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Discussion Starter #1
Yesterday I was Reading in Jack O´connor´s book “The Hunting Rifle” (p. 68) that .270 win factory loads were charged with 55 grains of du pont 15 ½ powder to produce 54,000 feet/pounds, resulting in a muzzle velocity of 3160 ft/s when firing a 130 grain bullet from a 24 inch barrel.

Is it posible to produce the same muzzle velocities when reloading with IMR 4350?

Independently to the type of poder used, should any load producing 54,000 feet/pounds result in a muzzle velocity of 3160 or should other factors be considered?

Why have Factory loads been reduced to limit the muzzle velocity to 3060 ft/s? Is this for safety reasons of as a commercial strategy to develop new calibers?

Thank you in advance for your comments.
 

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The Hog Whisperer (Administrator)
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E.O.,

The "pressures" that Jack O'Connor referenced were not actually in pounds per square inch. The pressures at the time were taken as a measurement of copper crushers, which are now known to have given different readings than actual PSI. Also, it eventually became clear that copper crushers were not very precise, either.

Modern reloading data is developed with measuring devices (strain gages, mostly) that are far more accurate and so it turns out that some old loading data was hopelessly optimistic, and in some cases, downright dangerous.

In addition, the numbers put out by the manufacturers often were an exaggeration. The manufacturers got away with that until the advent of inexpensive chronographs.

Having said all that, you can come close to those ballistics by the use of either IMR or Hodgdon 4350. Probably not exactly, but easily within 100fps or so and that should be just fine for a .270.

Good luck.
 

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The Shadow
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Also, that powder sold by Hodgdon, isn't made by the same people it used to be. How much different? Who knows, but when things change, they change.
 
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Not exactly your question, but I have just recently clocked a batch of Winchesters 130 grain Power-Point load. Advertised speed is 3060 fps. I got 3003 fps 6 feet from the muzzle of a 23 inch barrel.

Cheezywan
 

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Discussion Starter #5
E.O.,

The "pressures" that Jack O'Connor referenced were not actually in pounds per square inch. The pressures at the time were taken as a measurement of copper crushers, which are now known to have given different readings than actual PSI. Also, it eventually became clear that copper crushers were not very precise, either.

Modern reloading data is developed with measuring devices (strain gages, mostly) that are far more accurate and so it turns out that some old loading data was hopelessly optimistic, and in some cases, downright dangerous.

In addition, the numbers put out by the manufacturers often were an exaggeration. The manufacturers got away with that until the advent of inexpensive chronographs.

Having said all that, you can come close to those ballistics by the use of either IMR or Hodgdon 4350. Probably not exactly, but easily within 100fps or so and that should be just fine for a .270.

Good luck.
Thank you Mike, You´re right. Pressures were in pounds per square inch. I got the units all mixed up. How much IMR 4350 (grains) you would suggest for reaching those velocities?
 

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O'Connor's favorite powder for the .270 was H4831, still an excellent choice.
and I have measured 130gr Nosler BT at 3100fps or more when used with H4831. Most guns also shoot under 1' with the loads if the guy pulling the trigger knows what he's doing.
 

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The Hog Whisperer (Administrator)
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Here is the data I have:

Sierra 3rd edition, 130gr. bullet, 26 inch barrel:
IMR-4350, starting load 48.4gr. velocity ~2,700fps
IMR-4350, MAX load 54.9gr. velocity ~3,100fps

Speer #12 manual, 130gr. bullet, 22 inch barrel:
H4350, starting load 52gr. velocity ~2,733ps
H4350, MAX load 56gr. velocity ~2,949fps
IMR-4350, starting load 51gr. velocity ~2,873fps
IMR-4350, MAX load 55gr. velocity ~2,907

Nosler 5th edition, 130gr. bullet, 24" barrel
IMR-4350, starting load 51gr. velocity ~2,828fps
IMR-4350, MAX load 55gr. velocity ~3,078fps

Hornady fourth edition, 130gr. bullet, 24" barrel
IMR-4350, starting load 50.6gr. velocity ~2,700fps
IMR-4350, MAX load 54.8gr. velocity ~3,000fps
H-4350, starting load 50.7gr. velocity 2,700fps
H-4350, MAX load 56.3gr. velocity ~3,000fps

Hodgdon #26, 24" barrel, Hornady 130gr. bullet
H-4350, starting load 51gr. velocity ~2,865fps
H-4350, MAX load 54.3gr. velocity ~3,012fps

Hodgdon #26, 24" barrel, Nosler 130gr partition
IMR-4350, MAX load only listed, 55gr. velocity ~3,075

Note that in many cases the velocities are rounded to the nearest 100fps. I would take from the data that a safe starting load in the .270 for a 130gr. bullet would be around 50gr. of either IMR or Hodgdon 4350, and I would not exceed 55gr. without specific data from the manufacturer. A chronograph would be helpful if you have one. But that should get you started.

Good luck.
 

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The Hog Whisperer (Administrator)
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Also, that powder sold by Hodgdon, isn't made by the same people it used to be. How much different? Who knows, but when things change, they change.
Darkker is right, 4831 started out as WWII surplus and when newly manufactured 4831 was introduced, it was considerably faster. Just an example. Hodgdon has moved production of most, if not all, of their 'stick' rifle powders to the ADI in Australia. IMR was known to have changed powder formulas in the 1970s, and the list goes on and on.

So do be careful that you are not relying on very old data. Many of the loads listed with the original surplus 4831 would be considerably over pressure and dangerous with new manufacture 4831, either IMR or Hodgdon.
 
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