G'day, I just pulled this off AmmoGuide.com; it uses IMR-4064, which is the equivalent of AR2208:

Bullet Wt. (gr): 400

Powder Type: IMR-4064

Charge (gr): 75.0 (Full Case)

Muzzle Vel. (fps): 2467

K.E. (ft-lbs): 5408

Pressure: ?

Barrel Length (in): 22

Overall Length (in): 3.297

Load submitted by 'damgoodshot'.
This load was developed using Hornady round-nosed, jacketed, soft-point, flat-based bullets (RN interbond).
In terms of power, the developer considers this a MAXIMUM load and notes this charge fills the case.
The velocity measurement is by chronograph.
Hornady cases and CCI 250 primers were used in development.

COMMENTS:
Start with 70.0 and work up - max in my rifle