I ran a 10 shot load development and stuck with 42gr after afew trials. Today I went out with 20 loaded up shot 10 with magnetospeed sporter and then shot 2 groups of 5. Groups were just over .5 and .6 so I'm happy with those. MV average was at 2806 with SD at 9 but ES was at 32 out of the 10 shot group. My question is where should I go from here? Leave charge alone and mess with seating depth or neck tension? Any ideas are much appreciated. I'm new to reloading so take it easy with me this is my first time developing a load for my rifle.
-
Having trouble using the site?
Contact support
Range Report SD and ES
- Thread starter tripdoc6
- Start date
Your in pretty good shape already as that SD/ES isn’t bad, but if you want to tweak it more, dabble with a couple of seating depths (0.005” increments).
I guess I'm more concerned about the ES at 32 I thought that was really high and I should be in the teens?
There is no real hard and fast "rule" of where SD and ES should be, per se. For extreme narrow vertical dispersion at 1000 for F Class or other benchrest guys, sure.
Depends on what you want the ammo to do. Ping full-size IPSC steel at 1000 yards? You're more than OK with your numbers. Hell, the other day I made a fodder load to fire form my 7mm RemMag brass to my Tikka chamber. SD of 25, ES 70 or something and was hitting a full size IPSC at 600 all day with variable half to full value winds from 0 to 12-15 MPH. I made another random load with SD of 15 and ES of 50 or so and was holding 2MOA round steel plates to 600 as well. The limitations were me and my lackluster wind reading skills.
Point of the above is your stated numbers are better than most factory match ammo which based on my experiences have SD's of 15 or so, ES's of 40-50. The smaller you want your numbers to be, the more time and $$$ you'll be spending at the reloading bench. If that's what you want, then by all means, get it.
As @clcustom1911 said, it depends upon what you really are trying to accomplish. Just bear in mind that I have seen guys spend 6 months chasing the perfect load at the range bench and being frustrated while the rest of us were out shooting matches and having fun. When you are new, it is easy to read too much and find yourself down a rabbit hole.
I suggest you get out and shoot. If you really want to check, run the numbers and see what your Extreme low and high end impacts would be from center with an ES if 32. That’s only +/- 16 FPS from center.
I suggest you get out and shoot. If you really want to check, run the numbers and see what your Extreme low and high end impacts would be from center with an ES if 32. That’s only +/- 16 FPS from center.
What did the actual numbers look like and how are you charging your loads? Human error charging one cartridge heavy/light can cause high ES on a 5-shot group. The human part of the process is the most likely culprit from my experience.
Lash, you could not have said this better. I finally started have way way more fun getting out and shooting steel at varying distances than messing around trying to find the “perfect low es/sd load for my rifles.
To continue from my post above, I ran some numbers through the ballistic app. Using your average speed of 2806 FPS as your base, you would have to dial 8.8 mils for a drop of 316.3”. Your low would be 2790 FPS for a dial of 8.9 and a drop of 320.7”. Your high would be 2822 FPS for a dial of 8.7 and a drop of 312.1”.
That amounts to an extreme spread of 8.6” at 1000 yards or an average of 4.3” of off your aim point at 1000 yards. This means that if you are a great shot and can call all wind, you can easily keep all of your shots on a 10” plate, all day long.
I just wanted to throw out some perspective for you.
And yes, your loading habits and consistent neck tension are two very important factors in hand loads.
That amounts to an extreme spread of 8.6” at 1000 yards or an average of 4.3” of off your aim point at 1000 yards. This means that if you are a great shot and can call all wind, you can easily keep all of your shots on a 10” plate, all day long.
I just wanted to throw out some perspective for you.
And yes, your loading habits and consistent neck tension are two very important factors in hand loads.
This guy understands. I try to keep my ES numbers within reason to stay in a 1/2 MOA window at 1000 yards. Whether it is ES of 32 or 20, it doesn't matter as the vertical dispersion per the bullet, BC, velocity, etc. will allow me to tag a target 1/2 MOA tall. Again, benchrest and PRS are different, but the ammo isn't your limiting factor at that point. You're also measuring 10 shot groups. Unless it's for score on paper versus hitting steel (again, benchrest vs PRS), you'll be shooting fewer than 10 shots at that single target at that stage.
any chance you let one or two of those shots cook in the chamber a little bit longer and heat the powder up? I started getting way better ES numbers once I realized I was introducing my own errors by not being consistent or considering that factor.
