Thread: HOW IMPORTANT IS ES

Originally Posted by ebf

Not sure why, but I've always used SD rather than ES as a measure for reloading quality control. Once you get into single digit figure SD for 5 or more shot groups, your ammo is pretty decent.

Will be interesting to hear other folks opinions on SD vs ES.

Well here is something interesting, I just got a chrono so used it Friday. Only 5rnds as an initial trial so have to be careful reading too much into them.

I dont think much of SD as a quality control thing. Take this set, the 37gr shot the most accurate followed by the 39gr with the 38gr the worst. Did I Ioad the 39grain badly? and the 38grain super badly? I dont see why that would be the case. Interesting thing is the 1943 case v winchester case, 1gr more in the winchester but the velocity is still slower, ergo less internal volume (I should go measure it). The SD gave me an indication of the best group, 37gr 2208 and that was repeated in the 69gr and 77gr, least SD best grouping.

SD (left column),

ADI 2208
28-8-2015
303brit
case 37gr SD
1943 1 2161 2161
2 2182 2182
3 2169 2169
4 2147 2147
5 2082 2082
10741 39.1241613329
2148.2

case
winchester 38gr SD
1 2103 2103
2 2202 2202
3 2082 2082
4 2078 2078
5 2161 2161
6 2097 2097
7 2214 2214
8 2097 2097
9 2163 2163
10 2072 2072
11 2111 2111
12 2112 2112
13 2080 2080
27572 48.030305604
2120.9230769231



1943 39gr SD
1 2220 2220
2 2307 2307
3 2249 2249
4 2385 2385
5 2294 2294
11455 63.0594957163
2291


===============
another set,
===============
case 69gr factory
adi smk 2684 2684
guncity std ammo 2710 2710
good accuracy 2701 2701
2676 2676
2701 2701
13472 13.9391534894
2694.4

69gr tmk 24.0gr
2530 2530
2535 2535
2547 2547
2517 2517
good SD 12.4197423484
10129
2532.25


69gr tmk 24.4gr
2560 2560
2615 2615
2615 2615
2609 2609
2583 2583
12982 24.265201421
2596.4

69gr tmk 24.8gr SD
adi case 2612 2612
2208 2598 2598
2572 2572
2591 2591
16.6408132814
10373
2593.25
=============

So I am taking I need to add 150fps to approach the standard factory ADI load and its accuracy of < 1MOA, so I need some BM2.

I will have a look at the ES next.

These are Fed205MAR primers for the 69grain and Fed210 for the 303brit. I have some 210M I will try these to see if they improve the SD at all.

I would also say the wincester cases are more consistant for weight then the 1943 cases.