Boyd Allen
Active member
Some time back, I decided to try something that I think some of you may find interesting. All that it took to do this experiment was one of those caliber specific case trimmers that consist of an end mill, a steel tube, and a plastic insert that fits the front of the case, and a roll of electrical tape. The trimmer that I used is about 625” in diameter and weighs a little less than 2 ¼ oz.
I have a barrel, for my 6PPC, that shoots its best groups at the top node with 67 gr. bullets. When I tried some 62 gr. Watsons, I found that the amount of powder required, to tune out the vertical, required all of my skill to get the required amount of powder in the case, a real pain in the neck.
At this point, I decided to see if by adding weight to the muzzle (to lower its vibration frequency) I could reduce the weight of the powder charge required to tune out the vertical. I should add that conditions were very good during the experiment.
To add weight to the muzzle, I first put a strip of tape at 6:00 o’clock, running back from the end of the barrel a little longer than the case trimmer. I then held the trimmer under the barrel even with its end, and secured it in place with a double wrap of electrical tape, stretched as tightly as possible.
With the weight in place, the rifle was in tune, for vertical, with a half click (Harrell’s measure) less 133, 55 instead of 55 ½. This amounts to about a quarter of a grain of powder. Reducing the load by this amount made the cases a little easier to fill. To complete the test, I cut the tape and removed the weight, which caused the vertical to reappear, and then increased the load to its previous level (55 ½), which tuned the vertical back out.
The next experiment that I plan involves an old Hart Barrel that has done its best with light bullets going fast. Last time at the range, I found that a load that it likes with 67 gr. bullets has bolt lift issues. The next time that I go to the range, I plan of having a couple of pieces of steel rod that I can tape to the end of the barrel, so see if I can get to the same tune with slightly less powder. If it works, I will set about having some weight removed from the barrel by stepping it, and fit a weight to the muzzle, a fixed weight/position tuner if you will, to tune the barrel so that the top node load occurs at a usable pressure level. The reason for this is that the heavier bullet has some advantages that I wish to be able to use with this barrel.
I am not abandoning tuners, just trying a different variation on the theme. Comments?
I have a barrel, for my 6PPC, that shoots its best groups at the top node with 67 gr. bullets. When I tried some 62 gr. Watsons, I found that the amount of powder required, to tune out the vertical, required all of my skill to get the required amount of powder in the case, a real pain in the neck.
At this point, I decided to see if by adding weight to the muzzle (to lower its vibration frequency) I could reduce the weight of the powder charge required to tune out the vertical. I should add that conditions were very good during the experiment.
To add weight to the muzzle, I first put a strip of tape at 6:00 o’clock, running back from the end of the barrel a little longer than the case trimmer. I then held the trimmer under the barrel even with its end, and secured it in place with a double wrap of electrical tape, stretched as tightly as possible.
With the weight in place, the rifle was in tune, for vertical, with a half click (Harrell’s measure) less 133, 55 instead of 55 ½. This amounts to about a quarter of a grain of powder. Reducing the load by this amount made the cases a little easier to fill. To complete the test, I cut the tape and removed the weight, which caused the vertical to reappear, and then increased the load to its previous level (55 ½), which tuned the vertical back out.
The next experiment that I plan involves an old Hart Barrel that has done its best with light bullets going fast. Last time at the range, I found that a load that it likes with 67 gr. bullets has bolt lift issues. The next time that I go to the range, I plan of having a couple of pieces of steel rod that I can tape to the end of the barrel, so see if I can get to the same tune with slightly less powder. If it works, I will set about having some weight removed from the barrel by stepping it, and fit a weight to the muzzle, a fixed weight/position tuner if you will, to tune the barrel so that the top node load occurs at a usable pressure level. The reason for this is that the heavier bullet has some advantages that I wish to be able to use with this barrel.
I am not abandoning tuners, just trying a different variation on the theme. Comments?
