285 OKH, 7mm-06 Mashburn, 7mm-06

Historical Notes:

These cartridges are lumped together because they are practically identical and, except for headspace specification, they are also very similar to the 280 Remington. The 285 OKH is another O'Neil-Keith-Hopkins development which originally used a duplex loading consisting of different powders with different burning rates loaded one on top of the other. It also employed a long flash tube that ignited the powder at the front of the case instead of the rear. This was supposed to improve ballistics and apparently did to a slight extent, but was a lot of trouble and rather impractical for the average reloader. All of these cartridges originated in the late 1940's and early 1950's.

General Comments:

Because these cartridges hold about 2 grains less powder than the 280 Remington, maximum 280 Remington loads are not recommended. The various 7mm's based on the 30-06 case are worthy of mention because they were the wildcat forerunners of the commercial 280.

Source: Cartridges of the World

285 OKH, 7mm-06 Mashburn, 7mm-06 Reloading Data
Bullet (grs.)	Powder / (grs.)	MV	ME	Source
100	IMR3031 / 45.0	3110	2150	n/a
125	IMR4350 / 57.0	3195	2840	n/a
150	IMR4895 / 48.0	2890	2780	n/a
165	IMR4350 / 52.0	2820	2920	n/a
175	IMR4350 / 55.0	2720	2880	n/a

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