Five Easy Probes

[quickster47 †]

Actually, I still have my plans for a probeless bolt that could be made with some expert time in a machine shop.  I talked to some students at Tennessee Tech and we were looking at other ideas.  And then I was in contact with some of my old physics profs at Purdue but nothing came out of that.  Seems they were more interested in being retired like I was. 

Anyway, there are some other things on my plate and I may get back to all that one day real soon now in the near distant future. 

Carl

BTW, I still shoot my box stock 2240 more than any other airgun and must say I love it more and more.  But then I do have some of my other modded guns and they are still awesome too.

[Poorman Plinker]

I just saw a movie that centered around the "safety needle". This is a type of syringe that pushes into the skin and then retracts automatically. The movie was about the drama of distribution and monopoly and did not address the technology. However that might be the technology you are looking for. I too might be retired, but this is now my retirement pastime LOL

[Paul]

Thank you for taking the time to do this extensive test.
As a result I have ordered the extended probe with the hole in it,
can't wait to do some testing of my own.

[CraigH]

More great testing and information - I can hardly keep up.   8^)

I have been looking at the various bolt probe arrangements and thinking as to how they all operate, so this comes at an excellent time just as I am ready to order.

I'm not going to repeat all the information I have seen here on CAPO and elsewhere as to all the + /- of the two major styles, except to mention depth of seating with extended probes due to depth of skirt hollow, and skirt pinching with hollow probes.

So, I am thinking the best arrangement would be the hollow probe, but ever so slightly reduced in diameter and with a perhaps 45 degree relief on its end.  That hopefully to eliminate skirt pinching and perhaps even help seat the skirt itself to the chamber / barrel.

[quickster47 †]

Craig,

If you were always, forever and ever, going to use the exact same pellet in your gun then it would be easy to design an extended probe or hollow probe for the pellet.  Problem is we switch pellets quite often so we sort of need a probe that works with all pellets.  And that would be an extended hollow probe.  Properly designed it is your best choice.

Carl

[CraigH]

Thank you, Carl!

That is what I thought would be the answer.

Your tests are VERY enlightening!

[Rualert]

     Hey guys, so I'm really late this party, but great job Carl, and thanks for the data and info. Here's a though on the retractable bolt, take a page from Bob's (RSterne) book of knowledge. How about first we see if we have enough room in a standard steel or aluminum breech for a short slot back just low enough to allow the bolt to rotate down and have a lock. This slot could then be adjusted back until the front of the solid probe clears the transfer port. This may require a slightly taller breech, as I have seen it done that way but generally tall breeches that would also allow a full shroud to me added. I'm thinking stock height or maybe just a small amount taller fro those that don't want a tall breech. All of these design ideas would require I believe an o-ring groove in the back of the breech to seal the probe, thus removing the need for it on the actual probe.

Casey

P.S. Hey Ark, maybe something you have the tooling to prototype once you get caught back up. Don't remember if you have a mill Carl.
P.S.S. I may try slotting one of my stock breeches, just have to find the time.

[quickster47 †]

     Hey guys, so I'm really late this party, but great job Carl, and thanks for the data and info. Here's a though on the retractable bolt, take a page from Bob's (RSterne) book of knowledge. How about first we see if we have enough room in a standard steel or aluminum breech for a short slot back just low enough to allow the bolt to rotate down and have a lock. This slot could then be adjusted back until the front of the solid probe clears the transfer port. This may require a slightly taller breech, as I have seen it done that way but generally tall breeches that would also allow a full shroud to me added. I'm thinking stock height or maybe just a small amount taller fro those that don't want a tall breech. All of these design ideas would require I believe an o-ring groove in the back of the breech to seal the probe, thus removing the need for it on the actual probe.

Casey

P.S. Hey Ark, maybe something you have the tooling to prototype once you get caught back up. Don't remember if you have a mill Carl.
P.S.S. I may try slotting one of my stock breeches, just have to find the time.

Casey,

That's a great idea.  I have plenty of spare breechs in various configurations that can be made sacrificial lambs for this endeavor..  Also have a small mill so I'll see what I can turn up/out.

Carl

[CraigH]

Casely,

Great idea and remarkably simple concept.     It may be that the breech would only require a vertical latch farther back than the original latching point.  That is, push the pellet forward, then pull the bolt back to the new vertical latch point.  (If I hear the general concept correctly)

Carl,

The oil can (or was it tin can) returns!

[quickster47 †]

Casely,

Great idea and remarkably simple concept.     It may be that the breech would only require a vertical latch farther back than the original latching point.  That is, push the pellet forward, then pull the bolt back to the new vertical latch point.  (If I hear the general concept correctly)

Carl,

The oil can (or was it tin can) returns!

Another great idea.  Hopefully I will be able to try out one or both of these ideas later this week.  Adding another latch point may be the best approach as I was looking at a Crosman steel breech this morning and there is not a whole lot of room.  But time will show us.

Craig it could have been the can-can.    

Carl

[CraigH]

Yes, space is very limited.  For a horizontal slot and even another latch point.  Looking at the breech and bolt, which will have to be new for the enlarged probe, the bolt handle will probably need to be moved rearward on a factory steel breech.  The locking slot that Casey (not Casely  ) presented would be elegant, but I cannot see enough space, at least on a breech already machined by Crosman.

[oldgearhead]

Cool idea.

[quickster47 †]

Here's one to ponder on while I make a trip to the dentist this morning.

Carl

[oldgearhead]

Yes! The answer is in the slot, not the bolt...but sealing might be more difficult, or require a different leade design/size] 

[CraigH]

Carl,

If that breech and bolt are already fitted, about all that is needed is a properly located o-ring groove.  Definitely a hefty piece.  I would say around twice the weight (in steel) of a Crosman steel breech.

A very nice piece upon which to ponder.