Hi Guys
I have wondered about this and never asked so here goes.
In my ADI Smokeless Powders Guide for any given bullet weight there are a number of powders and charges given.
For example
For 55gn projectiles in .223
-AR 2207 22gns 3,190 fps
-BM1 24gns 3,175 fps
-BM2 25.5gns 3,240 fps
-AR 2206 25.5gns 3,260 fps
-AR 2208 27gns 3,285 fps

How does one read this table in regard to selecting a powder and a charge?
Why is there not a particular powder for a particular calibre?
I choose AR 2207 because that would give the most number of reloads for a given volume of powder and settled on 20gns as that gave good accuracy.
What criteria do you use when selecting a powder in reference to the information contained in powder tables?
Regards
Deafdog

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deafdog@one.net.au
www.deafdog.one.net.au

Powders are mainly nitrocellulose, the same stuff that was used as a plastic base for old movie films. The burn rate is controlled by the physical size of the granules, and by additives.

Different powders have different densities. Your cartridge case may hold just the right amount of one type of powder, and enough of another type to destroy your gun.

Flake powders meter poorly, rod powders meter reasonably well, and ball powders meter quite well.

The powder selection game is finding a powder that almost exactly fills the case, gives you enough pressure to get good muzzle velocity, burns long enough to utilize the length of your barrel, and slow enough that it does not create excess pressure in the first few inches of bullet movement. No one powder is good for all cartridges, but most cartridges can 'run' on several different kinds of powder.

When I first started reloading .223, I tried H322. The standard deviations on MV were terrible--45 fps or so. The problem is that if you fill a .223 case with H322, you will create a serious overpressure problem. However, this same powder is excellent for some other cartridges.

The diameter and weight of your bullets, and the amount of space in your cartridge case determine whether a relatively fast or slow powder is best for your application.

Deafdog,

Usually many powders will work at reasonable performance levels in a given cartridge/bullet combination, with a few being better than others.

Which powder is "best" depends on the shooter and the rifle. The ultimate performance is usually measured by some combination of accuracy, velocity, pressure, recoil and sound and flash level.

I like to use powders that are slightly compressed under the bullet. This seems to make the load insensitive to position and cartridge handling. I also like to choose a powder that is 99-100% burnt in the barrel. This reduces muzzle blast and flash, and lowers recoil a bit. (I was effectively temporarily blinded by a 300 WinMag with a slow powder load just at dawn one morning. I had no clue what the reaction to the shot was.)

Then I look for reasonable velocity at moderate pressure levels. This creates longevity of the cases and the rifle. I find that dropping back 75-100 fps can lower the peak pressure significantly.

Among the powders left to choose from I look for one that gives me the best groups, or lowest fouling, etc. If it is a good hunting rifle I usually stop when I reliably get sub-MOA groups. If it is a target rifle I look for the absolute best performance. (For target loads muzzle blast is not a very important factor.)

I do not have your powders in my QuickLoad modelling program, or I would try to tell you which one I would choose to start with.

The fact that AR2207 is the smallest charge, indicates that it is probably faster than the others. This will tend to make it very shooter friendly (lower muzzle blast and recoil), the fact that you are 10% under max loads indicates that you should be at moderate pressures. The only one of my guidelines this load violates is that it is probably not a full case. If the accuracy is good, this is not significant.

Ultimately the rifle will tell you which one is "best" !

Don

Deafdog,

Loading manuals usually list a range of ppwders that are "potentially" suitable for the caliber. This list usually runs from powders that a bit quick burning for the caliber to those that are a bit slow.

If we take the 223 as an example, 2208 is really a bit slow for maximum velocity and 2207 and 2206 are closer to what is required for top velocities.

HOWEVER, your 223 might give its best accuracy with 2206, mine might be with 2208 and someone else's with 2207.

I would say that most manuals list a range of powders that will provide from about 90% of the calibers potential velocity up to 100% of the potential velocity.

Your basis for selecting 2207 ie. accuracy from a powder that is reasonably suitable for the calibers velocity potential, is probably what most shooters would do.

As to the "number of loads per tin" I think some do that. Also, others might choose a powder that they already use in other calibers.

Don G's post has oulined selection quite well.

However there will always be some variation on his theme because of "personal" preferences. For example, if possible I prefer to avoid compressed loads.

Thus I am far more inclined to use 2208 in a 375 rather than 2209. But if 2209 was accurate and 2208 was not quite there for accuracy, then I would use 2209 and a compressed load. Some calibers such as the 375 don't really have many ideal powders. For example, 2208 is a bit fast for it and 2209 is a bit slow for it.

Note for Don G

Don,

2205 is like IMR4227
2207 is like IMR 4198
2206 is like IMR 3031
2208 is the powder Hogdon sells as Varget
2209 is what will be H4350SC
2213SC is H4831SC
2217 is H1000
2218 is 50 BMG. I don't know if Hodgdon sell this powder

As you can see they have a numbering problem with 2206 being slower than 2207.

Mike

Hi Guys
Thanks for the answers.
Mike375
What powder would you recommend for a .270AI
Regards
Deafdog

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deafdog@one.net.au
www.deafdog.one.net.au

Deafdog,

Of the ADI powders and for bullets from 110 grains try the 2213SC. The older 2213 is being discontinued.

Mike

Hi Mike
Thanks
Regards
Deafdog

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deafdog@one.net.au
www.deafdog.one.net.au

Mike,

Thanks. I will write it down this time!

Don

I look for highest velocity at lowest working pressures. This relationship results from powders which burn efficiently for a given load and provide optimal internal ballistics. That is to say, a pressure spike that extends evenly across the length of the bore and bullet acceleration that extends evenly across the length of the bore.

I lean toward bulkier powders because they produce better velocities at lower working pressures. That means less loads per pound, but also less bore wear. Sometimes economy is not where you think it might be.

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