Need help sealing TP on my .30cal 2240.

[BigBird]

2 is probably good for the caliber and valve.  I'm interested in the power out of a 5" and available air. There is a total FPE limit to the 2240 tube of course.  I would think that the valve (not your air supply) would be good for heavier bullets but maybe not the barrel twist (accuracy). Probably a good twist for round ball though.  If it is a dispatch gun it probably serves its purpose.  A 2260 tube (safely set up and tested) would get you more shots but look kind of odd without a barrel extension.

Some might suggest pinning the original valve (?) and trying CO2 or bulk filling.  I think the shot count may be better.  Not good for winter shooting though.

Did you thread the barrel on your lathe?  Do you have the rest of the FX barrel?  Maybe there is a 2260 or Disco tubee project in there too.

[Rob M]

on co2 hed barely be tossing the pellet, maybe 200 fps on a 5 inch barrel.. at 3600 psi , he will likely get decent velocity. 5 inches is super short..Wyoman built one recently , cant rememer his barrel length , but it was co2 ..i think he was getting 330 issh

[Backyard Shootr]

on co2 hed barely be tossing the pellet, maybe 200 fps on a 5 inch barrel.. at 3600 psi , he will likely get decent velocity. 5 inches is super short..Wyoman built one recently , cant rememer his barrel length , but it was co2 ..i think he was getting 330 issh

Wyomans barrel was 5.6 inch and around 315 at 9.5 FPE. I haven't really measured my barrel just was guessing about 5 inches. I will check and see. I should be able to get a little bit better numbers being on HPA.  Just checked my barrel is 6 inches.

[sfcnewy]

Very nicely done!!

[mackeral5]

Very neat build. 

[Rob M]

on co2 hed barely be tossing the pellet, maybe 200 fps on a 5 inch barrel.. at 3600 psi , he will likely get decent velocity. 5 inches is super short..Wyoman built one recently , cant rememer his barrel length , but it was co2 ..i think he was getting 330 issh

Wyomans barrel was 5.6 inch and around 315 at 9.5 FPE. I haven't really measured my barrel just was guessing about 5 inches. I will check and see. I should be able to get a little bit better numbers being on HPA.  Just checked my barrel is 6 inches.

i think on 3600 the numbers will be pretty good.

[mackeral5]

on co2 hed barely be tossing the pellet, maybe 200 fps on a 5 inch barrel.. at 3600 psi , he will likely get decent velocity. 5 inches is super short..Wyoman built one recently , cant rememer his barrel length , but it was co2 ..i think he was getting 330 issh

Wyomans barrel was 5.6 inch and around 315 at 9.5 FPE. I haven't really measured my barrel just was guessing about 5 inches. I will check and see. I should be able to get a little bit better numbers being on HPA.  Just checked my barrel is 6 inches.

i think on 3600 the numbers will be pretty good.

I think you are right.  The difference between 3000 and 3500 is very significant, and becomes even more significant with shorter barrels.

The only concern is getting 2 viable shots with the Cothran valve and such a short barrel and tube.  Being the .180 valve will indeed help, but getting the valve to close fast enough may be a challenge. 

[Backyard Shootr]

Had to take the gun apart to work on a leak and finally measured the barrel. It is 6 1/4 inches. So it's official. Just for the records. 

[BigBird]

I think you are right.  The difference between 3000 and 3500 is very significant, and becomes even more significant with shorter barrels.

The only concern is getting 2 viable shots with the Cothran valve and such a short barrel and tube.  Being the .180 valve will indeed help, but getting the valve to close fast enough may be a challenge.

Maybe a disco valve and put this to use for a rifle length tube?  I think a hogged out disco valve or another magnum valve with a light but swift hammer at the 3600 psi would do a little better.  However I'm all for extreme power.

Edit.  Nevermind this is a cothran tube which is smaller ID right?

[Hobbyman2007]

The Cothran tube has the same ID as the Crosman tubes. They are however a bit thicker. I would never put more than 3k psi in a crosman tube. Even with the valve secured properly with three screws I still pucker a bit when filling to 3k.

[Backyard Shootr]

I do have a Magnum Air valve that I can use if the Cothran valve doesn't work out. I talked to Don about what I wanted to accomplish and he's the one that suggested that I pump it up to 3500psi. He's very confident that his tubes can handle the extra pressure. After all he is the man that builds those 45cal monster pistol. And I'm only looking to get two good shots.   

[mackeral5]

I do have a Magnum Air valve that I can use if the Cothran valve doesn't work out. I talked to Don about what I wanted to accomplish and he's the one that suggested that I pump it up to 3500psi. He's very confident that his tubes can handle the extra pressure. After all he is the man that builds those 45cal monster pistol. And I'm only looking to get two good shots. 

I would just test and see what happens.  3500psi, short barrel, Cothran valve, .180 porting, this is fairly uncharted territory.  It will be interesting to see just how good the first shot is, but bear in mind it is a .300 getting strangled by a .180 port, so that is an obvious limit.  That same .180 port may be what allows you to get a second shot, however.  It it were a .250 valve the first shot would consume so much air I doubt the second shot would be worth wasting lead with, IMO of course. 

I look forward to seeing how this goes.

[Backyard Shootr]

Don also said I could open his .180 valve to .200 or .205 if need be with no problems. Plus just finished another barrel. Now I have a choked and unchoked to try out. 

[mackeral5]

Don also said I could open his .180 valve to .200 or .205 if need be with no problems. Plus just finished another barrel. Now I have a choked and unchoked to try out. 

I have numerous of Don's Mrod and 7/8 valves, but I have never owned/seen a .180, all of mine are .250's...  Would you mind sharing throat diameter of the .180 valve?  Later Mrod .250 valves have a .350 throat, I am curious what size throat is in the .180 valves.  I may have an application for one, depending on throat size....  thanks in advance.

[Backyard Shootr]

Don also said I could open his .180 valve to .200 or .205 if need be with no problems. Plus just finished another barrel. Now I have a choked and unchoked to try out. 

I have numerous of Don's Mrod and 7/8 valves, but I have never owned/seen a .180, all of mine are .250's...  Would you mind sharing throat diameter of the .180 valve?  Later Mrod .250 valves have a .350 throat, I am curious what size throat is in the .180 valves.  I may have an application for one, depending on throat size....  thanks in advance.

I didn't want to take my gun apart again but I talked to Don and he said he thinks .330-.335. But he had knee surgery and is all medicated up. 

[mackeral5]

Don also said I could open his .180 valve to .200 or .205 if need be with no problems. Plus just finished another barrel. Now I have a choked and unchoked to try out. 

I have numerous of Don's Mrod and 7/8 valves, but I have never owned/seen a .180, all of mine are .250's...  Would you mind sharing throat diameter of the .180 valve?  Later Mrod .250 valves have a .350 throat, I am curious what size throat is in the .180 valves.  I may have an application for one, depending on throat size....  thanks in advance.

I didn't want to take my gun apart again but I talked to Don and he said he thinks .330-.335. But he had knee surgery and is all medicated up. 

Understood on disassembling, maybe next time you have a reason to take the valve out it would be interesting to see.  I was hopeful the throat and balance chamber would be a bit more proportionally sized to the .180 exhaust.  That .330-.335 is in alignment with the .250 valves I have. 

thanks for asking Don.