The WFN is my widest meplat bullet and in 41 or 416 caliber, I make them down to 200 gr. Understand that I'll cut any weight or diameter bullet a customer asks for, from 22 up to 12 guage, but have listed in my catalog the most popular.
For your Encore a crimp groove isn't required. - You didn't mention the cartridge your gun is chambered for, but in asking for a 300 gr .416 bullet I assume you have a rifle cartridge, and if so, and if you intend to shoot at velocities over 1600 fps, for hunting purposes, I'd reccomend the LFN profile so it doesn't exceed the optimum displacement velocity as outlined in my book. (Wounding/killing potential.) If the gun is a 41 magnum, a 300 gr WFN would be a real good choice if driven at full power, which would probably be around 1700-1800 fps from the longer barrels. At any rate, best performance with breakopen guns in my experiance is obtained by seating bullets so they are pressed tightly against the rifling when the action closes. This improves ignition dramatically if the cartridge is capable of moving upon firing pin impact. If bullets are pulled when live rounds are extracted adjust seating depth a until bullets don't contact the rifing so hard.
If you email with any inquires I'll give more specific and personal answers and recomendations on bullet weight etc.