I really never tested too many powders with model 99 sav in 250-3000..Powder I used is #3031 with 87 gr Speer bullets ..Friends they like #4895/#4023...I think the 250-3000 in model 99 likes most powders from what you folks write.
my twist is 1-14 model 99s ...

i use #3031 powder,ccI primers,rem shells and Speer hotcor bullet in 87 gr or 100 gr but I like 87 the most for deer .. ...

I like H414 with all bullet weights..I don't quote loads but most books have starting loads and max loads.

A good rule of thumb with a 99 Savage in any caliber is load two grains short of book max as the action is a bit springy and not uncommon to blow a case in half with book max loads with some powders..

My favorite load however is an exception is a book max load of H414 with a 75 gr. GS Customs HP..That load will lay out a buck Mule deer or whitetail on the spot 99.9% of the time..and I know a young lady that borrowed mine to shoot a bull elk in dads alfalfa patch and she broke the near shoulder and the bullet made a one inch exit hole on the off side, that bull didn't made 30 yards..Range was 89 lazerd yards.

Ive shot a few elk and a lot of deer with my Sav 99 250-3000 and 100 gr. rem corelokts in my misspent cowboy youth. Never a complaint.

Very accurate info.Dad found out in depression that the 87 gr bullet put deer down better than 100 gr ..Now I am loading Speer 87 gr with #3031 powder now that I know i have 1-14 twist but 100gr was very accurate and bullet behind shoulder worked ..

my rem cases never blew apart at head until on the 3rd shot but like you said I never loaded at max ..I did find a old loading manual that has savage model 99 tested in loads if anyone would want to post it here i can make copy for ya ..'

I have a 25/35 IMP in a 99, case capacity is the same as a 250 sav when measured with water.
It has a preference for IMR 4320. I have loaded it with 100 grn bullets to 3063 fps ave. I have not split or ruined a case yet after 5 loadings with that load. The 26" barrel helps with the vel for sure, but 4320 seems to be good burn rate. I have yet to try H414/win 760 but find it to burn dirty in most things I use it in.

One more thing, may have to do with the case, not the sav 99. I reduced the dia of the expander ball so there is a lot of neck tension when seating bullets. Vel went up, and extreme spread went way down. A Lee factory crimp die might be worth a thought.

I tend to reduce the diameter of the expander ball in a number of my calibers..I do not crimp except with a double rifle. The reduction plus a powder that fills the case to at least half way up the neck works as well as a crimp.