We killed a slug of yotes with the following bullets out of custom and rem 700, 788's in 243
60g Sierra-46.5-48.5g of Win 760, Fed 210 primer(3700 fps)
75g Sierra HP-case full of IMR 4831(3500 fps)
80g Sierra-39.5-41.5g of IMR 4064; Fed 210(3400-3500 fps)
70g NOsler-47.0g H4350; Win primer(3600 fps)
Chickenleg's load of 46g of R#19 sound like a real good one, I am shooting 45.5g of R#19 with the 85g Barnes Tripple shock..tiny groups, very fast.
You never know what a rifle will shoot well. I have had more than a few 243's that would not shoot heavy bullets at all.
The 60g Sierra has been a stellar performer with Win 760, and that is an undertatement...does not tear up yotes at all. This light 60g HP is a tough bullet, will never blow up on the surface and will give good penetration from quartering angles. The NOsler 55g Ballistic tip in 243 has a better BC than it's 22 Calier counter part and you can push the 55's at 3850-3900 in a 243...makes the 243 better than a 220 Swift.
The 80g Sierra with the loads lised above gives the loudest "PLOP" that I have ever heard on yotes, extremely accurate and fast. Substitute the 80g Berger for small exit wounds.
70g Noslers with the above load just messes up a yote, this load really bucks the wind well, also.
We killed a lot of yotes with the Sierra 85g BTHP with a 37.5g of H4895 and a Fed 210 primer with a speed of only 3100-3150. This was also our Rock Chuck load. Siera has since toughened up the 85g BTHP putting it in a deer class of bullet. I would expect that R#19 and a Win primer would make the 85g BTHP bullet come alive. However, I have had a few of the Sierra 85g SPT zip right through some coyotes, which is why I got away from them, also with the 75g Hornady Hp.
The 243 is a stellar killer for yotes, lots of horse power.
If you have a 243 that is picky, order some of Euber 68g Benchrest bullets, flat base. This bullet has .2435 pressure ring on the heel, and will shoot very tiny groups in most 243's, and also kills yotes extremely well with around 44.5-45.5g of Win 760 with a Fed 210 primer.