Five Easy Probes

[breakfastchef]

Who'd have thunk it. This being the case, the lack of any object in the path of the airflow provided the highest fps. Kind of make sense.

OK, wait!! Let me make sure I have this correct. You use the probeless bolt, add the drum, add the pellet and lock it in, then open and remove the drum and re-lock and fire??


Is that right??
Rich

[mrb02334]

Carl, you have done some great work. I personly would like to thank you for the time and expense that you spent on this project.
So how long berore your one piece oil can bolts are aviable? I don't need a bolt handle, I have a screw driver that will fit in the hole!
Thanks again for your work.
Jon

[ped]

when i first got my as2250 i read about extended probes well not having one and being brought up with  mend or make do mentallity and being pretty resourceful i used to seat the pellet further into the barrel with an allen key i'd cut down
now wether this brought any gains i don't know because i didn't have a chrono at the time ,i then got a gmac hollow probe and haven't used this method since
might have to try this again
ped

[eric]

excellent work carl --- was there any variation in temps between those tests  ??

[quickster47 †]

So let me clarify this...the oil can was removed after setting the pellet? Or it is an integral part of the bolt that remains in place during the firing sequence?

OK, wait!! Let me make sure I have this correct. You use the probeless bolt, add the drum, add the pellet and lock it in, then open and remove the drum and re-lock and fire??

Is that right??
Rich

The 'oil can' is removed after seating the pellet.  The 'oil can' is not part of the probe, it is only used to push the pellet past the transfer port into the rifling and then removed.

The bolt is then closed again to seal off the transfer port and the entire air path to the rear of the pellet is clear.

Carl

[quickster47 †]

excellent work carl --- was there any variation in temps between those tests  ??

All the shooting was actually done from inside the house with the sliding back door open to the outside about 12".  Outside temperatures varied from 39 to 50 degress over the fours days of shooting/testing.  Temperature inside was 68 degrees.

No rain any shooting days and three of those days was sunny, but cool.

Carl

[Brent]

Just got a chance to see this. Very Cool!! Thanks Carl!! 

It so does make sense that with nothing at all in front of the pellet, that would perform the best. Never thought that far on it, but it so makes sense (just talking out loud... I know and realize you guys are already there. GOOD idea to try that Carl!).

I always thought the smallest diameter extended probe possible, like the wire probe, would do the best... If only by virtue of less air resistance. That does not necessarily play out here by much, but I am still leaning that way... and the last test seems to support that.

The thoughts/ thinking on a hollow probe versus an extended probe, being very much about the same... are proven here some more. That is good to finally know for sure!

There are thoughts that at higher pressures the hollow probe wins out. Hummm

So after stating the obvious (sorry guys... just glad I finally got to see for sure)... I am grateful for all the time and expense spent on this! "Thanks Carl"

[airguns100]

Yeah, i was wondering what the large round probe -oil can- was. So basically not having any probe proved more flow. I guess the next test would be what probe produces the most accuracy.   
I currently use D.C's SS tear drop shaped probes, and i'm going to assume it flows similar to the brass extended probe.

Great work, carl. I'm glad some one finally did that. 

[arkmaker †]

Thanks Carl!! That was an awesome time consuming test for you.


You should sticky this thread    It is worthy of "Stickiness". People are going to keep asking about probes for a long, long time to come.


Rich

[Brent]

Thanks Carl!! That was an awesome time consuming test for you.


You should sticky this thread    It is worthy of "Stickiness". People are going to keep asking about probes for a long, long time to come.


Rich

Yep... So true.

So let's go from here....
What do we use as the very smallest diameter, strongest wire possible... that we can drill out the end of our stock bolts for, and mount into them? I am really not sure?

[quickster47 †]

Good idea Rich simply because it does get asked over and over.

And as mentioned, the best probe appears to be one that just puts the pellet in front of the transfer port.

However, with that thought still in the air and looking at the results of the probeless (disappearing 'oil can' probe) bolt, I am getting an idea for a new fangled bolt that might just be a winner.

Carl

[arkmaker †]

All in all, I still like the hollow tip probe for the fact that it seems to make loading easier for me. I'll give up a few fps for the theory that the skirt gets pushed in square. Knowing that I am only a few fps off helps re-enforce my preference for it. Cause, I am not patient enough to remove the oil drum each time!!

[quickster47 †]

Yep... So true.

So let's go from here....
What do we use as the very smallest diameter, strongest wire possible... that we can drill out the end of our stock bolts for, and mount into them? I am really not sure?

For my extended probe I used some 0.081" stainless steel wire.  That size was probably the largest size that could be used safely without collapsing the inner walls of the o-ring groove.

I'm sure you could use some 0.0625" (1/16") stainless wire and get away with that size too.

Perhaps someone has already used a smaller size and will chime in here.

Carl

[Brent]

All in all, I still like the hollow tip probe for the fact that it seems to make loading easier for me. I'll give up a few fps for the theory that the skirt gets pushed in square. Knowing that I am only a few fps off helps re-enforce my preference for it. Cause, I am not patient enough to remove the oil drum each time!!

That's a really good point Rich! A square pellet would seem to shoot more accurately with the pressure hitting it evenly!

I am so not sure in asking this... for discussion by those that know better than me - but if we used something small in diameter to push the pellet in past the transfer port... does the lead in of the barrel up into the rifling... allow for the pellet to become, and/ or load not square at that point?

Can't wait to see your "new fangled bolt" design Carl!! 

[targettgii]

That must have been very tedious work Carl thank you very much for your hard work.