Originally Posted by
BillBrasky
........ For instance, the 175 and 180 grain SMK's have virtually identical BC's between 2800 and 1800 fps, but the heavier 180 grain bullet will need to be seated slightly deeper than a 175 grain bullet, correct? That would mean that the slightly smaller bullet with the same BC may have an edge because it would allow for more propellant which means a higher muzzle velocity and energy.
I think you are splitting hairs here. In theory, the lighter bullet should go faster, but the difference in weight in this case is so small it might get lost in the other variables. The BC's may vary slightly from the manufacturer's numbers also, and they will vary from gun to gun. Some guns spit the bullets out with a yaw angle and it takes awhile to stabilize, and they have a lower BC till that happens.
The 180 grain hunting bullet is most likely shorter because it won't have as long a nose, and maybe not a boat tail.
My question is whether the standard 180 grain hunting bullets are much more available because the amount of powder being lost is inconsequential regarding ME and MV, or if it's because the larger cases of the 30-06 et al., are better suited to the heavier bullet and it's cheaper to produce one bullet that works decently in all .30-cal weapons.
I would guess the weights that are available are because that is what we've always done. The 150, 165, and 180 are what has been marketed to the public from way back, and the match bullet weights were probably specified by the military.
If it doesn't make one bit of difference between the 180 and 175 grain bullets, then I was thinking of a 180 grain Partition or Ballistic tip as being my load of choice. If there is a substantial difference between the 175's and 180's, then it may be worth it to try out those 175 grain VLD's.
Realistically, the only place you can have substantial differences are in BC, accuracy, and terminal performance.
The differences in velocity are not worth the effort.
The differences in BC won't come into play until you get way out there.
The differences in accuracy matter a little more, but again, not until you get way out there, as long as you are getting decent accuracy to start with.
The differences in terminal performance can be important, but if you hit them where it counts it hardly matters, as long as you get some expansion. Sierra says don't use SMK's for hunting but some people do anyway. We have gotten pretty carried away with premium bullets these days but a deer won't notice the difference. Premium bullets just aren't necessary unless you are getting way out there, or shoot a magnum that blows up plain jane's.