Use H-414. I have a 20" 270 that shoot very well with factory Federal Premium with 130gr Sierras. You will get less muzzle blast with a heavier bullet.

It may be 20", I thought that the Internationals were 18 1/2. If so, even better. It's a very sweet handling little rifle. I will be ordering a Kahles 2-7 for it on April 1st.

If your Ruger only has an 18-1/2" barrel, you got robbed of 1-1/2"!

The Intermational has a 20" barrel.

As for what to load, any of the "standard" .270 loads will work.

My favorite has always been:

Bullet: Sierra 140 Grain HPBT
Powder: 53.1 grains of IMR-4350
Primer: Winchester WLR
Case: Winchester
Velocity: 2944 FPS @ 15' from muzzle
Optics: Original Leupold 3x9
Accuracy: <1", 5 shots, 200 yards

I load for a 20in Sako Finnlite in 270 (and have loaded for 4-5 others). The conventional wisdom is to use the same powders that you use in a longer barrel. I tried 6-8 different powders and my best velocity and accuracy came from RL-22 - a powder that you think would be too slow.
If I had that rifle I would try powders in the following order RL-22, H-4831, IMR-4831, IMR-4350, RL-19, H-4350. If a 270 won't shoot with one of these powders something is wrong with the rifle. I can also Highly recommend the 140 accubond it has shot great in my current 3 270's. I've also had good luck with the new Barnes 130gr Triple shock........DJ

I don't remember the length of my savage 110, but I used 54 grains of aa4350, cci large rifle primers, and 130 grain nosler ballistic tips. Did not have a chrony back then but it would group 5 at a 100 yds that could be covered by a quarter.