Bob Roller got it right. Your underrib sets the rod hole into the entry pipe. The rib is about .230 thick. Track's RP-HAWK-TE-7-I will probably be nearest correct and is made only in 7/16". Do not use their RP-HAWK-E-7-I (too much hump, but they make that one in 3/8" as well as 7/16). The skirt sets the belly line back to the trigger plate. From the underrib groove to the top of the skirt is .650. Add .230 to get .880 stock thickness below the barrel. The trigger blades to the sear set the level of the trigger plate. The Ron Long trigger plates do not need to be cut down. If you use that trigger, a 1 1/8" barrel will have a stock depth of about 2.1 from the front of the trigger guard to the top of the tang behind the snail, at least my copy of the Bridger Hawken does. The stock belly is a straight line from the plate to the entry pipe skirt, no fish belly. My Bridger stock depth is 2.030" on the tail of the skirt. The Bridger and Carson Hawkens and the "Robidoux" Hawken in Lincoln, NE and the S. Hawken in Cheyenne all have 1/2" ram rods. The Bridger entry pipe is .510 inside diameter, but the rod as measured by GRRW in 1975 is .500 front and .270 rear, inside the stock. Who knows if that rod is original to the rifle. The Carson rod is similar. It may be they tapered it to fit a "spring" tow worm on the end for cleaning. I doubt the hole is tapered.
Your lock panels are as thick as the bolster of the lock. But this heavy barrel needs tapered panels, wider across the front than at the tails. The Bridger Hawken has the lock plate bent in at the tail. Better to file the bolster. Carl Walker of the GRRW told me today he files about 1/16" off the back end of the bolster to get this taper. I think I do about .040. This narrows the lock panels at the wrist for a slimmer stock. My Bridger copy is 1.75" wide at the front of the panels and 1.57" at the tails.
