I dont know if this has appeared before, but I recently purchased some stuff from Sylmasta, and they do a range of syringe needles that may be suitable for MG barrels.
I have not yet played around to see what can and cannot be done, but they are easily cut by using a file to make a notch, and then snap off to the length required.
I have no association with the company, other than a satisfied customer.
I buy my hypo needles from the local Pharmacy ,without having to buy the whole syringe ,for the larger sizes I go to the local vet .They are quite cheap .They do make good replacement gun barrels for winged thingies.
Ti cut I palce the tube into my pinvice and use a knife edged needle file to cut a groove around the tube and then snap it off. Then file the end square .
"I'm not young enough to know every thing"