I know this could invoke a rather lengthy thread with all types of responses, BUT, I have wondered about this for years.
Virtually all of my center fire rifles will shoot a 3-shot group with 2 shots almost touching and one off a fair ways.Sometimes that fair ways is only a quarter inch while the other two are nearly in the same hole but it is definitely off. And, Sometimes it’s the first shot that flys off, sometimes it’s the second, sometimes it’s the third. Sometimes it’s vertical, sometimes it’s horizontal, sometimes it’s diagonal. YES, I have gotten nice, tight triangular clusters, but those are only about 25% or less of the time with most rifles. I have this same result with custom barreled rifles from barrel makers everyone here has heard of and I have it happen with factory. Here is the kicker though, I almost never have it happen with my three Savage bolt action rifles but maybe a few times out of 50 groups....
Since I have the convenience of loading ammo only 30’ from my shooting table at my home, I have many times went back in my office and reloaded 2, 3 or more of the same exact rounds, with nearly identical results more often than not.
I would like to hear what other’s have to theorize on this subject.
My own personal thoughts are this:
I do not believe there is any way possible to get the initial bore “perfectly straight and true” through the center of any barrel. I see this problem being compounded with smaller diameter bores. In my mind it is physically impossible. I do believe that maybe “hammer forged barrels might be more immune to this since the barrel is hammer forged around an already existing and assumed straight machined mandrel but to me, this process is also suspect.
On a conventional barrel, it is physically impossible to insure that the initial bore is perfectly straight. We are only talking thousandth of an inch here. There are hard/spots spots in all steel and I see no way to physically insure the hole inside the barrel is straight and true without cutting the barrel into pieces and measuring. Again, the smaller the bore and longer the barrel, the harder it has to be.
Yes the external portion of the barrel can be measured but not the inside and YES there have been many more barrels than one that have made it out the door with the bore straight and true, but in my mind these are more of a coincidence than anything else. The inside can be measured for uniformity in dimensions but not for straightness by any method that I am aware of.
If the barrel is not straight and true inside, then it has to heat up and vibrate differently with each shot thus causing the shots to deviate.
These are my thoughts. I am curious to see what others think.
I think that you have good thoughts.
