Tony Kent (Login tonyk60) Posted May 24, 2015 4:23 AM
I agree with JP, you will always get leading, just a fact of life running with HBWC. Because they are swaged the projectiles are inherently soft, otherwise you would never swage them. If you have miked the cylinder lead (that bit which the proj glides through before it hits the forcing cone) and your projectiles are at least the same size as your largest diam chamber then you are then on the right track to some sort of accuracy, as long as your barrel is no larger diam than this measurement.
Not knowing what sort of press you are using I can only tell you what i did to dramatically shrink my groups.
I use a Dillon which uses a insert in the powder die to bell and drop powder in, unfortunately the inserts are great for jacketed projectiles, not so for soft lead. So what I did was have a long insert turned up .001 larger than the diam as the projectile I am using, theoretically expanding the inside of the case to .358 to the same length as my projectile.
The issue with HBWC as we know, is that they are soft, if you want to see how much of an issue you have, carefully pull a loaded round and mike up the projectile. Brass cases are squeezed down to SAAMI specs by the die, brass will compress and then due to it's nature expand slightly. Unfortunately this happens also when you expand the case, expand and then contracts. By pulling the projectile you can see just how much the case compresses the soft lead, if the head of the projectile is undersize then this causes the leading. With my increased diam expander die and longer length the projectile is being held by the crimp, not by compressing the projectile down to .354.
Leading was reduced dramatically, accuracy increased also.
Each brass manufacturer uses different thickness brass, Winchester is great in my gun, Lapua isn't, RWS at a pinch. Each manufacturer has a slightly different head thickness also... but that's for another post....