Lets try this again... Dispatch gun

[YEMX]

I see the Op's point, have parts enough to make a few guns and then some, want to keep cost down and recycle the assortment of parts on hand ... never ending story 

Pretty much!!

I agree about the PP700, but that's slated for another experiment/build.  I'm turning it into a carbine.  Still haven't decided on whether or not to bottle it.  The only thing I know I'm doing to it is a .20 conversion.  I'm certainly not wasting a .20 pellet on dispatching!     

[YEMX]

I took some better measurements on some of the parts I have; I needed to double check on how long I need/want to make the main tube...  Getting closer to either sending the tube I have off, or buying a tube already to the OAL I want, so I want to make absolutely sure of all my measurements.  Y'all know how all my projects go!  I definitely need to do my due diligence!

I have a 14" barrel, and with the short LDC adapter I have, I'm able to go with a 15" long tube, and still be able to take off the dust cap w/no hang-ups.  I know .25" of air tube isn't much- but I'll take all I can get...  But not TOO much though, this pistol is already longer than I'd like    Well, yes and no.  To be honest, it's just about right.  The main tube is .5" shorter than a Prod, and the barrel is 2" longer with the OAL being shorter.  Plus it's got a slimmer profile, having a steel breech and no barrel shroud...  I'm much more happy with this version of the Dispatch Gun build.  I mean, it's no stubby 2240, but to be able to get the power I'm after in that compact a package, I'd have to use a .22 LR, and that's out of the question.  So here we are.  Also, I don't want to use CO₂, in case I have to use this in the winter... 

Perhaps a good compromise would be a tube length of a 2250: 10"  or maybe a 12" tube?  With a corresponding shorter barrel...  Everything else being the same...  It WOULD be significantly shorter...  I don't need a high shot count...  1-2 at most.  Plus I'd have a small tank for re-fills with me.  Or perhaps make a small refill tank out of a 500cc 4500 psi CF bottle...  I COULD do that...  oooohhhhh frak.      Let me think on this.

I'm thinking the longer barrel would help in the sound dept. though, yes?  i.e. a longer barrel would be more quiet than a shorter barrel (both shooting through an LDC of course)... 

So...  12" main tube, 11" barrel...  Everything else the same...  Yeah, definitely have to think on this...  That would be an OAL of around 14" or so...  Hmmmmmm  Prod is about 18"...  Hmmmm...  I dunno- it's more work to shorten the barrel too.  But would it be worth it to shave another 4" off the OAL? 

WHY AM I LIKE THIS?! 

[dmeguy]

If it was me, I'd forgo the gauge block. Check it regularly for leaks and always put it away full. Those extra ccs of air would go a long way in helping that second shot.

[YEMX]

If it was me, I'd forgo the gauge block. Check it regularly for leaks and always put it away full. Those extra ccs of air would go a long way in helping that second shot.

I don't have a choice about the gauge block- what would I do about the gaping hole in the tube?  Buying a gauge delete valve defeats the point, which is to use all my spare parts up...  I've only had to buy one thing- and really, I could have  assembled the gun w/o it, but I wanted to see what the hubbub was about...    I will be spending money on the tube too... Can't win them all...

[dmeguy]

Understood. I was under the impression that you didn't have the tube yet. I love me some Cothran PCP tubes!

If it was me, I'd forgo the gauge block. Check it regularly for leaks and always put it away full. Those extra ccs of air would go a long way in helping that second shot.

I don't have a choice about the gauge block- what would I do about the gaping hole in the tube?  Buying a gauge delete valve defeats the point, which is to use all my spare parts up...  I've only had to buy one thing- and really, I could have  assembled the gun w/o it, but I wanted to see what the hubbub was about...    I will be spending money on the tube too... Can't win them all...

[YEMX]

I have a factory tube I will probably end up modifying...  Or I may get a tube from Magnum airpower...  Don is going through some stuff, and I don't want to add to his long list of orders...  Also, If I'm going to place an order with Don, It'll be for a Powerhouse valve, new tube, rear cocking kit, and a barrel band 

[YEMX]

Well, getting a tube from Magnum Airpower is a no-go.  He doesn't machine his tubes in-house, he farms the work out to a local machine shop.  No biggie.  There's a few options to choose from.

I did end up spending a little bit of money on this build- I feel a little silly, but I didn't know that there's a slight difference between the breech from a Crosman Steel Breech Kit, and a Discovery's breech.  It's such a small difference, but it was enough for me to get a Disco breech instead of using the steel breech kit I have (which is fine, as I'm also assembling a 1322 and I want to use a steel breech on that too).  It's more than I want to spend at $25, but it's cheaper than the $40+ for a Steel Breech Kit, and it's exactly what I want.

Disco breech:


Crosman Steel Breech:


The Disco breech doesn't have the cut-out for the LPA rear sight...  Like I said- it's a small difference. 
 

