What SD and ES should I expect when reloading .38 Special? MY chronographed .38 Special reloads have an average SD of about 31 and an average ES of about 100 when testing 10 rounds. Should I try adjusting my loads and/or technique to get a lower SD and ES? I am using Berry's 158 g bullets with either 5.1g Unique or 5.5 g Longshot. All rounds go bang and seem reasonably accurate. Thank you.
Question on reloading.38 Special
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earplug
Member
My opinion
I don't own a chronagraph. I load for differant shooting games.
When I find a clean burning powder and bullet combination, I work on my shooting skills instead of spending time on shooting over a machine.
You might shoot some factory rounds over your machine and note what they clock at.
I don't own a chronagraph. I load for differant shooting games.
When I find a clean burning powder and bullet combination, I work on my shooting skills instead of spending time on shooting over a machine.
You might shoot some factory rounds over your machine and note what they clock at.
The Bushmaster
Member
By paying particular attention to your procedures you should be able to reduce that to 50 ES +/-10 and the SD to the low to mid 20's...If your rounds are accurate you really don't need to worry about your ES or SD. All you will get is anxiety attacks.
Whether people like it or not a uniform crimp on all cases helps and that means you will have to do the "dreaded triming" of all .38 cases to within +/- .002. You might, also, try a different powder. I have good results with W-231.
Let the wars begin...
Whether people like it or not a uniform crimp on all cases helps and that means you will have to do the "dreaded triming" of all .38 cases to within +/- .002. You might, also, try a different powder. I have good results with W-231.
Let the wars begin...
USSR
Member
Standard Deviation and Extreme Spread. ES is the difference between your highest and lowest velocity readings within a group of shots taken. SD is a statistics term, and you may want to read up about it.
Don
Thanks, Gentlemen, for your replies.
SD=Standard Deviation ES=Extreme Spread
OK, I'm guess I'm getting overly obsessive about SD and ES. But I would like to learn if my SD and ES results are in line with what experienced reloaders get. And if they are not, what steps might improve my results.
SD=Standard Deviation ES=Extreme Spread
OK, I'm guess I'm getting overly obsessive about SD and ES. But I would like to learn if my SD and ES results are in line with what experienced reloaders get. And if they are not, what steps might improve my results.
Hutch
Member
Don't know if it helps, but this is a test of some Cowboy Action ammo I cooked up on my Dillon XL650. No trimming of cases or other "undue" care given, as low cost and reliability are the goals for this.
This is for 3.9 of AA#2 powder and a 158gr TC bullet, out of a 3" bbl revolver
High: 777.5
Low: 711.8
E.S.: 65.7
Avg.: 749.625
S.D.: 27.4
This is for 3.9 of AA#2 powder and a 158gr TC bullet, out of a 3" bbl revolver
High: 777.5
Low: 711.8
E.S.: 65.7
Avg.: 749.625
S.D.: 27.4
Several of my .38 Spl loads have bad (to me) ES & SD numbers, but still shoot great. I have much better luck with all other calibers as far as ES & SD numbers go. Getting it below 75 & 25 for .38 Spl with most powders I've tried is challenging, at least for me.
Like The Bushmaster posted...If your load shoots great, don't worry about it.
Like The Bushmaster posted...If your load shoots great, don't worry about it.
jfh
Member.
I'm still analyzing my 38/357 database results--but I've reached the same conclusions that The Bushmaster has--typically, you can get SDs down to below 20, and an ES below 60. Some powders--True Blue, in the 38 cases, reliably goes below 10, and it also has a 1.0 gr.-wide sweet spot.
I even have one recipe that produced an SD of 1.2--and I don't plan to retest it for fear....
At any rate, as I analyze this stuff, I then go back and load my standard recipes--the ones that shoot good, reliably, in my particular guns.
Jim H.
I even have one recipe that produced an SD of 1.2--and I don't plan to retest it for fear....
At any rate, as I analyze this stuff, I then go back and load my standard recipes--the ones that shoot good, reliably, in my particular guns.
Jim H.
rcmodel
Member in memoriam
I have decided that SD & ES are somewhat over-rated.
Some very accurate loads can have pretty bad SD & ES numbers.
It doesn't seem to matter if the gun likes the load.
rc
Some very accurate loads can have pretty bad SD & ES numbers.
It doesn't seem to matter if the gun likes the load.
rc
ArchAngelCD
Member.
I agree, SD and ES are overrated. In professional controlled ammo tests it's found that many times the ammo with the highest ES can produce the smallest groups. They don't feel the ES caused the accuracy only that it really didn't matter.
I use ES and SD numbers as a gauge of how consistent my reloading procedures are. Of course if the ES numbers are excessive that would cause me to look hard at my chosen components. (powder may be too slow or not burning completely)
I use ES and SD numbers as a gauge of how consistent my reloading procedures are. Of course if the ES numbers are excessive that would cause me to look hard at my chosen components. (powder may be too slow or not burning completely)
Jim Watson
Member
A PhD of my acquainance studied the matter and found it was possible to make real match quality .38 wadcutter loads with a Coefficient of Variation (standard deviation as a percentage of the average) as low as 1%, corresponding to a 7 fps SD. Ordinary loads would be ok at 2% and blasting ammo went up from there.
