The only bullet I have shot in mine so far is the 150 gr Ballistic Tip. 90 gr of IMR 7828SSC with a Fed 215GM primer will comfortably launch it at 3375 fps out of my factory 26" 700. Groups run around .5" or a little less at 100 yds. I know this is a little lighter bullet than what you are looking at. You might also look at the 160 gr Accubond in addition to the Sierra 175. Best of luck with your rifle.
Groups that average .5" would be fine with me. I may try those ballistic tips. On another note, I'm a little unhappy with the fact that my dad, who has a .300 ultra, can get 3200+ fps with a 180 gr and I can't break 3200 with a 175. It seems to me that, with the same case capacity I should be getting at least what a 300 gets with a lighter bullet. I've never chronographed this, just what I've read in manuals. Any ideas why this might be? Any idea why there is little published data from the bullet/powder manufacturers?
Hick's with the 160 and factory barrels I am getting 3250 with no pressure signs. The 175's shot the best out of my gun at 3150. These loads are all worked up during the summer. Retumbo hasn't veried more then 20 fps with a 50 degree change and the US869 varied 50 fps. The best powder I have used so far has been H-50BMG with only a 10 fps change over an 80 degree change. I hope someone else can explain the reason the 175 grain in a 7 won't beat a 200 in a 30. From mine use they do but I settle with accuracy verses speed. Dave
I hope someone else can explain the reason the 175 grain in a 7 won't beat a 200 in a 30.
Well not that I am an expert on it, but I would say expansion ratio & bearing surface.
Depending on the bearing surface you will hit higher pressure signs in the smaller diameter longer bullet than you will in the fatter bullet with less surface.
Also even though not that much actual difference in bore size the .284 is still smaller than the .308 and when getting into top ressure loads this will make a difference in burn rates and pressure peaks over the distance of the entire barrel length.
the reason for higher speeds with larger diameter bullets is more surface area being pushed on. there was quite a debate on this a while ago, less bearing surface, faster burning powders and about 16 other things all come into play. just remember a larger dia bullet will usually be shot at a faster speed all things being equal.
i had a 7rum with a 30" barrel and shot the 180 Bergers around 3250 with 99 gr of 872. i know Retumbo would give more velocity.
Hicks, One of the guys at Sierra told me that they would never have loads listed for the 7mm RUM, after they had a bad accident in the testing lab. He told me the 7mm RUM was the ultimate overbore, and once you reach a certain point in loading, the pressure starts to increase dramatically, and that is what caused the accident during testing. He would not tell me the specifics of the accident or anything else, except that if I wanted the ultimate 7mm, to rebarrel to 7mm STW.