Tuning Crosman DPMS SBR build

I ended up going with the Tippmann 9ci tank. I bought a Ninja Rebuild Kit with it, so I have the extra shims to bring it up to 1100 psi. It comes with spare o rings and burst disk which is good to have on hand. I mentioned the AV tank in case anyone else comes along and tries it with it, since the AV tank is specifically marketed for usage with CO2 guns. It's not going to work with the ANT adapter out of the box.

I also bought a belt bag to carry the tank with a 42" remote line. I'm going to make sure that I can get that all working first before trying to mount it on the rifle. I wanted the 9ci so I would have the option to mount it later. Those 9/13ci belt bags are surprisingly hard to find. I could only find pouches for larger tanks at first, before finally settling on this bag: https://www.wtfidea.com/original-modular-13ci-hpa-tank-pouch-molle-pals/

I plan on putting some foam at the bottom so the 9ci will fit in it. Having a belt tank with remote line will be useful in the future in case I do end up deciding to do the 92a1 pistol.

If I had a 9ci tank, would have tried it. I do have one that is about 2" longer than the 13ci. 9ci should be plenty of air for a full R mag, and would mount on the gun a little cleaner than the 13. If I see a used 9ci bottle, will grab it. Have additional regs available.

You’re parts list is great, looking to do this to mine. Was wondering if you could tell me what fitting i need to go from E-bay side port canister to the hose you recommend. Also would be interested in the trigger modification if you have the time Thanks

You need this part to go into the co2 adapter. It's the part that sticks out of the mag. I also didn't realize you had to order it separate.

https://www.ansgear.com/Valken_Quick_Disconnect_Male_Fitting_p/valkenqdfittingmale.htm

I am also going to experiment with using a fill nipple (same dimensions, but won't let air escape).

https://www.ansgear.com/Valken_Stainless_Steel_Mini_Fill_Nipple_p/valkenminifillnippless.htm

There are also ninja brand versions of each of these. But they are lower profile and we are not certain if they will stick out far enough from the magazine. I'm ordering both to test them out.

https://www.ansgear.com/Ninja_Compact_Quick_Disconnect_Male_Black_p/ninjatank-compactqdmaleblk.htm

https://www.ansgear.com/Ninja_Tank_Regulator_MFV_p/ninjatank-mfv.htm

Using a fill nipple will cause the gun to stay charged if you disconnect the air. The ebay co2 adapter has a much smaller internal volume than a modified co2 cartridge, but the goal would be to get it to at least fire a full mag clip (25 bbs) with no loss in power. If it doesn't, than you will have to keep a remote line always connected to the gun, or explore ways to mount the tank to the gun. The drawbacks to using a fill nipple is that you have to open the mag and unscrew the co2 adapter at the end of each session to release the pressure in the mag. It's bad for the seals to store the mag pressurized.

Good news, no mods to the 92a1 mags are needed. The pressure bolt is a standard M22 thread, which pressure washers use. This piece exactly fits it:

Pressure Washer Coupler, Metric M22 15mm Male Thread to M22 14mm Female Fitting, 4500 PSI

https://smile.amazon.com/gp/product/B07FZ94HPX/

And the QD nipple has room to come out. However, the nipple is too far recessed to be able to fit the hose onto it. So I bought these to extend it:

Edit: Corrected 1/8" extension that actually fits in the pressure washer coupler:

Brass Pipe Fitting Long Nipple, 1/8" NPT Male x 1/8" NPT Male Extender Straight Connector, 1-1/2"Length 1200psi

https://smile.amazon.com/gp/product/B07L5HLNGN/

Brass 1/8" NPT Female × 1/8" NPT Female Coupling Coupler Hex Head Pipe Fitting 1200psi

https://smile.amazon.com/gp/product/B07487DR2Q/

This should work for both the Umarex Beretta 92a1 and the M9a3 mags since they are the same. For the Crosman P1, I recommend measuring the pressure bolt to see what diameter it is and if there is something similar that could work. If the outer diameter is 22 mm, than this same M22 coupler will work.

I think you're on to something! My plug measures 21.2 mm on the OD of the threads. Pitch looks 1.5mm. Comparing it to the threads on my pressure washer wand, it looks like the same OD and pitch. I'll have to brave the cold to go out and check the hose in the shed. Looking very positive, though.

If you want the stainless version and an overkill working pressure of over 6K, McMaster-Carr has one for $10 + shipping. I use them as a gauge extension on a couple of my PCPs. 



PS: I don't think that nut side of the NPT fitting will fit inside the pressure washer fitting, but there are probably other fittings that will.



PSS: I'm going to try this: M22 Fitting and just cut-off one side. That leaves me a shallower nut to deal with. Should be here on Monday, and will find out if it fits.

Good catch. I didn't notice that the nut was wider on that NPT female to male adapter. If you find a different one that actually fits, I'd appreciate the link.

