Help analysing OCW data please.

[Mungo]

Reading the above in some detail I conclude folk really need to get out more

Absolutely.

I do the stats so people realise they can just bang powder in a case and go shoot

 

[BE Precision]

Absolutely.

I do the stats so people realise they can just bang powder in a case and go shoot

no, they must start low and work up!

 

[Utectok]

I appreciate you probably have considerably more experience than I do.
If you feel I’m wasting my time and ammunition, would you be able to provide something constructive as to a better way to go about based on your experience?

Absolutely pick a good gun (you have). Pick good powder primers and bullets and pick a desired velocity load that is safe. Make up 10 rounds (with copper a 60-120thou jump is good lead stick to sammi spec) and check if they shoot well (under 1 moa) and show no pressure signs and that’s it…. move on with your life. If they shoot terribly and it’s not a fault of gun or gunner then change bullets or powder or primer in that order.
It’s seems to be well established by way cleverer people than me that all the other testing we used to do is chasing ghosts. Prove it to yourself do the same test again and see if they look the same I bet they won’t. I don’t mean to be harsh but I’ve wasted 1000 of hours and £ doing all this and I’m trying to save you from it!

 

[trucraft]

Right- here you go. The following are simulated data using parameters derived from the raw data presented in the first post. So the intercept, slope and residual variance are the same. Each set is created using RANDOMLY DRAWN velocities from distributions with the same variation as the real data.

What should be clear is:
(1) the patterns look identical to the real data - sometimes the velocities cluster at a given charge, sometimes they don't. Apparent fliers just happen.
(2) every single run contains apparent 'flat spots' that you might be tempted to consider as velocity nodes. They are not real - they are statistical artefacts.

What is the conclusion? I'd say it's cause for great optimism: it means that there is absolutely no need to worry at all, or bother with any further testing. If you want speed, pick the fastest safe load. If you want low recoil, pick the lowest velocity that will still give you good terminal performance.

View attachment 427528

Thanks very much, Mongo,
Really appreciate it and find it fascinating.
great to have an educated and quite different point of view to the standard load development theories

 

[trucraft]

or alternatively we could start looking to answer the OP's question and help him with the OCW method of assessment rather than velocities, my bad, i drifted into the Saterlee method at post #6.

OCW reloading instructions

OCW reloading overview and instructions

www.ocwreloading.com

the BE Precision method is 3 x 3 shot groups, near max book and just above, always seems to work for me. just pick the smallest raggy hole

Thank you.
I am just trying to keep an open mind on all results and all feedback. So anything constructive is appreciated.
My usual approach is somewhere between the optimum charge weight method of groups landing at a similar point of impact regardless of powdered charge and then trying to cross reference it with good velocity spreads.
It has worked for me in the past mostly.
But on other occasions, it’s had me chasing my tail and getting very frustrated with no clear results which definitely echoes what Mongo is saying.
before starting this load development I had been starting to read a bit about how sample sizes are way too small and most load development processes are just random dispersion as well as large amount of user error behind the rifle as Mongo has highlighted.

 

[Mungo]

no, they must start low and work up!

Sorry - absolutely.

Load development definitely worth doing to discover safe limits.

But unless firing hundreds of rounds, it won’t tell you much about accuracy.

 

[trucraft]

Thought i'd throw this into the mix
Just run his data through P-Max and the 62.1gr load gives Node 5 on the OBT chart. This matches the 62 on your chart above. He's not recorded the COL on the target but -using monoliths- seating back further from the lands should tighten the group, in theory.

