Still trying to figure out why the long throat length on the AR50 rifles. What's the advantage if any.

1) Safety.
2) it works just fine accuracy-wise
(Better can be had, but for a production gun it does as good as they can get it to do.
The National Match AR50 had a more traditional chamber cut
...and it shot not-so-good, they went back to what works)

So if you had a new barrel installed would the length be done different or same as factory? Not ready for a new one yet but I'm sure that day will arrive.

Depends who does it.

I did my own re-barreling with a 35" Feddersen 5-R Bull barrel.
Chambered it TIGHT with a 0.554"Dia neck Specification.
Throat is short, rifling is easy to touch if you so desire.
Did my State Arms Shorty the same way - just set barrel back 2.5 inches, re-chambered, installed a AR-50 muzzle brake.

I know a Gunsmith Artist in OK that would do your rifle when the time comes. He is an expert machinist and well known in the FCSA community.

What made you decide to use the Fedderson barrel and the 35" length?

When I used to compete in Eatonville I saw two good shooters with AR-50's.  They typically had a good group of four with a fifth flyer.  They both fixed the problem; one replaced his barrel with a heavier match grade one, the other had the back cut off and re-chambered to allow the bullet to touch the lands.  Both improved their groups and took turns beating everyone else until Rasmussen finally got his new rifle with the Bat action ready and creamed everyone with a 1.9" group.

Randy

Availability.
The purchase of two barrels from a fellow FCSA member for $325 each, last year.
The barrels required cutting the start and end of barrels to remove imperfect rifling from that operation, thus ended up near 34" length. 1" off one end, chamber cut on other end. Both ends threaded, one for action, other for AR-50 muzzle Brake.