05-14-2014, 02:11 PM
Tony Williams Wrote:The .300WM and (to a lesser extent, I think) the .338LM suffer from the usual problem that the COAL is too short to permit the use of the long-ogive bullets which give the best long-range performance. I suspect that the .338NM may turn out to be the optimum choice......interestingly enough, the Rem MSR is advertised as available in this calibre.The .338NM (Norma Magnum) is pertinent to this thread since it is essentially a "Grendelized" .338 Lapua Magnum. The case has reduced taper and increased shoulder angle to allow increased powder capacity in a shorter case. The shorter case allows a longer bullet to be used while maintaining the same cartridge OAL. The two cartridges have the same base diameter. See the comparison photo here:
http://en.wikipedia.org/wiki/.338_Norma_Magnum
The .338 Norma Magnum has increased flexability over the .338 Lapua Magnum:
- If desired, the .338 NM can match the performance of the .338 LM (when using the same bullets) while using a shorter rifle action (this is one reason for its creation).
- When matching the cartridge OAL of the .338 LM, the NM can use longer, higher BC bullets to increase its effective range.
- A longer bullet can have increased internal volume that can be used to make it more effective as a tracer, AP, incendiary, HE, etc round.
- According to General Dynamics, the differences between the 338 Norma Magnum and the .338 Lapua Magnum round make the Norma a better machinegun round:
http://www.dtic.mil/ndia/2012armaments/W...teimke.pdf