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April 9, 2015
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Here is Data of the 15-2 with a 12" Vented Barrel. Interesting comparison to the same ammo fired through the Super Mag. The .006" cylinder gap sucks the velocity away when compared to the .002" gap in the Super Mag. almost a 300fps difference in the MP-300 loads. Does anyone set the cylinder gap of their 15-2 closer than .006" What would be the adverse effects of the .002" cylinder gap on a 15-2? I am guessing it would increase velocity which I see as a positive, but would it negatively effect the forcing cone or the barrel? Too Much Pressure? Can wait to get back out and test more.
Set: 7
Created: 06/06/15 04:14 PM
Description: Dan Wesson 15-2 .357 12" barrel
Notes 1: 6.1 grains Unique
Notes 2: 158 grain plated hollow point
Distance to Chrono(FT): 10.00
Ballistic Coefficient: 1.000
Bullet Weight(gr): 158.00
Shots:
# FPS / FT-LBS
12 896 / 282
11 828 / 241
10 899 / 284
9 865 / 263
8 867 / 264
7 820 / 236
6 888 / 277
5 925 / 300
4 905 / 287
3 888 / 277
2 868 / 264
1 707 / 175
Average: 863.0 FPS
SD: 57.8 FPS
Min: 707 FPS
Max: 925 FPS
Spread: 218 FPS
True MV: 864 FPS
--------------------------------------------
Set: 8
Created: 06/06/15 04:19 PM
Description: Dan Wesson 15-2 .357 12" barrel
Notes 1: 18 grains power pro 300-mp fed primers small pistol
Notes 2: 158 grain hornady Xtp hollow point
Distance to Chrono(FT): 10.00
Ballistic Coefficient: 1.000
Bullet Weight(gr): 158.00
Shots:
# FPS / FT-LBS
6 1262 / 559
5 1275 / 570
4 1186 / 494
3 1304 / 597
2 1298 / 591
1 1241 / 540
Average: 1261.0 FPS
SD: 43.5 FPS
Min: 1186 FPS
Max: 1304 FPS
Spread: 118 FPS
True MV: 1262 FPS
“We cannot but pity the boy who has never fired a gun; he is no more
humane, while his education has been sadly neglected.”
-Henry David Thoreau
“When some of my friends have asked me anxiously about their boys, whether
they should let them hunt, I have answered, yes – remembering that it was
one of the best parts of my education – *make* them hunters.”
-Henry David Thoreau
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Dans Club
March 25, 2013
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The .006 specification was to prevent those Dan owners who could not understand how to take care of their guns from sending them back. The gape can be smaller, even .002 if you wipe the cylinder face after every number of cylinders shot. How many rounds will depend on how perpendicular the face of the cylinder is. Supposedly the large frame was more true but all the small frames I have seem very even. Another factor I think is that the small frame cylinder will expand more than the lg frame when it heats up. It is easy to adjust the gap at the range if it starts binding after a number of rounds if you use a smaller gap. I don't measure the gap, just eyeball it up to the light and cycle the action to check each chamber.
DWF Supporters
April 9, 2015
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Ole Dog said
The .006 specification was to prevent those Dan owners who could not understand how to take care of their guns from sending them back. The gape can be smaller, even .002 if you wipe the cylinder face after every number of cylinders shot. How many rounds will depend on how perpendicular the face of the cylinder is. Supposedly the large frame was more true but all the small frames I have seem very even. Another factor I think is that the small frame cylinder will expand more than the lg frame when it heats up. It is easy to adjust the gap at the range if it starts binding after a number of rounds if you use a smaller gap. I don't measure the gap, just eyeball it up to the light and cycle the action to check each chamber.
Makes total sense, thanks for the confirmation. Looking forward to collecting data on the effect of cylinder gap on velocities out of the 15-2. Less cylinder gap means less gas escaping means more velocity- Am I thinking correctly?? Seems like common sense, but I am not a physicist or a ballistics expert, this is just my hobby and it would certainly not be the first time I was guilty of muddled thinking.
“We cannot but pity the boy who has never fired a gun; he is no more
humane, while his education has been sadly neglected.”
-Henry David Thoreau
“When some of my friends have asked me anxiously about their boys, whether
they should let them hunt, I have answered, yes – remembering that it was
one of the best parts of my education – *make* them hunters.”
-Henry David Thoreau
Dans Club
January 17, 2015
Offline
I just had the gap a little too tight the other day at the range where I had to clean it to get it to advance to the next chamber. One thing I noticed on my 10" barrel is that if the gap is too tight, then it shoots consistently high left - I loosen the gap and it is a laser again. Why would that be?
As for your Chrono numbers, they seem low on the 158g with a 12" barrel. I average around 950 - 1000 FPS with 158 copper jackets using mid range loads of Titegroup and an 8" barrel (my favourite length to shoot).
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