Firebird-- I have not used a 40 gr. Nosler BT for the .204 Ruger on coyotes, but I have used the 40 gr. Nosler BT in my 22-250 on coyotes with great success. No runners, no big splash wounds and no big exit holes.
I use the 39 gr. Sierra and the 40 gr. Nosler BT in my Savage 12VLP in .204 Ruger on prairie dogs and the 40 gr. Nosler gives me a bit better helicopter actions and better red mist than the 39 gr. Sierras. The Sierras are a bit more accurate out of my rifle, but the 40 gr. Noslers aren't far behind. When I have my 12VLP sighted in at about 1.0" high at 100 yards for the 39 gr. Sierras, the 40 gr. Nosler BTs average about .75" high and 1/4" right at 100 yards. Not enough difference to be concerned about since my prairie dog shooting is not much further out than 200 to 250 yards and many times I get many shots in the 25 yard to 150 yards range, especially early in the year.
Here's a before and after photo of two prairie dogs sitting on a mound. I shot the one on the left with a 40 gr. Nosler BT out of my .204 Ruger. I can't remember the exact distance, but it was probably in the 100 yard range. My son did the photography work. Notice that the second prairie dog just kind of sits on the mound while his buddy, at least what is left of him, goes flying through the air above him.
The live PD ducks down into the hole just before the airborne PD hits the mound right where the other one had been sitting before the shot.
I don't think these 40 gr. Noslers will tear up a coyote like they do prairie dogs. However, like I mentioned early on, I have not tried these .204 caliber Noslers on coyotes. I have used the 35 gr. FBHP Berger on coyotes for three fur seasons, but I'll be trying the 39 gr. Sierra BlitzKings on them this year. The Sierra bullet has a BC of .287 compared to the .191 BC of the 35 gr. Berger. The Nosler BT has a BC of .239, which should serve you better in the wind than the 35 gr. Berger or the 32 gr. V-Max or 32 gr. Sierra.
I am currently using AA2520 for the 40 gr. Nosler BTs and that gives me 3,868 fps at the muzzle, but I have a load for that bullet with H4895 that I'll use when I run out of AA2520. My H4895 load for the 40 gr. Noslers is 27.6 gr. with WW neck sized brass and Remington 7½ primers. The muzzle velocity with 27.6 gr. of H4895 is right around 3,935 fps. I believe Hodgdon lists 27.7 gr. as the maximum load of H4895 with the 40 gr. Hornady V-Max. The V-Max and Nosler BT bullets are of different shapes, and that will create different pressure levels in your rifle, so it is a good idea you plan on starting down in the 26.0 gr. range and working up slowly.
Post some of the results of your tests done on paper and also results when you take that rifle out after coyotes.
