Weight sorting ammo question

[higginsdj]

I have just weight sorted my 200 new cases of Lapua Palma 308 win brass. Unlike my Winchester 308 factory once fired brass, the Lapua brass had a total spread of only 1.2 gr (the Winchester brass had a 5gr spread over 100 cases). Given my scales are only accurate to .1gr that could mean as low as 1 gr or as high as 1.4 gr. I currently bin my Winchester brass in 1 gr bins (157.0 - 157.9, 158.0 - 158.9 etc)

For the Lapua Palma brass there were 4 very distinct 'bins' at 170.9, 171.2, 171.4 and 171.6 gr. Would there be any benefit in 'binning' the brass to +/- 0.1gr lots ie a bin at 170.8-171.0, 171.1 - 171.3 etc or would there be no real advantage to be gained?

I currently also weight sort my projectiles into 1/10th gr bins (my 155gr HBC's weigh in at between 153.2 and 153.7gr) and set my seating depth to +/- 0.003".

Cheers

David

[higginsdj]

For the Lapua Palma brass there were 4 very distinct 'bins' at 170.9, 171.2, 171.4 and 171.6 gr. Would there be any benefit in 'binning' the brass to +/- 0.1gr lots ie a bin at 170.8-171.0, 171.1 - 171.3 etc or would there be no real advantage to be gained?

So is there no answer to my question? Do people not understand my question (or the way I have worded it?). When I mentioned it to people at the club they just smiled. The only actual feedback I received was from the local gun shop and he believed that often times people do things for accuracy that are beyond the rifles/shooters own inherent capability but he wouldn't say I was wasting my time.

What do you think? Am I wasting my time?

Cheers

David

[mike H]

For the Lapua Palma brass there were 4 very distinct 'bins' at 170.9, 171.2, 171.4 and 171.6 gr. Would there be any benefit in 'binning' the brass to +/- 0.1gr lots ie a bin at 170.8-171.0, 171.1 - 171.3 etc or would there be no real advantage to be gained?

So is there no answer to my question? Do people not understand my question (or the way I have worded it?). When I mentioned it to people at the club they just smiled. The only actual feedback I received was from the local gun shop and he believed that often times people do things for accuracy that are beyond the rifles/shooters own inherent capability but he wouldn't say I was wasting my time.

What do you think? Am I wasting my time?

Cheers

David

David,
You are wasting your time if you batch that lot.You did not waste your time weighing them,as you now know they are very even. I use a lot of Winchester once fired brass and after preparing them I batch them into 1grain difference between lots but if I change from one batch to another I cannot see a difference on the target.Another person I know gave up batching,he does weigh them after initial preparation and removes the few wide ones from the top and bottom of the lot.
Mike

[macguru]

If you are using lapua brass you are probably wasting your time batching the cases...

The difference would be negligible.

1. get a good custom barrel chambered by a reputable gunsmith.
2. weigh each powder load
3. Fire test groups +/- & tune the rifle at 100m, then 300m
4. try different bullets
5 try different seat depths

each of these is a lot more important

[Southcape]

I think anything that helps your mental game is not a lost effort.

Mentally you know your brass and projectiles have been weighed and batched and are consistent. It just removes that doubt and lets you focus on something else if things are not going to plan.

[aaronraad]

David

See if you can get onto one of the NSW F-Class team members. It might be best if you find out what they drink first.

As others have stated, there are a few other reloading factors you need to get right before sorting cases down to 0.1gr, especially Lapua. That being said and you're past the 80-20 rule, with all of your shooting and not just reloading, you might just start to find an improvement in accuracy. Only problem is though you have to be well set-up ($$,$$$) to measure the accuracy improvement. A centre/super-V count, over 10-shots strings, for a couple of ranges each week, isn't going to be enough to show the improvement/convince yourself.

...but here I am buying a +/-0.001gr balance to add to my +/-0.001gr scale.

Aaron

[Razer]

..but here I am buying a +/-0.001gr balance to add to my +/-0.001gr scale.

Aaron

Don't forget to cut that final single grain of propellant cross-ways cause if you cut it length-ways you will alter it's burning rate.

[RAVEN]

Create a batch for long range weather it makes a difference it’s very hard to gauge.
Linda's advice is spot on the space between the wing nuts will be in a good place and you know that this particular set of ammo is the very best component wise that is humanly possible to put together.

RB
Capt. SA F-Class Open Team
National Champions

[aaronraad]

..but here I am buying a +/-0.001gr balance to add to my +/-0.001gr scale.

Aaron

Don't forget to cut that final single grain of propellant cross-ways cause if you cut it length-ways you will alter it's burning rate.

