Originally Posted by davewilson
i would agree with the word "picky" and i would also agree with the 180 Bergers.
what i found works with this cartridge is to make it a 338!
The following is a "Quickload" comparison of a 338 RUM vs a 7mm Rum, both with 30" barrels, both with ~90% SAAMI max pressure using available powders picked for high velocity. In this example "long range" is 2000 yards.
cartridge 7mm RUM 338 RUM
Bullet 180 Berger 300 SMK
Powder H870 91.8gn Retumbo 96gn
Muz V 3170 fps 2725 fps
2k V 1117 fps 1044 fps
2k E 494 ft-lb 726 ft-lb
2k drop 1568 inch 2033 inch
2k wind 25.1 in/mph 27.1 in/mph
2k TOF 3.32 sec 3.74 sec
At some distance a higher BC projectile will have a flatter trajectory than one with a lower BC independent of initial muzzle velocity (within reason) . In the case of the 7mm RUM and 338 RUM however that distance occurs when both projecties are subssonic. The 338 needs more case capacity or higher pressure to equal the supersonic trajectory of the 7mm RUM than the 338 RUM case can provide.
The 7mm RUM offers a flatter trajectory, a little lower wind deflection, and most noticably less recoil. The 338 RUM offers more delivered energy, larger holes, and longer barrel life.
I woudn't bet on either to give best accuracy. on a given day. That would depend on a lot of factors incuding the atmospheric conditions even if the rifles and bullets were perfect.
I don't own a 7mm RUM but I have a 7mm STW which shoots 180 Bergers and 338 RUM which shoots 300 SMKs. I built both for 1 mile silhouette and they are similar in design and weight. (Rem 700's, 29 & 28" barrel, HS stocks, no brakes. The 7mm STW is much easier to shoot because of lower recoil and typically gives better accuracy (for me). The 7mm STW case has less capacity than the 7mm RUM but it still gives a lower time of flight and flatter trajectory than the 338 RUM.