[FuzzyGrub]

I think I learned that same lesson back when I built a 1377.  I think you can piecemeal it by buying the 2300S breech.

High power, quiet, and short as possible.   Quite the quandary, I've wrestled with myself.   I can't say there is a magical answer.       While I've settled with the 1701P length for pistols,  Mainly to fit in a holster, have wondered about going 2" shorter. 

[YEMX]

I think I learned that same lesson back when I built a 1377.  I think you can piecemeal it by buying the 2300S breech.

High power, quiet, and short as possible.   Quite the quandary, I've wrestled with myself.   I can't say there is a magical answer.       While I've settled with the 1701P length for pistols,  Mainly to fit in a holster, have wondered about going 2" shorter. 

I just ordered the Disco breech from Crosman.  I don't need the screws or bolt/knob or that filler piece for the back.  I just need the breech.  As far as tube length, that's where I'm at now.  I've got a few offers from various people for shortening the Disco tube- but I'm having trouble settling on a length.  Do I go with 15" and just slap this pistol together?  Or do I go shorter?  I was thinking between 10" and 12".  Not sure which.  I wouldn't need too many shots in one "session"- I don't run a trap line, and it's rare that I'd need to dispatch an animal...  But I like being prepared, hence the build.
 Thing's that I'm thinking about:

-  How much reservoir volume will I have with a 10" tube?  12" tube?
-  Barrel length- It's basically 1" longer than the tube.  Will a 11" barrel be enough to get 14+ fpe easily w/an unmodified Disco valve and hammer spring?
-  Wouldn't a longer barrel help with keeping the sound down?  i.e. would a longer barrel help the LDC do it's job?

I wonder if I'm over thinking this?  I just want to strike a balance between OAL, "efficiency" (i.e. easily making 14+ fpe w/o making the gun uncomfortably heavy to cock because of too much spring tension due to compensating for a shorter barrel), and the sound level.  I know it'll never be a 2240 shorty.  But does it have to be a Prod length? 

If I had the time and money, I'd build one of each: 10" tube, 12" tube and a 15" tube with appropriately sized barrels to match.  Then, using the same LDC, test which one sounds the best, and the power generated, note the cocking effort- that sort of thing.  Pick the one that best suits me and sell the others...  But alas.  I don't. 
 

[YEMX]

I'm just going to go with 15" OAL on the tube and call it a day.  I mean, overall- I've got some pretty good parts going into this build:

Blue Fork LDC adapter
Prod trigger
Hammer for the Prod trigger
Disco breech
(I think) a Hill TP.  It's his signature blue anodize, so I assume it's from Tim Hill

I'm over-thinking this.  Which leads to changes.  Changes lead to more money spent.  Nope.  15" tube.  I'm doing it.

[FuzzyGrub]

I haven't done any builds that were Disco based.   Tube and barrel, you are close to a Prod, and that is easy to get 16fpe for 24 shots.   But different valve and pressure ranges.  Seems reasonable goal though.

My 2201P is basically a Prod with 10" barrel and 1701P air tube.  I tuned to same power, but lost 8 shots a fill.   I only had a inch or two past the barrel in the shroud.   While I tried a number of things to improve it, without adding length, but still loud.  I needed the shroud for iron sights mounting to see over the top of the mag.     

[Blutroop]

My thinking is it would be easier to redrill all the mounting holes than to cut and rethread, and wait time for shipping. Also then you have a option of going with a prod valve for 3000 psi or a fortitude valve for more air volume or a hybrid. If you went that route you would also have the option of eliminating the gauge hole, and even eliminating the front trigger frame screw hole in favor of a external bracket.

[YEMX]

I haven't done any builds that were Disco based.   Tube and barrel, you are close to a Prod, and that is easy to get 16fpe for 24 shots.   But different valve and pressure ranges.  Seems reasonable goal though.

My 2201P is basically a Prod with 10" barrel and 1701P air tube.  I tuned to same power, but lost 8 shots a fill.   I only had a inch or two past the barrel in the shroud.   While I tried a number of things to improve it, without adding length, but still loud.  I needed the shroud for iron sights mounting to see over the top of the mag.   

Yeah, we're only dealing with 2k psi...  Maybe even lower, once I'm done "tuning".  Yeah, I figured a shorter barrel would be louder.  No biggie.  Nearly Prod length it is. 

My thinking is it would be easier to redrill all the mounting holes than to cut and rethread, and wait time for shipping. Also then you have a option of going with a prod valve for 3000 psi or a fortitude valve for more air volume or a hybrid. If you went that route you would also have the option of eliminating the gauge hole, and even eliminating the front trigger frame screw hole in favor of a external bracket.

