While at the range today, one of my loads for my CZ527 Fireball quit grouping for me. Previously it would average .5 at 100 yards. I was shooting out of the same bag (same batch) that has always shot great. Load was 15.5 Lil Gun and Sierra 40 grain BK. Instead of the pleasing groups this load as shot before, it was averaging over a inch.

My other favorite load is 19.4 H322 with Sierra 52 grain MK. It shot great as always and averaged under .5 .

Would warmer temperatures (outside) affect the load? Why would that load not group today and the other would? Like I said, previously it would run .5 or at 100 yards out of the same batch.

Joe A.

Joe did you get any new components for this load? Perhaps a new lot of powder or bullets. Was it you first group shot or was the H322 load first?

What was the wind factor? Doesn't take a whole bunch to affect 40 grainers.

The first groups fired was with a 3rd load consisting of the 50 grain Bks and H322. It was a new load and it shot terrible. I then went to the 40 grainers and they shot terrible. So I then thought it was time for an unexpected bore cleaning. Cleaned the bore and no help with the 40 or 50 gain BKs. Then I went to the MKS and got a .5. Tryed the BKs again and no luck. All in between the shooting I would let barrel cool while shooting rimfires.

The last three groups were a 40 grain BK, a 52 grain MK, and back to the 40 grain BK. Again, each BK went 1-1.25 and the MK went less than .5. There was little or no wind for the last 3 groups. Earlier groups, wind was variable.

There was no change in the components with the 40 grainers. Same batch that has always shot great untill today. Since I was running low on 40 grain Sierra BKs, I was sort of hording the Fireballs loaded with them and saving the rest for my Hornet. Just perplexing why that load would not shoot today. At least the 52 grain loads shot good and my 54 and 64 Anschutz rimfires really showed out for me.

Joe A.

Joe-
I had a load go south in my 220 Swift. Ashamed to admit it, but my case trimmer fixed the problem. BTY, the cases were on their third reload too...