Mauser M03 - Barrel Change Accuracy

I've been wanting to do this accuracy & repeatability test with my Mauser M03 system for a while. This isn't as big a test as I still plan to do one day, but it's useful nonetheless. Here's what I did, to assess how well the system holds zero after barrel & scope changes.

I fired a test shot with the 243 barrel installed on my Mauser M03 Deluxe stock and receiver. It was bang on, just above line of sight at 100m, as expected. I switched to the 6.5x55 barrel and fired a shot, to find that it was 1.2 milliradians lower and 0.9 milliradians to the left. I put the 243 barrel back on and moved to a new target sheet, shown in the picture below. I then fired alternating shots with the 243 and 6.5x55 barrels, changing and adjusting the scope each time.

I would have liked the 6.5x55 holes to be above the square, like the 243 holes, but I got the scope adjustment wrong with the first shot, so stuck with that for the next.

I fired only two shots from each barrel. I was hand-loading each round at the range, as well as changing barrels and it took quite a while to do. My video camera was whirring away up near the target throughout all this; I still haven't checked if I got all of the shots 'in the can'. :-) (I did - video now embedded below).

The results: the two shots in each group are 17mm apart, which is only slightly more than when I don't change the barrel with each shot. There was a wafting breeze blowing across the range and a difficult hot afternoon mirage to deal with. All in all, I'm impressed and so were the other fellows who watched my progress. A couple of them said they'd be happy if they could get accuracy like that from their hunting rifles, noting that they don't switch barrels, the scope, or make ammo on the spot. As explained in earlier posts, as a hunter it's where the first shot goes that matters for me, far more than where the second, third, fourth or fifth shots go.

I've still got some ammunition tuning to do and these barrels should become more accurate as the shot count climbs over 50, so stay tuned for even better results. :-)