My milling skills would probably butcher re-drilling and slotting the factory holes, the valve holes are critical to safety and I'll not trust my machining skills to that.  Also, I'm not sure the Prod or Fortitude valves are spaced the same as a Disco valve, with regard to the respective breeches.  If they're not, what you're proposing would ultimately be more work...  At that point, there would be less effort if I just bought a Prod.    

[YEMX]

Main tube is going out today! 

[YEMX]

I can't even have a simple project that uses up parts on hand!    It's ALWAYS something with my projects! 

-  The valve screws I have apparently aren't the correct valve screws for a Disco.
-  The tube I had modified is one of the bad tubes from years ago, so I can't use it.
-  I don't have an o-ring for the fill adapter, and looking at the schematic I have, the fill adapter I have is different- apparently Crosman either switched from 2 o-rings to one, or they switched to one o-ring to two on the fill adapter.  Either way, no o-ring... Luckily it's the same o-rings as the valve, and the dust cap.

So now I have to order a tube (that's hopefully correct), and valve screws (again, that are hopefully correct).  Jeeze Louise!!  So this project just got set back a few weeks.     Oh well, onward and upward!

[YEMX]

"Crisis" potentially averted!  Thanks to Pelletjunkie and a few others, I have a plan of attack.  I do need to get new o-rings though, since the one's I have a knackered.  But I'm going to try freezing the parts (valve and gauge block) w/the o-rings on, for a few hours (or half a day), THEN trying to install them.  I've done this while working on cars, but never thought to do it while working on airguns...  Lame Tom.  LAME.    So the tube I have is fine- I did more reading, and I don't have a "rough ground surface" on this tube.  I made sure to double check all the indicators of a bad tube, luckily this tube doesn't meet any of the criteria.  So I'm going to run it.  *shrug* 

I'll get back to this project in a few days when all the bits get here.

Oh- as an aside, I also added 2 more screws to the breech.  I don't know why, but I like the look of 3 barrel screws.  They're not perfect, but it wouldn't be a "Tom Project" if they were 

[Back_Roads]

 Dang I was ready to tell you sell the box of parts and buy a new project gun LOL, glad you are finding work arounds

[YEMX]

Dang I was ready to tell you sell the box of parts and buy a new project gun LOL, glad you are finding work arounds

Please no!    I'm trying to get the projects I have done so I can move onto other projects, like my 7mm Texan!

[BigBird]

Hey Tom,

Getting into this discussion a little late but I'd say modified 2260 tube for disco pins so you don't have to use the gauge block.  It was about $8 last time I bought one.  The holes arent that difficult to do with a drill press, (+filing sharp holes) just use your disco as a template.  You could cut down the Disco and make a pinned fill end almost as easy when your lathe is up.

The PRod trigger is easy to mod with a dremel or better with a drilled hole in front of the slot then join with a dremel and file.

For 2 shots a 2240 pinned disco valve would be doable I think.  I have a 2240 in mind that has a custom fill end that has a backward facing hole for a paintball tank/stock.  I hand pump so that isnt one that is top priority but it would yield a lot of shots.

[YEMX]

Hey Tom,

Getting into this discussion a little late but I'd say modified 2260 tube for disco pins so you don't have to use the gauge block.  It was about $8 last time I bought one.  The holes arent that difficult to do with a drill press, (+filing sharp holes) just use your disco as a template.  You could cut down the Disco and make a pinned fill end almost as easy when your lathe is up.

The PRod trigger is easy to mod with a dremel or better with a drilled hole in front of the slot then join with a dremel and file.

For 2 shots a 2240 pinned disco valve would be doable I think.  I have a 2240 in mind that has a custom fill end that has a backward facing hole for a paintball tank/stock.  I hand pump so that isnt one that is top priority but it would yield a lot of shots.

2260 tube has rolled stamps, and I don't really trust that w/PCP.  Arguments have been made for and against using 2260 tubes for PCP, but personally, I choose not to.  Also, a 2260 length tube (same length as a Prod) is a touch too long- I didn't want to shorten the barrel as well.  Ultimately, I chose to shorten the Disco tube to a half inch less than a Prod tube length, or 15" OAL.

You can use a prod trigger group no problem with a Disco, as long as you get the proper hammer to go with it.  Same with a Mrod trigger group- just need to use the correct hammer. 

No need to pin the filler, just copy the threads and re-use the factory filler...  Which is what I've done.  Unless you're talking about using a different filler altogether- or not threading the end of the tube?   

It would have been kinda cool to go shorter, but just in case I want to build a carbine in the future (or use my Crosman backpacker stock), I chose to go w/a longer tube.  Just keeping my options open is all.  Also, the longer barrel helps with keeping the noise down, in conjunction w/an LDC.  Besides- once you make it short, you can't go back...  But the 2260/Prod-ish length tube isn't SO long that it's unmanageable as a pistol, and it would make a pretty handy carbine w/a Mrod trigger group...