Rifle movment when shoting slugs

[8thman]

The airguns that I own are as light as possible and I know that there’s a price for that. In one hand the light are easiest for me to carry and maneuver at my age and on the other hand I know that I heavier gun is more forgiving . The lighter guns to me always requires more follow through not again mention the slugs slower exiting.

 

[thomasair]

Hi Scott, 

Your analogy makes sense on the surface, but is missing some key information.

There are 2 components to recoil. Primary recoil, and secondary recoil. In simple terms...primary is the recoil produced by the actual work taking place from the acceleration of the projectile. Secondary recoil is the what takes place after the projectile leaves the barrel due to the force of the propellant (compressed air in this case) exiting the muzzle.


The law of conservation of momentum tells us that an air rifle of a given mass will produce the same primary recoil force whether it is ejecting a slug of 34gr or a pellet of 34gr at the same velocity. It doesn’t know the difference. The rearward force of primary recoil is determined by the forward force of the projectile. Here is the part that you are missing. If you have a very tight slug compared to a looser pellet....the actual extra frictional force produced by the tight slug is pushing the barrel forward (opposite of recoil) to get Itself up to the same velocity as the pellet in the same space. The forward pushing frictional force is exactly equal to the additional rearward force that takes place from the extra push needed to overcome the stickiness. Primary recoil is not changed whatsoever based on the tightness of the projectile in the bore. If it was....then the law of conservation of momentum would be proven false.


Secondary recoil, however, can be increased or decreased with the slug or pellet going the same velocity. If you turn up the hammer force to get the sticky slug up to the same speed as the looser pellet in the barrel...you will be using much more air, and you will produce “extra” secondary recoil. But again...the primary recoil force will be the same because the extra friction will balance the equation in the forward direction.

To reduce primary recoil for a given projectile weight and velocity....you could increase the mass of the rifle as Yo said. To reduce secondary recoil you must redirect the force of the expelled air and use it to push the muzzle forward. 

Mike.

 

[Motorhead]

That too makes sense ... but NOT being a highly educated fellow on such matters leaves me to SEAT of the PANTS reckoning to whats experienced in life.



THANK YOU for taking the time to clarify your thoughts !



CYA this coming weekend ... Travel safe Michael !!



Scott

 

[thomasair]

I’m looking forward to it, Scott. I will see you there.

Mike

 

[Haganaga]

I got a great deal on a Rem 700 5R 300Winmag a few years ago, paid less than a few airguns I've bought since and it came with a decent scope and a Harris bipod but I digress. I shot that thing and after 20 rounds my shoulder was black & blue. It had a threaded barrel so I ordered a JP tank brake. Couldn't believe the difference. Kicked a little more than my son's Remmy in .223. My groups closed up and I could shoot all day till the ammo was dry. While I'm not saying that the kick is that severe in airguns, the secondary recoil is what's used in muzzle brakes and in powder burners is substantial enough to counter the secondary force and severely reduce the primary one. Now doesn't the moderators counter that second pulse to a degree? Some have the shrouded barrels, some have airstrippers and some have moderators on top of that.

 

[thomasair]

When you expand air is a closed area like a shroud or a can....it presses on all surfaces equally. There is not a way for the air to be made to primarily press on the surfaces that can push the rifle forward such as a muzzle brake. The muzzle brake works because the forward moving air contacts the forward surfaces of the ports in the brake as it exits the barrel. If you put a shroud or can around the brake...you take away its effect.

There may be some reduction in secondary recoil from using a can or shroud just because there is someplace for the air to expand before leaving...but it is rather small in comparison to the effects of a open air brake. I hear people say that cans and shrouds reduce recoil but cannot prove that with measurable testing methods. 


Mike