16ga.com ~ View topic - Does low pressure always result in low recoil?

Joined: 27 Feb 2014 Posts: 45

Sounds like a silly question, but I want to know the answer. My assumption is yes low pressure alway results in low recoil assuming the gun being fired is the same weight. Is this assumption accurate?

Joined: 26 Apr 2010 Posts: 3177 Location: NCWa

No.

recoil is a result of stuff in the barrel pushing back on the gun. A higher pressure generally would result in an equal load pushing harder, but the load is more important than the pressure.

There is NO relationship between pressure and recoil. Recoil is mass of ejecta and velocity. It is the force that flys rockets.

Member Joined: 08 Jul 2013 Posts: 325

The confusion comes about because it would seem that high pressure loads would produce higher velocities. But that high pressure might only last a few milliseconds. The low pressure load may have a higher velocity because although it's peak pressure is lower, it's average pressure is higher.

NO
The only factors are Mass And Velocity! If I move an ounce of lead 1000 fps the force of recoil is say X If I move an ounce of lead at 10000 fps the force of recoil is 10X .end of story For more complicated math look this up on Hodgdons site

Member Joined: 08 Jul 2013 Posts: 325

I agree--recoil is solely a product of mass and velocity. But lower pressure loads often produce higher velocities and that can be confusing.

Of course

Member Joined: 16 Nov 2006 Posts: 1338

Joined: 26 Apr 2010 Posts: 3177 Location: NCWa

One out of five unemployed, and everyone wants to be a physicist Rolling Eyes

Member Joined: 16 Nov 2006 Posts: 1338

Just trying to Keep it simple you are right about the 100x and now I remember that part. thanks

Joined: 15 Jun 2010 Posts: 1358 Location: Twin Cities, MN

Here is a discussion of this subject.
http://www.shotgunworld.com/bbs/viewtopic.php?f=13&t=405370
I am trained as a scientist, but not an engineer. If I understand it correctly there is a relationship between pressure and recoil, but it is neither linear nor exponential and the peak in pressure when a shell is fired occurs for such a short amount of time it is impossible for humans to perceive this. I, and others, have done trials (not controlled enough to call it an experiment) wherein I loaded 2 shells with all the same components to the same velocity, except I used different powders. In this case International Clays and Clays. No one was able to tell which shell they were shooting, including the guys who claimed they could tell these powders apart and that was why they loaded International. These folks did not believe my results. So, pressure can affect recoil, but most, if not all, of the time we can't feel it. Clear as mud. None of this will change anyone's mind.
When Longshot powder first came out a friend loaded up some 1 1/8oz 1400 fps loads at around 9,000 psi. As it was the same pressure as his 1145 fps target load he ASSUMED the recoil would be the same. Suffice it to say he could not give those loads away as the recoil was horrific. Some guys who tried them on long duck tower shots claimed that they put no lead on the targets because the shells were so fast. I didn't even bother to show them the math that at 40-50 yards their forward allowance (is that better than the dreaded lead word?) was only decreased by 4-6 inches, not yards.
Regards,
Jeff

Jeff , I THINK you are saying the same as Mike . If you load same veloc/payload load , but change the powder as you did ,vel stayed the same therefore the PERCIEVED recoil should have been the same . Actual calc recoil is probably a little different and you already know the pressure changed.

NO NEVER, one has nothing to do with the other!!!

Joined: 15 Jun 2010 Posts: 1358 Location: Twin Cities, MN

I have a friend who is a mechanical engineer who is playing with some of this math. I do believe that recoil is related to pressure, but it is a little more complicated and much more subtle than KE=0.5 M x V x V. DC - did you look at the Shotgun World thread? I might have to sharpen a pencil and look at some of this stuff myself. I would think that the artillery guys figured out a lot of this stuff decades ago. Maybe I can find someone at ATK who knows this math.
Regards,
Jeff