It is a bit of a myth that larger chamberings MUST have longer barrels to be faster the smaller capacity rounds of same caliber. Learned this from many years of building some rather extreme handcannons on the XP-100 platform.
in a 26" barrel, a 280 AI will be faster then a 7-08 obviously, but as barrel shortens, the 280 AI will always be faster. The velocity spread may narrow a bit but it will maintain a significant advantage, remember the 7-08 will also loose velocity. while the advantage in a 26" barrel may be 150 fps, in a 16" barrel it may be 100 fps but still faster.
excessive fireballs are generally a result of the powder type used more then anything and this is under your control to some degree by hand loading.
if efficency is big on your list, that being the FPS generated per grain of powder, then go smaller but a properly loaded 280 AI will solidly outperform any 7-08. As will a 7mm Rem Mag outperform any 280 AI in same length barrels when each are loaded to same pressures.
here in lies the issues. Its common to lean on the throttle a bit with smaller rounds to make them look more impressive then they are compared to the larger.
simply put, the fastest round in a full length barrel will still be the fastest in a shorter barrel, advantage may be slightly less but will still be faster.
similar debate as to a 7-08 AI being 100 fps faster then a standard 7-08. How is this possible with only a couple grains increase in powder capacity, simply put, most will run the AI to higher pressures then the standard round….
probably just ****ed a load of people off which was not my intent.
