Bruce
The sponge on the box is for sitting on . Casting as I do using a gas ring and an old saucepan I prefer to have everything as low as possible . The floor is as low as I can go and I need a seat at a suitable height.
The front of this latest boolit is tapered slightly and that is reflected in the engraving of the patch. I wanted to seat the boolit out further than the Mk1 and Mk2 to maximize powder space in the smaller cartridges I use such as the 7.62x39 .
Longbow
The problem I have been encountering when I cast faster with this particular alloy , is the boolit base tearing , as the sprue is cut. The sprue plate is 1/4" thick , and may be retaining too much heat compared to the mould block . With a normal GC boolit I never worry too much about the base , because once the gas check is seated , an even base results , that can do no harm as the boolit exits the muzzle and high pressure gas is expanding past it. I have the opinion that a perfect base is very important in regard to accuracy so I have been waiting for the boolit base to solidify completely before cutting the sprue .
The mould block is aluminium 1.25 inches square and 2 inches long .
I tried the boolit in my single shot 7.62x39 and achieved an average five shot group size at 50 meters of 27mm , or just over an inch . Nice round groups with no fliers and a velocity of 2150 fps caused by a load of 23 grains of AR2207 with 0.5cc of shotshell buffer between powder and boolit.
I thought I was on a real winner when the first three shots were touching , but reality set in with the fourth and fifth shots, and the subsequent groups did not improve upon the first. This particular rifle does not do much better with gas checked cast boolits . On a good day it will average 1.5 MOA with the Lee 150 gn FP at 2080 fps.