The Bolt Man
Member
- Joined
- Feb 22, 2008
- Messages
- 27
Today I tested Rainier 125 gr. HP bullets and some Raineir 158 gr. HP bullets.
I was feeling good that I have my cronograph running again after years of fighting with all sort of problems including muzzle blast or shock wave causing readings out of the norm. Even shooters next to me were causing readings with my cronograph. Fixed that problem with new sky screens.
I found a problem I didn't know existed with my test loads. Using a 125 gr. Rainier HP bullet and three different powders, 700X, Win. 231 and Titegroup I fired ten shot groups with varied powder charges. I noticed quite often the first round of five from my Ruger 357 Mag. Security Six would have a much lower velocity than the next four rounds. Sometimes more than 100 fps when the average velocity was only around 700 fps.. It happened with all the powders but more so with two of the three.
First I wondered if one of the chambers could be causing this. I ruled that out and started to consider variations in crimp and/or bullet retention. That could cause some problems, but not limited to first rounds fired after reloading the gun. Then I hit on what I think the problem is. I think it is a powder position problem. Think about it. Firing from a pistol rest. You load five rounds, close the cylinder and level the gun on target. The powder is mostly to the rear now, for me. Fire the first round and the other four rounds in the cylinder get jerked hard to the rear and the powder goes to the front and basicly remains there through the firing of the last four rounds.
Maybe I am just hoping I have the answer, but it will be easy to prove. I plan my next outing to be with some of the same loads, but half will be fired with powder to the rear and the other half will be fired with the powder to the front.
I have used this test with other calibers and powders so I could find the least position sensitive powder and load for that gun. It can really make a big difference in the group sizes.
I will include the results of my test on this forum.
If any of you shooters have had a similar problem I would like to hear about it. Especially if you fixed the problem.
I was feeling good that I have my cronograph running again after years of fighting with all sort of problems including muzzle blast or shock wave causing readings out of the norm. Even shooters next to me were causing readings with my cronograph. Fixed that problem with new sky screens.
I found a problem I didn't know existed with my test loads. Using a 125 gr. Rainier HP bullet and three different powders, 700X, Win. 231 and Titegroup I fired ten shot groups with varied powder charges. I noticed quite often the first round of five from my Ruger 357 Mag. Security Six would have a much lower velocity than the next four rounds. Sometimes more than 100 fps when the average velocity was only around 700 fps.. It happened with all the powders but more so with two of the three.
First I wondered if one of the chambers could be causing this. I ruled that out and started to consider variations in crimp and/or bullet retention. That could cause some problems, but not limited to first rounds fired after reloading the gun. Then I hit on what I think the problem is. I think it is a powder position problem. Think about it. Firing from a pistol rest. You load five rounds, close the cylinder and level the gun on target. The powder is mostly to the rear now, for me. Fire the first round and the other four rounds in the cylinder get jerked hard to the rear and the powder goes to the front and basicly remains there through the firing of the last four rounds.
Maybe I am just hoping I have the answer, but it will be easy to prove. I plan my next outing to be with some of the same loads, but half will be fired with powder to the rear and the other half will be fired with the powder to the front.
I have used this test with other calibers and powders so I could find the least position sensitive powder and load for that gun. It can really make a big difference in the group sizes.
I will include the results of my test on this forum.
If any of you shooters have had a similar problem I would like to hear about it. Especially if you fixed the problem.