After finishing the channel enlargement I immediately threaded on the muzzle break. I did expect a change of impact from the established 100 yard zero, but I was surprised that it was a 1 mil adjustment to the right with only a slight horizontal adjustment being needed.
With that said the mental anguish was only getting started.
The first shots fired with the new break were larger than expected, also I was testing two different loads at the same time, which complicated the process even more.
I decided to start my next season at the bench with a clean barrel, and a load that already shown potential to be accurate, and I also made 10 more rounds of a new charge weight that is pretty close to the maximum charge.
The cleaning, and loading were done during hurricane Mathew. Susan, and I rode out the storm at our apartment in Jacksonville. We live far enough away from the where the worst winds were going to hit land. We did have a full tank of gas, and extra just in case we needed to bug out at the last minute. This wasn’t necessary, and I was able to get all these things finished, and ready to go as soon as the storm, and it’s effects had passed.
The first shots with the clean barrel, and muzzle break were fantastic, if you consider patterns that look like they were fired by a blind, drunken monkey good.
Needless to say I was a little disappointed, and contemplated removing the break in fear of the break causing odd harmonics of the barrel. This would be sad because of the great amount of reduction in felt recoil.
The first ten rounds were fired in two groups both of which were open, and inconsistent.
The next range season started out poorly also, then the last two rounds landed almost on top of each other in the same spot of the fourth round fired in this group of six. These three rounds were about a half inch of the second round fired. With two rounds that were about an inch from the bullseye, one to the left, one to the right, this six round group became a four inch group.
Then the last five rounds just opened up back into a horrible group.
I suspected that my shooting form was bad. My suspicion was that by placing the bench rest too far back on the stock that was causing the rifle to pivot during the shot in part because of muzzle break pull off caused by the air column in front of the bullet traveling through the muzzle break before the bullet itself travels through the break. Depending on the design of the break this effect can be very hard to control, and predict.
Even though this may be a factor, it is not the root cause.