What do you guys find to be acceptable standard deviations in powder charge for 40gn class rounds (308, 6.5s.) In other words, what will you accept from throwing charges before you go into weighing them? SD of .05 grains, .1 grains, .2 grains? I realize that the distance being shot is a big part of this. Thanks in advance.
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Powder Charge SDs
- Thread starter Choid
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Well, I am resigned to weighing for anything I am going to be shooting out over 1000 meters, and anything that has really chunky powders like H1000 or n570, so I am really talking for fun shooting with 6.5C and 308, out to 1000 meters, but keeping in mind that I am as obsessional about stuff as anybody, lol. So basically I am trying to balance the ability to spend more time shooting and less time reloading where the difference is going to me minimal.
ETA: I've been using an autotrickler since v2, so I am trying to back off where I can.
I’ve been using a chargemaster 1500 since I started and honestly I would be shocked if anything more expensive gave any noticeable gains down range with my 260. Over 50 rounds I’m at around 10SD and 20 ES. Even if it dropped it to 5SD and 10-15ES would I notice that downrange? Doubtful
That being said loading 100 rounds with a cm1500 is not fast by any means. One day I’m going to upgrade to a autotrickler soley for the how much faster you can load.
That being said loading 100 rounds with a cm1500 is not fast by any means. One day I’m going to upgrade to a autotrickler soley for the how much faster you can load.
So just leasurly target shooting. I havent noticed any difference when managing to/tolerating a .2g charge variance across a given lot of rounds. So If my spec is 42.7g im good with 42.6 or 42.8.
If you are going to obsess, dont focus your obsesson on the reloading/ammo or the weapon system, obsess over execution of the fundamentals correctly over and over again.
Lack of fundamentals execution is the main driver of dissatisfaction with performance, not the hand loading (for most shooters, including me).
No one can can answer that question, you would need to test your particular rifle with your particular load
velocity variance with small changes in powder weight.
What size target are you trying to hit at what range? Use a ballistic calc and run velocity numbers
and you will find how much velocity spread you can have and still hit close to where you want.
Hitting a 36"x36" plate at 1000 does not require the same precision as hitting a 6" plate at the same distance.
velocity variance with small changes in powder weight.
What size target are you trying to hit at what range? Use a ballistic calc and run velocity numbers
and you will find how much velocity spread you can have and still hit close to where you want.
Hitting a 36"x36" plate at 1000 does not require the same precision as hitting a 6" plate at the same distance.
Like he ^^^, you will learn a lot more testing this out on your own. If the plan is to use a powder measure(thrower), choosing powder that meters well in your particular model will skew results in your favor. If RL 26 is your powder of choice, you may be hosed, if it is a ball powder or small kernal powder, your results may be more than satisfactory.
Yeah, where I load with 26 or 570 I am already resigned to the autotrickler. I'm going to try to grab some data today and see what works with what. I know I can throw 8208xbr with a SD of .025 grains in a dillon hopper, but I only have so many pounds of that left, and none seems to be on the horizon. If it were available, between that and Staball I could cut a huge amount of time. But I am stingy with the stuff.
Or run multiple CM. I run 3 and I can barely keep up reloading.
Is there a better way to measure how consistently a given drop system drops weights of powder? I don't do it while loading, I set up a test station and do it all at once.
So gathering data is obviously the way to go. I have two accuracy loads I've shot with 308 for years. One is with 3031, and the other is with 4064. With my Johnson's thrower I can get 3031 well within any reasonable charge spread, and that is running to case activated on a Dillon 550. With 4064, I have no luck. I am a little better than FGMM that I have taken apart spread wise, but not much. So 3031 is clearly the way here.
Interestingly, other than Staball, the Creedmoor class powder that is the best metering is RL16, which I would not have expected. Others that I have around that meter really well are RL15, which is great for 308 but I only have a half a pound, and RL7, which meters best of all, but I only shoot in my 204 Ruger gopher gun. I didn't even bother with anything chunkier.
Acceptable for those rounds I judged to be within .1 grains SD, but I may rethink that as I get to shooting them. Also, this method has a really long drop tube, which may actually give some advantage as far as consistent density inside the case, or so people told me when I was starting out. We will see.
