LOWERING ES and SD - Need advice achieving consistency

[Lawnboi]

Want low SDs tomorrow with the least work? Buy a dasher barrel.

Case and chamber mean more than anything you can do on the bench imo.

 

[Okie_Poke]

I've never achieved particularly good SD on 223 with a significant sample size. Some F-class guys might have tuned things with 10 special steps but IMO you're wasting your time chasing it. You'll get bent by the wind long before it matters as long as it's not atrocious. Teens is good enough for that cartridge for what most anyone does.

Hot tip - a whole bunch of people claiming super low SD/ES on the internet are spouting single small shot count sample sizes and not actual repeatable #s over significant sample sizes. Some cartridges just make it easy. Like i almost have to try to get double digit SDs with 6.5x47 but most larger cartridges seem to most commonly be in 9-14 ish range for SD with large enough sample sizes. I hear the BR variants are the same as the x47 in that regard.

If you must focus on something, Consistent powder charges, neck tension, and seating pressure is probably where id look.

If your primary interest is load experimenting and tinkering, by all means dive into the rabbit holes. If you want to get better at hitting stuff, get to good enough and spend more time shooting in a manner that makes you better at shooting (I.E. not endless load dev from the most stable setup possible).

Another vote for this. Out to 500 yards, this really isn't a rabbit worth chasing, though I myself am not immune from chasing it just to tinker.

Also, if you insist on chasing this SD/ES rabbit, I would add the following (probably before worrying about seating pressure so long as you're not doing weird things when you seat the bullets):

This:

-Get the best brass you can

and this:

Have you tried changing primer brands or bumping up to “match” primers? That would be a relatively cheap experiment.

I don't have the exact book or page reference handy, but in one of his Modern Advancements in Long Range Shooting books, Bryan Litz demonstrated switching brands of primers can reduce your velocity variation. If my memory is correct, he switched from one brand of match primer to another branf of match primer (Federal to CCI, or something) in a 300 Win Mag and it produced a statitically valid difference in velocity varation. If I remember, I'll see if I can find the reference this evening when I get home.

I will also reinforce @flyfisher117's expecation-setting on this. Here are two of my sessions of the exact same load shot out of the same rifle over the same Garmin chronograph. This is my "match load" using Lapua brass, H4350, Federal Gold Medal Match primers, and Sierra Matchking bullets. Powder metered by Chargemaster Lite. Redding Type S full length bushing dies and competition seater. As you can see, even with 14- and 20-shot data sets, there's still variation.

 

[streamerfish]

"Shooting 10 shot groups under 1 moa at 100 with Gunwerks 7prc. Been shooting steel out to 1,000+ at times and was thinking I could try to trim vertical dispersion some at extreme distances. 50fps ES is not uncommon for me w this rifle. I'm probably way overthinking this but thought I would ask. Enjoy the heck out of learning this stuff."

Your clearly on the right track with your loads, you wouldn't get good results otherwise.

Yeah, overthinking it. I have a tendency to that on things also at times (dont we all lol).

The simple math though, really tells us that once your getting pretty low in SD, maybe under 30FPS or 20FPS or something along those lines, definitely once you get close to 10, your just running out of real world improvement real estate to work with...Theirs probably 20+ other things that are having a bigger effect on your results at that point.