I got to shoot some of the rounds I worked up per my last post on this issue.They did not really shoot all that well as you can see. I shot 3 other factory loads and discovered that my rifle loves the federal premium smk's. I am not trimming brass yet, so my brass sizes could be slightly different for the five rounds I loaded, which might contribute to my range in velocities? I noticed the range in velocities between the 178 hornady and the 175 federal smk's were about the same, but the smk's performed better. Anyone have any ideas as to why that might be? I have a box of the 178 eldx's, I would like to load them up to perform like the smk's. what suggestions do you guys have based on what you see here? These were all shot at 100 yards, wind coming from directly behind me. Shot prone off a bipod.

Small variations in brass length should make very little difference, as long as the case mouth is not get crimped down in the chamber. Many guys will tell you brass has to get quite a bit longer than specification length before that can happen. I have no opinion myself on that because I have not examined every rifle out there.

I think the SMKs are more accurate than the Hornady bullet because of more precisely made jackets. Who knows, though? Maybe some rifles like the Hornady better.

I see 168 gr Hornady hand loads, Store bought ammo 175 SMKs, store bought ammo 168 OTM, store bought 178 gr ELD-X.

What are you doing here?

The 168 hand loads were where I landed from shooting a couple of ladders and then loading up rounds of the most promising area of the ladder. I wanted to load up a few more and see how they shot against some factory ammo I had and see how my hand loads compared. I was running the chrono just to see if there were any "patterns". Starting to think load development is more of a black art than science! I am not sure I know what I am doing!

It is all a SCIENCE project.

*Pick a bullet
*Use the most appropriate primers (pick one)
*Pick the most appropriate powder
*Pick a seating depth
*Test, and find the best powder charge

*If, you're still not happy, play with bullet jump/jam and find the best one, but keep the same bullet, same powder and lot, same primer, same brass

*If you're still not happy, keep all the same parameters you found to work best, but use different primers.

Based on how well the smk's seem to shoot out of my rifle, would it make sense to try to duplicate any of the parameters of that particular round?

You do not know what powder they used.

Other than that...

Not sure either but I don't think that gun will shoot much better no matter what you do.
Just my opinion.

unless its a 24" Bartlien

P.S.
Buy a case of the Federal 175 Premiums

Like JG said, it is definitely a science. You could always do what I did and pay a professional to develop your load. I too am not 100% confident in my ability to develop the very best load. Is your rifle factory?

It is factory. I bought a Howa heavy 24" barreled action and put it into an hs precision stock. I have not done anything to it other than put a scope and new bottom metal to accept magazines on
and start shooting.

Might not hurt to bed the action, and verify the barrel is free-floated from the recoil lug to the end.

I have verified the barrel is free floated back to the lug. I have not bedded it yet, I wanted to make sure I didn't have any issues with the new bottom metal befor bedding it.

The federal 175 look like a 5 shot group under an inch or right about. If it’s inch edge to edge that’s 3/4 moa. Not bad for a factory rifle imo

Looking good to me. You might see how well it shoots without the can.

I had not even checked that to see what it is! It mic'd out at .65. I sat down this morning and measured everything els but not that. I have measurements of unfired rounds from each of these groups, base to ogive, base to shoulder, averages, ranges in measurements. I almost enjoy compiling and looking at all of this data as much as shooting to collect it!