I will not mention loads. There are some good ones already mentioned above and I don't have mine where they should be yet. I will give a few hints based on some of the comments made:
My brass is all trimmed to same length and is same lot number. You are doing good using the fireformed brass and neck sizing. How is your trim length? Primer seating?
I seat my bullets about .008 -.010" from the lands. .03" is a pretty good jump. If the magazine in your Ruger allows it, seat your bullets out a little bit more.
I have several Ruger Model 77s and they rest in a heated room with a humidifier. I do NOT clean them religiously. (I am not saying they are dirty and grimey as they are NOT.) In fact NONE of my guns get the bore cleaned after 12-16 shots. Most of mine don't start shooting well until I have seasoned the bore with a couple of boxes (40 rounds) of ammo. I will not shoot my .22LRs for groups until they have minimum of 10 shots with the trial ammo down the bore. A couple of weeks ago I pulled out my hunting rifles to get them ready. I noticed a little dust on them so I did wipe them down good and ran a few patches down the bores. I was nearly thru with my first box (20 shots) before my 6.5x55 started touching shots consistently at 100. Is it me calming down or the seasoning of the bore? I don't know, but that is when it started to group. My .243 WSSM was shooting cloverleafs from the start, but they were in the wrong place on the target. I made a few minor adjustments and was about 12-15 shots into it when 5 shot groups closed to coin sizes.
Put away the cleaning rod and let those accubond season the bore good. See how the groups tighten up. My shots above were with Nosler Partitions. I am a solid believer in leaving the bore alone until the dirt takes away from the accuracy. Some target barrels that is a few shots. Most of my competition handguns it is many hundreds of rounds later. My FA revolvers need a good cleaning after about 250-300 shots. Only need it then due to soot build up on face of cylinder making it hard to rotate cylinder with tight barrel gap.
Dont wait 10 minutes between shots. Your body and brain are forgetting what you were doing and what you are there for. If I am going to shoot for groups, I usually blast a few shots as plinkers just to get the gun warmed up good. If I am loading a specific powder /bullet combo, I may load 20 of the starting load and then 10 of each load in succession until I fill a 50 round ammo box. I shoot about 10 of the starting loads to warm up, let the gun cool off, and then start with 3-5 shot groups with the next trial loads. If I need to, I go back and shoot a second round of shots to break any ties. Left over shots get put down the bore at extended ranges or at off hand targets.
You have a hunting rifle and some of the "bench rest" techniques you are using are doing more harm than good. (IMHO)
Steve