Thread: Testing a conventional approach to load development

Originally Posted by gimp

I do have a suspicion that the entire sport of benchrest is based on a fallacy, and is an exercise in playing in the noise and thinking it's meaningful.

So, just like pretty much all load development methods we've ever heard about?

Originally Posted by gimp

4x 5rd groups actually.


Barrel cooled between 5rd groups (even though it doesn't actually matter), fired each load alternately to minimise any differences in fouling etc. Fired 10rd of each then went and did other stuff (helping others sort guns) for a couple of hours then fired the last 10 of each. Wind very low and consistent, <1ms 12 o'clock. Temperature consistent at 12 degrees C through the day (kestrel). Parallax dialled out.

Shooting high numbers of shots through other rifles with different loads clearly demonstrates differences in precision, e.g. .223 with handloads 0.9moa group for 20, 1.5moa for 20 with factory "match" ammunition.


How do you propose to quantify a valid understanding of the real precision capability of a system?

Barrel cooling does matter, as do plenty of other factors, how much they matter? that is not exactly known. Getting up and changing your shooting posture, has an impact. Parallax dialled out will minimize parallax, not eleminate it completely. fouling can change things too. All minor effects, that generally are not too important when dealing with general hunting precision requirements. But when you are looking at 0.25 or 0.5 moa differences, these minor influences do start to matter. Another thing is poi shift: since you fired all those shots into the same group you would not know if later 5 shot groups had a different poi, compared to earlier ones. So even if one of them was tighter to start with it would be hidden if any poi shift occured. Essentially any "signal" (if it is there) is hidden within other "noise", and thats why both of them show no significant difference.

Not saying you are a bad shot or anything (you clearly are not!). Essentially what you did is try to "prove" that for 2 charge weights, both of which already shot very well in your rifle (for general hunting purposes) there would not be a difference, (despite 3 shot groups indicating that there would be) by introducing a many other factors uf unknown impact into the system.

Your system here (rifle, loads, you) seems to give good (

Originally Posted by Makros

So, just like pretty much all load development methods we've ever heard about?

There are just too many unknowns and maybes...

So to improve accuracy you try to reduce, eleminate or mitigate as many unknowns as possible, despite not clearly knowing if they have a real impact, and how large said impact might be.

The effects of those strategies are also diminishing. Obviously its way easier to half a group size from 2 moa to 1 moa than from 0.5 moa to 0.25 moa.

Thats why some people will weigh their primers, to select the most consistent ones, to give one example.

Would appear to me that many prefer to halve group sizes by stopping shooting halfway towards a larger group.

Originally Posted by Makros

Would appear to me that many prefer to halve group sizes by stopping shooting halfway towards a larger group.

Haha, yup they like kidding themselves.

Originally Posted by STC

Barrel cooling does matter, as do plenty of other factors, how much they matter? that is not exactly known. Getting up and changing your shooting posture, has an impact. Parallax dialled out will minimize parallax, not eleminate it completely. fouling can change things too. All minor effects, that generally are not too important when dealing with general hunting precision requirements. But when you are looking at 0.25 or 0.5 moa differences, these minor influences do start to matter. Another thing is poi shift: since you fired all those shots into the same group you would not know if later 5 shot groups had a different poi, compared to earlier ones. So even if one of them was tighter to start with it would be hidden if any poi shift occured. Essentially any "signal" (if it is there) is hidden within other "noise", and thats why both of them show no significant difference.

Not saying you are a bad shot or anything (you clearly are not!). Essentially what you did is try to "prove" that for 2 charge weights, both of which already shot very well in your rifle (for general hunting purposes) there would not be a difference, (despite 3 shot groups indicating that there would be) by introducing a many other factors uf unknown impact into the system.

Your system here (rifle, loads, you) seems to give good (

So how much shooting have you actually done? Ever shared your results? Shot in competitions?. I'd love to hear about the basis for your inputs on threads like this. Do tell us.

Originally Posted by Makros

Would appear to me that many prefer to halve group sizes by stopping shooting halfway towards a larger group.

the best is a one shot group right where you want it to be!

Originally Posted by Tentman

So how much shooting have you actually done? Ever shared your results? Shot in competitions?. I'd love to hear about the basis for your inputs on threads like this. Do tell us.

And I would love to see people like you keeping their frail egoes out of it...

Hey STC you should come along to the forum shoot on the Hunters Challenge course at Sparrowhawk . . . .

It might not be fatigue from squeezing a trigger 20 times, but when you shoot small bore or fullbore and have to rebuild your position for each shot, the inability to do it consistently and achieve a natural point of aim certainly separates the field.
I reckon you could induce bias across your load testing.


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Originally Posted by Dicko

It might not be fatigue from squeezing a trigger 20 times, but when you shoot small bore or fullbore and have to rebuild your position for each shot, the inability to do it consistently and achieve a natural point of aim certainly separates the field.
I reckon you could induce bias across your load testing.


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Interesting. I only know one really proficient sling and jacket fullbore shooter and he does indeed group test in the jacket/sli g. The smallbore guys here mostly drop the rifle in a machine to test ammo.

Small bore guts I know, add scopes and use rests when lots.
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“1. Define your requirements - what level of precision and velocity do you require? This requires sensible calibration of expectations - chasing smaller groups than most rifles can produce, and more speed than your chosen cartridge can generally produce, is perhaps not well-aligned to reality. Book max speed minus 15-50fps per inch for your actual barrel length is perhaps a good indicator of a realistic expectation for speed.
2. Select the most appopriate powder and bullet based on reasonably wide research, using good quality components
3. Load 10rd at a powder charge (within book data) that you predict will give the velocity target you'd like. It will be easier to be more precise in this estimate with more modern cartridges with lower variability in data. I suggest using more modern cartridges.“[/I]

I may be missing something in the wording but what I read here is that, based on your conclusion, we throw out the convention of working loads up slowly as a safety measure to avoid excessive pressure in any particular rifle, a convention we hear ad nauseum, and just load up ten rounds and go for it. No mention of even loading just one and checking for excess pressure, which still seems wrong, before proceeding to load up another nine or is every rifle the same now and this is not an issue?

Is there any evidence of anyone ever experiencing a dangerous pressure issue when loading the correct powder within book loads?


It probably is wise to be conservative if you're shooting a vintage rifle or a cartridge that isn't a modern bottlenecked case.

Being honest, i feel the two biggest things that effect group size (once you have the optimum powder with a consistent batch) is seating depth and primer type.

Excellent idea to compare best to worst Gimp. WTF didn't i think of that lol. It never occurred to me.

You can get random acts of improbable accuracy too. I once did a full day trialing all sorts of things. 200 rounds total. Then as a laugh i shot 5 ugly, scratched up pre pulled ELDXs that i had set aside as barrel warmers.
The bloody joke rounds all went through the same hole and i couldn't actually measure anything. Probably the tightest group in my life done with the shittiest reloading effort of my life. Did my head in

Validates my process which is as follows:

Biggest 7mm ELDM that your twist rate will stabilise
As much RL26 or Superformance as possible