Good luck cutting that M22 fitting, thats a good idea. Unfortunately, I dont think that it will work for the 92a1 mag, because it looks like the length of the threaded side on the M22 male to female is longer than the M22 male to male. And from the pictures, it looks like the 92a1 co2 adapter is more recessed than on the P1 mag. As it is, the M22 male to female is just barely long enough for me, so I can't give up anything on the length of the threaded side.

found an ordered this, has check valve inside going to give it a try

JFYI: When you get the fittings, check to make sure you received NPT thread. I received straight thread which was either M10 or BSPP, or NPT too loose, ie able to screw all the way flush without tension. Also make sure the male will fit your female. I have had some that won't latch.

Using a fill nipple will cause the gun to stay charged if you disconnect the air. The ebay co2 adapter has a much smaller internal volume than a modified co2 cartridge, but the goal would be to get it to at least fire a full mag clip (25 bbs) with no loss in power. If it doesn't, than you will have to keep a remote line always connected to the gun, or explore ways to mount the tank to the gun. The drawbacks to using a fill nipple is that you have to open the mag and unscrew the co2 adapter at the end of each session to release the pressure in the mag. It's bad for the seals to store the mag pressurized.

Click to expand...

I am interested in seeing what that string would look like running off just the air in the ebay cart and empty CO2 cart. My chrony is still blind to the little BB's. I'd expect a declining string, but have no idea how steep of a decent.

I'm new to this so I don't have a chrony yet, and the one I want is on backorder for a while now. I'll be watching to see if it drops off on the target like you.

For the 92a1 mag, to bring out the 1/8 port through the pressure washer coupler, I was thinking of using a macroline, but I was trying to avoid that since I only needed a 1" extension.

I found this instead:

Brass Pipe Fitting Long Nipple, 1/8" NPT Male x 1/8" NPT Male Extender Straight Connector, 1-1/2"Length 1200psi

https://smile.amazon.com/gp/product/B07L5HLNGN/

Brass 1/8" NPT Female × 1/8" NPT Female Coupling Coupler Hex Head Pipe Fitting 1200psi

https://smile.amazon.com/gp/product/B07487DR2Q/

I'll edit my previous post, so that others can found the part quickly.

I have been looking at the same, just in steel. I am waiting on getting the plug and seeing what length is really needed.

I already have that same coupler, in steel.

I agree that the macroline would not work well. I think it would come apart, from flexing in the hose.

I would use a short braided line over the macroline. 3.25" is the shortest I've found, though.

Joey, I'm getting ready to mod the Tippmann regulator to bring it to 1100 psi, with the washers from the Ninja rebuild kit. While this should bring it up 250 psi to 1100, I realized I didn't have a way to check the regulator output. Is there a standard part that people use to add a gauge to measure their output? How do you measure that you are running at 1400, is it just estimation based on the washers? Thanks.

My limited experience with shims, so far, the output matched the calculated. That is using a 2" glycerin filled 0-2K gauge. I don't know the accuracy.

In the other thread you mentioned getting an ASA adapter. That should have two 1/8 npt ports. One for the output line and one you can put a small gauge on. That being said most of the 1" gauges have accuracy +-100psi or more. The on/off should have a bleed in it, if you got that type.

Great thanks for pointing it out. I am getting an ASA to mount on the gun. That's a good idea. I'll pick up a 1200 psi gauge, so I can monitor pressure while shooting.

Also, I came across this product that may be a single package for the extended foster nipple that we need for the pistols:

https://www.ansgear.com/Tippmann_TPX_Pistol_Remote_Adapter_Kit_p/tippmanntpxremoteadapterkit.htm

However, I do not know if it long enough or if it has the right threads. I have an email out to ANS to find out.

We may now have all the parts to create it ourselves, but there is value in having fewer parts with fewer joints that can fail, assuming its long enough and has the right threads.

I'd say it is looking VERY good for this coupler working with the P1.

It cradles a CO2 or Ebay adapter, nicely, and has room to tighten it down.

It was no issue cutting off the opposite side with hack saw, and just a little touch-up grinding.

Note: On this adapter the ID is 14mm on one end and 15mm on the other. I cut off the 14mm ID end.

As I mentioned had a female coupler, along with a 1" male-male coupler, and looks like it will be just long enough.



Thank-you very much for the lead on the power washer coupler. This is much better than trying to use the crosman cap.

I was concerned that the 1" male-male coupler was going to be a touch short, once everything was taped and tightened up. I counter sunk the nut side of the pressure washer coupler, The female 1/8" npt coupler can slide into it, up to the nut section. I ended up with 1/4" of free play. That is plenty to get the threading started, etc.

I had to grind the top of the side plug for the Ebay cart. So that it would sit flush enough to fit the hole on the bottom of the mag. 

All taped up and ready to test with the DPMS, tomorrow.