Ya' gotta' try 150 before 200. You also must try loose powder .... preferably 777 FFF. I use 105 777 FFF loose & I'm 8-9" low at 200 using a 250 grainer. If your 100 grains is two pellets, you need to add a 30 grain pellet because 777 pellet powder is weaker than 777 loose. Hodgdon did this purposely to match Pyrodex pellets in velocity/energy for safety reasons. So again, if you're using two pellets 777, I only need roughly 85 grains loose FFF to match you PLUS my 105 equals 125 grains pellet powder.... pretty darn close to two 50s and one 30 grain pellet.