Powder charge weight - how consistent does it need to be?

[CUBUFF89]

Has anyone done a careful comparison between methods for weighing powder? I know that the FX120i will give very accurate results, but how accurate is necessary?
If my scale were only able to weigh to 0.1 grain will that have a real effect on ES and SD? Has anyone taken an identical load and measured velocity with powder charges that are weighed to the accuracy of the FX120i level and compared them to charges that intentionally vary by 0.1 just to quantify the difference?

I'm still in the dark ages with my Ohaus balance beam scale but I have only recently started shooting 6.5CM in enough quantity to where weighing each charge is a pain. The setup with the FX120i is much faster and certainly less aggravating. But does that level of accuracy translate to higher quality ammo?

The FX120i is tempting but a pretty big $ investment in a hobby that already costs an arm and a leg.

 

[ZiaHunter]

I guess it depends on what you are trying to accomplish. For F Class we are pretty anal retentive when it comes to loading and weigh to the kernel with a Entris 64 and have noticed a difference during ladder tests with as little as .1 grains. When paired with an auto trickler it goes relatively quickly. For most of my other rifles .1 difference is good enough and believe neck tension is more critical

 

[mdmp5]

I just worked up a load with 338 if you can believe it, where 90 - 90.2 grains doesn't shoot, but 90.3 shoots ¼ MOA. I almost didn't believe it but confirmed it on 2 separate occasions. For me, it's all about convenience and speed with acceptable precision. I use a chargemaster now. I used to use a Redding powder throw and trickle, but I wanted something that ran by itself so I can seat and charge at the same time. More precision is good, but it comes at a hefty cost. I think you are good with being within .1 grains. Anything claiming down to the kernel is overkill.

 

[Milo 2.5]

Has anyone done a careful comparison between methods for weighing powder? I know that the FX120i will give very accurate results, but how accurate is necessary?
If my scale were only able to weigh to 0.1 grain will that have a real effect on ES and SD? Has anyone taken an identical load and measured velocity with powder charges that are weighed to the accuracy of the FX120i level and compared them to charges that intentionally vary by 0.1 just to quantify the difference?

I'm still in the dark ages with my Ohaus balance beam scale but I have only recently started shooting 6.5CM in enough quantity to where weighing each charge is a pain. The setup with the FX120i is much faster and certainly less aggravating. But does that level of accuracy translate to higher quality ammo?

The FX120i is tempting but a pretty big $ investment in a hobby that already costs an arm and a leg.

I guess I have not done exactly what you are asking. If you build a gun, say your 6.5 cm, and for load development, if you just group at 100 yards and test farther out and find that 42.6gr is the only charge that is going to work for you, then the expensive scale is something you should consider. You have developed a charge specific load.
Now if you were to develop a load running ocw tests at distance, and find a window of .5gr of powder that will hold vertical farther out. Now the kernel splitting thing is out the door, and a .1gr or even .2gr variance will not disrupt your load, a chargemaster or most beam scales will do fine. Up until you experience a pressure dump<velocity loss and need to bring your load back to where it was, now you will be in a charge specific zone like in the first scenario and the expensive system will help.
I hope this helps.

 

[powercatmd]

A couple of guys I shoot with locally recently did this. Go to YouTube and look up Powder Drop Test Part 1 (I'm at work and can't share link easily). They compare Hornady, RCBS, Harrell's, A&D, and a Prometheus. I thought their methods were well thought out and provided some interesting conclusions. More or less confirmed what I learned the hard way: the Hornady was crap!

 

[Deleted member 10043]

+/- .1 gr. My lymans Gen 2 and 5 can do this consistently with single digit SDs and spread in the teens using both of them to charge a hundred cases. That is using regular dies. If you have a weapon that shoots like shit other than at one specific charge weight with a tolerance of +/- 0 grain than you might as well have it as a club or it is a misconception on your own part. It is as shitty has a Walmart 700. Think about it. What is going to happen the next time you need to change COAL. Come on. Start paying attention to things that matter like excessive runout, etc. Last I checked nobody is preparing for the Camp Perry Wimbledon Cup.

