success weighing bullets

[kennedy]

I bought no name bulk 55gr .223 bullets to reload for my armilite ar-15 with 20 in heavy barrel and 3x9 leupold and have never been happy with 100 yd groups. I started weighting the bullets and got a range of 54.8 to 55.4 grns. so I divided them into a low weight and a high weight group and loaded with 25.5 grains of varget. Now i consistently shoot 2 inch 10 shot groups at 100 yds. my cost 18 cents per round.

 

[ReloaderFred]

That's only .6 grain, so it begs the question of what they shot before you segregated them? Just wondering.

Fred

 

[kennedy]

the main grouping was the same with several flyers, now no flyers unless I flinch

 

[Dave P]

You might also sort them based on ogive-to-base length. This dimension will change the volume/pressure of the cartridge.

 

[kennedy]

next going to load up some sierra matchkings to see how it really will shoot

 

[murf]

why don't you get a box of federal gold metal match 69 grain and see how your rifle does. that will give you the best baseline for your group shooting.

murf

 

[Bart B.]

Sierra Bullets sees no accuracy problems at 200 yards with a half grain spread in bullet weight.

I've seen insignificant difference at 600 yards with that much spread. And very little at 1000.

The critical distance reference for bullet ogive measurements is the case shoulder, not the case head nor the bullet base. Chamber shoulders stop the case shoulder on rimless rounds at that point when fired and the case head will be away from the bolt face by the spread in case head to shoulder measurement. There'll always be a small spread unless your bullet seating stem touches the bullet at its same diameter as the barrel's throat does. On 22 caliber bullets, that's typically at about .222" diameter; that's the point to reference on the bullet. These places are what controls bullet jump distance to the rifling/throat.

 

[murf]

bart b., how does one get consistent bullet seating (assuming a correct seating stem) since presses index off the case head, not the case shoulder? is there a particular sizing method that results in a consistent case head to shoulder distance?

murf