HUGE


different powders have varying burn rates, therefore different pressure pushing the projectile out of the bore....equalling different bullet speed, which equals different bullet rpm.......all have an effect on accuracy.

One more for TAC here, I'm with Dryflash on the W748, no luck. Take the stuff you don't like and do a couple of mag dumps, it's good for the soul. Then you've got brass to reload. The beauty of it is, powder, primers and bullets are consumables. You'll buy more, no matter what. Also you'll try a ton of stuff before you settle on a load you like. I know very few people who have stumbled on to a good load with the first couple of tries.

What I've personally had the best luck with is the Sierra manual( I like their bullets anyway). I look at the velocities for the most accurate loads, and compare them to all of the other data I have available(several different manuals, online...etc..). I'll start below that and work up to it in small increments, keeping an eye out for signs of overpressure. There must be something to it as far as I can tell? It seems generally, according to the load data that I end up very close to their stated accuracy load? Just by the book, as I don't have a chronograph yet.  Does that make any sense? Sometimes things I say make sense in my little brain, but don't convey well

Just my opinion of component effect on precision from most effective to least effective:

1)  bullet

2)  powder

3)  case

4)  primer

I found out this weekend that with my rifle the difference between BL-C(2) and 8208xbr is a big one.

This was with a 16" BCM midlength firing 77gn noslers.

Powder can matter a lot from gun to gun. My Stag cannot be happy with TAC or 4895 and 55 Hornady FMJBT. However it likes Varget and h335 a lot.
With my 243 BDL, it loves 70 Sierra HPBTM when 4895 pushes it but not so much with 4064.

I can get a useable load with WW-748 in .223 and .308.

.223 I can use 26.0 grains of WW-748, Winchester primers and 52 grain Sierra Match Kings just under 1" groups.
.223 I can use 25.0 to 25.3 grains of WW-748, Winchester primers and Sierra's 69 grain Match Kings. Same accuracy as above. (2770 fps)

.308 I can use 43.0 grains of WW-748, Lake City or IMI brass, Winchester primers and 168 grain Sierra Match Kings seated at 2.810" (2480 to 2500 fps) Fired in my M1A's.

Powder selection is important. Go with the winners. If your going to shoot fmj's you'll never get great accuracy, so it really doesn't matter what powder you use within reason. Once you start shooting any of the match bullets run the powder that competitors use in that combination. Most of the work has been done through trial and error. They settled on certain loads because they work. If they worked for them they will work for you.

And the winner is?