if there is any news on the 2012 Codfish Challenge?

dr_subsonic's pneumatic research lab

the Lunatic Fringe of American Airgunning
Southwest Montana's headquarters for Airgunning Supremacy
Proud Sponsor of team_subsonic

...today I have been tinkering and running some chrony numbers. Got the valve cut down and re-oringed. Using the stock stroke (7-5/8") getting a pretty constant 333fps +/- a few fps using 7.9 grain pellets. However, after shooting at targets, I do believe it is a bit hotter than that fps mentioned. Later, I will run the chorny using lights to be certain an accurate reading is computing. The sun right now, due to the time of day and seasonal position, is at an angle enough to make me think wrong computing is suspect. Also, using the stock pump seal, which is essentially making the valve bigger in storage volume due to the conical face; a flat face is needed.

Now, the max stroke that can be had out of this Benji project is right at 10".

If this does not work out, I have purchased the other parts to turn the rifle into a few stroke/pump carbine, yet yield high velcoity. Purchased several Benjiman HB inlet valves to make flat faced valves. The difference in overall valve length between the 397 valve and HB valve will allow the pin holes to be moved back down the tube tus allowing a shorter gun. Will make (have one made) a flat faced piston to accomadate the valve.

"The majority of things in our lives are created by folks no smarter than the rest. Afterall, the world is comprised, and operated by C average people intellctually, academically, and morally. These people are often the great pioneers that set the precedent for what excellence should be."

its really gonna come down to a few fps im guessing + or -20


"i never was much for book learnin"

So Phil still has quite a-ways to go.

But I'm not counting any unhatched chickens - yet! LOL!

Steve

Decided to respond as I was ready to post here. Well, chrony was a liar earlier today. The figure is around 445fps, average - WITH a fatory stroke of 7-5/8". As it stands, the gun mods are NOT ready to go by any means. What is going on is the testing only phase (testing of actual application compared to the arithmatic theory). What I have done is use a factory piston and a factoy piston head with shims between, meaning I have to shake the piston down to ready it for air. The tension of the hammer keeps the valve open so drawing the piston out is a snap (no vacuum).

You guys want some proof?

"The majority of things in our lives are created by folks no smarter than the rest. Afterall, the world is comprised, and operated by C average people intellctually, academically, and morally. These people are often the great pioneers that set the precedent for what excellence should be."

"i never was much for book learnin"

Steve

Wouldn't figure you'd look like that, Steve. Engineers tend to be a little eccentric, tend to wear eye glasses, are very bright people, and live happy semi-retired lives.

Here in a bit I'll post some pics of the 397 exhaust valve and a video of some chrony work. Can't figure out how to get pictures off of the new phone I got (Blackberry Curve). Suppose smart phones are for smart people afterall. Huh, who would have thought. The video can be done via my laptop. Getting things set up now.

Oh, you will like this. After some work, using the stock piston travel, the gun is putting out in the high 480's as of right now. After the telescopic piston is made to travel the additional couple inches,I suspect things will be in proper order. Blah!!

Figure to be fair, first it must be tried to get some high figures using the stock piston travel. With the current setup, the piston cup conical void is acting as the storage vessel.

"The majority of things in our lives are created by folks no smarter than the rest. Afterall, the world is comprised, and operated by C average people intellctually, academically, and morally. These people are often the great pioneers that set the precedent for what excellence should be."

Steve

pics of anything?

dr_subsonic's pneumatic research lab

the Lunatic Fringe of American Airgunning
Southwest Montana's headquarters for Airgunning Supremacy
Proud Sponsor of team_subsonic