Re: .30-378 Wtby Mag vs .30-338 Lapua Mag vs .300 RUM vs .300 Jarrett
If you like toying around with wild cats, the go with the 300 jarett or 30-338 LM.
If you like using expensive crap brass, go with the 30-378 wby.
If you want an inherently accurate rifle with more of a selection of brass, go with the 300 RUM.
The 300 RUM gets my vote. The reasons?? While the 30-378 will be faster than the 300 RUM with a given twist, barrel length and bullet weight/style. You will only get your brass from 1 source, weatherby and it is not very concistent. The 300 RUM at least offers you federal, remington and nosler brass and its getting better year after year. Also, there is no pesky belts to work around, although, with some effort, you can bypass the belt altogether. Also, the remington 700 action is an all time favorite among most LR shooters and alot of good rifle smiths will not build a 30-378 wby on a 700. If a 700 is the action of choice and your smith wont build the 30-378, that leaves the 300 RUM or 300 jarrett as the likely candidates.
Ask your self which qualities are most important to you and what will make you happy. Confidence is part of the key to this sport. Remember though, that it is only part. Confidence also comes with a rifle and round that will lend itself to doing what you want. I want differant things than you and you want differant things than others here. If all you want to do is see how fast you can drive a 180 grain bullet, and dont have an aversion to the Mark V action, or dont mind building on an action with a smaller bolt for a huge case then the choice is simple. The 30-378. If you can afford a little less velocity and want better and cheaper brass, the 300 RUM or jarrett will work fine.
Long range shooting is a process that ends with a result. Once you start to focus on the result (how bad your last shot was, how big the group is going to be, what your buck will score, what your match score is, what place you are in...) then you loose the capacity to focus on the process.