bo79
I have a MHC gun something akin to to the LRH and really enjoy it. I have shot BH from and it will shoot it very well.
Which breech plug are you using? If you are using the standard concave breech plug that should work very well for you. I would NOT suggest drilling it out. If you are using the convex or the power stem they will lead to hang fires.
Which ignition system? FPJ or NFPJ - both will work although some really prefer the NFPJ. I am using th FPJ and I do not find a problem with it at all - IF your primer jackets are in good shape. If you are re-using the primer jackets you are going to have pay close attention to the leakage you may be getting.
Primers - I have used and I am still using CCI-209M primers and they are working for me. I also recently bought some Federal 209A to try as again some folks were suggesting they were getting better ignition with them.
This may be what is causing your slight hang-fires.... How snug are the sabots going down the bore? and are you seating the load tightly on the powder each time? Either one of these to items can cause the slight hang fire. BH is a smokeless, progessive buring powder (not a Nitro powder) but it requires compression to maintain ignition.
My suggestions to try would be.
1. Make sure you have the correct ignition sytem in your gun and the BP flash channel is clean.
2. Proper fitting sabots - they must be snug
3. Seat the load on the powder - then compress the load onto the powder.
I have not shot Harvester sabots in my MHC so I can not tell you about them and their fit. I have only used MMP HPH-24's and their Orange .457-.458/50 cal sabot.
Hope some of this helps...