GB has posted the most sensible recommendation, one that costs you about $4.00 for 100 new primers of known origin. Here is another option.
Correct me if I am wrong, but the primers are one of three possibilities. Large Pistol; Standard Rifle; or Magnum Rifle. All are manufacturer unknown.
Load 3 cases with an accurate load for that rifle in a mid-range to reduced-charge of powder and a cheaper bullet. Take a standard cleaning rod to the range. If they are Large Pistol, you may need to push the first round out of the barrel, but you will know. If the first fires OK, fire the 2nd for group. If OK, fire the 3rd for group. Check your group. If the results are as expected, I would be comfortable with the entire lot.
GB make the sensible recommendation that for only $4.00, "why bother" with a stuck bullet in the barrel and the possibility of barrel damage trying to get it out. My thinking stems from the premise that primers are primers are primers and there are none out that that explode and blow up guns on their own. The possibility of a stuck bullet in the barrel is the nagging issue as well as their unknown origin and intended function (standard rifle or magnum).