I do not have the exact capacities but hte RUM case has roughly 15% more case capacity then the standard belted magnum case. Pretty much splits the difference between the standard belted magnum like the 358 STA and the big Wby class cases.
I am not a huge fan of the topical metal surface finishes but there are many out there that swear by them. I guess that I am a bit more traditional wanting to see the metal in the rifle.
I will say that they will be a bit more weather resistant at least as long as the finish does not wear through. In my opinion the greatest advantage is low visibility but in typical hunting situations this is hardly a concern. I do not see a great need for these finishes on a big game rifle but there are others that do so take that for what you will, personal preference I suppose.
As far as making an action smoother, I do not know. I properly polished action is pretty damn smooth so is it better to teflon coat, in this aspect if the rifle is properly polished up, I do not see much advantage.
Teflon does reduce friction but it also wears faster then properly polished and lubed metal to metal contact. Again, personal preference and I do not see the need in a big game rifle.
The best feature about the 3 position safeties is that they positively lock the striker assembly in the bolt as well as the bolt handle down in the fully rear position.
While Rem triggers have gotten a bad rapp over the years, a properly adjusted Rem 700 safety is very secure and safe. If you are relying on your safety to keep a loaded rifle from discaharging under extreme use you are asking for trouble.
A rifle should be loaded when its ready to be fired and unloaded , at least an empty chamber all other times. While a three position safety is very useful it is not foolproof by any means.
Like any safety, if fitted incorrectly, they are very dangerous. Fitted correctly, like any modern safety, they are quite safe and reliable.
I do not know of any "gel" recoil pad. I use kick Eez pads and they are about as soft as I have seen. They do absord alot of recoil energy on heavy recoiling rifles, very nice pad.
I do not find Blind Mags all that hard to keep clean but I take pretty good care of my gear in the field. I have never seen a problem with these mags.
In a varmint or target style rifle, you will see an increase in stability and consistancy with a stock designed with a solid bottom blind mag.
In a heavy recoiling big game rifle, the difference in accuracy will probably not be as great as the increase in strength in the stock. Solid bottom stocks are vastly more rigid then an open bottom design. Rarely will you see a blind mag stock crack that has been fitted properly to start with.
With open bottom stocks and heavy recoiling rifles, this is not always the case simple because of the stock walls bowing between the action screws under the strains of recoil.
Mercury reducers do work but I feel they work as much by jus the added weight as anything. The best dampener of recoil besides a muzzle brake
These systems will vary from a few ounces to 1/2 a pound or so depending on model.
I certainly like to check out and test a Rem 700 extractor before I send them to a customer. A properly fitted Rem 700 extractor will perform very well with total reliablility with safe loads.
The Sako and M-16 extractors do offer a larger "bite" on the case rim for added support but each have their disadvantages as well. If there is a problem with the factory extractor then it is time to replace it and either of those mentioned will work. The M-16 design is perhaps the most secure as it is pinned in place but a tightly fitted Sako extractor is also very reliable and safe.