SpudFiles

Well, I just got in the order of parts to make my hybrid.

The barrel is 3/8" copper tubing, (1/2" OD, type L), and it was supposed to have a .44" inside diameter. I ordered a pack of 100 low-carbon steel ball bearings 7/16" diameter, (.4375"), and it turns out they don't fit!

The barrel measures .423" in inside diameter!

This is just a reminder to me that inside diameter of pipes varies way too much from batch to batch. I don't know what I'm gonna do now, but I've got a bunch of solid steel ball-bearings that I don't know what to do with. Probably gonna have to order some more ball bearings that actually fit, (more $). McMaster supposedly takes returns, though, so I'll see about that.

Short of buying a thread tap for the threads on rifle barrels, I don't think this problem will be solved anytime soon though...

EDIT: well, just solved my problem. Ordered some 13/32" bearings, (.40625"), which should fit beautifully, but now I'll have to add a magnet at the back of the barrel to hold the things in place.

I know people that that's happened to.

I prefer to get the barrel - then find an ammo for it afterwards.

Poor luck happens to us all. At the worst, you can be assured that your pipe is nicely pressure rated.

Yes, that was the most important thing... which is also why I didn't take a hammer and MAKE the damned things fit!

But, in the long run, it's cheaper, (in shipping), to pay for ammo and barrel at the same time. Now, if there were only a place locally where I could find aircraft bearings...

(Expensive ammo, but worth it, I think)

I wanted to get a .38 caliber barrel, so I could use buck-shot, but I couldn't find one.

It's possible to get pipe from the UK with a .394" ID if you're still tempted by that buckshot idea...

Only a .014" difference, which isn't a lot.

EDIT: 12mm copper if you're interested (10mm ID). You might be able to find it in the US as well, but I'm not sure.

Yeah, I can order that stuff, but I like tight tolerances. Guess it doesn't matter now, though, but a larger projectile's a plus anyway, for me.