Velocity variation is not very important to the pistol shooter but much of it can give a rifle shooter vertical stringing at long ranges.
One reason those old fashioned single shot rifles with "inefficient" black powder shoot so well is that good loads have very low velocity variation. When working up to my present .40-65 load I got to ES of 11 and SD of 3 fps. I had some lower than that but with a different bullet that was not as accurate on paper, so SD is not everything. But I would not stay with a load that grouped well at 100 yards but with a high SD that predicted stringing at 500.
Velocity variation is not very important to the pistol shooter but much of it can give a rifle shooter vertical stringing at long ranges.
One reason those old fashioned single shot rifles with "inefficient" black powder shoot so well is that good loads have very low velocity variation. When working up to my present .40-65 load I got to ES of 11 and SD of 3 fps. I had some lower than that but with a different bullet that was not as accurate on paper, so SD is not everything. But I would not stay with a load that grouped well at 100 yards but with a high SD that predicted stringing at 500.
I really like bullseye in my 38 Specials. It shoots to point of aim for the fixed sight revolvers, and it shoots very accurately.
Bullseye also gives tight SD’s and ES’s when compared to other powders that I have used. However, I am not good enough to prove that it makes much of a difference on target. For semiautos, I am of the opinion that when it comes to function reliability, tight SD’s and ES’s are better than a wide spread.
Handguns seldom give as tight as SD’s and ES’s as rifles. Don’t know why.
If you notice, with the 158 grain bullets and Bullseye, I have posted basically the same charge, same primers at different times. You can see that the data is variable. So don’t sweat the small stuff.
I have also posted data with blue dot. Notice how much larger the SD’s and ES’s. In this data set, Blue Dot shot poorly and left a lot of unburnt powder residue. So I am of the opinion that if you are seeing ES’s in the triple digits, the powder may not be appropriate for the application.
Bullseye also gives tight SD’s and ES’s when compared to other powders that I have used. However, I am not good enough to prove that it makes much of a difference on target. For semiautos, I am of the opinion that when it comes to function reliability, tight SD’s and ES’s are better than a wide spread.
Handguns seldom give as tight as SD’s and ES’s as rifles. Don’t know why.
If you notice, with the 158 grain bullets and Bullseye, I have posted basically the same charge, same primers at different times. You can see that the data is variable. So don’t sweat the small stuff.
I have also posted data with blue dot. Notice how much larger the SD’s and ES’s. In this data set, Blue Dot shot poorly and left a lot of unburnt powder residue. So I am of the opinion that if you are seeing ES’s in the triple digits, the powder may not be appropriate for the application.
Code:
4" S&W M10-5
158 LRN 3.5grs Bullseye Mixed cases WSP
19-Mar-06 T = 52 °F
Ave Vel = 749.2
Std Dev = 20.97
ES = 83.49
High = 793.7
Low = 710.2
N = 32
158 LRN 3.5grs Bullseye Mixed cases WSP
5-Aug-06 T = 100 °F
Ave Vel = 796
Std Dev = 13.89
ES = 55.24
High = 813
Low = 757.9
N = 23
158 LRN 3.5grs Bullseye Mixed cases WSP
22-Dec-07 T = 52 °F
Ave Vel = 768.6
Std Dev = 15.58
ES = 48.52
High = 787.6
Low = 739.1
N = 18
125 Valiant BBRNFP 7.5 grs Blue Dot Mixed cases WSP
22-Apr-06 T = 68 °F
Ave Vel = 867.3
Std Dev = 53.06
ES = 235.6
High = 959.7
Low = 724.1
N = 25
125 Valiant BBRNFP 8.0 grs Blue Dot Mixed cases WSP
22-Apr-06 T = 68 °F
Ave Vel = 990.2
Std Dev = 56.55
ES = 236.1
High = 1093
Low = 857.5
N = 25I've found that factory ammo usually has less than 20 fps in SD and less than a 4% of average velocity in ES and this goes for the cheap ammo too. Some of the better ammo that I've tested has single didgit SD's and ES of under 1%.
I don't like to see a SD of more than 25 fps in my .38's. High SD and the resulting high ES may shows me that either I didn't get consistent charge throws or at that particular charge weight the powder isn't burning consistently.
It is true that you can get decent groups from ammo that's doesn't have super low SD's or ES but if they're too far out of line the results usually aren't that good.
It is also true that you can get fairly significant differences in SD and ES when shooting the same ammo in different guns. An example is some 9mm reloads I ran the other day that produced a SD of 22.69 fps and an extreem spread of 52 fps when shot from a Walther P1 with 5" barrel but the SD dropped to 9.98 fps and ES to 26 fps when shot from a P38K with 2.75" barrel.
