Anyone know where I could find details on how these actions work? I've always been interested in straight-line actions since seeing them in biathlon events, but havn't ever seen details of the actions. I have seen one straight-line action designed like a pull-pin, with six or eight balls.
I believe some straight pull actions (Ross rifle, for one?) have a two or more piece bolt. The two pieces are threaded together with a very coarse-pitch, smooth thread. As the bolt is withdrawn, the bolt head, with the locking lugs, unscrews from the rear piece of the bolt, causing it to rotate, and unlock. Once the head is fully unlocked, the whole bolt assembly can be withdrawn. Locking of the bolt happens in the opposite order.
I would believe that biathalon rifles use something like a pull-pin, especially since I've noticed many of them are spring-loaded.
Here is a clip of how to take down a M95 Mannlincher bolt, it shows rather clearly how they work.
YouTube - The M95 Mannlicher Bolt
Blazer, makes a rifle that as best I can tell form the poor pictures I can find uses something kind of like an expanding collet with a ridge on it to lock.
I can't remember who makes the ball type you are referring to, as best I can figure they must work rather like an air quick disconnect.
I too am not real sure about the biathlon rifles. They almost look like they are a fully custom deal. I remember 12 or 16 years ago at the olympics most competitors used some kind of bolt or straight pull but one of the Russian's I think it was had a neat little lever gun. It was ugly as hell, kind of looked like the stock was still a stock blank. However, the lever only moved maybe 1" at most seemed to shoot very fast.
try this for one version of the Biathlon
YouTube - Anschutz Biathlon Rifle and 9003 Air Rifle
I've built quite a few rifles in Anschutz/Fortner actions.
Basically it's a straight pull action that uses a lock up system that I compare to a quick release air hose fitting. How's that for technical??
Nice and fast for follow up shots, short throw, and a bit of a biche to fit a barrel to/headspace properly.
I was the head "gun plumber guy" at the Anschutz National Service Center in Colo Spgs once upon a time.
Neat actions, spendy too!
Hope this helped.