You surely aren't doing anything wrong, just quantify your work, it should be as easy as shooting 5 of each, thrown vs measured at differing distances. Do the same with a chrono.
My philosophy is to control the things you're capable of controlling. Of all the things we can control, charge weight is one of the easiest. It does not take much to hit .1 gr on the nose every time if your scale has .1gr fidelity.
Finding this balance has been a challenge for me, but mine is with record keeping. I want to track everything and sometimes it's just too much. I think you just have to step back sometimes and take a long look at what you're doing. On the handloading side, I have a Chargemaster that I've been using for several years now. It does a good job and is pretty quick. Maybe streamlining you processes will speed things up.
wrong question - wrong problem.
nobody knows what is their charge ES/SD, because you need super accurate scale for that. 5000$+. so everybody looks at velocity ES/SD and accuracy on target.
YOU must determine what is YOUR acceptable accuracy of weighting charges, and that is based on your equipement. if you have cheap gun, dont bother and waste our time.
if you have good rifle, than look what equipement you have and how much time you want to spend for weighing powder: if you have good mechanical scale (rcbs, redding), than this is super accurate but very slow.
if you have autotrickler + AD120fx, than you can have the same accuracy as previous for 15 seconds of auto weighting.
so you must decide what is worth to you.
With a bad attitude like that, you'll never be able to afford an expensive scale.
I have a scale that is $490 and measures to 0.02gr precision. Not $5000. I trickle up to the same exact charge every time. i.e. 41.90gr every time. No 41.92, no 41.88.
Scales that only go the the tenth place work just fine though. Just do the same thing so the error is only in the scale.
Scales that only go the the tenth place work just fine though. Just do the same thing so the error is only in the scale.
not realy. if you want to be sure, you need far better scale that is yours.
if you could weight on 5000+ scale, you would see that your 41,90gr in NOT 41,90 every time. your scale is far far worse for this precision.
Just a little surprised that someone not weighing their loads ... would care about measuring and monitoring SD's. I'd think if you drop-charge and shoot acceptable groups, you just declare victory and keep shooting. But that's just my humble opinion.
I think you, and BritneyRears6969, miss my point. I am currently weighing and throwing with an autotrickler in an FX120i. I am trying to figure out, from others past experience, what they have found the relationship is between load performance and variance in powder charge so that I can speed up the process by using a tuned powder dropper when possible. It isn't a question of having the right equipment or caring, it is a question of time vs load optimization. IOW, I wouldn't be loading match 50 BMG with a powder measure, and I don't load bulk 556 on a scale, but where is that tipping point where it actually matters vs where we presume it matters but for no good reason. And yes, I could figure it out all myself, but message boards are basically knowledge bases.
So to speak to your question ... I've learned through experience two key points ... (1) Powder droppers are much less accurate giving high variance in charge weights (unless you trickle and weigh manually), and (2) weighing and measuring to specific tolerances always provides smaller Standard Deviations ... full stop. My original work was with a powder dropper and the best I could do was SD's in the 20's for 6.5-CM and 300-WM. I switched to a Chargemaster and weighing everything (along with just getting better at all steps in the process) and watched my SD's eventually trickle (Ha!) down into single digits, where they remain today. I put my Redding Competition Powder Dispenser up for sale after that epiphany and nothing I shoot goes without knowing the charge weight down to the tenth/grain.
Yes you are correct, but the 120i's linearity is ±0.03gr and a single grain of H4350 weighs ~0.02gr or ±1.5 kernels of H4350. Any better scale and I'd be splitting kernels of powder.
But yes, you could get a scale with better linearity so you can reliably measure down to the exact kernel of powder.
Not a bad question considering the term Precision is relative.
Whats acceptable SD for headspace?
Whats acceptable SD for bullet seating?
Whats acceptable SD for neck tension?
whats acceptable SD for X, Y, Z?
Added together can have some real effect down range. Thinking of it like tolerance stacking. Theres probably a formula if you can get these numbers below X, you will have a certain level of precision.
Whats acceptable SD for headspace?
Whats acceptable SD for bullet seating?
Whats acceptable SD for neck tension?
whats acceptable SD for X, Y, Z?
