Semi

I wish you might try the same thing again with the Mustang and a HPH-24 - I think it might be slightly tighter than the Short Black Harvester.

Have you ever tried to load a HPH-12 in the Mustang? It seems to me that the bore of the Mustang is larger than the a standard .502

From my limited experiance with BH, because it is a smokeless/progressive burning powder - you must have a fairly tight sabot/projectile fit to prevent 'hangfires' + I think it is important to compress the load.

When I shot BH from the Omega (.502) with a 25ACP - I was using a snug fitting 24 and both small rifle and small rifle mag primers... I did get a couple of 'hangfires' with the 400 primer - but things worked very well with the 450 primers. I also did not swab between shots at all - that little bit of fouling certainly helps the tight fitting sabot.