I have a used 700 in 25-06 that is giving me grief right now, but so far I have only worked with 120 Nosler Parts because that is the bullet I would like to use in it. I have tried several powders and some COAL changes but so far nothing is showing promise. Sometimes it's just the nature of the beast, when I have exhausted the suitable powder selection for the Noslers I'll be trying a 125 Maxtix bullet in it, and so on, and so on, and so on.................................
I have found 1/4 bores to be finiky anyway, but have always found a load except for an old Win featherweight (push feed, first year) in 257 Bob that absolutely would not shoot, period.
7RM is not a particularly difficult cartridge to load for and I have had several that shot very well with several different loads...........keep plugging along and you should succeed.
My personal method is to try a few loads and if nothing is showing any promise, my first change is to add forend pressure to the barrel, this works 50% of the time on sporter weight barrels. Next is to bed action and chamber only, float barrel and if still no improvement I again add forend pressure. There can be upwards of 100 test loads between each change, depending on my goals and expectations for that caliber and rifle. If it still won't play nice I will then re-crown it and try the loads that showed the best promise again. I had an 8mm RM that was giving me fits and I even rechambered it twice. The list can go on "ad nauseum" however somewhere you just have to say "enough" and either sell or rebarrel it, which I did with the Sako 8 RM and in 300 WM it shot 3/4" with 180 NPs and I took it to Africa and it performed flawlessly. I will also change scope and rings somewhere along the way, sometimes twice even, just to be 100% sure.