Added together can have some real effect down range. Thinking of it like tolerance stacking. Theres probably a formula if you can get these numbers below X, you will have a certain level of precision.
Exactly. It takes me just as long to size and set neck tension sloppily as it does to do it as well as I can. Likewise for bullet seating. The only place I identify as a tradeoff between time and precision is in powder charge.
I know I can drop Staball and CFE 223 at +/- .03, which really gives a negligible effect on velocity. I know I can't do that with Reloder 26, especially since velocity SD becomes more important with those cartridges as I am shooting them out farther. The questionable area, for me, is with things like RE 16, Varget and 4064. Can I drop charges well enough not to have a negative effect on what I am trying to do. After all, I am not trying to shoot standard deviations of velocity, rather to shoot targets and animals at various distances.
If I wanted to use Staball and CFE for everything, then I would be on easy street, but they aren't always the right choice.
Hello, I don't want to take away from what anyone said, as I am just another person with an opinion and some experience. I would say, for a long range load, if you talk to some F class shooters, I would estimate their loads are extreme spread of 20 or less as a target. ES of 20 would be good. there is a little write up about it here. http://natoreloading.com/Neck/
I’ll load +\- .02 on my regular load. Anything else I re-throw the powder. As far as acceptable SD. Anything under 10.
your possible SD of powder charge you could calculate from your SD of velocity.
let's say that if you have powder in your cartridge that gives +50fps for +0,2gr, than if you have SD of 10fps, your charge accuracy from this point of view is (10/50)*0,2gr = 0,04gr of powder.
BUT, bear in mind that velocity SD in not entirey dependent of your powder charge, it's about primer, neck tension, bullet unifomity, barrel... so let's say that your SD from powder charge is only 50%, so you can assume that your powder charge SD is 0,02gr... etc
yes, it has real efect, but I tink that those things that we do with our brass is exaggeration.
at the end, if you have good barrel, good cartridge and good bullet, and are in nice node, those brass preperation steps are almost non important for being perfect...
The FX120 is accurate enough. The idea proposed that only a $5000 scale will do is patently absurd.
If a bit better accuracy is required, the EJ-54D2 is great and actually cheaper at the cost of speed and some functionality. Accuracy beyond this will not yield different results as we are measuring a substance with kernel sizes in the 0.02 grain range -+1.
If a bit better accuracy is required, the EJ-54D2 is great and actually cheaper at the cost of speed and some functionality. Accuracy beyond this will not yield different results as we are measuring a substance with kernel sizes in the 0.02 grain range -+1.
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of course.
but if someone want to know what is his real charge for REAL 2 digits, just for academic intrest, you must buy scale that measure in 3 digits !
so you can see if 0,02gr is in fact 0,021gr and not 0,027gr, etc, and for this kind of accuracy you MUST buy scales of 5000$+.
but for reloading this is pure noncence, like you said...
The displayed resolution gives you no information of the internal resolution before rounding. The internal resolution of the FX is greater than 0.01, but it displays increments of 0.02 as basic sampling theory would dictate.
You also keep moving the goalpostst. Your statement was that:
”on [a] 5000+ scale, you would see that your 41,90gr in NOT 41,90”
this has to do with consistancy, not resolution.
Regardless, for discussions on the topic at hand your arguments are neither relevant not correct.
Much like audiophiles with $100 000 systems in acoustically untreated listeningrooms, even an FX is not performing to its potential if the environment is not controlled. To truly see what it can do, you need a very very stable base, minimal air convection and to a lesser degree clean power and an RF free environment. Without this your scale will perform at a lower level than its capability.
That being said, for reloading it performs as well as needed with a regular table, normal air convection , a cell next to it and unclean power.
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Oh how far we have strayed from the original post.
I would say acceptable for me is .2gn
Both my chargemaster and Hornady auto throw down to .1gn between the two I can keep it within a .2gn spread. I also have a gem scale that goes down to .015gn that I spot check with or use to trickle more precise test loads.
I would say acceptable for me is .2gn
Both my chargemaster and Hornady auto throw down to .1gn between the two I can keep it within a .2gn spread. I also have a gem scale that goes down to .015gn that I spot check with or use to trickle more precise test loads.
