EOL = extreme outer limits.
It took some digging but the 300 EOL is most likely the 300 ultra mag.
Some articles that lead me in that direction:
McMillan EOL Mountain Extreme Denali
Introducing: “McMillan EOL Line of Rifles”
McMillan International Group posts:
The new line of McMillan EOL Magnum Rifles. McMillan, Extreme Outer Limits TV, Berger Bullets and NightForce Scopes have teamed to make the most extreme line of long range hunting packages on the market. Each model is made to McMillan’s demanding standards. Custom reamers have been made for each caliber to maximize velocity and performance when using Berger bullets. There is nothing like these rifles available on the market today. Be ahead of the curve and call today for more information on the McMillan EOL line of rifles.
EOL Outdoorsman; McMillan EDGE Tech Outdoorsman stock, 26″ #5 fluted match grade stainless Schneider barrel with polygon rifling with Vias muzzle break.
EOL LRH; McMillan EDGE Tech LRH stock, 26″ SR60 contour match grade stainless Schneider barrel with polygon rifling.
We plan to inventory the EOL LRH in .338 Lapua and the EOL Outdoorsman in 7mm EOL Magnum, and 30-378 EOL Magnum. Any other combination of models and calibers may be custom ordered.
For more information and sales call 1-877-365-6148.
Kelly D. McMillan
Director of Operations
McMillan Group International, LLC