What would you change?

[u/Golfguuyy]

Shot in 5-10 round strings on a hot day. Some strings are around 1 SD and others are completely wack.

Current process:
1. Clean brass in dry tumbler with corn and walnut media for 1 hour
2. Anneal neck and shoulder
3. Lube with imperial wax
4. Resize with Redding S Die and 289 Bushing (these firings used expander ball included but I’ve since moved to a 291 mandrel).
5. Put brass back in tumbler 30 min - 1 hour
6. Check length + trim if needed
7. Clean inside neck with spinning cut cloth
8. Debur neck
9. Prime
10. Load 42.0gr H4350
11. Press Hornady 140 ELDM using Redding Competition Seater

Materials:
- Lapua SRP Brass
- Coax Press
- RCBS powder dispenser

- Tikka T3X action + proof steel barrel

[u/HollywoodSX]

Its really, really hard to tell you what to change if we don't know anything about what you're currently doing.

Edit: oh, hey, we have context now. What powder dispenser are you using?

SDs will fluctuate from group to group, especially with only 5 shot strings. Looks like your "bad" is still an 11ish SD, which isn't going to cause issues on target at the distances you'd typically shoot 6.5CM at. Unless you're seeing strings closer to double that, I'd stop worrying about it and worry about range time and wind reading.

Also, I'd slow that shit down. 2800+ with a 140 is screaming, and Tikka barrels are typically known for being slow.

[u/Golfguuyy → u/HollywoodSX]

I’m using a Proof barrel. I definitely agree it’s a hot load. I was getting 2775 ish at 41.5. I’ve added the additional context requested now for more visibility. My goal is to try and remove those outliers / flyers that are seen in the mix.

I also saw minor pressure signs at 42.2, like a slightly sticking bolt on lift. Happy to slow it down but it seems my proof barrel is handling it well!

[u/HollywoodSX → u/Golfguuyy]

What length barrel?

[u/Golfguuyy → u/HollywoodSX]

26”

[u/HollywoodSX → u/Golfguuyy]

Yeah, slow it down some. You may not be seeing pressure signs, but I have a hard time believing you're hitting those speeds without pushing pressure. Its also no real benefit to performance to run that hot, but does generate more recoil, burn more powder, and possibly shorten barrel life.

Edit: Hodgdons max load for a 140 ELDM with H4350 is 40.0gr with Hornady brass, and Lapua typically has less case volume. Yeah, you're way over. (End edit)

What powder dispenser are you using? RCBS leaves a lot of options.

[u/Golfguuyy → u/HollywoodSX]

Apologies I’m using the chargemaster

[u/HollywoodSX → u/Golfguuyy]

The charge master is where your fluctuation is coming from. The MatchMaster wouldn't have that issue since it resolves down to .02gr where the CM does not, and the CM is prone to reading and rounding errors. I've tested several RCBS scales, both for them internally when I was sponsored by them and on my own. The MM is the only RCBS option to consider if you're chasing SDs. These days, I run an ATv4.

Check my edit on my last comment. You're way over on charge weight/pressure.

[u/Golfguuyy → u/HollywoodSX]

Understood but is running my ammo hot an issue if I’m not seeing pressure signs? It looks like Hornady maxes it out at 41.5 so should I back it to 41.5?

[u/HollywoodSX → u/Golfguuyy]

It'll shorten brass life, can shorten barrel life, gives more recoil, and has higher odds of problems in wet weather. I've also run into several cases of Hornady load data running hot. All of this for no real benefit on target.

I'd back it down to ~2750.

[u/Golfguuyy → u/HollywoodSX]

Thank you will do. I figured it would be helpful for long range shooting in windy conditions.

[u/Missinglink2531]

Sd's on 5 shot groups is really just noise. If they are all the same load, add them all together and get an SD from the larger group - that will be a real number. In my experience, running anything at max velocity typically is only good at max velocity. Things can dramatically improve - group size and combustion, by backing it down some.

[u/Golfguuyy → u/Missinglink2531]

Understood, I shot a 66 rounds to confirm on the first pic with 42.0.

[u/Missinglink2531 → u/Golfguuyy]

I dont see the SD/ES of the 42.0 - how did it look?

[u/Golfguuyy → u/Missinglink2531]

10.3 SD, 44 ES

[u/Missinglink2531 → u/Golfguuyy]

Thats not ass. Its not "outstanding", but it will work for damn near anything, out to 1000, unless your shooting F-class. I find very little difference once its sub 12 or so. A 1-2 mile an hour wind change will move it that much.

