Anyone using the 107 SMK in 243 winchester?

Feb 15, 2017
642
30
28
Ohio
#1
I'm doing some load development and was wondering what other people were using for powder. Barrel is 26" with a 1:8 twist. So far I'm getting the best groups with RL 22.
 

MarkCO

Full Member
Dec 21, 2010
667
61
28
Colorado
www.CarbonArms.us
#2
H4831SC for powder. The 115s have proven to be the best for me, but the 105s and 107s are not that far behind.

I don't shoot groups for load development. I do a 10 round ladder test with 0.2 grain increments, then I do a 10 round with 0.1 increments around the node I like to tune it in. So far, that has been stellar.
 

264win

Sergeant
Oct 15, 2008
982
9
18
whidbey island wa.
#10
I ran these bullets for a few matches and liked them.
They shot great at the load that I run for Berger 105s. They also shot almost the exact same poi and trajectory.

I run 41.5 g H 4350 Fed 210m primer and Winchester brass. 3090 fps from 26" barrel.
Same load runs 2900 fps out of a 20" barrel
 
Mar 3, 2010
206
2
18
Farmington, NM
#11
I have a 243win, 1:8, 24" pipe that shoots 105 Amax over Varget at 2910fps. Very accurate. I'm going to try 107SMKs in that rifle with Varget and see what she does. I've heard good things about H4350 but haven't tried it the 243win yet.

I shoot ladders as well, probably similar to what MarkCO does. Local range has a large steel plate at 550yds that works well for ladder tests.
 
Feb 15, 2017
642
30
28
Ohio
#12
I ran these bullets for a few matches and liked them.
They shot great at the load that I run for Berger 105s. They also shot almost the exact same poi and trajectory.

I run 41.5 g H 4350 Fed 210m primer and Winchester brass. 3090 fps from 26" barrel.
Same load runs 2900 fps out of a 20" barrel
Thank you. I'll have to try that. Hopefully my rifle likes that.
 

MarkCO

Full Member
Dec 21, 2010
667
61
28
Colorado
www.CarbonArms.us
#14
Can you describe this second part in more detail.

Specifically the yardages for both rounds of testing.

Thank you
I don't care about yardage, 100, 200, 500 does not matter. I am looking only at the velocity data. I am looking for the level part of the curve plotting velocity vs. charge weight. With 0.2 grain increments, I usually get 2 nodes each with 2 consistent charges. Going by 0.1, I get 4 data points and can make a better choice for my final charge weight. When I take that data (after 20 rounds of load development) and load up 50 and basically go practice with it. I shoot a 5 shot group at 100, 600 and 1000. Never been disappointed doing it that way.
 

V-Ref

Sergeant
Jul 28, 2008
316
57
28
Eagle River, Alaska
#15
I don't care about yardage, 100, 200, 500 does not matter. I am looking only at the velocity data. I am looking for the level part of the curve plotting velocity vs. charge weight. With 0.2 grain increments, I usually get 2 nodes each with 2 consistent charges. Going by 0.1, I get 4 data points and can make a better choice for my final charge weight. When I take that data (after 20 rounds of load development) and load up 50 and basically go practice with it. I shoot a 5 shot group at 100, 600 and 1000. Never been disappointed doing it that way.
Interesting. Do you hang a target?
 

V-Ref

Sergeant
Jul 28, 2008
316
57
28
Eagle River, Alaska
#17
I just shoot at a piece of steel until my final load.
Appreciate you sharing. So to recap...

20 at .5 increments disregarding horizontal. Indicator of a "node" is vertical.

10 at .1 increments focused at the "nodes" discovered above. Again disregarding horizontal. Indicator of a "node" is vertical.

Say for instance 42.8 is what you arrived at after all that.

What now
 

MarkCO

Full Member
Dec 21, 2010
667
61
28
Colorado
www.CarbonArms.us
#19
Appreciate you sharing. So to recap...

20 at .5 increments disregarding horizontal. Indicator of a "node" is vertical.

10 at .1 increments focused at the "nodes" discovered above. Again disregarding horizontal. Indicator of a "node" is vertical.

Say for instance 42.8 is what you arrived at after all that.

What now
The indicator of a node is the least slope of the line, graphing velocity on the Y axis and charge on the X axis.

Once I have the node, I do play with the seating depth just a little, but typically, I am loading at mag length or in the range of about 10 to 15 off the lands. Then shoot 5 shot groups. I have literally cut my load development from several hundred rounds to under 50. I also don't do this until a barrel has settled just shooting a know good starting point load.
 
Oct 29, 2008
423
85
28
Denver CO
#20
Another approach is to load 15-20-ish rounds in .2-.3 increments and shoot over a chronograph (magneto speed) and not worry as much about vertical (shooters do muff a shot every now and then and you might not have 4-500 yards to shoot the ladder test).

Go slow as to not heat the up barrel too much and maintain consistency.

As stated, plot the velocities on y axis and charge wt. on the x axis. The nodes are were the curve is flatest (least amount of rise over run).

I find that just picking the middle of the node seems to work well (allows some slop?) but you can then repeat the process at the nodes in .1 increments - but I believe this is a waste.

Instead I select 2-3 charge weights within the node and shoot 5-shot groups at 1 MOA targets at 200 (local range limit). I select the load with the least vertical dispersion.

I then load up 30-50 of The "winning" charge at and shoot steel from 300-1,300 yards when the opportunity afffords. I gather drop data and monitor vertical closely.

FWIW I have a .243 barrel for my AI AT. And it shoots Sierra 107's great with both h4350 and h4831sc.
 
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