Gentlemen

I’m a little embarrassed to ask this again so I hope ya’ll go by the “there are no stupid questions†motto. I figured it would be best to start a new thread to showcase my ignorance.

quote:

Originally posted by bluetick:
quote:
Chamber pressure has nothing to do with recoil energy.


Ok I know I'm not the brightest bulb here so please explain that to me.

Shawn


The Hornady loading manual, the little one that they give away for free in the gun shops, explains this.

Recoil is determined by Mv and the "ejecta weight". The ejecta weight includes the wad and the weight of the powder charge. Although the powder is converted to gas on firing it still has the same total mass and is expelled with the projectile.

I have a pair of muzzle loading shotguns. A 3 dram load is 84grs of black powder (this is were "drams equvilent" come from, a Mv that is equal to to that of X # of drams of black powder)

Although it has a similar Mv to a 3 dram smokeless powder load, and is @ a fraction of the chamber pressure, the recoil is horrendous compered to smokeless. It is not as sharp, but it sure do raise 'er up when ya "touch 'er off.

Ok now ya’ll are going to see how thick I really am. I do think I understand what you/Hornaday are saying here. But if you take say a 30-06 and look at the max load in a manual for any number of powders they are all at or around the same chamber pressure? Now if we reduce these loads chamber pressure goes down? So does recoil energy.

Dont confuse pressure (psi) and energy (ft lbs). A .223 has a higher cahmber pressure (52,000 cup) than a 30-06 (50,000 cup) but the 06 has significantly more recoil. The two are related but not in a linear fashion. Reducing pressure, reduces velocity. Recoil is a function of velocity squared and the weight of the ejecta and the weight of the gun.

A blackpowder shotgun kicks harder because it uses nearly 250 grains of powder (if I read your post correctly thats three drams times 83 grains) and a smokeless round uses a little less than one tenth of that amount. The eject weight is significantly higher but the velocity and pressure are similar.

If the barrel is plugged, the pressure can go very high, but if nothing comes out, there is no net recoil.

I knew ya'ld get me to see the light. Thanks

Shawn

quote:

Originally posted by elkhunter:
Dont confuse pressure (psi) and energy (ft lbs). A .223 has a higher cahmber pressure (52,000 cup) than a 30-06 (50,000 cup) but the 06 has significantly more recoil. The two are related but not in a linear fashion. Reducing pressure, reduces velocity. Recoil is a function of velocity squared and the weight of the ejecta and the weight of the gun.

A blackpowder shotgun kicks harder because it uses nearly 250 grains of powder (if I read your post correctly thats three drams times 83 grains) and a smokeless round uses a little less than one tenth of that amount. The eject weight is significantly higher but the velocity and pressure are similar.

3 drams of black powder is 84grs, (1 dram = about 28grs) 84 grs is still a sizable increase in ejecta weight from say 17grs in a 3 dram (equivilent) smokeless load.

The velocity is similar, but the pressure is much much lower in the black powder load. That is why damascus barrels are able to withstand black powder loads with a wider margin of safety than with smokeless.

To be honest the gun that I was speaking of, although a 12 ga. double, only weighs a little over 6 #s, therefore the recoil is horrendous. In the other ML double that weighs over 7# the recoil, though not as severe as the lighter gun, is still somewhat more than what would be expected from say a Rem. 870 (similar gun weight) with a 3 dram eq. smokeless load. The ejecta weight is 67 grs. more for the black powder load. At a similar Mv with a similar weight gun it will be more.

This is all subjective, as I posted, the recoil with the ML is not as "sharp", but I believe in theory that only reduces the perception of recoil and not the actual ft #s. There is still a lot of muzzle rise though.

Take my word for it, when I used to shoot skeet with the lighter gun, it was pretty dramatic.

Especially when it was time to find the second bird from the doubles hurtling @ me out of the cloud of smoke! It was a real blast.

Pun intended.