers of felt recoil between fast and slow powders are the mass of the charge, the mass of the bullet, and the muzzle velocity. In fact, most of the online and formulaic recoil calculators make that assumption by specifying either a fixed average velocity of the powder gases or a simple multiplier of the bullet muzzle velocity.

Any other differences are at the extremes where one is pushing a very light bullet with a very heavy charge. The example of black powder charge only given above is an example of that extreme where the bullet weight is taken to zero.

I also realize that my use of the term "ONLY" was perhaps inaccurate for the general case. The choice of that term was to avoid a very long winded treatise on the physics of recoil, including the effects of post exit gas acceleration. I would submit, however, that it is good enough for the context of the discussion where we are addressing conventional smokeless powder weapons.
 
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