dh2
02-27-2015, 11:30 PM
Since getting back in to casting boolits I have been going little by little to see how many guns I can on a cast boolit diet, doing my testing over a chronograph, I have had some rifles take right to them, My 6.8SPC is being a bit difficult, it is the first version of the 6.8 SPC, I started out with an old Lyman mold casting a 128gr. boolit pushed it with IMR4198 this did cycle the action very well ,bullet speed had a wide range, and all over the target at 25yards.
Next try was with a 114gr. mold from a group buy, I am pushing it with 24gr. of H332 all shots close to the 2144FPS average, Action cycles good, had to have the COL very short because it was going in to the rifling before the bolt was closed , but at 75 yards I get a group over 3 inches. I have been reading up on the thread " high velocity with cast." because of the speed a lot is said there about neck tension. I am using a Lyman M die to be able to set the cast boolit with out damage. 40 rounds last weekend and no leading in the barrel. This group is to me not expectable for this rifle. I am thinking from past experience when things get close slowly work up on the powder charge to see if it will tighten up. to me this is fast moving for a cast boolit. Is there some thing else I should be looking at?
Next try was with a 114gr. mold from a group buy, I am pushing it with 24gr. of H332 all shots close to the 2144FPS average, Action cycles good, had to have the COL very short because it was going in to the rifling before the bolt was closed , but at 75 yards I get a group over 3 inches. I have been reading up on the thread " high velocity with cast." because of the speed a lot is said there about neck tension. I am using a Lyman M die to be able to set the cast boolit with out damage. 40 rounds last weekend and no leading in the barrel. This group is to me not expectable for this rifle. I am thinking from past experience when things get close slowly work up on the powder charge to see if it will tighten up. to me this is fast moving for a cast boolit. Is there some thing else I should be looking at?