So which is better, the OEM bolt probe, a shaped extended bolt probe, a small diameter rod extended bolt probe, a flow through bolt probe, or a probeless bolt design? This question gets asked over and over, and again and again on our forum and many others. And while this is a pretty exhaustive test it will probably never be answered to suit everyone. But that's okay. If you do the same tests your results might vary from what mine showed. Perhaps that is just the nature of the airgun beast.
I tried to be as consistent as I possibly could with my testing so as not to taint the results. But I will tell you this right up front, I am so sick and tired of taking this gun apart that it will take me a month or more to recover, I think.

To start with I built up a basic 2240 gun but used a Crosman Custom Shop non stamped tube and a 1701P trigger frame. Everything else is plain Jane 2240 stuff including the plastic breech and the front barrel band.
I used three different chronometers but finally settled on using a cb-625 chronoscope version 2 for all the final testing. While some may pooh-pooh this let me say that as long as you don't mix apples and oranges it doesn't matter which one you use. Just use the same one for consistency. Another thing was for me and this testing it was all about convenience. Mainly because I sat in the kitchen with the sliding door open and the screen door on the back covered deck wide open so I could shoot into the woods.
For the first test I wanted to characterize the 2240 so I fired 240 pellets and used eight powerlets. I would fire 30 pellets and then change the powerlet. I used the same pellets for all my testing, JSB Diabolo Exacts weighing in at 14.3 grams.
I will begin posting the resultant data throughout the day and evening as I have time.
Carl