Level of precision

[marchx]

Does level of precision in handloading required to produce single digit SD ammo differs from caliber to caliber?
Let's compare some fundamental criteria:
- powder charge variance
- headspace variance
-CBTO variance

Let's assume we have 0.2 gr variance in powder charge weight, 0.005 headspace variance and 0.005 CBTO variance.
This seems to be trivial conclusion, but shooting 10 shots out of .284 with aforementioned variance should theoretically produce smaller SD than shooting 10 shots out of 6BR with the same variance for the above parameters because (a) 0.2gr powder charge variance constitutes smaller % variance for 50gr charge weight than for a 30gr one (b) the same refers for 0.005 CBTO variance for a 180gr bullet vs 105gr bullet and (c) headspace variance.

If you agree on the above, isn't it fair to say that producing a single digit SD ammo is more difficult in case of smaller calibers?

 

[FeMan]

Although it sometimes happens, I have never tried to produce single digit SD ammo. I want small groups. Since I have a lab radar, I do watch speeds a lot. I have had some low SD loads that shot extremely well and others that did not. Most of my match loads end up with what would be considered poor SDS numbers.

In load development, I use 0.5% charge weight variance between loads and not the same increment as suggested in your example.

 

[JEFFPPC]

Operable word I read was trivial.

 

[Eagle Six]

If all you changed was what you specified in those specific increments it might be impossible to get single digit SD's, or you might easily get it on the first load! I don't know of anyone that only considers yours stated parameters when attempting to get single digit SD's.

Is there a specific reason you pose such a question?

 

[K22]

If you use stick powder, in my experience it is way more tolerant of slight powder variations, ball powder not so much. Here I am referring to results on target.

Precision also means different things to different shooters and disciplines. For me, I am in the 1/2 to 5/8 moa range as a targeted standard at 100 yards which is modest by today's standards but meets my needs. Once I hit that, I'm done with load development then I transition to practical shooting.

I guess you can make this hobby as complicated, frustrating, and painful as possible but if you define your standard, then work towards that it might mitigate a lot of the unpleasantness associated with this hobby.

 

[diggler1833]

In my experience; shooting cases with less capacity allowed me to achieve lower ES and SD, than cases with more capacity...assuming brass quality is equal and all other steps are performed similarly.

.223, 6.5x47, and even 6.5 Grendel are so much easier for me to achieve single digit SDs with, than .30-06 and 7mm RM.

 

[Chris Edmondson]

Does level of precision in handloading required to produce single digit SD ammo differs from caliber to caliber?
Let's compare some fundamental criteria:
- powder charge variance
- headspace variance
-CBTO variance

Let's assume we have 0.2 gr variance in powder charge weight, 0.005 headspace variance and 0.005 CBTO variance.
This seems to be trivial conclusion, but shooting 10 shots out of .284 with aforementioned variance should theoretically produce smaller SD than shooting 10 shots out of 6BR with the same variance for the above parameters because (a) 0.2gr powder charge variance constitutes smaller % variance for 50gr charge weight than for a 30gr one (b) the same refers for 0.005 CBTO variance for a 180gr bullet vs 105gr bullet and (c) headspace variance.

If you agree on the above, isn't it fair to say that producing a single digit SD ammo is more difficult in case of smaller calibers?

Assuming those parameters materially affect SD then yes, I'm inclined to agree.

Absolute tolerance values invariably have some proportionality worked into the number; 0.2gr powder variance is 0.4% of a 50gr charge, 0.8% of a 25gr charge. With a machine like AutoTrickler which is good to 0.02gr, that 50gr charge will see a .04% difference, .08% for the 25gr charge. There's really no substitute for precision if what's being measured is relevant to the outcome.

Then there's good 'ole confidence; even if something doesn't matter much, doing the best one can do to be consistent and precise has some psychological benefit I think

 

[dcali]

Yes, it's much harder with smaller cases in my experience.

 

[Webster]

In my experience; shooting cases with less capacity allowed me to achieve lower ES and SD, than cases with more capacity...assuming brass quality is equal and all other steps are performed similarly.

.223, 6.5x47, and even 6.5 Grendel are so much easier for me to achieve single digit SDs with, than .30-06 and 7mm RM.

You win by group size or aggregates. No trophies for ES and SD.

 

[marchx]

@Webster try print that small group with high SD.

 

[marchx]

Is there a specific reason you pose such a question?

Yes.

 

[Webster]

@Webster try print that small group with high SD.

