Personally I use the load data for just about every rifle I own. I use the new manuals, along with RCBS Load to compare data from all of the past major manuals as well as some from the past. It is nice to pull up say the 7mm STW with data from several books already loaded into the system, then pick the powders, bullet weight, and hit OK and view what they got. This only gives an idea on what to expect, but with a little thought, it also gives me the best powders to start with and have an idea of where I might end up.
As for the data not being close, that is figurative. I load for twenty comething different rifles. I have some which I deveolped loads for years ago and just tend to be satisfied with the results. The others I play with here and there through the year. When I decided to work with a new powder or bullet, or even a new rifle I do a lot of research from the manuals on what has worked for them. 98% of the time it will also work for me. For new handloaders or the occaisional handloader, they are an invaluable tool in getting things right, without blowing things up.
As for the factory loaded stuff, I as well as my bud shoot 90% handloads, but we have also found that some of the factory stuff is just too good to pass up. The Hornady light and heavy mag stuff is nearly impossible to duplicate with the components we have used. IT also shoots groups from the couple of rifles we have tried it in that even our best handloads have a tough time competing with. I just picked up a 7 STW before Christmas, and wanted to get it going quick so I ordered everything I needed for handloading and also found a great deal on some Federal loaded with the 150gr Nolser Solid Base. Hell it shot just over 3300 fps from the rifle I have, and put them under 1/2" at 200yds. SO I promptly picked up a doxen boxes for it. Hell I figure for what I will be using it for and out to 800yds with the groups I get, no reason to worry about a load for it. I do have everything to work on loads using 160gr stuff, but when it comes time to hunt, I just grab up a box and go. The same can be said for my T/C Contender in .223AI, and my Ruger .308, both shoot so **** well using the plain jane factory that I don't feel a need to try and improve on it. The .223 AI shoots the $12.99 40 round Win 50gr Varmint pack bullets into sub MOA groups out to 300yds, and the 308 will keep them under 1" at 100 easily. I tried on several occaisions to get something better for the .308 but ended up going back to the Green and Yellow Remmy 150gr Core Locts every time. At 10 bucks a box I just see no reason not to.
The factory "premium" loads which are out now are using powders which aren't openly available to consumers at this time, in some loads. However the older steadfast standard stuff which has been around for years does have available components which can duplicate the factory stuff.
I do try and find loads for every rifle and have since found a couple loads for the .223 and the 308, and am working with the STW, but for the most part, I will just store these loads away for the future since I can easily head to the woods with the factory knowing exactly what to expect.