IF the SD is in fact 9, then an extreme spread of 32 is perfectly normal. IF the SD is valid, note that 99.7% of rounds fired will be within +/- 3 SD's of the mean, -27/+27 leaving an ES 54 some percentage of the time. With only 10 shots over the chronograph we can say the SD is between 6.75 and 13.5 with 90% confidence.
ES is usable for only one thing, rejecting a load. If the ES in a given test is greater than 6*SD then you can just take a pass and try something else. Otherwise ES is pretty much useless. Sample size is important to statistical analysis, and for ES the sample size is always 2, even if the population is 10, 100 or 1000.
It seems most people fail statistics and probability. The math, IT BURNS, IT BURNS!
ES is usable for only one thing, rejecting a load. If the ES in a given test is greater than 6*SD then you can just take a pass and try something else. Otherwise ES is pretty much useless. Sample size is important to statistical analysis, and for ES the sample size is always 2, even if the population is 10, 100 or 1000.
It seems most people fail statistics and probability. The math, IT BURNS, IT BURNS!
When the chronograph results have you banging your head against the deck, go old school. Test 5 shot groups at 300. Unless, as referenced above, your in the top 5% of your disciples in the world, ED/SD reading are a rabbit hole. So many variables you can’t account for all of them. So skip the Sudo-scientific approach to load development and go off intended results. Being it’s your first load development keep it simple. Load with in the node and play with setting depth. Once you have an average of 1” at 300 per 5 shot group you home free.
A lot of great suggestions in this thread. ED/SD measurement have a place in reloading. But only to the tops shots. Everyone else is loosing trigger time and burning through projectiles and barrel life. My experience, not the final word. Hope this helps.
A lot of great suggestions in this thread. ED/SD measurement have a place in reloading. But only to the tops shots. Everyone else is loosing trigger time and burning through projectiles and barrel life. My experience, not the final word. Hope this helps.
Thanks for the replys and info I will just keep shooting them and maybe mess with seating depth alittle. I'm trying to get a load ready for my first prs match so I guess that is why I'm reading alot into it and worrying about all the numbers.
Excellent idea. The other day after I was shooting my 7 mm, I practiced doing hold hours with my 6.5CR 147 ELDm load. That load moves that about 2700 ft per second with Reloder 17 at 65 degrees. Its a temp sensitive powder. I have noticed that at 65 degrees the SD is approximately 6 and the ES is about 15 to 20. At 85° the SD is 15-ish and the ES is 40-50.
Either way, I was still able to do rapid transitions from 100 out to 600 with no problem on steel
So many times I’ve chased chronograph numbers when results down range proved otherwise.
Now I use the crony to get speeds and an idea about SD and then shoot them and see what my vertical really is.
Now I use the crony to get speeds and an idea about SD and then shoot them and see what my vertical really is.
THIS
I strap the V3 on during the first phases of load development just to get a ballpark. Too many times I have tweaked a load that shot lights out just because I didn’t like the chrono numbers. It’s insanity.
Sometimes I see an outlier when using the chrono, maybe a bullet is different than the rest, maybe a piece of brass is off, or less blast in a primer, E-scale being off .2 grains, who knows??, the point is there was something wrong with that one outlier that shot too fast or too slow compared to the rest. Feel free to not include it in your ES unless this is happening often in which case it bears investigation.
Believe the vertical at distance rather than the chrono by confirming a few times - The use of "positive compensation" wins benchrest matches and if it will do that then we are GTG.
Believe the vertical at distance rather than the chrono by confirming a few times - The use of "positive compensation" wins benchrest matches and if it will do that then we are GTG.
Although I don't reload, I am always making measurements of the factory ammo that I use. I totally agree with you.
I have some buds that reload and they always throw out high and low of a string. I never knew that until I watched them make chrono measurements. I think that is totally wrong unless it is a true outlier that you rarely see.
This is why I seldom care about ES. I record it and compare to historical measurements.
SD is a much more statistically significant parameter.
Some really good advice and knowledge being passed along in this thread. The only thing I would advise is to just shoot what you have. Don't change load or seating depth or anything. Spend the time shooting and not worrying.
An ES of 32 should only be concern when there is wide variation shot to shot along with it. SD is the true reflection of just how good your load is and single digit is the goal. Without seeing the other recorded shots in that string my guess would be that they are much closer to the same and you had the one that was 32 FPS away. I'll take that any time I can get it.
