You helped me out in the question of 'blow by'. Now another question.
Some people are convinced that a short barrel produces more recoil than a longer one. The argumentation is, that the escaping gasses are leaving the muzzle with much more pressure and power, than from the muzzle of a longer barrel. That could be the reason the rifle gets more throw back.
This apart from the weight of the barrel. It is obvious that a heavier barrel gives less sensation of the recoil and a lighter barrel seems to produce more.
Is there any sense that more muzzle pressure produces more recoil with the same loading specs, short versus longer barrel?

Thanks a lot,
Jan

If the shorter barrel gives you a lighter gun you well have more recoil. Less weight more recoil.

One thing you do get is more muzzle blast and that could cause you to think the gun is recoiling more.

The shorter barrel also produces more noise, and that noise is closer to your ear. The added "blast" increases the amount of recoil perceived by the shooter.

As far as the powder contribution to recoil goes, at the muzzle the pressure is in the 8000psi range with a velocity (on exit) of approx 1.5 times the velocity of the bullets. IOW I think you would have a hard time quantifying the difference in gas velocity on actual (free) recoil level (perceived recoil is not the same thing)

quote:

Is there any sense that more muzzle pressure produces more recoil with the same loading specs, short versus longer barrel?

Interesting question. Here is what QL comes up with.

I used a rifle of known weight (with a 26” barrel) in 7mm Remington Magnum. I used the same load in barrel lengths of 22” and 26”.

My original load (at 26”) produces a MV of 3,110 fps and 3,221 ft-lbs. Shorting the barrel 4 inches, the MV is 2984 fps and 2,966 ft-lbs. I don’t know how much my barrel weighs per inch but I took off a pound of weight for the 22” barrel.



Not much difference between the two barrel lengths except for muzzle blast.

To me a short barrel carries more muzzel blast. The overall gun is lighter but also the barrel is lighter. With a heavy recoil rifle the lighter barrel allows for more muzzel lift and for sure the appearance of more recoil.

I think blast is the main issue. The increased blast makes it seem like more recoil. You will have a lighter rifle which increases recoil but you have lower velocity which reduces recoil---which offset is the greatest I'm not sure. Shoot a .357 mag without hearing protection and it seems like a real tiger yet seems pretty mild with protection.

All stated as clearly as can be stated. Less weight = more felt recoil and shorter barrels = ears closer to muzzle.

Interesting subject to "hot stove" about. It's just abstract enough that there will never be a real answer. At least one that satisfys everyone.
Me? I'm not gonna cut 4" off of my magnums just to see if they kick more. The argument is kinda like the fellow that asks if he cuts 2" off the barrel of his rifle, will that make it a highly nimble woods rifle?

Thanks for your answers so far. I'm fully aware that a shorter barrel produce lots of noise, could damage your ears and give the impression the recoil increases, enhanced by the lesser weight of the rifle. Even an inforced muzzle whip could be possible.

But the question was, in fact, if the escaping gasses of the muzzle blast, with increased pressure, could induce more calculated recoil.
I know it's a rather difficult question, but I have faith in your knowledge...

J.

I don't have anything to say what is the pressure at the muzzel. Taking a 300wmag with a 180gr and full load of 7828. At 20" of bullet travel the chamber pressure is around 18000 at 26" the chamber pressure is 14000. If you assume the pressure at the muzzel equals the chamber. Taking a.308 dia Coverting that to lbs then the gas pressure would be 28% higher after 20 vs 26". I ASSUME then one could increase the gas effect on recoil by 28%. That would be an increase on probably the smallest contibuting factor.

However if powder charge was left the same velocity would drop would that offset. To keep velocity the same would require more powder in the shorter barrel.

So after all this rambling I have no clue what effect if any simple gas pressure would have.

It is a difficult question and difficult to answer.

Once the base of the bullet clears the muzzle the effect of the explosion ends. Recoil starts after the firing pin strikes the primer, which is the last forward motion of the gun until the bullet exits the muzzle and the shooter recovers. Is it possible that the escaping gasses of the muzzle blast could induce more recoil? It’s possible but I don’t know how you would measure its effect on recoil. Remember, we’re talking less than 1.3 ms from the time you pull the trigger until the bullet exits the muzzle, 26 inches away. That doesn't give you much time to collect empirical data on external events like muzzle blast.

My question to you is; do you lay awake, unable to sleep at night over things like this?

I think that felt recoil has less to do with barrel length and escaping gas than with stock design. Some stock designs kick like mules no matter the barrel length.

No, Mickin, I do not sleep less without knowing this exactly. Sometimes I wonder 'bout some matters on reloading. I am an outdoorwriter on ballistics in some hunting magazines in the Netherlands and someone came up with the suggestion that more muzzle blast (due to a short barrel - 18 inches by example) could generate more recoil. Personally I don't believe this happens, but I appreciate your input.

I do totally agree with your remark that the stock is of very much importance to withstand recoil.
Thank for your answers, Ramrod, Mickin and others!
J.

