2240 Transfer Port Questions

[guitarplaya39]

I've seen mention of the "poly tube" transfer port mod. How much of a gain will this get? And is drilling out the port in the barrel required to see any gains? Also, has anyone tried a 3d printed transfer port?

[Back_Roads]

 I do the "Ice Maker Tubing" transfer port often, and yes drilling the barrel port is needed if more power is the goal, if not no drill is ok. aBit of a trick to get it just right, I find heating witth a lighter a bit helps get it to form better.

[Struckat]

I don’t think a printed one would work as it is a seal and need some flex.

[avator]

The factory ones don't flex... they are metal.
You would need to use the rubber seal/gasket for a printed one.

[Airnut]

TPU works fine with 100 percent infill and a good print file.
Stay with the stock size seal. On a stock 2240 it waist a lot of gas and a larger port/ seal only makes it waist more with minimal gains in velocity.
If you want more power the best bang for your buck is a longer barrel and a SSG valve for efficiency.

[guitarplaya39]

Thanks for all the input. I was thinking about trying to print some out of PETG since it seems like it may "squish" like a crush washer. Guess there's only one way to find out!
Also, what's the best way to drill a larger port in the barrel? Without getting nasty burrs on the inside?

[Back_Roads]

 Put a snug fitting wood dowel in the barrel, a set of jewelers files comes in handy too.

[Van]

   The short barrel on a 2240 will only waste more CO2 with larger transfer port and mods as many have said.  The max fps in a stock gun is about 460fps.  I like more power in my 2240 so I have a Mountain Airgun Power Valve ($35) that comes with internal mods and a larger port for the icemaker tube mod.  A 10" 1322 barrel or longer wastes less gas for more fps.   You have to drill the barrel port to 11/64" to match the power valve and really need a steel breach to do it right.  I like to drill a shallow recess in the barrel to 1/4" for the icemaker tube to just crush fit into. My 10" barrel with these mods gets 565fps on a warm summer day. The same mods on a 2260 with 24" barrel got me 675 fps all with Crosman hollow points.  You only get about 15 good shots at that power though, so it might not be so great if you just punch paper. I shoot metal veggie cans at longer ranges mostly and like to knock the $^^& out of them. It also comes in handy for short range pest control. The 10" barrel by itself is a great power mod if you don't need to max it out. Here is a picture of one of my barrels drilled to 11/64" and a 1/4" recess for the tubing which with a lite crush fit does not leak.

[Airnut]

This is what you can expect with a 10.5" barrel and a SSG valve.
I have mine tuned for a happy medium between power and shot count using CPHP. 14.3
I can tune it for more power at the expense of a lower shot count.

[CraigH]

As per Van and Airnut, the 2240 uses too much gas in stock form.  Any tuning to flow more gas will waste more gas.   Employ an SSG for more efficiency with any tune.

[AKM]

Air gunners love to waste gas and make big noses. The sound of a stock barreled 2240 and drilled out ports must be outrageous.

[Rick67]

Air gunners love to waste gas and make big noses. The sound of a stock barreled 2240 and drilled out ports must be outrageous.

I don’t have an AG in the US I didn’t detune 

[Gippeto]

Should you decide to try the polytube mod, a simple jig makes square cuts easier. Use a standard single edge razor blade...fits in the slot.

https://grabcad.com/library/polytube-cutters-1

[Van]

   Any of the many tubing cutters work well also even the ones in the plumbing departments. I like to insert a 5/32"OD brass rod in a 1/4"OD icemaker tube for support to make a perfect square cut. Getting the length of the port tube right requires a bit of trial and error to get the squish seal right so as to not close up the ID.  I make them a little long and trial fit cutting shorter till if feels right when press fitted. 

[Mzq284]

This is what you can expect with a 10.5" barrel and a SSG valve.
I have mine tuned for a happy medium between power and shot count using CPHP. 14.3
I can tune it for more power at the expense of a lower shot count.

That's pretty good power out of a 10 inch barrel. Decent shot count, too. Can you please list the spring wire diameter and starting length and preloaded length? I'm currently figuring out how to make an internal SSG for these guns, I'm going to need 7 for myself, plus another 3 or 4 for friends and want to come up with a drop in SSG. Tall order, I know. 

Looking at your pictures again, you used a nut off brakeline for the gap adjuster, that's a cool idea. Looks like you can change springs through the rear cap without taking the gun apart. Excellent.  👍

[Airnut]

Peter
If memory serves me right. I used the stock 2240 hammer spring.
Pre load is 1.1365 (1/16" hammer gap)but that will very from gun to gun.
You will have to tune each ssg to its gun. A chrony will be a must have.
The brake line fitting 3/8 x 24. I believe. MAN its been a long time since I have messed with them. If you use the brake line fitting be careful when you buy them. Make sure the center hole is drilled on center. I found that the brass ones were better than the steel ones. Any offset of the hole will cause the valve to drag.
PM me if you need any help.
Have fun!
Frank

[Mzq284]

Thanks for the reply, Frank. I made an SSG for my PRod,  it seems to work well in conjunction with a JSAR balanced valve. But, it's not a drop in, I drilled out the rear cap and used a hollowed out piece of 3/8" threaded stock for the adjuster, with a knurled collar for a jam nut. I have my work cut out for me on these, it's going to be a tight fit.
I might borrow your brake line nut idea when I build one for my 3622, I'm not too worried about it sticking out the back of that one.
Thanks again, Frank.