 

[yakstone]

To me it is more of a personal decision, how anal do you want to be and what are your goals?
As you know, consistency is the key in this sport / hobby.
Run the tests that you mention in your question and decide for yourself.

 

[lash]

+/- .1 gr. My lymans Gen 2 and 5 can do this consistently with single digit SDs and spread in the teens using both of them to charge a hundred cases. That is using regular dies. If you have a weapon that shoots like shit other than at one specific charge weight with a tolerance of +/- 0 grain than you might as well have it as a club or it is a misconception on your own part. It is as shitty has a Walmart 700. Think about it. What is going to happen the next time you need to change COAL. Come on. Start paying attention to things that matter like excessive runout, etc. Last I checked nobody is preparing for the Camp Perry Wimbledon Cup.

Culpeper is not wrong here. Plus, if you are using a Chargemaster or other scale that measures to 0.1 grains, you are really measuring +/- 0.05 grains. Think about it. I have a hard time believing that you need more measuring accuracy than that.

Plus, I've found that for me, the biggest things affecting consistency and ES/SD is neck tension and then runout. However, feel free to buy the most expensive scale you can afford and spend as much time measuring your powder to the nth degree as you want, if that's what gets you your satisfaction. I personally would much rather be squeezing the trigger. I am one of those that find loading to be a tedious and time-consuming necessity to support my shooting. Others find that the loading process itself is a source of satisfaction. Different strokes and all.

 

[ruebarb]

The Chargemaster is +/- 0.2 and that is when it is holding its calibration. It likes to drift, so your accuracy really is +/- 0.5 if you don't catch it.

 

[lash]

The Chargemaster is +/- 0.2 and that is when it is holding its calibration. It likes to drift, so your accuracy really is +/- 0.5 if you don't catch it.

Interesting. Your information is based upon what data?

I assume your information is for an out of the box Chargemaster with no modifications or tuning. I use the aftermarket insert and mine is tuned to slow down to trickle only one kernel of H4350 at a time once it gets within .5 grains of target weight. Those that expect it to do this out of the box get what they get. If you want something to work like you want it to, you have to spend just a bit of up front time setting it up correctly first.

Since my .260 SDs on a 10 round string are less than two digits every time I measure them and I see those results at 1000+ yards, I will stick with what I have. You, on the other hand, should definitely spend more money to get more powder measuring accuracy.

 

[Gunfighter14e2]

OP

A proper load for X gun will not care about a 0.2-0.3 grain differential, there are other factors that quickly trump 0.001gr charge weights.

 

[ruebarb]

Interesting. Your information is based upon what data?

I assume your information is for an out of the box Chargemaster with no modifications or tuning. I use the aftermarket insert and mine is tuned to slow down to trickle only one kernel of H4350 at a time once it gets within .5 grains of target weight. Those that expect it to do this out of the box get what they get. If you want something to work like you want it to, you have to spend just a bit of up front time setting it up correctly first.

Since my .260 SDs on a 10 round string are less than two digits every time I measure them and I see those results at 1000+ yards, I will stick with what I have. You, on the other hand, should definitely spend more money to get more powder measuring accuracy.

The accuracy of the displayed value is +/-0.2 (assuming it didn't drift), this has been verified against a FX-120i, this is consistent with the testing performed by other who have made the same comparison. The consistency of the amount being dispensed is +/-0.1. with all the modifications.

I use a Chargemaster and an Autotrickler, they both have their uses. The drifting is the fatal flaw of the chargemaster, keeping it is on all the time helps that issue or warm it up for 2 hrs and don't have a temp swing where it is located. Also calibrate every time you use it.

 

[lash]

The accuracy of the displayed value is +/-0.2 (assuming it didn't drift), this has been verified against a FX-120i, this is consistent with the testing performed by other who have made the same comparison. The consistency of the amount being dispensed is +/-0.1. with all the modifications.

I use a Chargemaster and an Autotrickler, they both have their uses. The drifting is the fatal flaw of the chargemaster, keeping it is on all the time helps that issue or warm it up for 2 hrs and don't have a temp swing where it is located. Also calibrate every time you use it.

Where's the testing data?

