All my loading manuals are in storage. 165 miles away and I have a hankerin to do up some ammo for my little 375 W AI.
The data I used to develop what I've been shooting . 250 gr TTSX BT AND 250 gr Sierra sptz bt . I got from Barnes and over on AR forums.
Used the Scoville data conservatively.
Am pushing them @ just a bit over 2500 fps now.
19" barrel.
Thanks in advance !

I'm sure you can find loading data for the plain ole 375 Whelen, online. When I started loading foe my 375 Whelen there was little to no data, so I started with 35 Whelen worked fine as a starting place.

My 375 AI has iron sights, I've done hardly any load development with it so far. I have a Leupold one piece base for it and may have it installed. The jacketed load and cast loads I have shot so far shot decent enough, but was limited by my eye sight
My jacketed load is:
Speer - 235, H335 - 60 grains

I'll be interested in your load development, here's some loads for a 375-06 from load data:

I found 375 WAI loads on Alaska Outdoors supersite

Forum>Alaska Shooting Forums > Alaska Handloading dated 2008

I've never put a jacketed bullet down the barrel of my 375 Whelen. I've found cast bullets to be accurate, powderful, and very inexpensive. With two double cavity molds and make more bullets in one afternoon then I can shoot in a year.

I feel that the 375 Whelen and WAI are excellent cast bullet cartridges.

The main reason I went the AI route was the dies and the reamer were immediately available. The straight 375 Whelen was a long wait. I didn’t/don’t see a down side to the AI, but I’d been happy with the 375 Whelen too, I think. I know some feel the AI shoulder is better, IDK. The case capacity difference wasn’t part of the equation for me.

I have had a 375-06 for the last 8 years now. I know this isn't exactly for 300 grain bullets, but I have been using IMR 4320, 60 grains with the nosler 260 accubond gives me 2600 fps out of a 24 inch barrel. I have found about the same amount of RL 15 gives me the same velocity the 4320 was just more accurate.
Good luck I'll use my 375-06 for anything with the Leupold CDS dial I can take it all the way out to 600 yards.