Sounds good. I am happier to hear of someone else with one. Not having any idea of where to start or where the limits might be, presents a daunting task.

YOu can load to sticky then back off if you want. You will never reach the scary end of things, due to the case shape (taper) and action you are dealing with. It is a strong action, but it's rear locking will show pressure signs very early. Don't be concerned it won't.

2,300fps to 2,350fps is probably fine unless your friend actualy has a #4 rifle adn they are mox, but they don't sound like it, not a #1 MK 4. Maybe I'm confused on the proper designation. I have a #4, where-as the other rifle on my same action was a #5 - the Jungle Carbine. Am I incorrect in these designation?

I thought all #1 Mk 3's were pretty much the same SMLE's etc, strength and load wise, that it was the #4's and #5's that were in the different 'strength' category. My cousin and others he used to shoot with, have/had #4's re-barrelled for the .223 as well as for .308.