I posted this under Medium Rifles but not sure if this belongs in reloading! Anyway: Two sets of five rounds shot on 18 November through a 23.5" barrel BRNO ZKK 600. Bullet seated on cannelure and crimped with Lee Factory Crimp die. BOTH with 55.0 grains H4831 and Hornady 150 grain Interlock bullet:

REMINGTON 9 1/2 PRIMER: 2799fps, 2846fps, 2784fps, 2859fps, 2730fps.

CCI LARGE RIFLE: 2803fps, 2801fps, 2801fps, 2831fps, 2811fps.

So a slightly higher velocity and a lesser spread with the CCI. But at the same time the CCI showing greater signs of whatever pressure there was than the REMINGTON.

It has been my experience that the Remington caps are harder than the CCI or any other cap or that matter.

My 270 likes 57.5 grains of H4831 under the 150 grain Speer and Hornady bullets. I use this rifle in very cold temperatures so I use CCI 250 primers. My rifle is a custom using a FN commercial mauser action and I can load my bullets .2 farther out than most magazines will allow. Very accurate and easy on brass.

IMO, what is to be applauded is the consistancy of the load using the CCI primers. Neither load is to be sneezed at but it looks like your load using the CCI primers is about as good as it gets with a .270.