Jim, I didn't try the 36 gr Varmint Grenades. They are suppose to come out of a 22-250 straight. The issue isn't bullet weight but the length causing issues with the twist rate. But ya gotta know, these are not target bullets. None will produce accuracy that I consider acceptable for varmint hunting. If you get an inch group at 100 yds, you're miles ahead of most everybody else. Might give them a try. I've tried others and haven't found one yet that's worth squat for varmint hunting ranges in South Texas.
My brother and I hunt Federal land and local airports. We had the same issues with the bullet selection and the other BS. WE ended up with steel buckshot. Yeah, ya gotta get fairly close but because the animals generally haven't been hunted, we were actually able to get within range. We used a scoped Remington 870 with a full choke. The ammo was made by Remington and we used the 3" magnums. The scope is a Leatherwood and works great. We could reach out to about 75 yds with it.
As I was typing this, I think you might ask about a steel core penetrator bullet like the M109 bullet. They are 62grs in weight. They come out of my 223 bench guns like they think they're match grade. Don't know if they'll come out of a normal twist 22-250 1:14". If you have a 223 1:8" twist, this may be the answer or a good reason to go buy another gun. I never asked about these mostly because we are hunting a lot of airports and a rifle bullet of any kind just isn't going to work. We can't afford a ricochet of any kind. Best of luck though. It can be a challenge conforming to Fed standards but it can be done. Maybe not how you would like to do it but the hunt is more important than the kill anyway.