How much do you want to spend? Timney 510's are a nice upgrade for about $150. The Calvin Elites are even better but more expensive. Trigger Tech Primary's are super as well. You can spend more and get better triggers, but for a hunting rifle I would draw the line here.
I had my nonadjustable Ruger trigger worked by reputable smith. The pull and break improved dramatically at much less cost than a replacement trigger assembly. Happy with the result, just another option.
Not sure what your looking for exactly. I have an M77 MKII in .243, I haven’t messed with the trigger on it. I just use it as a hunting rifle and the factory trigger serves its purpose for what I’m doing with the gun. I have a couple other rifles that had very stiff triggers in them from the factory. I’ve installed trigger return springs from Mcarbo in those. The springs are inexpensive and usually lighten the trigger pull by a pound or two. I don’t personally don’t need match grade triggers, just want them light enough I don’t pull the rifle off a deers heart or a squirrels head. Those Mcarbo springs accomplish that for me.
Any of those already mentioned will be a noticeable upgrade for that Ruger. I also agree that a combination of a crisp trigger with a safe for hunting pull weight doesn’t need to break the bank and cost what a competition trigger does.
The rifle has a 3 position safety. I took my rifle to my gunsmith and he checked the pull on it and on my Tikka. The Tikka , I set to 2.2# pull and that is where I like it. Checked it for slam fire and it is safe. Yes I know it is a bolt action but after reading about so many people saying to be careful about how fast you close the bolt, I tried my best to get it to slam fire and could not. The pull measurement on the Ruger M77 MKII was 7.112 pounds. He is going to set it at 2.5# for me and charge me $40.00. So it will not be adjustable like the Timneys but it will be where I can shoot it.