I read with GREAT interest your writings on load development. This is an area I have spent a great deal of time being frustrated with. My current project is developing a good 300-600 yd load for a tight necked 300RUM rifle that I had made. Just from a varying temperature standpoint I think your method really makes sense. I am curious about one thing though. Why did you use 100yds? I am preparing a load using your 'modified Audette' process at 300yds. and just wanted to know why you went back to 100. I ask as I have found some loads that are awesome at 100 only to have them disappoint beyond that.

Not trying to speak for Dan, but I have used his method on several rifles. I have done it at 200yds but believe (and have read)that 300yds is better. There is no way the rifles I have done this on could do the Ladder method at 100 yds. The bullets would be so close after the 4th shot I wouldn't be able to identify which bullet went where. I have had great results with this method on a .223 SpaceGun and a long range rig in 6.5-284. If you want some target/data results let me know and I will email them to you. Good luck with the new cannon!!!

Keith

[ 12-20-2002, 01:45: Message edited by: wksinatl ]

Thank you Keith. When you worked up the 6.6/284 what range did you perform this at? Did you find your load at that range worked well at others? Very curious how you went about it. Thank you,
August

Thanks for the interest and kind comments, Ultraman...

My reasoning for the initial (phase one) test at 100 yards is that some variables enter the picture at longer ranges that you shouldn't be concerned with until you find the right amount of powder for the bullet you're using.

What Creighton Audette sought to do with his ladder method at 300 yards was to find a "zone" or sweet spot where the charges all clustered together. He would then choose the center charge and call that his load.

The main reason I begin at 100 yards is to reduce the effects of wind. I also believe it is very important to shoot three shots of each variation, rather than just one. It's easy to pull a shot, or to get a bad round for one reason or another.

Also, believe it or not, there are situations where a light charge will land right in the group with a heavy charge at 300 yards, due to the fact that the slower bullet follows a higher arc from the muzzle. (The bullet exits late in the recoil arc, and "lobs" into the group with the flatter shooting bullets). This would of course skew a 300 yard ladder test. Add in a 5 to 10 MPH wind and you're all over the paper...

I have found that when you identify an optimal charge weight, the groups will form in the same location on the target relative to the point of aim at 100 yards. <Take a look at this link for a better description of my method. Here you will see the results posted by other shooters who used the same load with excellent results, as well as one shooter who independently came to the same OCW (optimal charge weight) figure that I did by using my loading method.>

http://216.219.200.59/cgi-bin/ubbcgi/ultimatebb.cgi?ubb=get_topic&f=13&t=000256

Audette's method seemed, from my understanding of it, to be directed at developing a load for an individual rifle.

My method is more directed at developing the optimal powder charge for a particular cartridge/bullet/powder combo. These OCW recipes work in most rifles chambered for them. (Ken Waters published a book called "pet loads" which contained load data of a similar stripe--purported and proven to work well in most rifles). So it's not an uncanny idea...

Anyway, take care, and let me know how things go...

Dan Newberry
green 788

I've tried my variation of this idea a few times, using a 223 and a 243. In both cases I used 150 metres (165 yards approx). I fired the sequences 3 times. This is an attempt to remove the errors that I put in. I also plot the positions of the various bullets, and create 'virtual' 3 shot groups; so I end up the the 'ladder' data, and a single 3 shot group (for each increment) to go with it.

John,

Firing the sequence three times would certainly work. Then just plot your virtual groups, as you say, and evaluate the results. This would achieve pretty much the same thing I'm doing with the round robin method, with the possible exception of weeding out the effects of a hot or fouled barrel, or fatigued shooter.

I believe that it is very important, once all groups are on paper, to draw the correct conclusion from the results. As I mention in the link, the smallest group isn't always the charge you should go with. When you see a small group, all that means is that those bullets all exited on a good harmonic node of the barrel. Altering seating depth can tune a load to such a node.

What you want is a three group string in which all nine shots fall inside MOA (one inch) on the overlaid targets. (It is difficult and perhaps impossible to evaluate the results of this test when fired by a rifle not capable of consistent MOA accuracy).

The first phase of my load development method does not determine the most accurate load for the rifle shooting the test.

Phase one merely determines the best amount of the partucular powder for that cartridge/bullet/powder combination. This amount of powder should remain the same for the overwhelming majority of rifles chambered for the load in question. By choosing the charge weight from the center group of the three group string, you'll have the best powder charge identified.

Once you have identified the best powder charge, you can go on to tuning that recipe to your rifle's tastes. A couple of shooters I've corrosponed with got good results by simply switching to a different primer. Normally, I like to use seating depth variations to accomplish the fine tuning.

But you don't alter the powder charge (the Optimal Charge Weight) simply to get onto a good harmonic node of an individual barrel.

Think about this: When you're working on developing a load, what you are really doing is altering the barrel time of the bullet. You want the bullet to exit the muzzle at a stable point in the harmonic whip. There are a few different ways to alter barrel time. Obviously, changing the powder charge will alter the barrel time, but remember, if we change the powder charge away from the OCW, a temperature extreme or odd component or lot can cause an MOA wrecking pressure change.

Another way to alter barrel time is to change the brass case brand. Have you ever heard someone say something like "My rifle hates Remington brass. It only likes Federal brass."? Well, what that really means is that when the shooter switched to Federal brass, the interior dimensions of the brass case changed enough to alter the pressure, which altered barrel time, and badda bing!--gave him good groups. He could have altered barrel time in other ways and gotten good results with the Remington brass.

Primer changes alter barrel time, and would be my second choice to OAL adjustments. If OAL adjustments aren't practical (short magazine length, for instance) then go to primer swaps for fine tuning.

Dan Newberry
green 788