Double decimal precision powder scale

[usmc0326]

I have rcbs chargemaster and dillon 650. I am looking for a double digit decimal precision reloading scale. Any suggestions? All of the ones I have seen from the regular mfg's are single decimal ie 35.0. I am building a new long range rifle and I would like to get the ES/SD down to benchrest numbers to limit the vertical spread at 1000 meters+. Which I can tell isn't happening with the scales and powder measure I have currently. It seems I can be a couple kernals off and still have the scales display the same tenth values. At the same time I don't really want to drop 1400 bucks on a Prometheus.

[noylj]

Why would you even think you need one? Powder impulses are not sensitive to ±0.1gn, so you will get nothing out of loading to ±0.05gn or less.

Look to Sartorius GD503 Class II Balance or equivalent. You can find them for a little under $1000, if you REALLY think that it is important.

[a.roberts]

Here are a couple from Uniquetek.

Neither of them read to a single tenth though.

http://www.uniquetek.com/site/696296/product/GT1391

http://www.uniquetek.com/site/696296/product/GT1251

[usmc0326]

0.05 grain resolution is more than enough. Thanks roberts.

no- they actually are with precision rifle. Pistols etc aren't that sensitive, but when your shooting at targets 1200+ meters away 40 fps difference between two rounds at 1000 meters means the slower bullet will strike 16 2/3 inches lower than the faster shot. So yes, it actually does make a difference. For reference a lot of precision rifle matches your presented with Moa targets. And at 1000 yards the target could be 10 inches to represent 1 Moa. So in a game of hit or miss. Having High ES/ SD is not very beneficial to making good hits in a comp. When I have scopes/ rifle combos that are in the 4-5k range in price, what is the sense in loading ammo that doesn't match the performance of the platform your using.

[Hi-Power Jack]

0.05 grain resolution is more than enough.

when your shooting at targets 1200+ meters away 40 fps difference between two rounds means the slower bullet will strike 16 2/3 inches lower than the faster shot.

USMC, not sure about rifle, but will .05 grains of powder

produce a 40fps difference in rifle?

It seems to take 0.20 - .40 grains of powder, in 9mm major,

to move the velocity 40fps.

[Foxbat]

Be careful there... that the scale has .05gr "resolution" says nothing about its accuracy or even more importantly - repeatability.

The last one is really the parameter you need, not some "resolution". One can have ten digits on display, that is the easiest part, it costs pennies. Making sure the reading remains rock solid cost a fortune.

Anyone with "two decimal" scales out there should make a small weight, say, about 5gr, and check it regularly, under different conditions, room temperature, time of day, etc, to see how repeatable they are. I can assure you that a scale repeatable to less than 20-30mg is not something you buy for a hundred bucks.

If you look at the two links provided here, you will see what I mean. The more expensive scale has "accuracy" (it should really NOT be called that way, as it is NOT accuracy) of .02gr, but repeatability of .04. Unfortunately the conditions for repeatability spec are not listed, so it is not clear what it means. Strictly speaking, that scale is only accurate to about .06gr.

The less expensive model does not list the repeatability at all - that's got to tell you something.

Edited April 3, 2012 by Foxbat

[Powder Finger]

these run very well

http://www.6mmbr.com/mxx123test.html

do a search on that site for tips on drift n such.(warmup, static, air movement, etc....)

also on German's site.

http://riflemansjournal.blogspot.com/

this month he has a post on static guard.

[Dirty Rod]

0.05 grain resolution is more than enough.

when your shooting at targets 1200+ meters away 40 fps difference between two rounds means the slower bullet will strike 16 2/3 inches lower than the faster shot.

USMC, not sure about rifle, but will .05 grains of powder

produce a 40fps difference in rifle?

It seems to take 0.20 - .40 grains of powder, in 9mm major,

to move the velocity 40fps.

In my 700, going from 44.3 to 44.5 of Varget took my average from 2616 to 2631 so .05 looks like its worth about 4fps at my sweet spot but every rifle is different. Of course, my skill level and the fact that I rarely get out past 800 negates the need for that kind of accuracy.

I do have some friends that shoot to 2200 regularly. I'll ping them and report back if they load to something other than +/- .1 and have recommendations.

[ChrisMcCracken]

Just curious... If you weight 10 pulls at a time on a +/- .1 scale, is that good enough to not need a +/- .05 scale? I'm still using a manual scale, and that's how I've gotten around the issue. Sure it doesn't tell you how consistant each individual powder charge is, but its good enough for adjusting to an average charge weight.

I'll be the first to admit that I'm not an expert, not loading precision rifle or shooting long distances. Its just a poor man's alternative.

[Hi-Power Jack]

0.05 grain resolution is more than enough.

when your shooting at targets 1200+ meters away 40 fps difference between two rounds means the slower bullet will strike 16 2/3 inches lower than the faster shot.

It seems to take 0.20 - .40 grains of powder, in 9mm major,

to move the velocity 40fps.

going from 44.3 to 44.5 of Varget took my average from 2616 to 2631 so .05 looks like its worth about 4fps

I'm guessing??? that a .05 grain difference would produce a

1.7" drop at 1,200 meters, then? If that's true, I'd also

guess that should be insignificant considering the distance

and all the other variables afoot?

