My youngest lad is 6'-7" with about a 6'-10 wingspan and huge paws, I built him a longrifle when he was in highschool with a 14 1/2" pull/4" drop. I have always used a tri-stock I designed myself, before I'd ever even heard of one. So we fit it to him with his heavy hunting cloths on, cause it's mainly for hunting. I can and do shoot it too, with light clothes on. It's really too long for me with my hunting gear on though. I'm 6'-1" tall. The rest of my flintlocks rifles are in the 13 3/4" to 14" range.
edited:
Now get this....my Beck is 13 3/4" pull/3" drop, and my Rupp/Lehigh is 14" pull/4 1/4" drop. The sights on both rifles line up instanly when shouldered, without any stock crawling. The difference is in the stock shape or comb profile, straight or curved.