My Red Dot loads from the past are as follows:
- 140g LRN, 3.0g Red Dot, 731fps.
- 158g LRN, 3.1g Red Dot, 763fps.
Don't forget that there are many variables to consider that affect velocities and pressures.
Jacketed bullets in 1905
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My Red Dot loads from the past are as follows:
- 140g LRN, 3.0g Red Dot, 731fps.
- 158g LRN, 3.1g Red Dot, 763fps.
Don't forget that there are many variables to consider that affect velocities and pressures.
DWalt
Member
When it comes to MV for a revolver, believe nothing you read in a reloading manual or elsewhere. Every revolver makes its own rules, even two which are otherwise identical, when shooting identical loadings. This is principally attributable to slight differences in the barrel-cylinder gap and possibly other slight dimensional differences in chambers and barrels. Don't forget that barrel length makes a large difference.
If you want to know the MV of some specific load in a specific revolver, the only way to know for sure what it is, is to chronograph it using that revolver.
If you want to know the MV of some specific load in a specific revolver, the only way to know for sure what it is, is to chronograph it using that revolver.
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Took the various revolvers to the range and chrono'd them with an assortment of ammo. All of them worked just fine. I'm writing off those few rounds as an anomaly. The rest of that batch of ammo is now relegated to the "highly questionable" box, and scheduled for disassembly.
And BTW, y'all were right ... the larger gap of .010 didn't seem to matter all that much. I expected it would, but it was not that big a difference.
Thank you Gents for your input.
And BTW, y'all were right ... the larger gap of .010 didn't seem to matter all that much. I expected it would, but it was not that big a difference.
Thank you Gents for your input.
Ballistics By the Inch ran tests on the effects of increasing barrel-cylinder gaps.
BBTI - Ballistics by the Inch :: Cylinder Gap
BBTI - Ballistics by the Inch :: Cylinder Gap
DWalt
Member
That is interesting information, and it took a lot of work to get it. I once did a somewhat similar test using a Colt .357 vs. a S&W K-38 Masterpiece, both having 6" barrels. I carefully loaded some .38 Special ammunition (I think I used 158 grain SWC bullets) for the test. While I did not measure the B-C gaps, the Colt's gap was so slight that only the tiniest sliver of light could be seen through it, very close to zero. The K-38 gap was somewhat larger visually, my guess it was maybe 0.005", possibly more. The average MV difference using all chambers of the cylinders was close to 100 ft/sec in favor of the Colt. My test goal at that time was merely to demonstrate that significant MV differences exist between similar revolvers, which it did.
Somewhere among my old reloading manuals from the 1970s is one from Hornady or Speer (don't remember which) that contains an article entitled (something like) "Why Ballisticians Get Gray" that thoroughly discuses the MV differences existing among different revolvers firing the same loads.
Somewhere among my old reloading manuals from the 1970s is one from Hornady or Speer (don't remember which) that contains an article entitled (something like) "Why Ballisticians Get Gray" that thoroughly discuses the MV differences existing among different revolvers firing the same loads.
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