I would have the rifle checked. It could be a firing pin protrusion problem or something like that.

FWIW, I've had and shot 45-70s for the past 30 years and neither of the Marlins nor the Ruger #1 has had the least bit of trouble igniting primers in Winchester, Remington, Federal, Hornady, or Starline brass I've used. But I suppose a fellow might see a bad lot of brass also.

Sometimes, the air you 'let in'matters less than the air you 'let out'.