So I bought a noveske 7.62 12.5 Leonidas barrel a few years back been sitting on it and the receiver set since then. Decided recently to finish this build. Finish the whole build and realize the carbine gas tube I installed on it was short so it took the hand guard and all that off. put a mid length on, it it's too long scratching my head I then remembered the barrel came with a switch block with a pre-installed tube pulled it out and saw it's between carbine and mid length but that block doesn't fit under my hand guard. I've attempted to Google and find this length but have come up empty if anybody has any ideas or information on this length I'd really appreciate it. Carbine total length is about 9.750, mid is about 11.750, the tube and block that came with the barrel, tube length is about 11.000 even.

I believe what you may have is what is called "patrol" length gas.  Halfway between carbine and mid.

Never even heard of that length but from what I'm seeing it sounds right. Thanks for your reply and I'll give it a shot.

Dremel the gas block til it fits?  Cut the mid-length tube?

Lol as a machinist I was already thinking about doing that but the dog leg in the gas tube hits the contour of the barrel for the chamber before it gets to proper depth. Plus, then it's a custom tube. Not that it would be hard to remake nor should ever need a replacement, but I'd rather stick with something that's off the shelf, even if it is a weirdo length.

is this a gen 1 leonidas barrel ?

the gen 1 n6 was built off the armalite ar10b platform

i believe the gen 1 12.5 n6 leonidas used an armalite ar10b carbine gas tube , double check this with noveske

i would call noveske and see if they have any gen 1 switchblock handguards laying around if you have a switchblock for it.  if your going to shoot it suppressed you'll want the switchblock

i have a gen 1 leonidas from before the switchblock was an option and it was a bear to tune for a suppressor.  i picked up a micro switchblock for a gen 3 n6 leonidas and notched the rail for it.  if your a machinist it should be a piece of cake for you

This seems a likely answer to the situation, an Armalite AR10 carbine length. Although I don't really remember them making many, mostly they made 16" midlengths using a length a little longer than traditional midlength.

IMG_5536 by SmëgHead, on Flickr" />

Noveske 10.9”?

9 hole vid here….

They don't specify if there is a difference for cartridges.

4:10

Gazzzz systems overview

Intermediate is in between midlength and rifle, not in between carbine and mid. In between carbine and mid would be the "patrol" length or whatever people call it, and AR10 carbine.

The AR10 lengths are so that those barrels could use standard handguard lengths, with the gas tube being longer for the longer length needed in the receiver.