Reloading for PRS

As I stated above... at only 300 yards it doesn't mean much, but as you get out to about 500 yards it really starts to matter. At 1000 yards this powder charge variation will cause at least 10 inches of vertical for a 308. For an F Class shooter after a 5 inch bull at 1000 yards, this is death and you'll get your butt handed to you every time.

You can do the math from your own load data.

The accuracy of the RCBS scale is only within about 0.4 grains... This is not exactly front page news. I tested as has many others.

Take your average velocity from a 1 grain change in your powder charge and divide the velocity difference by 10 and multiply by 4.
That will give you the average velocity deviation that is generated by the variability in powder charge alone.

Feed the two velocities into your external ballistics calculator of choice and see what vertical you'll get at 1000 yards.

The velocity spread sensitivity is in direct proportion to powder charge... meaning a 223 is far more sensitive to this as a percentage of the overall charge weight than a 308 would be.

Keep in mind that this is not the only variable that comes into play at long range, but it is one variable that you control if you accept the fact that you can and should.

Think about it...

what's more accurate?
a cheap 1 decimal place or a lab grade 3 decimal place scale?
Do the math... its only obvious.

The only argument against such logic is that you don't want to spend the money on a better scale, and that's your prerogative, but please reset the temptation of deluding yourself into thinking you got an A game because you use a chargemaster.
 
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I will do a test today if I find time. 10 charges of 4831sc an my charge master and I will compare on my FX120i. If you are correct I will bow down to your opinion.

35 grs is what I will do.
 
Mo, I have to respectfully disagree with your assessment of the Chargemaster. I use it for .233, .308, and .338LM. I've shot less than 3/4moa at 700m with my .223 Chargemaster loads. And multiple times (not just once). The same with my .308 Chargemaster loads. And these were out to 1km. I just find it hard to believe that your assessment of its "inaccuracy" holds any water.

How can my results be possible with this "poor at best" measuring tool? I find it extremely hard to believe that the Chargemaster has an error factor of almost a half a grain. I know it's not the most accurate measuring tool there is, but it's not as bad as you say. And my results disprove your theory.

Just isn't so.

Edit: Also chrono'ing my loads show a variance of less than 5fps.
 
Ryan.M.Anderson said:
I will do a test today if I find time. 10 charges of 4831sc an my charge master and I will compare on my FX120i. If you are correct I will bow down to your opinion.

35 grs is what I will do.
Click to expand...

Why only 10?
The bigger the test lot the more correct the result.

Remember you are after the extreme spread.
 
6MT said:
Mo, I have to respectfully disagree with your assessment of the Chargemaster. I use it for .233, .308, and .338LM. I've shot less than 3/4moa at 700m with my .223 Chargemaster loads. And multiple times (not just once). The same with my .308 Chargemaster loads. And these were out to 1km. I just find it hard to believe that your assessment of its "inaccuracy" holds any water.

How can my results be possible with this "poor at best" measuring tool? I find it extremely hard to believe that the Chargemaster has an error factor of almost a half a grain. I know it's not the most accurate measuring tool there is, but it's not as bad as you say. And my results disprove your theory.

Just isn't so.

Edit: Also chrono'ing my loads show a variance of less than 5fps.
Click to expand...

Have you looked into the accuracy rating of your chronograph?

The chrony web site states
from 30/fps. to 7000/fps. and with better than 99.5% accuracy.

so 0.5% 3000 fps is 15 fps... so how can you trust 5 fps reading?
 
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Cause I am not going to spend more than 10 minutes over something dumb on the internet. I can also just tell you to google "chargemaster accuracy" and you will find a video (one of the top 10 links) showing it is more accurate than .4 grains.

I don't think the CM is the best thing ever which is why I recently bought a 120i and autotrickler but it also isnt garbage. I shoot past 300M all the time and the wind is my bigger opponent.

I
 
Did 20 grains of Varget instead. I calibrated the CM but did no warm up as I unplugged it with my foot by accident. Lowest throw was 19.96 grains, the highest was 20.04. List is below (CM was 20.0 each time). The FX has been plugged in for about a week. The CM has a brass reducer insert and the timing has been adjusted for a faster throw.
20.02
20.04
20.00
19.98
19.96
19.98
20.00
20.04
20.02
20.04

Is the CM perfect? No, it is not. Is it more accurate than .4 grain? I think so.
 
Ryan.M.Anderson said:
I will do a test today if I find time. 10 charges of 4831sc an my charge master and I will compare on my FX120i. If you are correct I will bow down to your opinion.

35 grs is what I will do.
Click to expand...

Simple test... find your most accurate 300m load using your CM. Let's say it is 35.0gr as indicated by the CM.

Let's also assume the output on your FX120i shows the same number for this one powder sample.. 35 is 35 on both scales.

Load 5rds at 34.8, 34.9, 35.0, 35.1 and 35.2 using the FX 120i.

Load 15 rds using the CM at 35.0gr. Shoot 3X5rds groups interspersed in your testing.

