Thanks for letting us know the answer to your dilemma.....others on the forum can learn from it.I am ashamed to admit this, but I was reading the scale incorrectly. I have been using a beam scale and each tic mark is 5 grains not 10. Someone said check my scale and well. I fell well you know. But anyway at 35gr I now have 1389fps. It has been a few years since I have reloaded so check two or three times get my head in the game. Barrel length does make a difference but not that much.
How ever the 900fps load's are right on at 50 yards and very pleasant to shoot.
Sorry for the trouble and thanks
Did you check the weighing scale?I have been Reloading for some 40 plus years both pistol and rifle and I have not had this ever happen before.
A few years ago I finally bought a 45-70 a marlin 1895 classic and for the last few years I have been buying Federal power shok 300gr cartridges just building my brass collection.
Now that I have a few rounds I have started loading them up. I have loading manuals for the last again 40 years and just recently bought the lyman 50th anniversary and the cast bullet manuals.
The powder that I have chosen is IMR4198 it seems to be in all three categories springfield to ruger no.1. The starting out charge is 31.5gr. for about 1310fps and goes to 35gr. for 1450fps. I am loading a 405 rnfp hard cast.
At 34.5gr I am only getting about 890fps and something seems off. I have tested with the chronograph with federal ammo and it is right on at 1874fps the box states 1850fps.
Just wondering why I am not getting what the manuals say I should be getting. Also chro is about 15ft from muzzle.
First of all, welcome to LRH and enjoy it. Unless I misconstrued what you are trying to convey, it cannot be your barrel length since your chronograph is reading near factory ammo's claim.