Originally Posted by remingtonman_25_06
Was looking over swift sciroccos the other night and came across something that doesn't seem right to me.
They claim a .571 BC from a 130g .264" bullet, how the hell do they come up with that??? Thats higher then any bullet that I can really think of besides the 140g VLD/AMAX, and its really not to far off of those. Beats the pants off any other 130 and 140 bullet reguardless. How do they gain almost a whole .1 value greater??
The 129g SST is pretty sleek and slender itself for a lowly .485
The 130g AB is also advertised at about .488
Anyone care to share thoughts or experiences with this bullet?? Love to hear it.
Think I'm going to make me a phone call to Swift tomorrow while I'm at it, pick there brain a bit...
I measured a G1 BC of .491 for that bullet. G7 BC is .251.
It's got a decent ogive design, but a poor (short and steep) boat tail for base drag reduction. Certainly not a design that could possibly produce a .571 average G1 BC. Even at 3000 fps, the G1 BC is just .515, degrading to .453 at 1500 fps.
A thick jacket for a long bullet...? Sure it makes the bullet longer, but that doesn't mean high BC. Lengthening the nose and tail will reduce drag, but lengthening the bearing surface does nothing for drag so it's irrelevant.
None of my analysis included group shooting (precision) testing so I can't comment on that. They may be extremely precise, but the BC claim is not accurate.