Thanks for taking the time.
I don’t fully understand what you’ve said?
I’m not familiar with Pmax

 

[Ronin]

PMax is a program (free) created by Geoff Kolbe of BBT (Scotland) that is a very accurate and invaluable tool (to me ) for giving a very accurate prediction of pressure for load development

I’ve used it since inception and it rarely is less than a few fps off reality

As others have said - all the loads are good starters with nothing to take away other than the rifle shoots

Personally I’d pick load two and use that with possibly some seating depth variation

LTS usually perform best .050” off the lands if not further

You may also see a reduction in pressure allowing you to test larger powder charges (should you wish to pursue VO (your choice)

Last point - listen to Mungo - he’s right

 

[rabbit fingers]

Anyone know how the idea that small changes in charge weight have an effect on poi? Smokeless powders have been around for little more than a century and reloaders presumably as soon as they were available to them. So where did it start? Anyone know? @Laurie maybe?

 

[trucraft]

PMax is a program (free) created by Geoff Kolbe of BBT (Scotland) that is a very accurate and invaluable tool (to me ) for giving a very accurate prediction of pressure for load development

I’ve used it since inception and it rarely is less than a few fps off reality

As others have said - all the loads are good starters with nothing to take away other than the rifle shoots

Personally I’d pick load two and use that with possibly some seating depth variation

LTS usually perform best .050” off the lands if not further

You may also see a reduction in pressure allowing you to test larger powder charges (should you wish to pursue VO (your choice)

Last point - listen to Mungo - he’s right

Great.
I have just found a basic free version. I’m assuming there’s a much more in-depth version of it available?
Velocity predictions are considerably lower with H 1000 then I’m getting currently unless I’ve done something wrong!

 

[Jelen]

Thanks for taking the time.
I don’t fully understand what you’ve said?
I’m not familiar with Pmax

I see you've already found it and it's the only version, you don't need anything more. It isn't 100% accurate but it's certainly good enough to save wasting £100 on a tub of unsuitable powder, or blowing 5gr of unburnt powder out the muzzle every shot .

 

[Ronin]

Great.
I have just found a basic free version. I’m assuming there’s a much more in-depth version of it available?
Velocity predictions are considerably lower with H 1000 then I’m getting currently unless I’ve done something wrong!
View attachment 427558

That’s the only version and you get best results from measuring accurately H2O weight with seated bullet of choice

Empty case and weigh add has via primer pocket and re weigh that gives you powder weight

I’ve found it to be pretty much non on with in a few fps using RS powders

 

[trucraft]

That’s the only version and you get best results from measuring accurately H2O weight with seated bullet of choice

Empty case and weigh add has via primer pocket and re weigh that gives you powder weight

I’ve found it to be pretty much non on with in a few fps using RS powders

That’s where I’m going wrong then I’ve always thought it was H2O capacity of a empty fired case to top of neck

 

[trucraft]

I appreciate to some people this is probably the most boring thread on the whole forum.
However, personally, I’m finding it fascinating and potentially learning a lot.

 

[Mungo]

I appreciate to some people this is probably the most boring thread on the whole forum.
However, personally, I’m finding it fascinating and potentially learning a lot.

Normal people don’t read the reloading section… or if they do, they only have themselves blame.

 

[Ronin]

That’s where I’m going wrong then I’ve always thought it was H2O capacity of a empty fired case to top of neck

That makes a lot of difference to internal case pressure modelling

 

[Jelen]

That’s where I’m going wrong then I’ve always thought it was H2O capacity of a empty fired case to top of neck

No, as Ronin says. Empty unprimed case. Seat bullet add a little bit of blue tack and weigh. Use a syringe (Amazon) and fill through flash hole with water. Plug with blue tack and weigh. This will give you the UCC (Usable Case Capacity) which you input to P-Max.

 

[Brave Echo Niner]

I appreciate to some people this is probably the most boring thread on the whole forum.
However, personally, I’m finding it fascinating and potentially learning a lot.

And if the reloading section happened to be the only one I regularly peruse - what does this say about me…

 

[JockStalk]

And if the reloading section happened to be the only one I regularly peruse - what does this say about me…

Descended from that famous Irishwoman

Anne O’Rack

 

[lambic]

I am going to repeat the OCW method in the near future, 7 years after doing it last. Due to upgrading some case preperation equipment.

I wonder if I will get the same results as previously ......