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11-25-2010, 03:20 AM
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published ballistics and barrel length.
Is there a "standard" barrel length ammo companies use for their tests? None of them say anything about the length of the barrel in their information.
For instance; Federal .44 Special 200 grain lead hollow point. The Federal website states "870 fps muzzle velocity." Fine. Is that from a four inch barrel or a ten inch barrel. Without that information, the velocity tells us nothing...or is that the real play?
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11-25-2010, 06:39 AM
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I'm no expert by any stretch of the imagination, but I believe ammo and powder companies use single shot "pressure" barrels whose lengths are longer than barrel lengths typically found on handguns.
The lengths are sometimes listed in reloading manuals and other literature, but the only way to find out how the same ammo performs in any particular gun is to buy or borrow a chronograph and measure it yourself.
Even if you happen to find an article written about the ammo you are interested in, fired from the same guns you want to use it in, the muzzle velosity won't be the same.
Closer than the pressure barrel data perhaps, but not the same since no two guns are exactly the same.
Here's a website with the most comprehensive data I know of when it comes to barrel length vs velosity:
Ballistics by the inch
They also have some data using actual handguns - maybe you'll luck out and find your gun and ammo in the test list.
Hope this helps,
John
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11-25-2010, 08:58 AM
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If you check the manufactureres web site you'll see that some manufacturers list the barrel length for some loads. Winchester is pretty good about listing the barrel length used for their ballistics but they are NOT uniform about doing this because some loads have no data listed. IMO, listing the barrel length and type is a recent addition and they are slowly filling in the blanks.
As for the barrel lengths used, most commonly it's 4 inches. However, for rimmed ammunition I've seen both 4 and 6 inch vented barrels listed with 4 inch being most common but certainly NOT universal.
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11-25-2010, 10:25 AM
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Ammunition manufacturers are much better than they used to be at providing information about testing conditions. If you look carefully at the small print in most ballistics tables, there will be a small notation about what kind of barrel was used. Before about the mid-70's they provided NO information and most testing was done in 8-10" unvented test barrels to give the highest velocity possible. Then the advertising gurus would add 10% to be sure they exceeded their competitors ballistics. For example, it wasn't uncommon to see .357 velocities over 1500 fps with 158 grain bullets and clearly nobody was getting those velocities from any revolver being manufactured. Only the NRA provided any realistic ballistics information and they relied on an outside testing facility. When consumer grade chronographs became available, all that began to change.
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11-25-2010, 11:42 AM
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buying a chrono and shooting a bunch of stuff through it is an eye-opening experience. i will admit that the manufacturers have improved a little in the last few years, but generally, the posted data has very little relation to reality! the really annoying thing is when the gun-mag-media just repeat the factory-supplied silly-data word-for-word instead of actually testing.
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11-25-2010, 12:37 PM
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Amen to everything that ar15ed just said. I truly love it when "boutique" ammo makers like Double Tap and Buffalo Bore and Cor-Bon post the model of the gun from which the ammo was tested. Nothing like digging around on the Remfedchester major ammo company site and learning that the .38 Special numbers were clocked from a 10-inch vented test barrel. ("Yeah, that ought to be the rough equivalent of my 1 7/8" 37-2 . . . .  )
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11-25-2010, 12:55 PM
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...Sounds like chronograph time....Oh well, I sorta thought that would be the case. When I get my gun back from the gunsmith, that is what I will do...
Thanks for the information!
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11-25-2010, 08:11 PM
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Quote:
Originally Posted by n4zov
Ammunition manufacturers are much better than they used to be at providing information about testing conditions. If you look carefully at the small print in most ballistics tables, there will be a small notation about what kind of barrel was used. Before about the mid-70's they provided NO information and most testing was done in 8-10" unvented test barrels to give the highest velocity possible. Then the advertising gurus would add 10% to be sure they exceeded their competitors ballistics. For example, it wasn't uncommon to see .357 velocities over 1500 fps with 158 grain bullets and clearly nobody was getting those velocities from any revolver being manufactured. Only the NRA provided any realistic ballistics information and they relied on an outside testing facility. When consumer grade chronographs became available, all that began to change.
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That is correct. The funny thing is many people on this forum maintain that the older advertised numbers mean those loads were actually hotter than what is available today. When S&W ammo went from using unvented test barrels (nearly 11" for the .357 magnum) to quoting velocities from real revolvers about 1979, their numbers dropped by over 20% in many cases. Most of those published numbers from the 50's, 60's, and 70's were pure fantasy.
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11-25-2010, 09:24 PM
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I don't know if they still do it, but Lyman reloading manuals used to have a section at the back where they listed factory load velocities as fired in the test weapons they used for load development. There were some significant differences between catalog and chronograph in many cases.
One of the issues that affects some load data is that test barrels, by definition, have to provide worst case sceanarios from the viewpoint of the data provider. That is, tight chambers, minimum headspace and tight bore/groove dimensions to create the highest possible pressure situation. Your standard production weapon generally isn't going to display those characteristics and will therefore "shoot slow".
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11-27-2010, 04:05 PM
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Double Tap lists several different gun and barrel length for the
handgun ammo they sell.
CCI/Speer does list the barrel length as
well as muzzle velocity, 25 yards 50 yardss and 100yards
as well as bullet trajectory when sighted in at 25 yards
Cor BOn lists barrel length as well...
Randall
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11-27-2010, 09:35 PM
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Quote:
Double Tap lists several different gun and barrel length for the
handgun ammo they sell.
CCI/Speer does list the barrel length as
well as muzzle velocity, 25 yards 50 yardss and 100yards
as well as bullet trajectory when sighted in at 25 yards
Cor BOn lists barrel length as well...
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As has already been stated on this thread.
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