22xx PCP build (w/o any 22xx parts)

[smdub]

Im a little new here so first a little background.  I bought a great 22xx PCP conversion at the Roanoke show last year (RJ breech, stainless air tube, corcoran stock, carbon shroud) which REALLY got me enjoying these little 22xxs.  That things a little tack driver and QUIET!  Only had loud MkIs before that.  Bought a 160 @ the same show an having a blast w/ it too, but I digress.  I also have multiple mills/lathes/welders/etc and can make most anything needed for a conversion. So...

I bought a 2250B a while ago to mod.  The one thing thats really lacking on my PCP conversion is the trigger.  It was the only thing that wasn't 'worked over' and shows it.  After reading the PRod/1701P trigger frames fit and are avail I thought my prayers were answered.  So I ordered 2 this week;)  That got me to thinking, how about building a 22xx PCP w/o ANY 22xx parts.

Grip frame/trigger:  I have the PRod ones on the way
air tube: I can get another extended stainless one from from Cothran
breech: again Cothran or several other sources.
bolt: multiple long probe sources avail.
barrel: Mac1 HW for $60.  I can machine out a breech to hold a 15mm barrel easily (or visa-versa)

Which leaves:
valve:  for PCP I read some things about using the disco valve.  Does it fit in a 22xx diameter tube?  Is there anything more suitable?
hammer: prob just use a 22xx one, but could machine one from scratch just to 'do it'.

And something not necessary but I like the looks and the existing shroud/ldc I have is very back yard friendly:
shroud: I can make up delrin bushings to fit a tube.  Has anyone tried Ti?  7/8 - 1" thin wall tubing is cheap.  Would give it a different look than another carbon.  Though that gives me evil thoughs about making a Ti air tube too;)

Though I wonder a little why I just don't buy a PRod to start w/.  But whats the fun in that?

Thoughts?

[1377x]

disco valve or b&a boss disco valve(good choice if wanting a little more power at the expense of shot count)
the hw barrel may be a bust. i hear mac1 is using lw barrels now
you will need a challenger/p-rod striker ,modded or custom 22xx hammer to use the p-rod gripframe/trigger group
you can get maurader baffles from crosman that will save on machine time get as many as you need and tube the length you want

[arkmaker †]

I'm all over that Ti tube. What is your source if you don;t mind sharing?? I never thought about it think it would be cost prohibitive. Also, is it seamless? Not that it would matter for a shroud, but now you have me thinking Ti tube 

[eric]

Though that gives me evil thoughts of making a Ti air tube too;)
                                                                                                                                                                                                          make sure it is tested --- hydro tested --- if you haven't gone this route before

[arkmaker †]

I believe the tensile strength of titanium is much higher than SS. Will need to do my homework first before jumping off the cliff

EDIT: to rich for my blood to purchase Ti seamless tube to use in place of the 2240 or disco tubes. Would cost 50+ bucks per foot before machining. The welded tube on the other hand is priced right for a shroud or two

[1377x]

a 12" tube would make a nice pistol though.if doing the machining yourself consider it free time well spent

[arkmaker †]

The largest tube size I saw at Metals Online was 3/4" and I think you need 7/8" for a disco or 2240 bulk valve, right? There are probably other sources, but at $50 a foot, I'll pass and have to admire one from afar 

[smdub]

Hmm, I didn't get emails when people replied.  I was surprised this morning that I didn't stir up at least a little interest;)  I see I'll have to remember to check the "notify me" box. 

1377x: thanks for the info on the valve and other parts.  I wasn't exactly sure what was included w/ the grip frame and was just waiting for them to come in.  I've seen the notch people have to do to the hammer to work w/ a 22xx air tube.  I hadn't seen the B&A page so its bookmarked now.  As far as using stock crosman baffles: that would only be possible if the shroud is the same ID.  Easy to make new ones though.

ark: Im a mountain biker too (have even welded my own steel HT frame) so my first thought was those Ti sources like Nova:
http://www.cycle-frames.com/bicycle-frame-tubing/TUBES-TITANIUM/
But then a web search turns up plenty of others cheap (and longer).  Here is a 7/8 thin wall for ~$11/ft:
http://www.ebay.com/itm/TITANIUM-TUBING-3AL-2-5V-875-OD-X-020-W-X-72-LONG-/251035244761?pt=LH_DefaultDomain_0&hash=item3a72ddd8d9
No need for seamless for a shroud.  The external weld seem should be near invisible anyway.  Polish/brush finish should hide any remainder (and you can always put any remaining trace of a seam towards the airtube.)

Eric/ark: yes, the burst pressure for Ti tubing is quite a bit higher than SS.  $50 too rich?  A cothran 2250 SS tube (only) is $45.  Just add some holes/slots and thread the end;)  But I haven't priced 7/8" seamless tubing (22xx air tube size) to know if there is a better price or not.  Hydro testing is always a good idea on prototypes but if using seamless Ti tubing (from a reputable supplier) w/ same dimensions as SS there should be no concern.

Wonder how much work to make an *ALL* Ti gun (external visible parts)

[1377x]

i cant remember the size of the tube for the marauder baffles,the guy who makes the shrouds/ldc here uses a delrin tube with the m-rod baffles workd pretty good
i have a custom brass ldc attached to my 2289g the internals are custom

[smdub]

What OD is the mrod barrel?  Shroud? Sounds like the HW/LW barrels are typ 15-16mm which is definitely bigger than the stock 22xx.  Mac1 seems pleased w/ the thicker barrel but don't know if thats just because they could ditch the MkIs sleeve on the LDs.  Definitely makes an unsupported barrel quite a bit more stout. 

IIRC, my 22xx pcp has a 14.5" barrel in a 17.5" shroud w/ 4.5" of LDC space ahead of it (barrel is in the RJ breech 1.5").  I'll just peek inside its shroud and duplicate what they did.  I have nothing against plagiarism;)  I now understand the meaning of 'mouse fart' quiet.
(sorry for the poor pic. its the only one I can find here @ work.)


Edit: corrected lengths

[eric]

depending on the caliber LW runs between 11mm and 18 mm for airguns .the .22 mrod barrel is 7/16 in./11mm  .not sure about the the HW(match grade), they probably just run either 15 or 16 mm so tim didn't have a choice in that respect,but the HW were less expensive than the LW and at the time better quality