243 Load Thread

I don't have a 243 but a 6mmSLR instead. pretty much the same capacity. Starting load of 43 gr. VV160 and a SMK 107 or 105 Hybrid is lights out and 3000fps in a 26" barrel. 7 mils to 1000y. H4831 is similar in burn rate to VV160. 43.5gr. was 3100fps but I backed it down to get zeroed and broken in.
 
I have 5 .243s and have settled on H4831SC. I load from 75 to 115 grain. Have used 3031, 4350 and a few others, just really like H4831SC and I don't load tons of them, so hand trickling each load is not a big deal. I tried some H1000 in 2019, but then the shortages came and I really never pursued it.

H4831 usually gives me SDs in the 5 to 15 range. Three factory loads gave me SDs from 22 to 31. Interestingly, all 5 seem to shoot the best loads the best and the worst load the worst. 43.3 grains was the best charge weight in my rifles for both 105s and 115s in the fast twist barrels. 43 grains with 75s and 95s in the slower twist barrels. Under 43 grains, SDs were higher.
 
I did some testing and load development today.

This combination is going to work well.

105 BTHP
45.2 IMR 4955
Winchester brass
Wolf LR
3,040 FPS

The ladder test was done at 316 yards.
 

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Recent load development for
1:10 twist 22” barrel
Magnetospeed V3

10/17/23
60F 40% 30.04in

Berger 95 Classic Hunter
*RL22 47.5 gr
Lapua x 1
Fed 210M
*COL 2.0380
*BTO 2.2835
3353, 3371, 3348, 3370, 3370
3349, 3361 SD 10.2 1.2” mild-mod pressure

Berger 95 Classic Hunter
RL22 47.5 gr
Sierra x3
Fed 210M
*COL 2.050
*BTO 2.2600
3272, 3282, 3292, 3325, 3344
SD 30.3 2+” no pressure
*BTO 2.750
3353, 3330, 3330, 3323, 3329
SD 11.5 1.25” mild pressure
 
Last edited:
Older loads, various powders.
22” 1:10 twist
Magnetospeed V3

9/18/21
84F 50% 30.06mmHg

Hornady 100 gr BTSP Interlock
Varget 34.5
FC brass x1
Fed 210M
COL 2.050
BTO 2.2765
2849, 2820, 2817, 2810, 2829 SD 15 1.5”

Hornady 100 gr BTSP Interlock
Varget 34.8
FC brass x1
Fed 210M
COL 2.050
BTO 2.2765
2842, 2805, 2823, 2856 SD 22.2 1”

Hornady 100 gr BTSP Interlock
IMR 4350 42.3
FC brass x1
Fed 210M
COL 2.050
BTO 2.2765
3001, 3007 1.25”

Berger 95 VLD Hunter (1:9 rec’d)
RL15 37.2
FC brass x 3
Fed 210M
*COL 2.060
BTO 2.2900
2931, 2910, 2890, 2959, 2904, 2956 SD 28.4 No pressure.

Berger 95 VLD Hunter (1:9 rec’d)
RL15 37.0
FC brass x 3
Fed 210M
*COL 2.060
BTO 2.2900
2929, 2850, 2929, 2898, 2858 SD 32.8 1.5”

Hornady 100 gr BTSP Interlock
IMR 4350 41.5
FC brass x1
Fed 210M
COL 2.050
BTO 2.2765
2933, 2968, 2957

9/20/21
75F 68% 30.21mmHg

Hornady 100 gr BTSP Interlock
RL26 47.5
FC brass x 2
Fed 210M
COL 2.045
*BTO 2.275
3140, 3155, 3130, 3126, 3165 SD 34.3
Mod pressure ring
Poor group
3173, 3057, 3053, 3150, 3105 SD 54
2”
3076, 3106, 3070, 3026, 3072 SD 28.6
2” mod pressure

Hornady 100 gr BTSP Interlock
RL26 48.3
FC brass x 2
Fed 210M
COL 2.045
BTO 2.275
Hornady 100 gr BTSP Interlock
RL23 44.5
FC brass x 2
Fed 210M
COL 2.045
BTO 2.275
3051, 3017, 3097 1.5”


Hornady 100 gr BTSP Interlock
RL23 45.0
FC brass x 2
Fed 210M
COL 2.045
BTO 2.275
3092, 3063, 3042, 3081, 3066 SD 19.0
1” min pressure ring