 

[canezach]

@lash here's someone else's report on Chargemaster v. Auto-trickler. I'll admit I haven't tried it myself, but I'm always a sucker for more data, so I'll probably do some comparison testing this weekend with my FX120i and Chargemaster and report back.

http://www.snipershide.com/shooting/threads/chargemaster-vs-a-d-fx120i-and-auto-trickler.6252862/

I'll say I've never had a problem producing accurate, sub-10 SD and sub-20 ES ammo with my Chargemaster. I upgraded to the FX120 for two reasons: 1) I'm a sucker for more precision, so being able to differentiate between a single kernel of powder appeals to me, even though I know the effects downrange are minimal, and 2) the auto-throw and auto-trickler allow me to throw charges in less time with far fewer overthrows than my Chargemaster, which does have the reducing insert and is tuned to my desired speeds. I honestly do not see a huge difference downrange, though my SD and ES numbers are slightly tighter with the FX120i

 

[lash]

Okay, so I see where they are indicating +/- 0.1 gr variation. I also see that all of the tests that are reporting discrepancies are indicating that they did "the mods", specifically the programming mods to speed up the machine. In contrast, actually slowed down the trickle mode so that I literally can see it drop one grain of powder at a time. Yes, it is tedious and even more so to me since I do not have my presses inside where I charge my cases. I also practice consistent startup and use; to include powering the machine up at least 1/2 hour before use, I do my powdering in a location of the house where there are no A/C or heat ducts nearby to create currents, I use a dampened circuit for power, I have the brass insert for flow control and I always re-calibrate before starting.

As mentioned, my SDs are consistently sub 10 over a 10-shot string and that is with a charge weight of 41.8 gr H4350. I'll restate that a tool is only as good as you can get it to perform for you and what I deem as plenty acceptable does not necessarily mean that another will be happy with it. So far, I have yet to see any data that shows the CM to be a +/- 0.5 gr scale.

I did spend some time trying to find any data so that I wouldn't be throwing down an empty challenge, but have yet to see any. I did see plenty of people complaining about their CM accuracy, but most had little to no experience with them and plenty of people are simply after speed. I get that. Especially if you have your press nearby and are optimizing your loading time. However, that is not the only way to slice the pie and trying to get both speed and serious repeatable accuracy out of a mid-range at best scale/powder dispenser may be asking more than is reasonable. If you wish to sacrifice some speed, you can gain some repeatable accuracy.

Oh, and mine does not overthrow charges either. Likely because it is slowed down at the end of each charge.

 

[Deleted member 10043]

Hell, I run a 50' power cord to a shed and run two at the same time.

 

[redneckbmxer24]

I'm very anal in regards to all of my loading techniques and if mine are anything but exactly the target weight I'll add, remove, or even swap kernels with tweezers until I'm spot on which is going to be within .01gr in either direction before the fx-120i's accuracy.

My ES's are also typically sub 5fps and I shoot 5 shot strings very frequently that have an ES of 0-3 and an SD of 0-1. Being anal about exact charge weight isn't the only reason for these results but it's certainly a major contributing factor and wouldn't be happening otherwise.

 

[CUBUFF89]

A couple of guys I shoot with locally recently did this. Go to YouTube and look up Powder Drop Test Part 1 (I'm at work and can't share link easily). They compare Hornady, RCBS, Harrell's, A&D, and a Prometheus. I thought their methods were well thought out and provided some interesting conclusions. More or less confirmed what I learned the hard way: the Hornady was crap!

Thanks for pointing me to the video. This is exactly the type of comparison I was looking for. These guys have a level of precision I'm not capable of. That's why I was turning to others to find out if someone had investigated this.

 

[Devildog]

You need to decide how much $$ you want to spend. For the money the charge master with an insert works really well. I used to be anal about my loads but for most of use we are banging steel not benchrest shooters so you need to decide what your goals are. Heres a chronograph of 10 rounds thrown with the chargemaster. I can’t complain.

 

[powercatmd]

Thanks for pointing me to the video. This is exactly the type of comparison I was looking for. These guys have a level of precision I'm not capable of. That's why I was turning to others to find out if someone had investigated this.

You bet. Both of these guys know their stuff and are very competitive in ELR and PRS matches.