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Chornograph shenanigans
nemesisenforcer
Member Posts: 10,513 ✭✭✭
Took the chronograph out today to do some testing and got some bizarre results.
It was all 44 magnum loads shot out of 1 revolver: my S&W 629 with 6 inch factory ported barrel, all bullets 240 grain cast semi wadcutter, all primers CCI large pistol. Only powders and charges changed
Chronograph: Caldwell Ballistic Precision chronograph placed approximately 6-8 feet from muzzle of pistol.
Results (all figures the average of 4 or 5 shots):
.7cc Unique: 1382 fps
1.0cc Unique: 1366 fps
.7cc Autocomp: 1376 fps
1.3cc IMR 4227: 1380 fps
1.6cc IMR 4227: 1387 fps
as you can see, not only are the velocities remarkably similar and consistent, but they're incredibly high, especially for the lighter charges. I'm sure that something is wrong. I've never seen anything like this before.
Thoughts?
It was all 44 magnum loads shot out of 1 revolver: my S&W 629 with 6 inch factory ported barrel, all bullets 240 grain cast semi wadcutter, all primers CCI large pistol. Only powders and charges changed
Chronograph: Caldwell Ballistic Precision chronograph placed approximately 6-8 feet from muzzle of pistol.
Results (all figures the average of 4 or 5 shots):
.7cc Unique: 1382 fps
1.0cc Unique: 1366 fps
.7cc Autocomp: 1376 fps
1.3cc IMR 4227: 1380 fps
1.6cc IMR 4227: 1387 fps
as you can see, not only are the velocities remarkably similar and consistent, but they're incredibly high, especially for the lighter charges. I'm sure that something is wrong. I've never seen anything like this before.
Thoughts?
Comments
You may be getting muzzle blast.
Volume measure is subject to density which can be influenced by settling in a power measure from operation(shaking) or bridging in the hopper due to not enough shaking. Reporting the actual grain weight of the charge would be more useful
I agree with the un-burnt powder causing interference. Try shooting over fresh new snow just to see how much powder actually goes down range.
Volume measure is subject to density which can be influenced by settling in a power measure from operation(shaking) or bridging in the hopper due to not enough shaking. Reporting the actual grain weight of the charge would be more useful
They weren't charged with a hopper, i use the Lee dippers.
I thought gas/powder might be interfering with the results /maybe a low battery. I'll follow up hopefully before the end of the year and report back.
2. Position the unit 10 to 15 feet in front of the muzzle of a firearm or if using with a bow, at least one full arrow length in front
https://www.btibrands.com/wp-content/uploads/2014/05/chronograph-and-kit-master-instructions.pdf
Per the instruction manual:
2. Position the unit 10 to 15 feet in front of the muzzle of a firearm or if using with a bow, at least one full arrow length in front
https://www.btibrands.com/wp-content/uploads/2014/05/chronograph-and-kit-master-instructions.pdf
Instructions? What the hell are those?