A couple of my friends shoot and are quite happy with the .22-6mm Remington, a cartridge that's very nearly (but not quite) the same as my .220 Howell. They've both asked me to compare some ballistics of our two cartridges. Somebody in one of these forums asked the same thing (I can't remember which board). Anyway, for anybody who cares, here's one way that they compare.<P>Since they have very nearly the same case capacity and use the same bullets, I settled on one bullet (the 75-grain Hornady A-Max, which all three of us like) and one velocity (3,500 ft/sec) for my first comparison � to see (a) which powders and charges would propel the same bullet at the same velocity in each case and (b) the peak pressure resulting from each charge in each case.<P>In the .22-6mm Remington (gross case capacity 56.6 grains of water)<BR>52.0 gr �� Ramshot Big Boy �� 56,540 lb/sq in.<BR>48.4 gr �� IMR 7828 �� 56,896 lb/sq in.<BR>49.0 gr �� Vihtavuori N560 �� 54,994 lb/sq in.<P>In the .220 Howell (gross case capacity 61.2 grains of water)<BR>54.6 gr �� Ramshot Big Boy �� 50,465 lb/sq in.<BR>50.7 gr �� IMR 7828 �� 51,299 lb/sq in.<BR>51.3 gr �� Vihtavuori N560 �� 49,835 lb/sq in.<P>For my second comparison, I used the same bullet and the same three powders to see which charge of each powder would produce which velocities at the typical SAAMI maximum peak pressure of 60,000 lb/sq in.<P>In the .22-6mm Remington<BR>52.8 gr �� Ramshot Big Boy �� 3,563 ft/sec<BR>47.9 gr �� IMR 7828 �� 3,459 ft/sec<BR>50.2 gr �� Vihtavuori N560 �� 3,596 ft/sec.<P>In the .220 Howell<BR>56.6 gr �� Ramshot Big Boy �� 3,766 ft/sec<BR>51.1 gr �� IMR 7828 �� 3,631 ft/sec<BR>53.8 gr �� Vihtavuori N560 �� 3,794 ft/sec<P>Once again, for my third comparison, I used the same bullet and the same three powders to see which charge of each powder would produce which velocities at the maximum peak pressure of 50,000 lb/sq in. � the pressure maximum that I prefer.<P>In the .22-6mm Remington<BR>50.4 gr �� Ramshot Big Boy �� 3,368 ft/sec<BR>46.6 gr �� IMR 7828 �� 3,358 ft/sec<BR>47.6 gr �� Vihtavuori N560 �� 3,394 ft/sec.<P>In the .220 Howell<BR>53..9 gr �� Ramshot Big Boy �� 3,549 ft/sec<BR>49.8 gr �� IMR 7828 �� 3,531 ft/sec<BR>50.9 gr �� Vihtavuori N560 �� 3,570 ft/sec<P>All these figures are results from the same classic lumped-parameter equations, so any built-in calculation error in these equations applies equally to all the loads I've listed, leaving these comparisons of the two cartridges valid.
