How does one select a powder for a particular caliber when accuracy is the primary criteria? I've read Lyman's 47th, but they seems to be interested in a balanced take; velocity, accuracy, and ballistic uniformity.
Where, within a powders minimum to maximum loads will one generally find the most accurate load?
I seem to be getting different bullet pulls when I neck size. Some heads seat easier than others. Is this problem caused by the ductility of the brass or possibly a slight difference in the diameter of the bullet?
Thanks for your time and TIA for all responses.

BEJ,

I suggest you pick the three powders that give teh highest velocity for your caliber/bullet combination, then work up loads using these powders. If you are still unhappy with the accuracy of your loads, then you can start playing around with the seating depth.

Your problem with inconsistent bullet tension is probably due to the brass being of uneven thickness.

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saeed@ emirates.net.ae

www.accuratereloading.com

Good question.

First of all, it depends on a number of things. What range are you shooting for? What degree of accuracy is acceptable to you?

If you are firing at relatively short ranges (out to 200 yards), you might be well served by a number of cartridges. My immediate choices would include .223, .22 or 6mm PPC, or similar cartridges. The bullet choice would be extensive because in my experience these calibers work very well at these ranges with a wide range of bullets.

200 to 600 yards? I personally like three old standbys--the .308, .30-06, or the .220 Swift. I know that there are many, many more calibers that perform equally as well, or even better than these three, but I like them. Again, the bullet selection is quite extensive.

600 yards and over? Here, I personally like the .30 caliber family; to me, they seem to have just the right balance of weight, length, and BC to hit what I'm aiming for. My long range cartridge of choice is the .300 Win Mag.

As for powder, I read long ago in one of the Speer manuals that the best load is one which fills the case to the base of the seated bullet. There are loads that differ from that rule, however, that will prove accurate in your rifle.

An excellent reference for this purpose is the Nosler Reloading Manual. For each cartridge listed, they have loading densities for the individual powders used. They also list the most accurate load as fired from their particular rifle or test barrel. It is worthy to note that the greatest accuracy was determined to be with loads that usually had a loading density of 90% or more.

In my experience, I have found that for my guns the most accurate load is usually found below the max load. I don't have my data in front of me, but my accuracy load for my .300 Win Mag uses a 178 grain Hornady AMAX, and loads that are about 5-7 grains below the published maximums.

I have also found that accuracy depends on two things, assuming that your rifle is in trim, and ready to shoot well. These are uniformity and repeatability. Accuracy is a matter of rifle harmonics; the barrel flexes when fired. The trick is to make the barrel flex exactly the same way, each and every time it is fired. To do this, you must eliminate the variables as much as possible: use brass with the same headstamp, from the same lot, weighing the same from case to case; trimming to the same length; neck thickness, primer pocket depth and flashholes turned, trimmed, uniformed, and deburred the same way, and to the same degree. Powder must be hand thrown and trickled on a good accurate scale. Bullets need to be measured for concentricity, weight, and length. Primers can also be weighed; make sure they are from the same lot, of the same brand and type, and seated to the exact same depth, each and every time. Loaded rounds can be measured for bullet runout, and seated with competition or in-line seaters.

As for repeatability, you must set yourself up for success. A good, stout bench of the right height, a comfortable chair, sandbags as needed, and a good rest are all necessary.

Finally, you play the most important role--firing the rifle or handgun exactly the same way, with the same squeeze and exact sight picture and alignment, each and every time.

As for your neck sizing, are you using mixed headstamps? Also, are all of your cases from the same lot? Thicknesses of the case can vary greatly from lot to lot, even from the same manufacturer.

Also, make sure that your cases are lubed uniformly when sizing. Too little lube will result in distortion of the case neck, when the expander is pulled through.

I hope all of this helps. If you are a new reloader, here's hoping that you can find as much enjoyment and fascination as I have over the years. Good luck, and great shooting.

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Happiness is a 200 yard bughole.

[This message has been edited by Powderman (edited 05-12-2001).]

Typically you will get the best combination of accuracy and velocity from loads where propellants are at or near 100% density, or higher, in the case. You can "guesstimate" by seeing where the various powders at maximum charges fill the case. They should be close to where the base of the bullet will be seated. These will be the slower powders shown in the loading manuals, some of which will indicate which are the compressed loads. The more scientific way is to determine water capacity of the powder chamber and convert that into the powders best suited for that case. Usually there are easily a half dozen powders meeting the criteria from which you can select from available powders. You can then proceed normally to develop loads starting with reduced loads from those given maximums, increasing the propellant progressively until you determine best accuracy. Some powders respond quite nicely to compressed loads. Particularly for me, the Alliant line of powders seem to attain peak velocity and accuracy at maximum charges which are usually compressed if the proper powder has been chosen.

The reason ballistic uniformity is stressed in your manual is that at longer ranges velocity will affect vertical dispersion more markedly.

The bullet grip is not only affected by the thickness of the brass, as Saeed mentioned, but also by the ductility and elasticity of the necks. That in turn is affected by the work hardening brought about by repeated reloading. Annealing is the answer to that, something I do about every 5 loads, depending on how much the neck is worked in that particular cartridge and die. Uniformity of the brass in ALL aspects is one of the major factors affecting accuracy. Bob

Neck tension -- what they said above.

I keep my brass in lots according to the number of times it's been fired. I may start weighing cases and bullets and grouping them by weight as well as by times fired.

Bulkier powders produce higher velocities at lower working pressures. I look for that combination of velocity/pressure which is the best. These powders seem to fill up the case too (.223 at any rate).

I don't think powder matters as much as accurate reloading.

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PowderBurns Black Powder / Muzzle Loading Forum:

www.hotboards.com/plus/plus.mirage?who=powderburns

Good advice above. One other thing: The most accurate load at 100 yd. will not be the most accurate at 200 or 300. You should probably decide what your range will be and load for that distance.

All the advice above has been excellent. Another factor is your rifle, most particularly your barrel. If your barrel does not like a particular size bullet you can do all the other accuracy tweaks until you are blue in the face and you still will not have the accuracy you desire. Sometimes your barrel will not shoot the size bullet you want to use, the next barrel of the same chambering may love that same bullet. Good Shooting.

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