A lot of hand-reloaders use magnum primers with ball type powder,it's supposed to be harder to ignite under certain conditions.
Remington 7 1/2's are Small Rifle Benchrest.
I don't use magnum primers in small rifle even though Speer data does,also Lee states using Magnum primers with Winchester 296, and I guess these days that would include H110 as well.
I do use large pistol magnum primers in .45 Colt loading using H110-W296,learned the hard way had some squibs with complete charges, Wolf LP's just weren't hot enough to ignite the full charge in such a large case. Pulled down the 20 I had loaded and reprimed with CCI Large Pistol Magnum same charge weight and everything went BOOM instead of PUFF.