55bt-fmj 223 load with 20.8 gr's of h335=2300fps?

[ajhardle]

I shot a 5 shot group with this load measuring .87"and 1.2 And 1.4 for the next steps up when developing a load, so I loaded 100 rounds, and finally got out with a chronograph.2300 fps. I separated a round when I got home, and it measured 20.8 gr. Then checked to make sure it was the correct powder. It was.
Then I realized I didn't use magnum primers. Does that make the difference?