A few things. Do a search on this board for OCW or Optimum Charge Weight. Do another search on this board for Audette Ladder.
I have been using the OCW method as it is pretty straight forward and relatively easy to dial in.
How close to the lands you decide to load, for me anyway, has usually been a function of "how close can I get and still fit the magazine?". I try to load about 3 thou off the lands if I have the opportunity. You will up the pressure as you load close to the lands so starting well under max is important.
I have never found the fastest round to be the most accurate. But the spread between most accurate and fastest is usually not more than 100 to 150 FPS. Some powders just will not perform well. If you stick to the known accurate powders you are usually in good territory. Lighter bullets tend to do better with relatively faster powders. The real benefit of a .243 is you can get the round moving fast. I took an antelope at 225 yards with an 85 grain Partition from a .243 Ackley Improved.
I have found with the OCW method that I can load with or without a crimp. Once you find the sweet spot for your barrel, brass/primer/powder/bullet combo (and brass length and COL is important as well as jump to the lands) it is something you can replicate year to year.
The best thing you can do, and you state you are doing it, is to know the dimensions of your chamber relative to the round. Not knowing means guessing.
Since this is your hunting rifle you don't want to get it overly hot. The .243 is way oversquare so its a blowtorch on the chamber. I usually take two rifles, sometimes three, to the range so that I am giving a good five minutes between shots with my hunting rifles. I will also clean the barrel every three shots or so. It helps cool it and you will hunt with a cold rifle.
Post a pic of your target when you get back from the range!
Coltdriver,
I just tried the OCW method based on your post
OCW Overview - Dan Newberry's OCW Load Development System
I have been using the ladder method of load development with pretty good success (before that I guesstimated). Decided to try the OCW method after reading your post for initial load development with my new Ruger RPR, IMR4831 and Berger Hybrid 105. I used plain WIN .243 brass, primer pockets uniformed, shoulder bumped back .0015" and the necks sized .0020" and the bullets .0020 off the lands. Used the OCW method to develop 5 powder charges with 3 shot initial groups. I made a spreadsheet that makes the calculations easier, literally just plug in max charges from 3 sources and it averages and determines the powder charges to be tested.
Keep in mind that this method is just to determine the optimal powder charge, not the ultimate accuracy (yet). The goal is to determine a "resilient" charge that covers different temps etc. Accuracy gets tweaked later with neck tension, OAL, and maybe some more brass prep. Anyhow, it seemed to work.
I tested loads last night after work and all 5 groups were sub MOA, largest being .7220 and the smallest coming in at .3605 at 100 meters.
#1 0.6230
#2 0.3910
#3 0.7220 (Scatter group) From Newberry's page
I show all of the targets above because I want to illustrate the importance of the "scatter group."* This will be one group of the round-robin sequence that seems to inexplicably open up.
#4 0.4095
#5 0.3605
One weird aspect of this testing is you shoot the loads at their respective target using a round-robin method. So, it's one shot at each target using it's respective load, then rotate to the next target/load for 3 iterations on each of the 5 targets.
According to the method, the group size isn't that important yet, but what is important is which loads impact the target at the same POI, which in this case were #s 2-4-5. All shot reasonable groups and right at the same basic POI. So I'll pick the middle of the 3, which will then "in theory" provide a "resilient" powder charge that is "harmonically" stable and compensates for temperature and pressure variations and still put the round at the same POI.
Next step is to check the chosen load against a lighter and heavier load (.3 grain increment), then on to chrongraphing and tweaking OAL etc. Results so far are pretty promising.
Chuck