On a calm day, shoot groups and compare the overall group size AND vertical of these loads. Was there a FX load that shot markedly smaller and flatter then the "35 CM" load average? Repeat to confirm

Do you find that the group size and shape of the CM loads are more variable then the FX load at its ideal value?

Over time, you can compare the overall groups and hit rates using both scales.

If you CM is working with +/- 0.1gr, the CM group will yield the same extreme size and shape of the FX loads from 34.9 to 35.1

If +/- 0.2gr, then from 34.8 to 35.2gr or there abouts. What you are likely to find is that the CM groups size and shape will oscillate with some tight and some not. Orientation will also vary with some groups flatter then others.

The FX groups will be very consistent in both size and vertical with the same scale value. As you tweak your load, making ammo with vertical 1/4 MOA or less at 300m is certainly possible with top tier components and rifles.

When you overlay your CM groups vs the FX groups at 0.1gr increments, I think you will see where the CM groups, although the same "value", will look like the various groups shot with the FX loading.

Another way of describing is the that SD and ES of the CM is much larger then the FX.

Much easier to just compare the scale outputs but nothing is more graphic then seeing bullet holes on paper and how that can vary with a small change in a variable.

Ultimately, this improvement may not change your scores because wind is truly the main enemy (and trying to get a stable position) BUT it can help to reduce the vertical dispersion at distance. It will make your drop chart far more reliable and repeatable. Might also help reduce incidence of "flyers".

I see that many targets used in PRS are taller then they are wide. Some much taller... so maybe the benefits are limited but it never hurts confidence to know the impact area of the rifle is much smaller then the target IF the shooter can figure out the conditions.

YMMV

Jerry

Looks like the output of the CM you have is very good... some not so much so it is best to test to see what each unit is giving you.
 
Shibby! said:
Hahaha


I'd have to agree. Is the CM perfect? No. Is it much better than .4gr, asbolutely.
Click to expand...

Unfortunately, there have been units where the dispensing error has been +/- 0.2gr with the occasional drop even more. So the possible error could span 0.4gr or more.

Was it every drop, no but there were variations in the amounts to cause accuracy minded shooters some concern. A very technical F class shooter did a test on his unit over many drops and weighed on a very expensive lab scale. I think his wildest drop was 0.6gr off. Maybe those issues are greatly reduced with current units?????

I have personally seen/worked with a CM that varied a few tenths in random fashion and did this quite often.

Is it common? who knows which is why I suggest that your unit be tested against a known quality scale over a large sample size so you know. maybe there is no problem... maybe there is????

There are a number of F class competitors who use the CM as a dispenser and then trickle on a quality scale. Works great for them.

I went with the FX120i/auto trickler route and skipped the possible headache. Also, the mechanics of the CM scale are such that they can fail internally ie break with useage. Is this common? don't know but have fielded requests for warranty support to know it is not out of the question.

RCBS is usually superb with their warranty support but how much "bad" ammo is going to be made along the way????

How stable is the scale to drift? Again, something all users should check and confirm for themselves.

Any scale from any manf can malfunction. Always best to have a way to check things are going as planned... before things get spicy during firing.

YMMV.

Jerry
 
BadAsMo said:
If you never noticed you had issues like this with your chargemaster....

A) you are not a frequently winning competitive precision shooter
or
B) You don't shoot far enough, and often enough to notice.

As I stated above... at only 300 yards it doesn't mean much, but as you get out to about 500 yards it really starts to matter. At 1000 yards this powder charge variation will cause at least 10 inches of vertical for a 308. For an F Class shooter after a 5 inch bull at 1000 yards, this is death and you'll get your butt handed to you every time.

You can do the math from your own load data.

Trust me that the accuracy of the RCBS scale is only within about 0.4 grains... This is not exactly front page news. I tested as has many others.

Take your average velocity from a 1 grain change in your powder charge and divide the velocity difference by 10 and multiply by 4.
That will give you the average velocity deviation that is generated by the variability in powder charge alone.

Feed the two velocities into your external ballistics calculator of choice and see what vertical you'll get at 1000 yards.

The velocity spread sensitivity is in direct proportion to powder charge... meaning a 223 is far more sensitive to this as a percentage of the overall charge weight than a 308 would be.

Keep in mind that this is not the only variable that comes into play at long range, but it is one variable that you control if you accept the fact that you can and should.

Think about it...

what's more accurate?
a cheap 1 decimal place or a lab grade 3 decimal place scale?
Do the math... its only obvious.

The only argument against such logic is that you don't want to spend the money on a better scale, and that's your prerogative, but please reset the temptation of deluding yourself into thinking you got an A game because you use a chargemaster.
Click to expand...

Actually I do shoot a lot at longer range and have won a few competitions and all my ammo was loaded with my chargemaster. I'm not to cheap to buy something better I just don't see a need too. Maybe you got a bad one or something. None the less for you to say it's junk and that ppl that use them are just to cheap to buy something better or to say that we don't shoot at longer distance or compete is just ignorant. You don't know me or my reloading practice or my shooting ability. Your opinion on the chargemaster is just that an opinion and your entitled to it.
 