It happens sometimes. I have shot hundreds of .350" to .400" groups with my varment rifle with a big ES. Shot a couple .150". .250" groups are common with a good bullet. None of my rifles shoot small ES (6BR & 6BRX). Erik Cortina says he shot a few good groups at 1000 yards with a big ES. I heard guys say it doesn't matter a lot at short range. I just shoot groups at 100 yards and stick with what shoots small groups. If I shoot a ladder test most of the groups are round and not vertical. I most have got a very good barrel. Obviously I am not shooting compitition. If you read the component list for a big SR match most of the shooters are using similar powders and a narrow range of powder charges. Don't remember if Tony Boyer mentions ES in his book. I will look it up. Don't care what ES is since any GH I see out to about 350-400 yrds. is dead 1 shot.

After looking at a lot of Erik Cortina viideos it.s obvious that the top shooters all have very special skills that few people have. They spend huge amounts of time and money to stay at the top.

Do whatever makes you happy. Be realistic about what you can achieve.

 

[J.D.Erwin]

Does level of precision in handloading required to produce single digit SD ammo differs from caliber to caliber?
Let's compare some fundamental criteria:
- powder charge variance
- headspace variance
-CBTO variance

Let's assume we have 0.2 gr variance in powder charge weight, 0.005 headspace variance and 0.005 CBTO variance.
This seems to be trivial conclusion, but shooting 10 shots out of .284 with aforementioned variance should theoretically produce smaller SD than shooting 10 shots out of 6BR with the same variance for the above parameters because (a) 0.2gr powder charge variance constitutes smaller % variance for 50gr charge weight than for a 30gr one (b) the same refers for 0.005 CBTO variance for a 180gr bullet vs 105gr bullet and (c) headspace variance.

If you agree on the above, isn't it fair to say that producing a single digit SD ammo is more difficult in case of smaller calibers?

marchx
I think you have too determine what's your goal is for that particular load. I never consider my es/sd went building a tune I jugde by group size and it repeating reload after reload bottom line if you ain't grouping you ain't completing

 

[Eagle Six]

Yes.

What would that be?

 

[Charlie-NY]

Large cartridges with heavy for caliber bullets seem to produce the best SDs for me. Single digit loads are not all that uncommon. But some of my lowest SD loads produced the largest groups, and visa-versa. Last week I shot an eye-opening .55" group at 417yds. The SD of that load, according to the LabRadar, was 27. That's higher than almost any load I use.

 

[Ned Ludd]

It can be much more difficult to generate and maintrain low ES/SD with a relatively small cartridge such as .223 Rem. I do not know whether that is true for all [relatively] small cartridges.

FWIW - maintaining low ES/SD in a load is far more important for F-Class shooters than it may be for the other disciplines. This is likely due to the long strings of fire used in F-Class. For those commenting along the line that low ES/SD is of limited importance, perhaps it is in certain shooting disciplines. However, try competing at a high level in 1000 yd F-Class matches with a load that has poor ES/SD values. It might change your opinion.

 

[MagnumW]

I assume those super accurate BRA’s and Dashers would be much easier to maintain low es than my firebreathing 338 Lapua AI with 106 grains of n570 pushing a 300 gr. Think precision tack hammer vs sledge hammer. Scalpel vs Machete. Tweezers vs pliars.
But maybe I’m mistaken? I typically shoot es of 10 to 15 and sd’s in the low single digits with this LapuaAI. Don’t load for little ones. ?????

 

[diggler1833]

You win by group size or aggregates. No trophies for ES and SD.

Was the OP asking about SD, or was he asking about winning trophies and group aggregates? I forget.

 

[marchx]

I antricipated that argument that low SD does not equal small group. If we can drop that for a minute.
My working hypothesis is that consistent velocities over a string of 20 shots requires much more meticulously prepared ammo in case of 6mm caliber than in case of .284 or even 6.5. If you are a very good handloader you probably will not notice the difference because you apply very high standard of precision to every caliber you handload. And let's not talk about groups- shooting small group is combination of multiple factors (shooting skills, weather, rifle setup, ammo- on that particular day). I am trying to isolate a single factor-quality of ammo measured by SD and/or velocity spread.

My personal experience (a micro-scale) is that over longer string of shots (20-30) in bigger caliber like 6.5 creed I can get 10fps spread, whereas with the same string of shots in 6BR I get 15-20 fps spread. I apply the same standard of precision to handloading both calibers.
So, for a madiocre handloader like myself the counclusion would be that bigger caliber would be theoretically more forgiving for lack of precision in handloading (arguments in my first post of this thread). I posted this so you can verify my hypothesis (I certainly can be missing something here- line of reasoning seems to oversimplify things, but hey- that's the reason of discussion, to verify assumptions)

 

[Doom]

As for powder variation, .2 gr in a 223 is around 24 fps, 308/6.5CM is about 12 fps, magnums are around 8-10 fps. But I will caution you that getting a real single digit SD is very difficult, if not impossible. I won't get into the statistics and sample sizes along with instrument accuracy.