However, its shoulder was moved forward to increase powder capacity, the case neck shortened and the case length stretched from 2.500 to 2.620 inches. Maximum overall cartridge length remained 3.340 inches to accommodate function in all. 30-06 length actions, while the shoulder angle is 25 degrees.These. 308 Norma in 1960 and even “loaned” reamers to gunsmiths wanting to convert an existing.ģ0-caliber magnums included (left to right): the.
308 Norma offered slightly greater powder capacity. Shooters and hunters since the 1890s.īoth of the above cartridges became relatively popular, but that was short lived.Winchester finally announced the. 30 caliber from Winchester, but when that didn’t happen immediately, they necked the. Norma recognized the value and widespread appeal of a. By comparison, they were “short action” magnums. It is important to note that the belted magnum case was chosen because it offered the powder capacity to reach the desired performance, but also because Winchester was already making cases and retooling would have been costly. 458 is more or less a straight case and needed the belt for proper headspace control however, the. 338 feature a 25-degree shoulder for positive headspace and the belt was not necessary. Since Winchester was already manufacturing the belted magnum case, it was the logical choice to develop new cartridges during that era.IMR-7828 and IMR-7828ssc share the same burn rate. However, loads developed with the ssc version may not allow charge weight duplication when using the long cut version.There was an obvious void in the new Winchester magnum cartridge lineup, as it lacked a. 300 H&H became widely popular in the U.S.Įach of the above cartridges is based on the. And established a superb reputation as a general purpose big-game cartridge. This chronographs at an average 2907, 10 shot group, the spread was +/- 10 FPS.ĭuring World War II, Roy Weatherby sought to improve its ballistics and blew the case out to significantly increase the powder capacity, which became the. This is the accuracy load for my 300WSM with a 24' bbl.Due to the long sloping case, the belt was necessary to provide positive headspace control.
300 H&H had an overall length of around 3.600 inches and could not be housed in most. However, Winchester chose to move the shoulder forward and increase powder capacity.300 remained somewhat exotic to U.S. 300 Winchester Magnum.Start your loads low and work up in 2 tenths of a grain increments. I have found a wonderful node with the Hornady ELD-X 200 gr with IMR 4955.700, SPS, 300WSM that I load 180 gr. It is supposed to land somewhere between H4350 and H1000 on the burn rate, but it is very close to H1000. My load is max magazine length and 70.0 grains of IMR 4955 in Nosler brass (worth the cost, they last MUCH longer) with CCI 250 large rifle magnum primers.Just use the 7828 SSC powder using the standard 7828 loading data. IMR 7828 is awesome in a 243 with the 100 gr Partition. 300 WSM but it developed more.Many people expected Winchester to neck down the.