recoil

[oomcurt]

I've been tryin to wrap my mind around this for some time.... My belief is recoil is not felt until the round has left the barrel, yet, others I have talked to say not so...it is generated as soon as the powder ignites. I would welcome feedback on this. Also...in a different thread it has been mentioned that the rate of twist seems to have a bearing also...I dunno...seems to me as soon as the round starts it's rotation, which is immediate when ignition has begun...it shouldn't make any difference. My reasoning is until the projectile leaves the barrel...the whole reaction is contained inside the barrel.... Opinions please....

many thanks,
Curt

[Flint62Smoothie]

Newton's 3rd law ...

[size=150]    For every action, there is an equal and opposite reaction.[/size]

It doesn't matter that it initiates in the barrel, or 'closed' system ... as in truth, it isn't a closed system at all.  To put it simply, the projectile could NOT move forward within a resultant force moving backwards.  I know why you would reason the way you do, and I am sorry if I can't explain it any better, but know that the recoil moment is initiated upon the start of the ignition process.

BTW, 'felt' recoil and the true recoil forces (re: from interior ballistics) are an entirely different subject.  Barrel weight, stock length AND DESIGN, plus your build and stature, etc.  are but a few of the factors that bear on one's ability to feel or tolerate recoil.

There are 4 studies of ballistics with projectiles:
* Internal ballistics, the study of the processes originally accelerating the projectile, for example the passage of a bullet through the barrel of a rifle;
* Transition ballistics, (sometimes called intermediate ballistics) the study of the projectile's behavior when it leaves the barrel and the pressure behind the projectile is equalized.
* External ballistics, the study of the passage of the projectile through space or the air; and
* Terminal ballistics, the study of the interaction of a projectile with its target, whether that be flesh (for a hunting bullet), steel (for an anti-tank round), or even furnace slag (for an industrial slag disruptor).

[Fletcher]

yeah what he said.....

Just remember if you shot your ML from outsdie the space shuttle, you would go backwards just as fast as the roundball went forward just as soon as you pulled the trigger.

The good news, you would not feel a bit of recoil.

The bad news - you are the recoil and it may be a bit hard to get you back since you weren't tied down!

The rest of the story, you would not make any noise either!

[vermontfreedom]

recoil starts on ignition

tell, do you think you'd feel the recoil if firing a shot from a barrel thats 50 feet or 50 yards long at ignition or when the bullet leaves the barrel?

you would feel the recoil long before the bullet leaves the barrel

perhaps the reason you think it doesn't start until bullet exit is because of the extremely short length of time in the firing process between ignition and when the bullet leaves the barrel for normal sized barrels

[ridjrunr]

I've always considered it to be a matter of resistance.Like if yer round ball weighd say 300 grains and then the next one weighd 900 grains  (and both were shot with the same charge)well there is more resistance to move that weight forward,thus more recoil.At a trail shoot last year a guy double balled and when he shot all people in the group said " double ball" because we felt it in the ground.Maybe captchee remembers that(I think it was Daisy?)Thats my thoughts anyways.ridjrunr good thread

[Wyoming Mike]

I agree pretty much what everyone else said.  The recoil starts when the powder is ignited.   I found this out years ago when I got a bronze brush stuck in my barrel.  The whole end had come apart so there was nothing to get ahold of.  I was still pretty green and had no clue how to get the thing out of there.

I decided to blow it out.  I went to the range and put in about five grains of 4F and touched it off.  The brush didn't come out but I felt a little bit of recoil that told me that the brush had moved a little. If followed that up with a ten grain load and popped the brush out.

A gun is just a simple heat engine.  When the powder goes off it is accelerating the ball from rest to 1000+ feet per second in the space of your barrel length.  That is the action.  The reaction is that acceleration working in the other direction, recoil.  The reaction is going to happen as long as the ball is accelerating in the barrel.

Rifling affects recoil in that it is adding angular momentum to the linear momentum of the ball.  This adds a little bit to the linear recoil and adds a little bit of torque.  It not much in a slow twist rifle but the effect can be felt when you are shooting magnum pistols.  These have a fast twist and a lot of velocity and you can feel the pistol try to twist in your hand.

[Captchee]

Basically what everyone else has said . Recoil starts at the time of ignition , be it  muzzleloader or other . Its caused by the  force needed to move the  projectile  which is in constant resistance  even once its moving .
 This is why rifling also plays a roll . The faster the rifling , the more resistance is imparted to the projectile .  When the projectile leaves the barrel  there is no more back pressure being imparted

[oomcurt]

My thanks to all who replied....finally I understand it.

[Uncle Russ]

Basically what everyone else has said . Recoil starts at the time of ignition , be it  muzzleloader or other . Its caused by the  force needed to move the  projectile  which is in constant resistance  even once its moving .
 This is why rifling also plays a roll . The faster the rifling , the more resistance is imparted to the projectile .  When the projectile leaves the barrel  there is no more back pressure being imparted

I agree with Charlie on this. The rate of twist does make a difference in recoil, just as he explained.....

I will add that many folks often say only added weight, with the charge and all else being equal, will make the recoil stronger.  

However, what they forget is that once you have a round ball that weighs "x", then you must extend the length in order to add weight, extending the length extends the bearing surface, and the longer the projectile, the tighter / faster the twist required to stablize it, and the tighter the twist, the longer the dwell time (due to increased resistance), and all this amounts to more felt recoil.

(General Julian Hatcher has some wonderful notes on this in Hatcher's Notebook. If you are like me, you may have to read it a half-dozen times to get the grasp of it, but this book is one of the greatest ever written on the subject of ballistics for sportsmen.)

Uncle Russ...

[Kermit]

So then can one posit that given all other variables being controlled and equal, a smoothbore would impart the least recoil?  

[Captchee]

if all being the same . same caliber , same stock desgin  same patch  shooting the same projectile , then yes a smooth bore would be  slightly less in recoil . but only slightly

[Loyalist Dave]

What the topic is currently discussing is really felt or perceived recoil is it not?  In 1804 it was noted in England that faster twist in American Rifles (compared to the Baker's 1:120 twist rate) gave an unpleasant recoil.  What was being observed was the torque that resulted from the ball's inertia vs the twist in the barrel.  That's one factor.  Try shooting a patched 7/8 ounce ball from a Jaeger, and then shoot the ball without a patch, and finish with 7/8 oz of shot, and you will find three different recoils, while using the same mass and same amount of propellant.  (Albeit a crude test, but it does work)

Another factor is, as was mentioned, stock dimensions, and shape, to include the size and shape of the butt of the firearm, and the butt plate.  Wider, with rounded edges, will exert the backward force over a larger area on a shooter = less pounds per square inch, so less felt recoil overall.

LD