Alright, so I finally found the rifle that I had been looking for, a Gunsite scout in 308 with the laminate stock, stainless barrel, and flash hider. This will be used for a woods gun on deer, hogs, and coyotes if they run through.

Anyway, I reload my own 308, and my go to for my savage 10 is a 165gr Sierra game king. Now I’m curious what grain works best in the Gunsite just so I don’t have to waste a ton of time reloading 165s and 150s. I had a savage that I couldn’t find the right load for, and I tried everything. It ended up like federal blue box 150s from Walmart. Strange. So if someone here can steer me the right way on of the rugers prefer the 150s or the heavier 165/168, then it would help me out tremendously.

AFAIK, most Ruger GSRs were made with a 1-10" twist barrel.  By all means verify this, and report back with cited info.

1-10" ROT is ideal for bullets about 150gns, all other things being equal.  It is common for expert handloaders to make ctgs which will greatly exceed, in accuracy, modern factory made ctgs.  Milsurp ctgs, are usually well below commercial ctg level of accuracy.

FWIW, I make "generic, Milsurp ctgs", using a chronograph to determine bullet velocity with handloads compared to genuine Milsurp ammo, as well as stated official bullet velocities.  I spend a "good deal" of time and effort in case preparation, and it pays off.

Suggest you shoot your Ruger GSR rifle with many suitable types of ammo and take careful notes.  Eventually the ammo your rifle "likes" will become apparent.

Stock up.

At the same time, strongly suggest trying out different types of optics.  Likely the proper choice of optic will serve better than the "exact" bullet.

I started out shooting 168 bullets in my Ruger Scout.  It was good and I didn't give it much more thought.  Later, I ended up with a box of 150 grain ammo and at the range, at 100 yards, they were very accurate.  Not sure that helps you, but that has been my experience: both good, 150 was a little better.

Mine behaved similarly well across a few bullet weights. I’ve tried 125, 150, 165 and 180’s. I settled on 150’s as a blend of weight and velocity. The short barrel means heavies are pretty stinking slow.

My average performance is at or slightly above MOA with a fixed 2.5x scope. I’m thrilled with this.

Thanks guys. This is what I was looking for. I’ll try some 165 sgk just to see, but I’ll also try some 150 hornadys and 150 sgk

I don’t reload, but Hornady Precision Hunter with 178gr ELD-X bullets are as accurate as any load I’ve tried in my 16” GSR, which I’ve owned since they were first introduced (at least 13 or 14 years ago now.) It’s still my go to deer rifle, I love it.

Mine shoots 1 MOA with Winchester Silvertip.  I just got stupid lucky with that, and stocked up on Silvertip as a response.

The heavier the bullet and faster it was going, the better mine liked 'em.

I had the opportunity to load some “lighter” loads for my Ruger GSR this year for my daughter in law to deer hunt with. She is recoil shy and I finally settled on a Hornady #3035 150gr RN (30-30 bullet) over 25.0grs of Allianz 2400 powder.  Stacked them in one hole at 50yards and less than an inch at 100 yards.  It was right around 1950-2000 fps, so basically turned it into a 3030
She killed two nice deer with it this year, 1 at near 100 yards and it worked great.

When I get it back from her I’m gonna load some 150gr RN designed for the 308 (full power) and try them out.

As said by others, it's always useful to experiment with different bullets/loads.  Each firearm has its own "likes".  Since the GSR barrel Rate-Of -Twist (ROT) is 1-10", starting with bullets of "about" 150 gn is suggested. By all means "branch-out" and take careful notes.

Note that the Ruger GSR is (or has been) made in different barrel lengths, the longer barrels usually imparting more energy (velocity) to the bullet. Probably a very slight difference, but something of which to take account.  It "may" be that the slightly longer GSR barrels may be more "friendly" to heavier bullets.

Just a guess.  Experiment and take good notes.  Every firearm is a little different concerning what ammo it "likes".

Well, I tried my luck. I actually got sub moa with my 165 handloads. 150s were about 1.5 moa. I have the stainless model with the 18” barrel

Suggest GSR user include barrel length into their observations.