Are bullets usually same weight to 0.05 grains?

[usmc0326]

0.05 grain resolution is more than enough.

when your shooting at targets 1200+ meters away 40 fps difference between two rounds means the slower bullet will strike 16 2/3 inches lower than the faster shot.

USMC, not sure about rifle, but will .05 grains of powder

produce a 40fps difference in rifle?

It seems to take 0.20 - .40 grains of powder, in 9mm major,

to move the velocity 40fps.

No but the powder throws of my chargemaster can be off by up to about 0.1 and still read the same. (It rounds up or down to the tenth), So my charge weight could actually be anywhere from 43.15 to 42.96 and still read the same which a tenth grain can give you higher es/sd in the 40 range.

I also know that my chronograph is accurate to about +/- 1.5-2fps.

So when my scale doesn't register a difference in charge weight when the machine tries to stop trickling and 1-10 kernels fall into the pan I know that isn't helping long range performance.

Foxbat- I am very aware of Met Cal. I am mainly looking for a "proofing scale". So similarly the evaluation of a given scale requires another scale or a standard right? That is essentially what I am doing. I didn't know of any non lab scales which had decent resolution/ consistency. I almost bought a Prometheus but I figured I would save the cash and get a new suppressor. Also keep in mind the charge mass varies based on humidity etc. Probably going with something from Denver instruments or similar anyhow.

Dirty Rod - I am not really sure what the fps/ 0.1 grain is with my 6.5 but I am pretty sure that there aren't very many variables left to get the Standard Deviation and Extreme Spread down. I already neck turn, primer pocket uniform blah blah benchrest prepped cases. The last thing remaining is powered charges less than a tenth of a grain for that last little bit of SD (along with new krieger barrel).

Edited April 3, 2012 by usmc0326

[Graham Smith]

If you can trickle 10 granules of powder into your scale without it changing, I'd say there's something wrong with your scale.

As an aside, you are unlikely to get the kind of precision on a progressive press that you will with a turret or single stage. I might be wrong, but...

Edited April 3, 2012 by Graham Smith

[noylj]

Again, if you really think that 0.05gn of powder can have that big of an effect (and I see too many other variables that can still have bigger effects), then go with quality and get the Sartorius GD503 Class II Balance or equivalent. You can find them for a little under $1000. Anything that is NOT a class II balance is simply a sales gimmick and not worth the trouble. Get the equipment you need with the quality you need. I wouldn't trust a 0.05gn balance--that is just a 0.1gn balance with an additional digit bouncing around. Also, be sure to get at least one class II check weight--as near your targeted charge weight as possible. These will run about $50 each. I think 1 gram is a little over 15 grains (something like 15.4grains/gram, maybe)--so you might want a 3 gram check weight.

PS: Last I heard from the ballisticians, EVERY shot will have an unknown number of unburned kernels exit the bore--every time, for every gun. However, you know what you need and I am not competing--just arm-chair quarterbacking...

[Dirty Rod]

Dirty Rod - I am not really sure what the fps/ 0.1 grain is with my 6.5 but I am pretty sure that there aren't very many variables left to get the Standard Deviation and Extreme Spread down. I already neck turn, primer pocket uniform blah blah benchrest prepped cases. The last thing remaining is powered charges less than a tenth of a grain for that last little bit of SD (along with new krieger barrel).

Well good luck with it. I hate brass prep so I guess I'm satisfied knowing that shooter variability more than negates any accuracy benefit I will receive from neck turning or more precise powder scale. I've heard some of the folks whispering about case weight and internal volume changing as the case wall stretches. I also recently had the pleasure of learning about the importance of bullet trimming. Thank God that 4-6" steel at 500 is all I'm after.

I did ask the folks that I know that shoot extreme distance about their scales and I got everything from a Prometheus and some brands I've never heard of down to a 20 year old beam scale.

Again, good luck with the ES.

If all else fails .. you could always Uniform Your Powder ....

http://bulletin.accurateshooter.com/2012/04/powder-kernel-uniforming-for-ultimate-long-range-accuracy/

Edited April 4, 2012 by Dirty Rod

[Graham Smith]

If all else fails .. you could always Uniform Your Powder ....

It might be worth mentioning the fact that there's reloading for regular shooting and loading for extreme shooting.

Some of the extreme lengths shooters go to with loading are for unlimited class bench rest shooting railguns. These aren't even rifles as we understand them. They're an action and barrel bolted to a very large and heavy base. See the photo here.

It's important to take this into consideration. It's one thing to want to load consistent ammo but there are limits at which you won't seen any improvement no matter what you try until you start throwing tons of money into the gun itself. And lets not forget the shooter while we are at it.

I use a Lee Turret press and a PACT scale and dispenser. Not the best but not junk. I'm getting a SD of about 14 for a 155gr .308 load over 45.5 grains of powder. That's pretty good considering that the scale drifts a bit from time to time.

Edited April 4, 2012 by Graham Smith

[Bill M]

You might want to check out Denver Instruments. They have a nice array of scales. I use to have the MX123 and a good set of check weights. I would warm mine up for several hours before loading, then make sure there was no breeze from the furnance or window getting to the scale.