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I've reformatted a remarkable post to the old Fun Supply Forum, Ken Pang has done a huge amount of work relating to the durability of air rifle springs, as you can see from the choice of rifles it was a few years ago. Sadly as neither I nor any of the current members of the Yellow Forum, the successor to the Fun Supply forum, have been able to contact Ken this is posted with out his explicit consent. If you know how to contact Ken please let me know !!!! How long do you keep your springer cocked? Here's a test.December 28 2001 at 10:04 PMPosted by Ken Pang on December 25, 1999 OBJECTIVE: To determine the effect on a mainspring if airgun is left cocked for an extended period.Preparation: Airgun was disassembled, thoroughly degreased, examined, lightly lubed with a mixture of Silicone oil & moly, then reassembled.Procedure: After reassembly, airgun was fired 10 times to eliminate any excess lubricant which would contribute to dieseling.Muzzle velocity in FPS recorded at each period in time was the average of 5 shots.
At each period, gun uncocked and left uncocked for 72 hrs to allow the spring to regain as much as possible of its original power (memory effect). The gun was cocked and uncocked a number of times to get the cylinder walls lubed and then 2 shots fired over a chrono. The average of these 2 shots were taken. All pellets have been sized and weighed then batched according to weight. All pellets used in this test were of uniform size and weight. All airguns were .177 cal and all velocity readings are in feet per second.
While the percentage reduction in m. velocities varied, reduction was generally around 25% of original m. velocity taken prior to commencement of test. It should be noted that these percentage decreases are theoretically optimistic as the air gunner would more likely experience reductions in velocity greater than the statistics shown here. Dieseling, weight & size (diameter.) of pellets used, improper lubrication, temperature, conditions of usage etc. can all have an adverse impact on the life and power of a mainspring. This test does show that leaving a spring airgun cocked, no matter for how long, will adversely affect the life and power of any mainspring. Custom springs will be more resistant to decrease in power but the process will still occur over a longer period of time. I do not suggest that you change the ways you hunt but I point out, as Tom Gaylord has done very well, that be prepared to pay the price of higher maintenance. Comment From R Best.While one hour doesn't seem too horrible, the figures from 2 hours on are disturbing. It also agrees with an experience I had with a C-1 (Webley Vulcan). The gun had been left cocked---on a gunrack in someones pickup truck-- for two weeks. When I tested it afterwards, it was down more than 150 fps with Premiers. Pissed me off ! I wound up buying a new spring from Beeman because of this. RBThis is why don't keep mine cocked for more than 1/2 hour at a time. (Rus is one of the US's leading airgunsmiths). I regard Ken's effort as quite remarkable and very valuble as it shows BY TESTING what effect leaving a springer cocked has on the rifles FPS and I would rather it wasn't lost in the depths of a forum. |
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