I am new to the forum. Although my father was a well respected mechanical engineer in Minneapolis, he has passed and can no longer help. I am a gunsmith and develope and install muzzle breaks for large caliber rifles. I designed a test sled to measure the difference in recoil with and without the break. My first design used a helical compression spring from a Browning auto shotgun. It gave consistant results. But I think that a spring, as it compresses, increases in tension. Thus compairing two different calibers would not really have equal results. I tried just using weight as the as the force to overcome but results varied from shot to shot. I then attempted an excellerometer, but the available circuit board did not have sufficiant frequency responce to capture the very brief signal. I just completed testing a hydraulic one way cylinder (Bimba 124) with a Bradly flow control valve. Sadly the piston seems to have stopped working very well.
Here's a picture of the sled
The sled upper assembly holds the rifle in a cradel. the lower assembly is attached to the bench. the lower has square delrin rods attached to both sides as a race. the upper has nylon butcher block material with a channel to slide on the delrin. the sled slides rather easly.
My first question is :can a helical spring be made that has equal force through 4 inches of travel?
the second question is: would a single pully at the end of the sled, with a cable attached to a weight hanging free have a consistant travel under recoil?
Any thoughts would be appreciate. My goal is to have a portable reasonably priced piece of test gear.