An ES of 32 should only be concern when there is wide variation shot to shot along with it. SD is the true reflection of just how good your load is and single digit is the goal. Without seeing the other recorded shots in that string my guess would be that they are much closer to the same and you had the one that was 32 FPS away. I'll take that any time I can get it.
Throwing out data you don't like provides garbage results. "Outliers" are still valid data points. The same thing applies when shooting groups. "Flyers" still count. You shot it, it's part of the group. That's the whole point behind using SD. With a suitable sample size (20-30 rounds) we can predict with a fairly high confidence level the spread of velocities we will see in the rest of the population. If the SD is 10, we can expect 97% of the next 1000 rounds to be +/- 30 fps of the recorded mean. That means over the entire population, we would expect an ES of 60 fps, +/- a bit.
Looking at the vertical spread of a group is fine, but can be misleading as you don't actually KNOW why a bullet landed where it did.
Like it or not, velocity variations determine vertical spread if the aim is fixed. At 1000m, 20 fps might only be +/-.2 mil, average aiming error is .1,
If I know my SD is inside the required value for the desired results, then I can put ammo aside as a cause of vertical spread. Unless I have a number of groups downrange, once again 20+ rounds at that distance, I can't say that just having a small vertical spread has any real long term relation to the next shots to be fired. If I do have valid group data, then the chronograph would be redundant, just telling me what I already know.
Looking at the vertical spread of a group is fine, but can be misleading as you don't actually KNOW why a bullet landed where it did.
Like it or not, velocity variations determine vertical spread if the aim is fixed. At 1000m, 20 fps might only be +/-.2 mil, average aiming error is .1,
If I know my SD is inside the required value for the desired results, then I can put ammo aside as a cause of vertical spread. Unless I have a number of groups downrange, once again 20+ rounds at that distance, I can't say that just having a small vertical spread has any real long term relation to the next shots to be fired. If I do have valid group data, then the chronograph would be redundant, just telling me what I already know.
Outliers only tell you that something went wrong, why would it make sense to include one shot in 20 or whatever that is 75 fps lower or higher than the next one to it. That to me makes it completely invalid to include. It doesn't happen often but it does happen.
Also chrono's are not perfect.
Also chrono's are not perfect.
Just because you don't like the data point does not make it invalid. Some 3 percent of the time a round will be more than 3x the SD off the mean, unless you can point to the exact cause of the excursion that 's something like equipment failure, it's a perfectly valid data point.
Certainly a chronograph can have a glitch and display an obviously wrong number, like 1800 fps when the rest of the rounds are at 2850 and the odd shot still lands in the group. Fine, delete that one. But getting one at 2715 is not out of the question, so unless you dinged a skyscreen or hit the bayonet on the Magnetospeed or similar, it still counts. Sorry.
Certainly a chronograph can have a glitch and display an obviously wrong number, like 1800 fps when the rest of the rounds are at 2850 and the odd shot still lands in the group. Fine, delete that one. But getting one at 2715 is not out of the question, so unless you dinged a skyscreen or hit the bayonet on the Magnetospeed or similar, it still counts. Sorry.
I agree with Cory 100% "fliers" and "outliers" in both groups and chrono data should be included. I think its comical how many times on youtube I see excuses about pulled shots and fliers, don't want to hear about it the group is what it is.
I shoot with my magneto on all the time I have stacks of data on excel lots of 20-40+ shot strings and chrono data. The pictures posted of 5 shot chrono data are laughable see it all the time, yeah ive had an ES of 3 over 5 shots as well by luck. The truth is over 20 to 40 shots my SD will USUALLY be in the single digits up around 8-9 but sometimes will go over 10. ES can vary from 20's to 40's. I'm extremely sceptical of people claiming single digit ES with 40 shot strings. I'm sure it has been done but would take benchrest prep to do it in my view.
I shoot with my magneto on all the time I have stacks of data on excel lots of 20-40+ shot strings and chrono data. The pictures posted of 5 shot chrono data are laughable see it all the time, yeah ive had an ES of 3 over 5 shots as well by luck. The truth is over 20 to 40 shots my SD will USUALLY be in the single digits up around 8-9 but sometimes will go over 10. ES can vary from 20's to 40's. I'm extremely sceptical of people claiming single digit ES with 40 shot strings. I'm sure it has been done but would take benchrest prep to do it in my view.
