Tinker,
Thanks for that.

Numbers between threaded holes on right side rear bridge would be good.
Also does it have the barrel mounted recoil lug?
Thanks mate.

458 Win Mag 300 grain loads.

Winchester brass
Fed 215 mag primers
Brno 602 custom rifle with 22 1/2" Magnaported barrel.
300 grain Taipan weldcore bullets. (no longer available with weldcores)

Powder AR 2207
(close in buning rate to IMR 4198)

63gn 2371 fps
64gn 2420
65gn 2445

68gn 2535
69gn 2554
70gn 2582
71gn 2638
71.5gn 2661
72gn 2684
72.5gn 2701
No excessive pressure signs whatsoever.
Accuracy was good but you need a strong bullet to survive that sort of velocity.

Shot and recorded on 23rd August 1992.