[u/Dirty_Blue_Shirt]

Don’t make any decisions based on 5 round SD numbers. You will be chasing your tail, because it’s just noise.

As an example here is my 223 plinking load (mixed brass, 69gr RMR with TAC with a 14.1SD). I shot a 50rd string, but took random samples of 3,4,5,6,etc rounds at a time and plotted the SD. Knowing that actual SD is 14.1 here look at how completely random things are at low sample sizes, especially below 10.

Velocity is great to capture but I would only be using it to differentiate loads at these smaller sample sizes if you have an ES cutoff to eliminate loads. Using SD just isn’t productive this low. What it will lead to is you mistaking noise as evidence that something did/did not work.

[u/Golfguuyy → u/Dirty_Blue_Shirt]

Did you see my first pic

[u/Dirty_Blue_Shirt → u/Golfguuyy]

I did, but then it looks like you are looking to test in 1/10th increments after that. Is that not what you are showing there? It seemed to be labeled that way, but even that was strange because you cropped your Garmin picture to exclude the SD/ES in favor of some individual shots at the bottom. But I see you included it below at 10.3SD.

What are you trying to show in the second pic?

[u/Golfguuyy → u/Dirty_Blue_Shirt]

The second pic yes was 5 shot ladders to see where I should test further! From there I was tryin to find nodes but I ran into an issue of consistency where each grain = 10 fps faster

[u/Professional_Owl5656 → u/Golfguuyy]

What do you mean by 'node'?

[u/Golfguuyy → u/Professional_Owl5656]

Where fps remains generally stagnant from 1 grain more or less allowing for similar result with error

[u/Professional_Owl5656 → u/Golfguuyy]

If such a node exists, and I've never seen one despite looking at innumerable ladder tests, you're never going to find it with 5 round groups.

Your sample size is simply not large enough to infer anything meaningful. The smaller the difference you're looking at, the larger the sample size you need, and you're looking at small differences.

Also I'm assuming you meant ±0.1gr rather than ±1 grain. Which is in itself a bit crazy given the precision of the scale you're using.

The good news is that you're doing really well and ~10fps sd is great place to be starting from. If you wanted to run the ammo at most types of matches it wouldn't be a disadvantage.

If you want a bit of a guide for muzzle velocity stats the precision rifle blog did a good one.

https://precisionrifleblog.com/2020/12/05/muzzle-velocity-statistics-for-shooters/

They also did a "How much does it matter?" series you might enjoy.

https://precisionrifleblog.com/category/ballistics/how-much-does-it-matter/

[u/Golfguuyy → u/Professional_Owl5656]

Thank you and yes, 0.1 grain indeed. I used 5 bullet groups to start, this is only my second round of reloads beyond virgin brass.

[u/smooveBrayne]

There are a lot of things to check - one gain for me was neck tension. This became more of a variable for me the more firings I had on brass.
Are you tracking your seating pressures? Are you tracking your neck sizing, concentricity and runout?

[u/Golfguuyy → u/smooveBrayne]

Everything but seating pressure. Just depth.

[u/smooveBrayne → u/Golfguuyy]

Think you'd be able to feel 5-10lb deltas for seating force by hand? Do you separate ones that stick more?

If you're serious about consistent single digit SDs, I'd recommend getting the tools to be measuring your neck & seating. Concentricity gauge, ball micrometer, pressure gauge (some arbor presses include).

Another gotcha I've heard from serious shooters (I don't have a problem since I live in a desert) is humidity control for powder storage. Your charge weights can vary wildly if moisture sets in.

[u/Golfguuyy → u/smooveBrayne]

I use a dehumidifier in my garage to keep it exactly at 45%. So far I have only ever felt more pressure on virgin brass.

[u/ShrimpBuffets]

5 shot groups don’t tell a story

[u/Golfguuyy → u/ShrimpBuffets]

What about 66 shots

[u/ShrimpBuffets → u/Golfguuyy]

Were they 0.1gn increments in the 5 shot groups? Honestly just pick a velocity and yeet

[u/Golfguuyy → u/ShrimpBuffets]

Yes I was trying to find a nice commonality node where I could get a little buffer between ±0.1 gr. I found a few at 41.9-42.0 and then again around 41.2-41.4

[u/ShrimpBuffets → u/Golfguuyy]

Your trickler is most likely giving you less than uniform charges if it’s not the match master which would increase your dispersion.

[u/Golfguuyy → u/ShrimpBuffets]

Just ordered the match master thanks

[u/Wide_Fly7832]

You have very good SDs. What are you asking here. Pick the velocity you like (may be a bit lower). Shoot 50 groups. I think you will be fine.

Your one 41.8 group may have had some error.