Transfer Port Thingy

[breakfastchef]

That is a timeless, classic link.

http://www.network54.com/Realm/CFTech/Bioportupdate.htm

This is what I followed.   Also while angleing valve port, opened up to .170 as well.    Just wanted to match up with ID of tubing I had.

[airriflenut]

I'll jump in right quick with my two cents worth from my 1377 Crosmods build last year that was to be a "power build" from the start.   As most know, the Crosmods breech is TALL, that is a long transfer tube to move air.  I don't have my specs on the Crosmods transfer tube, nor do I have all of the detailed specs on the aluminum tube I made (o.a.l. length, shoulder lengths or diameters, etc), it was made from an aluminum spacer .250" o.d., 1" long and for a #8 screw.  I do however remember what I drilled that tube i.d. (and barrel and valve ports) to...I used a #16 drill/.1770".  I use nebulizer tubing on both the barrel and valve shoulders of the transfer tube.  There are really no length dimensions of the vinyl tube to give, each one is cut ever so slightly long enough so that I get a slight compression fit when it's all screwed down.

With all that said I have no way to document any increases or decreases in fps since I don't own a chrony (not in the budget and I'd rather spend the $$$ for more guns to mod).  I DO believe that I have built the "power build" I set out to do.  Of course there have been a lot of mods with the valve as well so it isn't a "transfer tube only" mod that has given me what I have now.

I'm sure there is a mathematician or air flow engineer that could calculate the best "this and that" to get optimal performance...I'll just keep tinkering until I get what I need done, isn't that supposed to be part of what makes modding so much fun?