whats the minimum load you guys use to reliably take down the animals?

From a 7-08 Rem. point of view...naturally, a Sierra 130 MK @ 2550 MV FPS for CPT.......A 168 Sierra MK @ 2650 MV FPS for the Ram. I have no idea of remaining energy at the target.

I currently use 120 grns smk molly coated (around 2700 ft/sec) (38 grns of varget) for cpt and 140 grns smk molly coated (around 2550 ft/sec) (36.5 grns varget) in my 260 rem.

Plan to change to 107 grn smk molly coated and 142 grns smk molly coated. Test the 140 versus the 142 and the 142 flew flatter. It hits about 3 inches higher at the rams. It also does not move around as much in the wind.

Ive noticed besides Tim that quite a few guys use a lighter grain load on the rams using Varget. Is this the case with most powders (rl 19 to be specific) or is it simply do some load testing to find out

Heavier bullet is going to produce more pressure if the powder charge is the same.
Reducing powder charge for heavier bullets is needed so pressures don't do bad, bad things to your rifle.

Bill is correct. Varget tends to drive up pressures with heavier bullets. I was using a maximum load of Varget to push 168 gr. Sierra Match Kings at 2650 fps for rams with my 7mm-08 and I was starting to notice some of the cases were getting loose primer pockets. I cut the load down by one grain to 2550 fps, and at least in Tucson and Phoenix, all rams hit have gone down, even when hit low in the belly. I did have to add 1 MOA of elevation.

As far as the .260 goes, pushing 139/140/142 grain Match bullets at 2650 fps. seems to do the job. I did loose one ram at the AZ HP championships a week ago, but so did a lot of other shooters, due to a strong wind coming in from behind the rams. I was shooting 140 gr. Bergers on my Std. rifle. I was using 140 Hornady A-Max bullets out of my Hunter rifle at the same velocity and lost no rams. The A-Max bullets seem to be a little bit tougher than all the others, while the Bergers seem to be the "softest".

It would take a second chronograph to prove it but I believe that the A- Max's have a much higher ballistic coefficent than most other match bullets hence more energy on the Ram target. There's a good reason why my ammunition box is marked "Ram Killers" on it! I don't always believe the B. C. figures given by manufacturers, there are to many variables.
I run 162's A-Max's 2332 fps from my 7 IHMSA and have never lost one, according to Hornady the energy would be 1020 foot pounds on the target, they fall quickly to that load reguardless of the position of the hit. That speed is easily obtained from any 7-08. I believe the mininum foot pounds of energy required to topple rams under all conditions not just ideal conditions is 850 lb's.