Water leaves no voids in the internal volume comparison test, and knowing the cases are all well formed to the chamber on the outside, this leaves but one place for the additional brass to be on the heavy ones IMO.
One could verify this submersing them in liquid and measuring displacement, but internal volume is all I'm concerned with.
Hey I have a keeper,Rem 700 sporter weight in 300 RUM.180 gr nosler gold partion in front of 97.5 H1000 gives me 3367FPS and 7/8" 5 shot 100 yds .Vias muzzel Brake,sounds like atom bomb.BBL very hot after just three rnds.But who cares!!! Long live the 300 RUM.With out muzzel brake recoil is a nightmear!!! With brake 6or 7 rnds in a half hour is about all I can take.Might sale it for right price!!!
How does it profit a man if he gains the whole world but loses his soul?
I can't agree with the 300 Ultra-Mag reccomendation over the 300 Wby at all. The 300 Wby will outshoot the Untramag any day of the week. I have a 300 Wby, and a friend of mine has a 300 Ultramag while yet another friend has a 300 Win mag. We all go out to shoot at a range north of Byers Colorado which goes all the way out to 1000 yards. My best 3 shot group with the 300 Wby at 100 yards is 1/2" and is always under 1 ". The best group I ever shot at 300 yards was 1 1/2". I think that this shows the potential of the gun. Yes the cost of the rifle and shells is high but worth it if you want the best in performance. One problenm with the Remington UM is a lack of bullet choice. The last I looked the only shells you could get were Remington brand (a 150, and 2x 180s Core Lokt and now a Boat tail (match). The UM bullets are harder to find than the Wby to date. I just checked again and they have added another 150 and 2 more 180s but the Wby still has a better selection as they load Hornady, Nosler and Barnes bullets. Just like with any gun you have to find a bullet that shoots well on your gun. I found that the Wby doesn't seem to care which bullets I use. Its very forgiving with bullet type, and barrel temperature. I have seen a lot of guns with a 2" difference between a cold barrel shot and the next 2 bullets. Not with the Weatherby. Its very consistent. The Weatherby uses a Kreiger button rifled barrel which is a good barrel. You get what you pay for. Weatherby guarantees out of the box an 1-1/2" or better group at 100 yards or you send it back in. There aren't any Ultramag guarantees like that. So on to the head to head comparison. I can completely outshoot the Ultramag with the Wby from a benchrest at 100 yds. I have done it in person at the range. I should probably shoot the Ultramag at longer ranges but if it can't shoot 1-1/2" at 100 yards its not gonna do it at 300 yds. Now the problem with the comparison was that I shoot Noslers and the UM was shooting Remington Core Lokts. The UM needs a better bullet for a real comparison. There may be better rounds for the UM coming out that will tighten up the race, But right now the Wby is years ahead of the UM. The head space issue has been debated forever. the Wby doesn't suffer accuracy problems because of extra headspace. The Wby has to have the extra headspace because of the high pressures generated. The 9 lug Wby bolt is the strongest in the industry. It has to be because of the high pressures generated by the ammunition. The bottom line is that the UM was created to compete with the Wby and Remington did meet the velocity specs. However, the Wby rifles are of higher quality than the Remingtons. Remington is going to have to put better barrels on their guns to compete with Wby thus raising the cost. The bottom line is that Wby has a guarantee on accuracy which tells you what you need to know.
I completely disagree with the .300 weatherby being better than the .300 RUM. Yah yah, accuracy guarantee so what? Who really needs one? I have a Remington LSS .300 RUM and it will outshoot your weatherby as you described. I have shot 3 shot groups at 800 yards of 3.5" and 4" with the 150g CT B-tip and 1.5" 3 shot group at 525 yards with the 200g Accubond. Both are handloaded by me. I dont shoot groups at close range as it defeats my purpose of a LR gun. Who needs a Weatherby when you can have a .300 RUM? Not meant to start a ******* match here, but your knocking the RUM, I'm knocking the Weatherby. I'm smart enough to know that 1 observation doesn't mean its an average. Bottom line is finding a good load that will shoot. In my opinion though, the RUM is on top of the Weatherby.