I'm at a big disadvantage

[mugsie]

I have this nice rifle I just finished building and would like to work up a target load for it. I am limited to 100 yards only, so I would guess the ladder test is out of the question (I understand it's better performed at 200 yards or more). So - what would you recommend in shooting for the smallest groups?

The way I did it for my other rifles was to select a bullet and a powder, shoot groups varying the powder by .2 grains around the min / max. Once I find the tightest group, then I begin varying the distance to the lands. This will usually give me a bullet, powder, seating dist and brass for that particular combination. At 100 yards it's not far enough to highlight any inadequacies, so is there a better method considering I'm only working at 100 yards.

[Nefarioud]

Check out Dan Newberry's deal on OCW http://optimalchargeweight.embarqspace.com/

I was skeptical, but it seems to work. I've done ladders then shot this method and vice-versa, the data seems to coincide.

[Captain Finlander]

I agree with the concept but have been very successful with load development using the old standard. Your .02 grain adjustment is to small for initial load development.

The first thing I do is consult the charts in several books for a particular load that matches the goal I am trying to achieve. Keep in mind that the book data is representative of actual tested results so a couple of grain reduction should be a safe starting point. For instance I want a 3000 fps 150 grain load for a 270 win. out of my 24" barrel, so I reduce my loading enough to achieve my goal within 5 - 4 shot strings. Using a .5 gain deviation between charges is quicker. I also select a powder that shows consistency in more than one book.

Step 1
Make yourself a test box of 20 perfectly matched once fired brass. To do this I prep 100 cases to be exactly the same length, uniform the flash hole, etc... I then weigh each one setting aside 20 that are the same weight. More or less brass is made up in wall thickness changing the internal dimensions slightly.

Step 2
Divide the box into fifths. Wrap tape around the plastic, foam or cardboard holder from a 20 round box. Use a marker to divide it into fifths. In each of the 1 fifth divisions you can write the load data for those 4 rounds. Example: 55 grains of H4831SC, 55.5 grains, 56 grains, 56.5 grains, 57 grains. Note your OAL seating depth, bullet weight, and other load data on the outside of the box.

Step 2.5 Optional
You can weigh each bullet to ensure that your test box is perfect. Bullets can show as much as +/- .3 grain spread. This could create a situation where bullet 1 is 153 grains and bullet 2 is 147 which will throw off your test.

Step 3
Starting with a clean barrel shoot 2 or 3 spoilers shots to foul the barrel then let the gun cool to static temperature between successive shots. No farther than 100 yards.
(assuming your rifle is free floated)

Step 4
Out of the 5 - 4 shot strings one will be tighter than all of the rest. This load, if not perfect, is within less than .5 grains of it. (My 270 put 4 under a dime with 56.5 grains of H4831. My 25-06 will put 5 in the same hole with 53.4 grains of IMR 4350 pushing a 75 grian Hornady HP). If you play with seating depth this point you'll have to repeat the process. I seat to the lands or as close as I can get.

This is the same method as described in all of my reloading manuals dating back some 50+ years and is probably similar to what you have already done.

[Uncle Jack]

That's pretty much the method I use except I mark the cartridges with marking pens. I either color code the base of the cartridge (red = 55.0 grns, blue = 55.5 grns, green = 56.00 grns, etc., etc.) or just write the load on the side of the cartridge.

Marking the cartridge box works just fine unless you knock the box over on the shooting bench.

uj

[laportecharlie]

Cap Finlander,
You better check the math in step 2.5. A +/- .3 grain spread will yield a ES of .6 not 6.
Charlie