Longtime Handgun guy needs rifle advice

[Sevens]

Got my first "real" center fire rifle to play with. It's a Howa 1500 Varmint in .223 with a 24" heavy barrel. I believe that it's got a 1 in 12" twist. I'm looking forward to some great distance fun with it.

I've been a hardcore, VERY avid handloader for handguns for years and years. I currently and actively load 16 different handgun rounds with fantastic results. But the accuracy I'm looking for in handguns shows up at 10-25 yards.

I've dabbled in rifle, made a few here & there for a few friends with decent results -- but I never expected anything astonishing by simply loading some safe, functioning rounds in rifles that I didn't get to work with hands-on.

Now, I'll be doing my first true rifle handloading for precision. My goals, in order:
1) sub-1" group on paper at 100 yards
2) any kind of group I can live with on paper at 300 yards (don't know WHAT to hope for?!)
3) banging steel plates at 100 to 300 yards...
4) getting SMALLER steel plates and banging them at 100 to 300 yards
5) ultimately, take the rig & ammo to South Dakota and shoot P-Dogs with them

I have lots of brass to pick from, but it sounds like I should simply let all the R-P, PMC, Federal and WCC sit and simply use the load of L-C brass that I have. Good enough.

But bullets...
Do I simply pick ONE bullet and play with different powders and different COALs? Or do I pick multiple different bullets and instead play with ONE powder?

In bullets, I have EIGHT different on hand ranging from 40 grains to 60 grains in weight.

In powder, I have only H335 and H4198 that are appropriate for this round.

Given that my ultimate goal is prairie dogs...should I just start with my 40 or 60 grain Hornady V-Max bullets? Or should I use the BIG box that I have of Midway bulk 55 grain PSP slugs that I *believe* are Nosler overruns?

Or am I over thinking all of this and I simply need to throw together something that'll go BANG and see what the rifle has to say about it?!

I appreciate thoughts & comments.

[4runnerman]

Welcome to the rifle phase. First off you are starting with a very good set up. Howa's are sub MOA rifles. All rifles have there own little quirks if you will.
1 in 12 is a comon twist Should be able to run well into the 60 to 65 gn bullet weight with it. Picking a powder and primer and bullet is the biggy.
What i do when i first get a new rifle is google your model and see what others are shooting and reporting on it. KInd of gives you a general starting point. This is not a plug,but go to reloaders nest.com. There are a multitude of loads there and you might find some one that is shooting your same rifle.
Take load data from that sight with agrain of salt. 1 inch groups at 100 yards should be a cake walk for that rifle. Since the farthest you mention is 300 yards i would think you should still be pulling less than 3 inch groups with ease also. Your brass pick at 100 yards will make next to no difference,that will start to come into play at a distance. Hornady or Nosler or Serria,,Never seen a dog care which one he gets hit with. Shoot the one your rifle likes and go with that. Myself, I shoot 60 gn Hornady's. With a 223-powders are all over the place, H335,Varget,Tac,RL-15, ect ect. Read Dan Newberrys load development and have fun.