Five Easy Probes

[JEBert]

It would be much easier to design a bolt with an end that just directed the air to the front without regard to placing the pellet.  Then have a hand-held probe that would push the pellet in, perpendicular to the bolt to a point just ahead of the transfer port.   You wouldn't need to close the bolt on it, just have it the right shape to fit into the chamber and length to push the pellet to the right place while the bolt is open. The hand-held piece might have to be held to the gun with a lanyard to keep from losing it.
Cheers,

[ped]

i used to use an old allen key(hex driver) cut down to so that it  pushed the pellet past the port i then got a hollow probe and never used this method(i didn't have a chrono so i never new how well this worked)
ped

[JEBert]

i didn't have a chrono so i never new how well this worked

How was the accuracy?

[BerkshireHunter]

Just stumbled on this, great testing. Never thought the different probes would make that much difference. (And I thought a stock 2240 was closer to 450 fps) Each gun's different.   

[quickster47 †]

Each gun can be very different.  Also, Crosman advertises the 2240 as "Up to 460 fps" but they never ever list the actual pellet and pellet weight they use to achieve that velocity.  Heck, with a Prometheus alloy pellet I can get 550 fps but it won't have much stopping power because the pellet is so light.

Carl

[Cwlongshot]

Just stumbled on this, great testing. Never thought the different probes would make that much difference. (And I thought a stock 2240 was closer to 450 fps) Each gun's different.   

Same here!!  I have been searching the web for this kind of info. Very nice to find it right here at home!  Yesterday I modified my own probe on my '77. I was going to remove the factory brass .010 beyond the O ring. But after drilling decided to just thin it to give support for the steel probe. BUT all I really needed to do was drill deeper for that support.   

I have picked up a couple more probes and will mod one for my 2240 too. 

I agree it would be a crying shame if this post was not stickied!!

THANK YOU SO MUCH for all the effort and expense providing this information for all who follow!!! 

[Colt25]

Both my 13xx guns have OEM bolts that I have filed down the probe on a lathe.

~5 fps increase. It's laughable.

[splat]

Just found this, VERY interesting and thanks for all your work.
It seems to me that the perfect answer would be for someone at Crosman to design a gun where the bolt is the valve/gas store.
pull bolt back and it connects at rear to accept a charge of gas, push forward and lock. then bolt contains one shot worth of gas.
No transfer port to snag, no directing gas through two 90 degree turns to get it behind pellet.
lol who knows one day they may make the perfect gun (probably the day before they become obsolete in favour of laser blasters).
again thank you. ATB.

[arkmaker †]

Just found this, VERY interesting and thanks for all your work.
It seems to me that the perfect answer would be for someone at Crosman to design a gun where the bolt is the valve/gas store.
pull bolt back and it connects at rear to accept a charge of gas, push forward and lock. then bolt contains one shot worth of gas.
No transfer port to snag, no directing gas through two 90 degree turns to get it behind pellet.
lol who knows one day they may make the perfect gun (probably the day before they become obsolete in favour of laser blasters).
again thank you. ATB.

That would be an Air Force gun...... also would take all the fun out of modding these bad boys!! 

[Gipper49]

I realize I am kinda late to this party but how about a 2 prong fork type probe?  The 2 prongs would be perpindicular to the breech when loading then parallel(sp?) when loaded.  Or think of it as a slotted flow through bolt.  Then you could taper the slot for best flow.
If that still doesnt make sense make a Peace sign and then flatten your wrist.

Brian

[quickster47 †]

Brian that sounds like an interesting idea.  Make me one and I'll do some free testing for you. 

Carl

[The Robin]

Just been reading through this thread as a newbie, very interesting reading and also great work on the testing 

[sshewins]

Hey Carl, thinking in terms of cavitation of airflow, how does this idea sound. A hollow probe, BUT, instead of just drilling  it per se, use a round dremmel type bit and only going as far as necessary to meet up with the port opening. Basically, like porting and polishing on a hot rod engine.

My minds eye has a perfectly smooth air pathway.  Take more work to do, but perhaps the benefits would be similar to your oil can set up, and slightly more practical.

[arkmaker †]

Hey Carl, thinking in terms of cavitation of airflow, how does this idea sound. A hollow probe, BUT, instead of just drilling  it per se, use a round dremmel type bit and only going as far as necessary to meet up with the port opening. Basically, like porting and polishing on a hot rod engine.

My minds eye has a perfectly smooth air pathway.  Take more work to do, but perhaps the benefits would be similar to your oil can set up, and slightly more practical.

I like it

[quickster47 †]

Hey Carl, thinking in terms of cavitation of airflow, how does this idea sound. A hollow probe, BUT, instead of just drilling  it per se, use a round dremmel type bit and only going as far as necessary to meet up with the port opening. Basically, like porting and polishing on a hot rod engine.

My minds eye has a perfectly smooth air pathway.  Take more work to do, but perhaps the benefits would be similar to your oil can set up, and slightly more practical.

I like that idea also.  Will give it some serious thought.

Carl