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Barnes themselves have stated they went to the TS or banded system to reduce pressure and to increase accuracy. They have been forthcoming with that information. They have succeeded in both of these requirements from my own observations. The smooth sided varieties did indeed increase pressure if loaded too closely to the lands. I also witnessed that, BUT if given the proper 'run' before contact did not produce higher pressure in bolt action rifle barrels over other normal bullets when driven at identical velocties.

It is possible Barnes found out many or most doubles have very short throats (just an suposition of mine - no empirical evidence) and it is possible Barnes found out their solid solids produced excessive pressure in those chambers, therefore the change to the banded principal. Banded bullets make common sense when using homogenous solids. The bullet's multipal cannelures are there to allow the metal that is displaced by the lands to flow somewhere other than being impressed into the bullets sides and stringing off the bases as possibly happened before and this works in both regards listed above - to reduce pressure and to improve accuracy.

Making the bullets undersize which further reduces stress and pressure seems as a calculated measure to further make them suitable for double rifles of normal bore sizing. The old rifles are more prone to bore/groove size variations - one must know ones rifle, it's chamber size, bore size and groove diameter. For many handloaders (unfortunately not all), this is normal. First thing I do with a new rifle is to learn it's idiocyncracies - what 'size' is it? Do I have to make my brass from others? Do I have to make my bullets or are their comercial bullets available? I shoot undersize bullets in my 9.3x57, with no worries about excessive errosion, and do it at considerably higher pressures than a .470 produces. I know the barrel will last many seasons of my considerably test shooting inclined nature. It's fun to shoot and it shoots those undersize bullets very accurately.

Peak pressure is just that - pressure readings taken at the highest pressure developed by a given load. It stands to reason that if the peak pressures are reduced, they are lower at all times or places as the bullet passes up the bore. However to prove that would require pressure readings taken every inch or perhaps closer points maybe further apart would suffice, along the barrel and compared directly with identical readings with whose bullet, what load? It is possible a 'solid' bullet produces higher muzzle pressure or mid barrel pressure than does a 'standard' bullet. Again, pressure readings must to taken to prove or disprove this. As well, strain gauges would need to be placed to show whether or not the 'solid' solids produce more or less barrel distortion as the bullet travels up the bore. We are talking about an entire repetoire of tests needed to prove just one aspect of the claims.