I don't like to see a SD of more than 25 fps in my .38's. High SD and the resulting high ES may shows me that either I didn't get consistent charge throws or at that particular charge weight the powder isn't burning consistently.
It is true that you can get decent groups from ammo that's doesn't have super low SD's or ES but if they're too far out of line the results usually aren't that good.
It is also true that you can get fairly significant differences in SD and ES when shooting the same ammo in different guns. An example is some 9mm reloads I ran the other day that produced a SD of 22.69 fps and an extreem spread of 52 fps when shot from a Walther P1 with 5" barrel but the SD dropped to 9.98 fps and ES to 26 fps when shot from a P38K with 2.75" barrel.
fecmech
Member
One factor that will give you high es and sd is the use of mixed cases in the .38. There are slight differences in manufacturers wall thicknesses and case capacities and this will result in variations of bullet pull and crimp which translate into greater velocity variations. I find Bullseye and 231 powders give uniform ballistics (30-50 fps es and 10-15 sd's for 10 shot strings) using same manufacturers brass. I would not worry much about the ballistics, only grouping ability of a given load. Years ago while simultaneously chronographing and Ransom rest testing I saw many times where 2 rounds that were 50 fps apart velocity wise go through practically the same hole on a 50 yd target. Let the target tell you which loads are good or bad.
That is what I figured, so I bought some brand new Starline brass, trimmed it, and my ES & SD's were no better than in the mixed brass.
I am talking about light target loads. I am sure the full pressure stuff will have better ES & SD numbers. More pressure often helps ES & SD numbers.
fecmech
Member
My wadcutter load of 3.1/Bullseye has an es of 54 and sd of 18 fps. Out of my K38 off bags it will average 2.75" 10 shot groups at 50 yds. BTW some chrono data from 30 years ago ( when I did a great deal of testing) for Winchester factory match wadcutters, ES was 67 fps. Remington factory wadcutters was 71 fps es! They grouped right at 2" at 50 yds.
Again, thanks for the replies. I may try Walkalong's experiment for myself. Buy some Starline brass, trim it to size, reload carefully, and see if my SD and ES numbers improve. His results remind me of my first Science paper on glass making in middle school. I carefully followed all the instructions our teacher gave us to write our paper: 1) find and read references 2) take notes from references 3) make an outline from your notes 4) write a rough draft 5) revise the rough draft 6) write the final paper. When I got my paper back I was given a grade of 79% with the note
"too long!" From then on I wrote all of my papers with a shorter process.
"too long!" From then on I wrote all of my papers with a shorter process.
My results were statistically indifferent. (Not enough to matter)
Take the same load, at the same time, with the same gun. Shoot 6 over the chrono and record. Do that 2 or 3 more times and check out the differences. It may surprise you.
It takes a big sample to give a true test and really tell you something when it is close.
Take the same load, at the same time, with the same gun. Shoot 6 over the chrono and record. Do that 2 or 3 more times and check out the differences. It may surprise you.
It takes a big sample to give a true test and really tell you something when it is close.
For a revolver, unless you run SD and ES for each chamber on your cylinder you are wasting time and components. Try this. Take a cast lead bullet and try to drop it through each chamber. Some may fit tight, some may fit loose. Unless you have your chambers bored identically and cylinder timed correctly, you can change powder, primers, brass and projectiles until the cows come home and still not get the really low ESs and SDs that the BR crowds will ooh and ahh over.
That is a good point.
I have a 6" Model 14 that gives horrible ES & SD's with various loads, but will shoot them through one hole if the shooter is capabale. I have never checked the throats etc. It shoots great, but gives velocities more comparable to 4" guns along with bad ES & SD numbers.
I have a 6" Model 14 that gives horrible ES & SD's with various loads, but will shoot them through one hole if the shooter is capabale. I have never checked the throats etc. It shoots great, but gives velocities more comparable to 4" guns along with bad ES & SD numbers.
Snowboy
Member
the quality of bullets can make big difference on those measures. For me, Berry's bullets were far from doing the most reproductible loads in my S&W686 using W231 4.0 GR. I tried several bullets companies and Berry's had the bigger SD & ES with all other variable unchanged for the loads. Maybe the weight or the ballistic of the bullets aren't similar from one bullet to another
Jim Watson
Member
Back when I was shooting PPC, the Police Marksman's Association tested a brand of wadcutter bullet and their reloads with their own bullet. Their first reaction to the reloads was, "they are in mixed brass, how accurate can they possibly be?" The answer was "Very." Good bullets carefully loaded shot accurately. The NRA had found that out years earlier.
Things are different for a rifle shooter. In a .308 match load, 50 fps is worth 5" of elevation at 600 yards. Adding even .8 moa to your basic rifle and shooter accuracy is not a good idea if you want to score well.
Things are different for a rifle shooter. In a .308 match load, 50 fps is worth 5" of elevation at 600 yards. Adding even .8 moa to your basic rifle and shooter accuracy is not a good idea if you want to score well.
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