Finding a musket cap in thick grass can be done easily, if you put the place where the cap fell between your and the sun. Then get down close to the ground, so that you are looking at the ground where the cap fell at a low angle to the sun, and look for the light glinting off the cap towards you. Think of the poor guy who has to mow that area. If his blade hits that cap, it not only is going to go off, but it is going to send shrapnel all over the place. Find the cap if possible.
You don't need musket caps on a shotgun. If you will simply take an empty gun out into the night, or in a closed dark garage, for instance, and fire both the musket cap and a #11 cap off a nipple, you will find that both send about as much flame out the muzzle of the gun.
The ignition problem you were having with the standard percussion caps is most likely related to the fact that the nipple is worn, or peened over, because the hammer does not strike the nipple square to the face. The new nipples and musket caps will work well for a time, but then you will get a misfire, UNLESS you check the contact between each nipple top and the hammer face, and grind away the high spots so that the hammer will act like a paper punch if you take a soft paper towel, fold it over once, and then put it over the nipple and release the hammer to fall. You should get a full circle almost " cut-out " of the towel on the edge of the top of the nipple. If you don't get a full, even circle, the hammer is not hitting square and you will need to remove the high spot.
When the hammer hits squarely on the nipple, the entire nipple takes the force of the hammer blow, and not just part of it. The nipples last longer, are much likely to begin to collapse and bulge outward just below the top, making caps difficult to seat completely. The main concern you should have with any percussion cap gun is the condition of the interior hole through the nipple. As the hot flame of the cap( standard or musket) fires through the constriction, the heat slowly anneals and then burn off some of the inside of the nipple, until the hole enlarges. Once the hole enlarges, groups open up, patterns strike lower, as velocities also drop. If you shoot regularly, its worth the small expense to put a new nipple in each barrel each year. Some nipples on some guns have lasted for years. I tend to be a bit " thrifty " myself. But if I were shooting every month in competition, You can be sure I would put new nipples in my gun each year, and more often depending on the load I am shooting, the cap I am using, the brand of nipple I chose, and how many rounds a year I am firing. I would recommend both the Uncle Mike's Hot Shot nipple, and the AmpCo Sure-Shot nipple for your use. But stop using the musket caps, unless you are using a substitute powder.