This isn't a hard question to answer. It's all a matter of pretty simple physics. As long as there is no muzzle rise, the maximum felt recoil will be related to the mass of the bullet and powder ejecta coming out of the barrel and the time over which this all takes place. Thus if there is no muzzle rise, if the weight of the rifles is the same and if the velocity of the bullet and weight of the bullet and other ejecta is the same the recoil of different barrel lengths will be the same.

Of course, in real life, it's a bit more complicated. If for reasons of stock design or load, one barrel rises more than the other under recoil, then less of the force vector will be directed posteriorly and felt recoil will be less. By the way, given the same load, muzzle pressure would be less with a longer barrel but I doubt the difference would be detectable between barrels of only 4 inches of length difference between them.

On somewhat of a digression, the stock configuration makes a BIG difference in felt recoil and a lighter rifle doesn't necessairly make felt recoil more intolerable. For example and of a purely subjective nature, the recoil of a 416 Remington Magnum I shot with a nonscoped weight of 7.5 lbs. didn't feel any worse than some 30/06 rifles I've shot.

Assuming that a barrel is long enough for all of the powder to burn before the bullet exits the barrel (contrary to popular belief, this only takes a few inches with even the slowest powders), and assuming guns of the same weight, then the energy that exits the muzzle is identical whether from a longer or shorter barrel. Even if the bullet is traveling at a slower speed when exiting a shorter barrel, the mass of the gas will be under higher pressure and will therefore exit the barrel at a proportionally higher speed.

Now note that I said the "energy" is the same. Energy and momentum (which determines recoil) are not the same thing. However, the mass of ejecta remains the same, with part of the ejecta travelling slower from a short barrel (the bullet) and part of the ejecta travelling faster from a short barrel (the gas). It would take a complex set of calculations to determine if the net moment is different, but my instinct is to say no.

Regardless of any deminimus differences the recoil from guns of the same weight should be essentially the same, regardless of the length (within reason) of the barrel.

Stonecreek--It is true in the case of a .22 rimfire that just a few inches is all that is needed to burn all the powder thus develop max pressure and velocity. Past that point you have friction and thus a velocity drop. Most larger cases you get more velocity with a longer barrel (up to a point) generally a 26" will have a velocity gain over a 24 for example. This velocity gain is from more pressure developed and increased velocity does increase recoil. Increased velocity increases energy too---they wont be equal, but energy is not the topic on this thread. This formula is for recoil factor and is a reference point not a pounds are anything. Bullet weight (in grains) + powder charge (in grains) x muzzle velocity divided by 3500 (constant) divided by rifle weight (in pounds) gives recoil factor.

recoil is largely mental -- that is, the more you anticipate recoil, the more you feel it ...

shorter barrel, at the same weight, has next to nothing to do with it.

quote:

Originally posted by carpetman1:
Stonecreek--It is true in the case of a .22 rimfire that just a few inches is all that is needed to burn all the powder thus develop max pressure and velocity. Past that point you have friction and thus a velocity drop. Most larger cases you get more velocity with a longer barrel (up to a point) generally a 26" will have a velocity gain over a 24 for example. This velocity gain is from more pressure developed and increased velocity does increase recoil. Increased velocity increases energy too---they wont be equal, but energy is not the topic on this thread. This formula is for recoil factor and is a reference point not a pounds are anything. Bullet weight (in grains) + powder charge (in grains) x muzzle velocity divided by 3500 (constant) divided by rifle weight (in pounds) gives recoil factor.

Actually, the increased velocity is NOT from more pressure but merely from a little more time for the expanding gasses to work on the bullet. The maximum pressure developed would be the same in a long vs a short barrel, provided the barrel was long enough to burn all the powder, and pressure would be a little less in the longer barrel at the time the bullet exited it. Also, when you're talking about 2 inches in barrel length in a longer barrel where an inch gets you an extra 15 to 20 fps in velocity, the resultant number from such a small velocity change will be very small compared to the others.

Another possible reason could be that the shorter barrel is stiffer and does not soak up as much of the recoil vibration, thus more felt recoil.

quote:

Originally posted by jeffeosso:
recoil is largely mental -- that is, the more you anticipate recoil, the more you feel it ...

shorter barrel, at the same weight, has next to nothing to do with it.

I have a mental block with the 500 NE!

Muzzle blast contributes about 40% of the recoil by vertue of the 'rocket engine' effect. Fit a decent muzzle blast suppressor and recoil 'goes away'. That's because the muzzle blast that used to contribute to recoil is now 'pulling' the gun forward. (I'm not talking muzzle brake but suppressor-brake).


This rifle has one which adds 50mm to the overall length. It reduces muzzle blast considerably and muzzle flash completely - even in the dark - and reduces recoil to the extent that no buttstock to shoulder contact is necessary. It's a 303 Brit - a rifle without one and with firm shoulder pressure cut my eyebrow! It works better with slower powder with more muzzle blast. So effectively, a longer barrel may or may not have less recoil depending on whether the muzzle pressure reduction has a greater or lesser effect than the increase in buller momentum a longer barrel gives. ramrod340's graph illustrates this. Don't underestimate the thrust generated by the escaping gasses at the muzzle. Apparently bullet acceleration continues to a lesser extent after it has left the muzzle by the gasses impinging on it's base. (For a very short distance).