Here are a couple of loads I use for hunting coyotes for my .243.
40 gr. IMR 3031 70 gr. Nosler Ballistic Tips 3500+fps muzzle velocity.
42.5gr. IMR 4064 70 gr. Nosler Ballistic Tips 3500+fps muzzle velocity.
The loads I mention are a little on the hot side. If you choose to try either load you might want to start 10% low on the powder and work up.
I am using them in a custom made .243 Sako Forester L57 action with a 26" Lija barrel 1:12 twist. The original barrel on the Sako had a 1:10 twist. The loads shoot reasonably well out of my Ruger # 1 also. The Ruger has a 1:9 twist.
I also have had good luck using IMR 4895 and Winchester 760 powders.
I have used both Federal or CCI primers which seamed to work equally as well.
And then there are things that didn't work well for me.
The results were less than stellar with H380. My sentiments are the same for Varget. I couldn't get tight groups using Varget for .243 loads but worked rather well for loads in my .308. I am not fond of Sierra Bullets. My experience with them is they lack quality control. I have noticed a difference .005" with in a batch. I wouldn't recommend buying Winchester brass. I have had problems the the cases bulging and slitting.
Everybody is going to have their own ideas on what they like and what works for them. The next guy may come along a swear H380 is the best thing since sliced bread. Personally I take what everybody has to say about reloading with a grain of salt. What has worked for me and my rifles may not work for you. I have seen the same caliber, model, and brand rifle where identical loads wouldn't group equally as well in both of rifles.
For whatever it is worth here is a comparison of trajectories of my .243 Sako 70 gr. Ballistic Tips and my Remington .22-.250 VLS 50 gr V-Max.
Sako .243 +0.8' at 100, 0.0" at 200, -5.5" at 300 yards.
Rem .22-.250 +0.8' at 100, 0.0" at 200, -5.0" at 300 yards.