Take a gun the will sub .25 moa if you have one. Shoot kyl rack at 600+ yards. This will tell you your ability as a shooter. A well tuned gun is like cheating. You pretty much know exactly where the bullet will go when the shot breaks.
Knowing that, test some different loading methods against that standard. If you are happy for the application, proceed. If not, fix the system.
With a sub 3/8 moa gun I can hit the 6 in plate at the 800 yard burm between 8 and 10 times per ten rounds once I know the wind call.
With 223 loaded on a Hornady progressive press with 8208 I can hit that same target 5-8 times in 10 shots with a cheap Criterion prefit. Good enough to use as a trainer.
Also, if you shoot enough you can tell when there is a problem. With some guns it is hard work or impossible to shoot a .5 moa group at 100 yards. With a really well tuned gun you will shoot sub .2 at 100 yards, but I'm not typically that good of a shooter. What I find is I get 3 to 4 in one tiny hole and the shot where I say "Oh shit, I blew it." opens the group to 3/8 to .5" instead of 3/4-1".
All of this is entirely dependent on a shit ton of variables. Some systems have wide nodes and some don't. It is entirely dependent on the system and what size target you expect to hit every time and at what distance. Everyone else has given good advice. The bottom line is you just have to go play around and figure it out.
Knowing that, test some different loading methods against that standard. If you are happy for the application, proceed. If not, fix the system.
With a sub 3/8 moa gun I can hit the 6 in plate at the 800 yard burm between 8 and 10 times per ten rounds once I know the wind call.
With 223 loaded on a Hornady progressive press with 8208 I can hit that same target 5-8 times in 10 shots with a cheap Criterion prefit. Good enough to use as a trainer.
Also, if you shoot enough you can tell when there is a problem. With some guns it is hard work or impossible to shoot a .5 moa group at 100 yards. With a really well tuned gun you will shoot sub .2 at 100 yards, but I'm not typically that good of a shooter. What I find is I get 3 to 4 in one tiny hole and the shot where I say "Oh shit, I blew it." opens the group to 3/8 to .5" instead of 3/4-1".
All of this is entirely dependent on a shit ton of variables. Some systems have wide nodes and some don't. It is entirely dependent on the system and what size target you expect to hit every time and at what distance. Everyone else has given good advice. The bottom line is you just have to go play around and figure it out.
This was kind of the impetus of my questioning. I have a Tacops 308 that is a legit sub quarter gun, and it is built, like all of Mike's guns, around fgmm 168. My longest KYL on my property is 500 yards, and it makes easy work of it, so I started thinking that FGMM shoots great, but the powder charges are kind of all over the place, which started me down this path of thinking, because I "clone" the same load with 43 grains of 4064 measured to the .01, and there is literally no difference in performance over the factory ammo in this case...
To be more short and succinct, there are too many variables to really predict. You just have to try it.
I have had loads with h1000 in a 243AI where massive variances would hit the target in the same spot at 775 yards. The load had an SD of 18 but because of positive compensation it would shoot sub 3" at 775 regularly and sub 2" at 615.
I have also had loads that would shoot very well if loaded carefully, but the "node" was only + or - .1 grains. These were in a 6 Dasher were I tend to be very lazy with load development because everything shoots. I likely wasn't really in a node, but had sub 10 sd and sub 30 es and sub 3/8 5 shot groups at short range, so I ran with it. Same load also shot a 5.5" group at 1000 on an e target that was a side stage at a match. I thought there was no way it would shoot close to small enough to win, so I kind of half-assed it. When I was finished I wished I would have actually tried to shoot a tight group. This is the same gun and load where I can run it like shit and still end up with a sub 1/2 moa group. The point is, it obviously performs very consistently, but doesn't seem to be a wide node or maybe even a node at all.
If someone knows how to predict what will be very forgiving and what won't, I would love to know. I certainly haven't figured it out. You can see it through ladder testing, but I don't know how to just predict it without testing.
There does come a point in the transonic or subsonic range where velocity spreads will bite you regardless of PC. I typically don't shoot that far, but when they put an elk target at a mile at a match it is nice if your gun/load will hold vertical well enough to hit it.
