I’d go with a 140 grain bullet if it’s just a child shooting white tails. I started with Nosler BTs in my 7-08 and now exclusively use Barnes TTSX since they are more consistent with the groups out of my pencil barrel 700 Mountain Rifle. 4451 should be a good powder and I use it as well for this round. I think I’m at 43 grains and using Remington 9-1/2s. Velocity is 2750 FPS.So I started reloading for a 7mm-08 for my daughter to use this hunting Season and I started with a ladder test with 162 eld x bullets and imr 4451 and going of hodgon reloading website I am at max at 45 grains for that bullet and I am getting 2650 velocity which is ok in my eyes for a 20” barrel with no pressure signs at all but when you shake the round there is still room in case and the powder shakes so do you think it would be ok to keep working up in small increments looking for pressure?