Engineering101
Well-Known Member
I've seen quite a few folks buying 338 Lapuas. I always wonder why when the 338 Edge or even a plain vanilla RUM seem to stack up better. The volume of the cases (per QuickLoad) in grains of water are:
108gr - 338 Lapua
110gr - 338 RUM
113gr - 338 Edge
Also, the bolt face is bigger on the Lapua which puts more force on the bolt at the same chamber pressure. Overall cartridge length for the Lapua is 3.681" per SAAMI standards versus 3.600 for the others so magazines and actions have to be slightly longer.
Lapua brass is hands down better than Remington brass, but that isn't an issue since Nosler came out with brass for the RUMs as it is excellent.
Also Nosler says in their latest handbook, "The 338 RUM delivers surprising accuracy for a large magnum cartridge. It has become the standard 338 caliber test round for the Nosler Ballistics Lab." They could have picked a lot of others including the Lapua as their standard – but didn't.
The highest velocity that each can drive a 250 Accubond in equal length barrels is 2,941 fps for the Lapua and 2,990 fps for the 338 RUM. (Nosler reloading guide number 7.)
From what I can see the 338 Lapua has only disadvantages compared to the 338 RUM let alone the Edge so what gives? The disadvantages are not large but still, why do they sell? Savage for example doesn't offer a 338 RUM but they build more than one Lapua model. What am I missing?
108gr - 338 Lapua
110gr - 338 RUM
113gr - 338 Edge
Also, the bolt face is bigger on the Lapua which puts more force on the bolt at the same chamber pressure. Overall cartridge length for the Lapua is 3.681" per SAAMI standards versus 3.600 for the others so magazines and actions have to be slightly longer.
Lapua brass is hands down better than Remington brass, but that isn't an issue since Nosler came out with brass for the RUMs as it is excellent.
Also Nosler says in their latest handbook, "The 338 RUM delivers surprising accuracy for a large magnum cartridge. It has become the standard 338 caliber test round for the Nosler Ballistics Lab." They could have picked a lot of others including the Lapua as their standard – but didn't.
The highest velocity that each can drive a 250 Accubond in equal length barrels is 2,941 fps for the Lapua and 2,990 fps for the 338 RUM. (Nosler reloading guide number 7.)
From what I can see the 338 Lapua has only disadvantages compared to the 338 RUM let alone the Edge so what gives? The disadvantages are not large but still, why do they sell? Savage for example doesn't offer a 338 RUM but they build more than one Lapua model. What am I missing?