Five Easy Probes

quickster47 † · March 25, 2013, 03:59:47 PM

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

droid · March 25, 2013, 04:05:40 PM

I'm looking forward to this Carl, I have never been convinced that the probes make a major difference. So you will settle the argument with this for me.

quickster47 † · March 25, 2013, 04:09:10 PM

Quote from: droid on March 25, 2013, 04:05:40 PM
I'm looking forward to this Carl, I have never been convinced that the probes make a major difference. So you will settle the argument with this for me.

You will be surprised at the results and what ends up being the best probe as far as increased FPS. I know I was.

Carl

droid · March 25, 2013, 04:11:14 PM

To be honest Carl, I was under the impression that the standard bolt can outperform some of the so called "upgrade" ones, so I will wait and see.

quickster47 † · March 25, 2013, 04:23:56 PM

So the first results I will show are the average of those 240 pellets fired in batches of 30 pellets at a time. This gun is not a hot shooter and I really suspect it is in the middle of the production bell curve. Some will be better and some will be worse.

This is the OEM bolt/probe in brass as it come from Crosman. Nothing done except a tiny drop of Pellgun oil on the o-ring.

Carl

Tater · March 25, 2013, 04:26:58 PM

Cool tests, can't wait to see the results.

crossliner · March 25, 2013, 05:14:07 PM

Quote from: Tater on March 25, 2013, 04:26:58 PM
Cool tests, can't wait to see the results.

Same here

airguns100 · March 25, 2013, 05:19:50 PM

Nice test, Carl. I'm really glad your doing this. Super interested in finding out what you find here.
I'm going to guess, and say second from the left in the photos "extended skinny probe" might allow for greater flow. I can't wait to see.

breakfastchef · March 25, 2013, 05:20:45 PM

I am leaning toward your choice.

Quote from: airguns100 on March 25, 2013, 05:19:50 PM
Nice test, Carl. I'm really glad your doing this. Super interested in finding out what you find here.
I'm going to guess, and say second from the left in the photos "extended skinny probe" might allow for greater flow. I can't wait to see.

quickster47 † · March 25, 2013, 05:37:16 PM

The second results are from the average of 240 pellets fired in batches of 30 pellets at a time using the shaped brass extended probe. Again the only thing done was a tiny drop of Pellgun oil to the o-ring. I also changed the powerlet after each 30 shots.

Carl

droid · March 25, 2013, 05:39:20 PM

Well I was wrong already. Good difference on just these two

HappyHunter · March 25, 2013, 06:02:31 PM

Thanks for taking the time and doing all the legwork on this, Carl

I'll be keeping an eye on this one for sure!

Quote from: airguns100 on March 25, 2013, 05:19:50 PM
I'm going to guess, and say second from the left in the photos "extended skinny probe" might allow for greater flow.

That is my guess too. Hope it's right seeing as that is the one I use in all my guns!

Todd

Cross Pistol Packer · March 25, 2013, 06:26:07 PM

The results of the flow through bolt I will be most interested to see Carl.
Fitted to my 2260,it leaves little room to load a pellet,if I dont have a good power increase over stock bolt its history.

KevinP · March 25, 2013, 06:44:54 PM

Awesome test so far ...

quickster47 † · March 25, 2013, 06:52:42 PM

Here are the results from the third test. These are the average of 240 pellets fired in batches of 30 pellets at a time using my homemade extended probe made from a piece of 0.081 stainless rod. Again the only thing done was a tiny drop of Pellgun oil to the o-ring and also a change of the powerlet after each 30 shots. I tried to make this probe the same length as the brass probe to keep the testing consistent although I'm not too sure it makes much of a difference once the pellet is seated in the rifling past the transfer port.

Carl