OzFclass

I've just finished my F-open build and have commenced load development. Barrel is a Bartlein 29" HV 1-8.5 on an Impact 737R action setup as a single shot.

All these were shot at 300Y prone, pretty happy with all the shots although the mirage was running pretty hard (at least .5MOA distortion).

My question is where would you go from here? Everything shows promise with the Hornady 130 ELD-M probably being the stand out if you discount shot 3. Powder charge was 41.1 of 2209 across the board. I just wanted to keep things simple for this first projectile test and see how they performed and what sort of speed I was getting. SD came good after the initial very clean bore hit with the Sierra's.

So with the rifle seemingly lining everything, what would you suggest my next step be to get my load dialed in?

There's a number of things to consider such as bullet seating depth - have you tested this? Does your barrel have a tuner? What brass are you running - small or large primer pockets? Have you tested primers? All of these factors can, and do affect accuracy.

And finally, what is an acceptable level of accuracy that you are chasing? I don't know of too many guys running a Creedmoor in F-Open, but it's a popular cartridge in Sporting Hunter and performs well in this environment...You can probably squeeze a bit more out of it, but consider one aspect at a time.

It all brand new LRP Lapua brass. No tuner. Primers in this batch were CCI 200's. As for accuracy I'd want it to be at least repeatably .5 MOA for confidence sake but stacking them wouldn't hurt either. I understand the 7mm's are the go in F open but I'm happy to give it a crack with the 6.5CM. I guess at the moment I'm trying to settle on a projectile and then move on to everything else you mentioned.

Try Berger projectiles again refining your SDs or Hornady ATips.
Let the barrel decide on one of those two.

If you shot the Sierras down a clean bore I'd be giving them another go.
On 5 round groups, you shouldn't discount one shot without reason. If you didn't call that shot, (ie you know you pulled it) it counts. Its a possible problem, don't ignore it.
Personally, I'd keep repeating that test with seating depth changes, and take it to longer ranges. New brass, new barrel, it will most likely change with fireformed brass and a "seasoned" (100-200 round) barrel. But by the time you get there you'll have a good idea of whats going to work.
The groups are good but at 300 in good conditions you should be aiming to put them in (or at least cut the edge) of a 1" dot. I'm not saying you need to do that every time, but "the gun" should be able to.