I lie should be +/-0.001g not gr...no wonder those lead cores keep coming out a bit heavy.

[higginsdj]

Aaron

Don't forget to cut that final single grain of propellant cross-ways cause if you cut it length-ways you will alter it's burning rate.

My 'cheap' digital scales are not responsive enough so I use my Dillon Balance scales to measure out each load to +/- 1 large kernel of powder. The Dillon and Lee balance scales produce the same result but weigh in 0.1gr more in value on the digital scale. In practice I don't care what the actual weight is (other than +/- 0.1 gr) but I keep each bullet in a set of 12 to the kernel in weight compared to each other bullet in that batch. I am, of course, assuming that the balance beam is accurate/consistent to kernel at least for the duration of measuring out the powder for that batch of 12.

As an aside, I saw a Youtube video of a lab scale used for reloading (lab scale accurate to 0.001 grains) and weighed AR2208 type kernals at between 0.015 and 0.025gr in weight.

Cheers

David

[DannyS]

Hi David, you must have plenty of spare time

I weigh my powder charges to 1/10th of a grain, in my opinion,,trying to get much better than that is a waste of time. I could be wrong but I doubt that your balance scales woud be accurate enough to weigh a charge to plus or minus 1 kernel.

More points are lost due to errors in reading the wind than can be gained by going to extremes in reloading.

Cheers
Danny

[John S]

Most shooters have their own views on what constitutes accurate ammunition.

To add to the "pot" here is an article by Stuart Elliott:

http://www.benchrest.com.au/downloads/C ... %20why.pdf

See www.benchrest.com.au as to what equipment is available.

I have found this article very useful in producing accurate ammunition.

Cheers

John S

[higginsdj]

Hi David, you must have plenty of spare time

I weigh my powder charges to 1/10th of a grain, in my opinion,,trying to get much better than that is a waste of time. I could be wrong but I doubt that your balance scales woud be accurate enough to weigh a charge to plus or minus 1 kernel.

More points are lost due to errors in reading the wind than can be gained by going to extremes in reloading.

Cheers
Danny

I thought the accuracy of these balance scales was to do with the actual measured weight rather than consistancy of the balance. So are you saying that these scales are only 'repeatable' for a fixed weight (regardless of actual weight) to within 0.1grain as well?

Cheers

David

[aaronraad]

Hi David, you must have plenty of spare time

I weigh my powder charges to 1/10th of a grain, in my opinion,,trying to get much better than that is a waste of time. I could be wrong but I doubt that your balance scales woud be accurate enough to weigh a charge to plus or minus 1 kernel.

More points are lost due to errors in reading the wind than can be gained by going to extremes in reloading.

Cheers
Danny

I thought the accuracy of these balance scales was to do with the actual measured weight rather than consistancy of the balance. So are you saying that these scales are only 'repeatable' for a fixed weight (regardless of actual weight) to within 0.1grain as well?

Cheers

David

There are a few critical descriptions relating to mechanical and electronic scales/balances in terms of their Capacity:

Resolution: How much they can display/readout, not neccessarily accuracy related.
Non-linearity: How inaccurate the scale is when measuring non-calibration weights.
Repeatability: Inaccuracy of the scale when measuring a calibration weight.

So yes, all scales are 'repeatable' for a calibration(known) weight but their span is non-linear for an un-calibrated (unknown) weight.

Take for example my first electronic powder scale the A&D HL-100:

Capacity: 100g
Resolution: 0.01g
Non-linearity: +/-0.03g
Repeatability: +/-0.02g
Calibration weight: 100g or 50g +/-0.002g

Converting and rounding up to grains (gr)

Capacity: 1500gr
Resolution: 0.2gr
Non-linearity: +/-0.5gr
Repeatability: +/- 0.3gr

I wouldn't be more confident in saying the my scales are 1500gr +/-0.5gr becasue I never measure 0gr and never measure 1500gr. To overcome this I have 2g, 5g, 2x10g extra F1 grade calibration weights as indicators on top of the 50g & 100g weights.

Essentially you need a scale with a resolution of +/-0.005g to achieve a +/-0.1gr resolution, but Non-linearity and Repeatability are what you are actually paying for!

You can reduce the non-linearity by always approaching the final weight from under or over, but never alternating. I always prefer coming from under.

Mechanical balances have the same issues, but for reloading most are actually designed as grain scales not gram scales to begin with and avoid the unit conversion issues.

[johnk]

I have a fine collection of soft pointed projectiles which, when I stumble upon a working load, I trim to give the same scale readout. Therefore, any time I use the scales again, the appropriate load-equivalent projectile tells me what value I should read off my scales to duplicate the load.