Perception of recoil and time in motion of rifle, black powder vs smokeless powder

[mrcvs]

I have shot smokeless powder over the years, and black powder, although not as much, but never have I fired black powder and smokeless powder in the same firearm and been able to report on the differences, based on recoil. I fired a .32-40 Winchester 1894 carbine that was manufactured in 1915, so it can shoot both types of powder. There is a graph that depicts the firing of smokeless powder vs black powder in the following forum:

http://smith-wessonforum.com/s-w-antiques/347980-44-russian-2.html

I could not get the graph to copy, otherwise I would have done so. My experience is that the recoil was much milder with the black powder vs. the smokeless powder, probably because the pressure is lower. The recoil and increased pressure seems like more of an explosive reaction with smokeless powder, however, by definition, black powder burns more explosively and smokeless powder burns more combustibly. Also, the total elapsed time during which the rifle was in motion seemed considerably greater with regards to the black powder vs the smokeless powder.

Are my observations what you have experienced? I suppose the less abrupt nature of black powder in action vs smokeless powder in action is why some antique firearms cannot be fired with smokeless powder -- the jarring nature of it all can lead to destruction.

[bigted]

just an opinion from the uneducated peanut gallery;

my OPINION ...[and that is all i have]... is this... the blackpowder ignition is sudden and complete in the first thrust. it allows the pressure to build suddenly and in a place where the barrel and action complete each other as the strongest place in a firearm. this sudden "explosion" happens quickly and so fast that the boolit has little chance to move ahead enough to remove the pressure or shock wave away from the strongest area for the containment of the pressure.

smokeless however does a couple things in my [again OPINION] is this ... the powder does NOT burst into ignition in a complete manner ... rather it BURNS in a manner to build pressure over a prolonged period of time and therefore it builds pressure in a longer section of barrel and in this way the pressure is spread and added to over a longer section of the firearm. this building of pressure moves the burst point into just the barrel alone where the strength is lowered and contained in a weaker vessel. also smokeless with its prolonged 'burn' allows for the recoil to be prolonged and built in a fashion that makes it "develop" recoil after the trigger is pulled. this prolonged recoil is the evidence that the pressure as well as the felt recoil is stronger and longer making it last long enough to act as a continuous recoil lasting long enough to act different then the sudden burst of energy manufactured by the blackpowder ignition.

in addition i believe that this long burn of smokeless powder can create many shock waves behind the boolit as it travels down the barrel ... this causes a hammering effect that is so destructive to the old metal.

these are just opinions that my poor old mind has arrived at over a couple decades of contemplating this with a 8th grade education. so somebody should either object or confirm these "opinions" with more smarts then myself. i just offer these up for contemplation.

[gkainz]

Did you mean this graph?
http://img.photobucket.com/albums/v495/Driftwood_Johnson/Pressure%20Curves/pressure_curve.jpg

found some more on page 1 over on your linked page but can't link directly to them ... let's see if they will attach here ...

[mrcvs]

Yes, the top graph is the one I had in mind.

Your other graphs fail to show much difference between black powder (FFFg) and smokeless powder.

[Boz330]

I have only fooled with both in a 40-65 and a 38-55. Lots of smokeless in the 40-65 and I was trying to duplicate the velocities so that sight settings would be the same. MY experience was that the smokeless powder (Unique) that I used produced less felt recoil than the BP. I could shoot that load all day, but the real BP started getting to me after 60 to 80 rounds. Like Ted said this is just my opinion and YMMV. The smokeless powder used could have a big influence on recoil as well.
The other thing was that he was using shotgun info and I think that could make a big difference over a BPCR.

Bob

[bigted]

good to see ya here Bob. been in the world taking care of my dad after open heart tripple bypass surgery so have not had a chance to try those boolits yet. now getting ready for a move so will be awhile but i have em tucked away for future use and again ... thanks.

i also was struck by the shotgun data. i wonder if it will translate to rifle recoil as well.

[montana_charlie]

This a 'presumption' from trying to visualize the action as black powder propells a rifle bullet.

First, if you put any propellant in a closed chamber, hold that chamber against your shoulder, then ignite the contents, you will feel no recoil.
Because nothing in that chamber moves, there is no opposite movement to feel.


When you fire a black powder charge, it reaches peak pressure (I believe) before the bullet moves out of the case.
Because nothing is moving (yet), there is no felt recoil ... just as with the detonation in a closed chamber.
When the bullet does start to move, it causes pressure to drop continuously until the bullet exits the muzzle. It's possible to believe that the bullet started fast, but is slowing down as long as it's in the barrel under decreasing pressure.

Since pressure is dropping, the 'opposite movement' (your rifle) is moving rearward with decreasing force, so it feels more like a 'push' than a 'smack'.


When smokeless is used, the bullet begins to move almost immediately, so the rifle begins to recoil earlier.
And, it is moved rearward by an 'increasing' pressure in the barrel so the recoil impulse gets 'harder' (instead of decreasing) as time goes by.
When being hit by a swinging door you feel a touch of impulse as the door makes contact with you, but the intensity increases continuously until all of the kinetic energy has been transferred to you.

Similarly, you feel the beginning of the recoil early in the ignition of smokeless propellant, but that impulse increases continuously until pressure peaks with the bullet halfway down the barrel.

In both scenarios you feel it as a 'smack', I presume.

CM