Thread: Accuracy expectations

Originally Posted by Cigar

My play with GRT didn't want to match up either. I ran the OBT calibration which changes burn rate or something to make predicted match actual and that made things fit a lot better, but also reckoned they are compressed loads at close to (or above) max pressure.
Have you tried lower charges? The Optimal Barrel time function reckoned there may be a node at 25.3gr of 8208 at a mv of about 2609fps.

Thanks very much for that @Cigar I was just thinking too, that the chrono distance was 10 yards. Maybe that was a missing element that made calcs difficult?

Funny you say that about the lower node, the first group of the test was 3 fouler shots 24.2, 24.7 and 25.2gr which made a beat wee group. Average velocity across the three of 2550fps. The 25.2gr load was 2616fps, so pretty close to the GRT prediction.