Mystic Precision said:
Unfortunately, there have been units where the dispensing error has been +/- 0.2gr with the occasional drop even more. So the possible error could span 0.4gr or more.

Was it every drop, no but there were variations in the amounts to cause accuracy minded shooters some concern. A very technical F class shooter did a test on his unit over many drops and weighed on a very expensive lab scale. I think his wildest drop was 0.6gr off. Maybe those issues are greatly reduced with current units?????

I have personally seen/worked with a CM that varied a few tenths in random fashion and did this quite often.

Is it common? who knows which is why I suggest that your unit be tested against a known quality scale over a large sample size so you know. maybe there is no problem... maybe there is????

There are a number of F class competitors who use the CM as a dispenser and then trickle on a quality scale. Works great for them.

I went with the FX120i/auto trickler route and skipped the possible headache. Also, the mechanics of the CM scale are such that they can fail internally ie break with useage. Is this common? don't know but have fielded requests for warranty support to know it is not out of the question.

RCBS is usually superb with their warranty support but how much "bad" ammo is going to be made along the way????

How stable is the scale to drift? Again, something all users should check and confirm for themselves.

Any scale from any manf can malfunction. Always best to have a way to check things are going as planned... before things get spicy during firing.

YMMV.

Jerry
Click to expand...


I double weigh all my loads on a quality beam scale. As mentioned, it's not perfect, but quite good most of the time with the modifications done to the power cord, tube, programing, etc.

Once again, lets consider costs. The CM can be had for around $300. (not long ago, it was less than 3), and the lab scale and auo trickler is about $1000. Maybe around $800 awhile ago. I think the scales jumped from $400-600.

So considering the cost, they are pretty good. Especially when you take the time to double check the weight with another, known scale that doesn't drift (mechanical).
 
http: //www.autotrickler.com/index.html

This guy seems to offer a decent trickler for the FX120i

Over the last 15 or so years I've had two chargemesters sh!t the bed with their electronics. Ymmv
 
beltfed said:
http: //www.autotrickler.com/index.html

This guy seems to offer a decent trickler for the FX120i

Over the last 15 or so years I've had two chargemesters sh!t the bed with their electronics. Ymmv
Click to expand...

This is what I am running now and it is a pretty slick unit. Set up took all of about 10 minutes and you are good to go. If you are being very picky it is not any faster than a CM but apparently Adam is looking at an integrated set up with a powder thrower - it would be an upgrade to the trickler.
 
Shibby! said:
I double weigh all my loads on a quality beam scale. As mentioned, it's not perfect, but quite good most of the time with the modifications done to the power cord, tube, programing, etc.

Once again, lets consider costs. The CM can be had for around $300. (not long ago, it was less than 3), and the lab scale and auo trickler is about $1000. Maybe around $800 awhile ago. I think the scales jumped from $400-600.

So considering the cost, they are pretty good. Especially when you take the time to double check the weight with another, known scale that doesn't drift (mechanical).
Click to expand...

Definitely the cost of the FX/trickler is much higher then many other methods. I find it a good investment given my end use needs and volume required/time saved... it is not for everyone for sure. But like shooting match barrels installed by a great 'smith, it is sure hard to go back to "good enough" in a factory rifle.

If you double weigh with your CM (as many do), it becomes a powder dispenser. here there are much cheaper options and the difference can be put towards a better scale. Ultimately, it is the scale that has to work within the end user needs. Getting the volume of powder close enough to speed up the process is pretty simple and can cost very little for "good enough" gear.

YMMV.

Jerry
 
Ryan.M.Anderson said:
This is what I am running now and it is a pretty slick unit. Set up took all of about 10 minutes and you are good to go. If you are being very picky it is not any faster than a CM but apparently Adam is looking at an integrated set up with a powder thrower - it would be an upgrade to the trickler.
Click to expand...

Do you drop a charge of powder into the pan before letting the dispenser do its thing? When I am using mine, a charge is waiting for me in the time it takes to put the pan on the scale, reach over for a bullet to seat into the case that was charged last. I really can't see a chargemaster working as fast. This process has sped up the charging steps in my reloading to 1/3 the time needed before... and a lot less cussing.

But if you go from an empty pan, then of course. I use a scoop which gets to around 1/2 to 1gr under target.. the trickler needs to see the end charge coming so any closer actually makes the trickler work slower and less precise. I think 1 gr under is ideal.

maybe this can help speed up your process?

Enjoy

Jerry
 
I've been using the Omega vibrating trickler myself. It has fast and slow buttons too.

Since it vibrates, it shakes out the kernels and you can change the vibration harmonic with the sliding weight on the dispenser straw to suit various powders.

I throw the initial charge and then tweak with this.

p_100010962_1.jpg


This is the Vibra HT balance that I use. I like this model because it is very dust tolerant and not vulnerable to current fluctuation like the load cell models. A nearby cordless phone does not affect the performance of this one, but does on most other types.

This particular model is accurate enough to weigh 1/10th of a kernel of Varget. The worst it ever drifts is about 4/10ths of a kernel of Varget but that's with the AC or Furnace on. It's very stable with HVAC off and windows closed.

HT_01.jpg
 
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