Calum,
Another issue you may find, especially if the Ped is new out of the box, is that the issue cone (nipple) diameter may be too narrow to permit adequate fire from reaching the base of the cartridge (Sharps rifles require the flame from the percussion cap to make two turns before reaching the powder charge compared to a single turn for a muzzle loader). The NY boys had to drill out the diameter of the first shipment of Ped Sharps to 1/32 and this appears to resolve some of the poor ignition issues. I did the same for my Ped. I then had a NSSA gunsmith remove the gas check from the breechblock and epoxy the 'not so floating' gas sleeve into place.
As Brian discovered at Malvern Hill NPS a couple years ago; the type of cartridges used in the Ped will also play a factor. The Ranger at NPS had us turn in all our cartridges earlier in the day then issued them to the boys just before the demonstration commenced. Brian wound up with a pasteboard packet of my rds and you could have heard him whooping for joy all the way to Richmond.
A number of shooters use the "O-Ring Solution" to help reduce blow-by crud buildup between the gas check and breech. You can find the procedure on the NSSA website. Essentially you file off a few millimeters of metal off the bottom of the O-shaped base of the gas check that fits around the internal cone. Then place a 3/4 inch O ring neoprene washer into the well of the breechface, coat it with lithium grease (this prevents the washer from becoming degraded by heat and flame of combusting cartridges) and replace the gas check. The washer is flexible enough to push the gas check forward to seal the breech, while allowing the block to easily move up and down during loading. Shooters report Peds seizing up after 10 shots in untreated rifles to upwards of 60-80 rds. after the O-ring conversion.
For more details on the Ped you can read my article on this forum comparing the strengths and weaknesses of the three types of reproduction Sharps used by USSS reenactors today.
http://www.berdansharpshooters.com/Ever ... Sharps.pdfBill Skillman
Randolph Mess-USSS