OU812
posted this
03 April 2017
The best bullet fit will not shoot accurately if powder charge is not correct. Get the powder charge correct and the better fitting bullet will shoot best. Hard alloy bore riding bullets should be round, snug slip fit at muzzle and seated inline with bore. I have experimented with fatter bore riders in my rifle and seen worse to no difference in accuracy...must have been that fatter caused too much pressure rise...needed slower powder.
I know it is not mentioned nor recommended much, but 748 ball powder works very well in my 223. The muzzle blast also sounds more lazy or softer than the quicker burning stick powders. Some say that 748 is sensitive to outdoor temperature swings...I shall see.
Once you find the perfect powder you will need to keep pressure consistent. Neck sizing only is one way to keep pressures more consistent.
I bump my bore riders and one thing that I have noticed is that some of the bullets fit die differently before bumping. Some are light slip fit and some must be tapped into die before bumping. After bumping all bullets exit die with near same resistance. Bumping helps keep pressures more consistent because bullets are now more consistent in size.
I know bumping sounds logical, but even this will not work if powder is either too slow or too fast or pressures changed because you have changed something from last accurate test. Such as inconsistent bumping pressure from one batch of bullets to the next or age hardening of alloy. These are just a couple of things that can cause inconsistency when shooting cast.