QB extension problems

[Tgomez82]

I purchased a bulk fill extension for one of my QB's and now I have a problem. The coupler that came with it mates the QB threads of the extension to the QB air tube leaving crosman threads exposed on the fill side my QB bulk fill cap obviously does not fit that. I checked the website and the crosman bulk fill cap is out of stock. So I am stuck with an extension that is no good to me. It came with a collar on the fill side but the internals out of my bulk fill won't work on it.. any suggestions?? Can I buy the fittings to build the bulk fill cap should I have it cut and rethreaded to fit my QB bulk fill cap?

[Bentong]

I purchased a bulk fill extension for one of my QB's and now I have a problem. The coupler that came with it mates the QB threads of the extension to the QB air tube leaving crosman threads exposed on the fill side my QB bulk fill cap obviously does not fit that. I checked the website and the crosman bulk fill cap is out of stock. So I am stuck with an extension that is no good to me. It came with a collar on the fill side but the internals out of my bulk fill won't work on it.. any suggestions?? Can I buy the fittings to build the bulk fill cap should I have it cut and rethreaded to fit my QB bulk fill cap?

You need to get with Tim if that's where you got it. You should have bought the collar that you need to use the QB bulk fill cap.  https://www.mac1airgunshop.com/crosman-co2-extension-tube-p/m1co2extube.htm

[Tgomez82]

I emailed him before my purchase to let him know that was my intention and ordered accordingly still received the wrong collar. I have emailed him since and he said I had to use the crosman collar on the fill end with the guts out of my bulk fill adapter but they are completely different, I emailed again and no answer, I decided to give in and just order his crosman bulk fill cap for another $40 plus shipping and they show out of stock.

[a1rgunz]

I had the same issue with my extension tube. I'm guessing your bulk fill internals will pass through the provided collar? My solution was to use one of these grade 8 hardened washers between the bulk adapter and collar: https://www.fastenal.com/products/details/11101304.

As you can tell, it is a perfect fit:


I made my own bulk fill adapter by drilling a small hole all the way through the stock end cap. A 1/8" npt hole is then drilled and tapped short of going all the way through. The washer is added to the top and a male foster fitting with check valve is installed through the washer hole. I used a ball point pen spring for better check valve performance.

This has worked fine for me, but use at your own risk. Definitely do not try using a washer of a unknown strength.  In spite of all this working well for me, I'm ditching my extension tube in favor of a 13ci Ninja bottle in the near future for better shot consistency.

[Tgomez82]

Thanks Geo I mite so that for the time being hopefully my collar is the same ID as yours so that will work. I am running co2 and have a hand pump on the way I won't be pumping over 850 rite now anyway, until I pin the valve and by then I would have hopefully found  a more permanent solution.

[Tgomez82]

Geo, I stopped by a local machine shop and had them fix me up a couple of these washers as my local hardware store didn't have the heavy duty grade 8 like you had. After some cleaning up and tinkering to get them to seal I'm happy with the results

[a1rgunz]

Glad to hear you're up and running!