Loads, powder and muzzle speed and safety

jeanlikethis

jeanlikethis

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Would it be right to say:

Always stay with lighter bullets, slower twist ratio, and slow burn rate powder to stay in safe side?

From the date collected, seems slow burn rate power, under the same PSI, will deliver higher muzzle speed, and moderate recoil, but at the cost of more powder usage.

In 6.5x55 reloading, (defined by PSI)

4064 maximum charge is 38 gr with 2563 fps.
4350 maximum charge is 45 gr with 2667 fps.


Feels like fast burn powder bursts quickly and thrusts the bullets out, while slow burn powder expends slowly and constantly push the bullet up to the peak speed during firing.
 
No.

Twist is not an issue. it is what it is for your rifle.

Regardless of powder and bullet, the manual only lists what was safe in their rifle. For your rifle, start with the Start load, and see if that is ok. If it is, work up from there.

In 6.5 I once saw a Start load that was much too hot for a given rifle.
 
Most every cartridge design appears able to use a number of powders within a limited variety of burn rates. Mostly it depends on the type and design of the cartridge as to whether it will use fast, medium, or slow burning powders, or some limited combinations of those with the various bullet weights popular with that particular cartridge. Generally speaking, the powders with charge weights that allow a higher load density, percentage wise, will generally produce more accuracy and velocity than the others. This is for any given bullet weight. There is much more to it than that, but I'm sure you get the idea.

I can load all of my full power milsurp cartridges with IMR 4895. This powder will work in 30-06, 303, 6.5x55, 7.62x54R, 223 Rem, and others. I keep some 4064 around for match Garand loads, but for primary milsurp loads, I use IMR 4895. It's very versatile.
 
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jakester said:
Generally speaking, the powders with charge weights that allow a higher load density, percentage wise, will generally produce more accuracy and velocity than the others.
Click to expand...

Do you want to say that powder allows high gr while within the PSI limits is going to produce more accuracy and speed? Is that the reason 4350 is somewhat outperforming 4064, according to some reloaders.

I checked lots of forum and people do suggest 4350 over 4064 for 6.5x55. For bigger caliber like 7.62 (x 54r, 55), they suggest 4064.
 
Generally speaking, yes. The greater the powder charge, the greater the amount of gas volume which generally increases velocity. Since you've used 6.5x55 as an example, then yes. IMR or H4350 would be a better choice than IMR 4064 if you plan to use 140gr and heavier bullets in a bolt action rifle. However, If you're loading for a Semi Auto rifle, like an AG42b Ljungman, then I would then prefer IMR 4895 or 4064, instead of 4350 as they have a burn rate and pressure curve more suitable to Semi Auto Rifles. As for 7.62x54r, I would favor 4895 and 4064 if duplicating service ball loads.

The very basic rule of thumb that applies to most every type and style of cartridge is that the slower burning powders are more efficient with the heavier bullets, and the fast to medium powders are more efficient with the light to mid weight bullet selections.
 
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Thanks, that is very educational.

I stock some 4064 and 4350 for my own hand load.

One question, to reload 7.62x25, you have any suggestions, powder wise?

Thanks.
 
I get from on line search for 7.62x25:

Powder 1200FPS 1300FPS 1400FPS 1500FPS 1600FPS 1700FPS
IMR 800 X----5.8gr-------6.4gr-------7.0gr(max)
BLUE DOT 6.4gr 6.8gr 7.3gr(max)
Accur #7 7.2gr 8.0gr 8.7gr(max)
Accur #9 7.8gr 8.9gr 10.1gr(max)
Alliant 2400 8.6gr 9.6gr 10.7gr 11.8gr(max)
VIHT N-110 9.6gr 10.1gr 10.7gr 11.2gr 11.8gr(max)
H110 10.3gr 11.2gr 12.0gr 12.9gr 13.7gr 14.2gr(max)
WIN 296 10.2gr 11.3gr 12.3gr 13.3gr 14.4gr(max)
 
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It is wise to buy at least TWO reloading manuals that are published by a REPUTABLE source or manufacturer. Lee, Hogdson, Lyman, Sierra, Speer, and Nostler to name a few, all test their loads to ensure SAFE reloading practices. However, be aware that any of these were shot in a pressure barrel or specific firearm, which is generally indicated. These loads were considered safe in firearms of good condition, under normal circumstances.

HOWEVER, changing any of the components, (such as primer, case or bullet,) could result in different pressures. Even using a bullet of the same weight from a different manufacturer could change pressures.

The purpose of a firearm is to accurately send a projectile into a target. In most cases, the top loads giving maximum velocity are really not the most accurate loads. It is not really good to have something moving like a bat out of hell if you can not hit anything with it.
 
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jeanlikethis said:
Would it be right to say:

Always stay with lighter bullets, slower twist ratio, and slow burn rate powder to stay in safe side?

From the date collected, seems slow burn rate power, under the same PSI, will deliver higher muzzle speed, and moderate recoil, but at the cost of more powder usage.

In 6.5x55 reloading, (defined by PSI)

4064 maximum charge is 38 gr with 2563 fps.
4350 maximum charge is 45 gr with 2667 fps.


Feels like fast burn powder bursts quickly and thrusts the bullets out, while slow burn powder expends slowly and constantly push the bullet up to the peak speed during firing.
Click to expand...

A "slower" powder requires more powder to produce the same "peak" pressure as slower powders, and produces that pressure over a longer time period. Regardless of powder, it is completely burned within a few milliseconds (inches), but the decreasing pressure is still high enough to accelerate the bullet - to a point.

All powder contains essentially the same amount of energy per grain, so more powder produces more energy (in the form of high pressure gas), and this translates into higher muzzle velocity (MV).
 
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