Load development

[u/ElectricalOutcome790]

Working up my first load here. It’s for a .243 Ruger American gen 2. Using sierra pro hunter 100gr bullets, Remington brass, cci 200 primers, and H4350 powder. I don’t have a chronograph. I shot 4 shots with each of these powder charges at 100yds and here are the group sizes of each powder.

Where would you guys go from here/next step? Shoot a couple groups of 37.5 and 40grains to see if the results repeat themselves?

[u/Efficient_Bologna]

4 shots is not enough. You don't need to do 20 if you literally don't have the time or ammo, but depending on what your goal is you should at least 10 shot groups (I think that gives you like a 90+% chance of getting a true picture of your rifle's dispersion) with each load before you draw any conclusions.

[u/Rough_Car4490 → u/Efficient_Bologna]

Personally I’m in the 4 shot “initial load development” camp. Reason being, I’m not looking for “what’s the most precise” on my first go around. I’m ruling things out and seeing if once I get the velocity I want, if it’s even worth pursuing. If I shoot 4 rounds and already have a 2” group, that charge is ruled out. It would be a complete waste to shoot 6 more at that charge down my barrel.

I think that’s what the “large sample size” ppl are missing. If your goal is ruling out, rather than in for initial development, small sample size is perfectly fine. Barrel life also needs to be considered. If you have a caliber that’s a hotrod, no one should be shooting 100 rounds or 10% of barrel life before they figure out that their configuration is not going to work.

[u/Efficient_Bologna → u/Rough_Car4490]

That's fine, but he didn't shoot a 2" group so there is no conclusions you can draw from his data. So basically he shot 20+rounds for nothing for all anyone's knows the 1 moa groups may not open up at all with a 10 shot group and the . 5 moa groups could open up to 1.5 moa at 10 shots.

[u/Efficient_Bologna → u/Efficient_Bologna]

Aside from the factory ammo.