Armson Barell Threading

[RichardBaggins]

I have an Armson barrel that is cocker threaded but has a longer distance from the breach to the shoulder above the threading, by about 2.2mm, than a standard cocker barrel. When threaded into a marker it's leaving a considerable gap between the body when threaded in, even with an oring around it.

Anyone know why that is? It's always made me wonder if what I have was out of spec or for another kind barrel threading.

[scottieb]

Old TASO threads are cocker threaded. I can't recall if the shank is longer or shorter on a TASO though.

In short, I'm of no help.

[RichardBaggins]

Old TASO threads are cocker threaded. I can't recall if the shank is longer or shorter on a TASO though.

In short, I'm of no help.

It's more than I head to go on than before! I actually have a direction to start looking now lol

[DocsMachine]

Spartans used a slightly coarser thread, they don't interchange.

And having measured a good number of barrels, I'd wager that difference is simply manufacturing slop. Simon from Inception found the same thing, trying to come up with a 'standard' for ID bodies.

The key is that there was no real "published standard" for 'Cocker threads until fairly recently, so before that, most garage-shop manufacturers (which was most of the industry until fairly recently) simply "cut to fit". That meant there's a surprisingly wide range of dimensions. Things have gotten better as these garage shops have improved their equipment, and I think it was helped a lot with Simon publishing what he'd determined as a proper spec. but still, there's every chance that Armson barrel you're measuring is a good 30+ years old at this point.

TL;DR, yeah, chances are good it's just sloppy specs.

If it annoys you, and the barrel hasn't been bored for inserts or whatever, turn a couple mm off the breech hood. The 'official' spec is 1.250" (31.75mm) from the breech face to the shoulder.

Doc.