Thursday, August 17, 2017

Shooting a spring powered air rifle

To an Airgun Friend
I was aked the other day why an airgunner could not shoot his new Gamo and well as his "Old .20 caliber".   This is my response.

Those .20 caliber pump air rifles of our youth were the high point of American air rifles, and they still influence our approach to air rifles.

Those air rifles shot with a simple mechanism. A spring and a hammer are retained by a trigger. Release the trigger and the hammer strikes the firing valve stem, opening the valve, and air rushes into the barrel, propelling the pellet out the barrel. The power came from a pump built into the rifle. The pump pressurized the air before the shot is fired.

A century of shooting these air rifles left American airguners with a sense that an air rifle was like a scaled down .22 rim fire.  Now that spring/piston airguns have become popular, that sense has been challenged. With spring powered guns, like your Gamo, some new shooting techniques are needed for good results.

Spring/piston airguns have an entirely different firing cycle. They carry their pump behind the pellet rather than under the barrel. Well before the shot, a spring is compressed behind a piston. The spring drives the piston to compress the air after the trigger has been released. There are no valves, just two seals that only hold pressure for micro seconds. This is an elegant system, but elegance comes with a price.

The pellet doesn’t leave the barrel before near the end of the piston’s stroke. The piston can bounce off a rebounding wave of compressed air near the end of the compression cycle before it is finally stopped by the end of the cylinder.  This sets up forces that weren’t there in that .20 pump air rifle, and they all happen before the pellet leaves the barrel

You can shoot that .20 like a .22 rim fire. Hold it firmly from trigger squeeze to follow through. Steady the rifle on a tree trunk or a fencepost and it will reward you with a good shot. Shoot a springer that way and your heart will be broken. Springers aren’t bad. It only means that your shooting technique has to accommodate the springer’s Newtonian world of action and reaction.

Isolate the action reaction cycle with your hands. Grasp the rifle lightly. Let it pulse in your hands during the shot cycle. Don’t rest it on a hard surface unless your hand is between the gun and that surface. Generations of airgun hunters and plinkers in Europe have done excellent shooting with spring piston airguns, and you will too.

Good shooting,