Ladder test - please help evaluate results

[Yerman]

Hey guys...I just finished my first ladder test. Here are the results...

Rifle is a .308 Remington 700 SPS Varmint with a 26" barrel in 1:12 twist

Wind was up a little bit so my shots are a little sporadic left and right, but I think there is a clear elevation change as the loads increase.

Shots were fired at 500 yards.

Loads are:
Sierra .308 dia. 175 gr. HPBT MatchKing in Norma Brass and Varget Powder
Load #1 - 40gr - 2465 fps
Load #2 - 40.5gr - 2507 fps
Load #3 - 41gr - 2530 fps
Load #4 - 41.5gr - 2578 fps
Load #5 - 42gr - 2580 fps
Load #6 - 42.5gr - 2634 fps
Load #7 - 43gr - 2675 fps
Load #8 - 43.5gr - 2738 fps
Load #9 - 44gr - 2755 fps
Load #10 - 44.5gr - 2776 fps
Load #11 - 45gr - 2765 fps



Let me know what you think. Thanks.

 

[hondo1312]

I'd run another ladder test from shots 5 through 10, with charges from 41.7 to 44.8, preferably from 100 yds or more farther away from your first one. I've only done one, so hopefully someone else will come in and confirm or tell you not to listen to anything I write

 

[mattwaage1]

7-8-9-10 looks like a good place to start. reload in smaller increments and verify it wasn't a anamoly.

 

[Bob 964]

I agree that your optimal charge weight should lie in the 7-8-9-10 node. I would not recommend using 0.5 grain increments in the .308 --- too large. If I were you, I would repeat the test using the following load weights: 42.8, 43.0, 43.2, 43.4, 43.6, 43.8, 44.0, 44.2, 44.4, and 44.6. Once you find your optimal charge weight, then you can test different seating depths.

 

[rduckwor]

7-8-9-10 charge range. Run an OCW at 100 yds and 0.3Gr increments, three rounds each charge wgt.

That will give you your answer.

Good Luck,

RMD

 

[Yerman]

Thanks for the replies. I was actually thinking of changing over to OCW now that I have a close approximation of the optimal charge weight. The range I go to is usually fairly empty so I can drive down to my target after every shot to mark it, but when people are there, its very difficult and a long process to wait for everyone to finish shooting so I can mark my shots.

What is the main goal of the OCW method? Just shoot different charge weights until I get the tightest group? I need to read up on it a little more.

 

[hondo1312]

You can take a red, blue, and green sharpie and color one bullet with each color, and shoot 4 shots in a ladder at a time instead of running back and forth after each shot...the one you don't color will leave a black hole. Just make sure you keep a note card or something as a legend.

 

[Yerman]

So the color from the sharpie on the bullet comes off as it goes through the paper and leave a colored hole? That is pretty cool.

Does it leave anything behind in the barrel that could foul it up?

 

[trailrider121]

7-8-9-10 charge range. Run an OCW at 100 yds and 0.3Gr increments, three rounds each charge wgt.

That will give you your answer.

Good Luck,

RMD

Same as above, but I would do the ocw at 300 yards min. Gives betters results.

 

[hondo1312]

So the color from the sharpie on the bullet comes off as it goes through the paper and leave a colored hole? That is pretty cool.

Does it leave anything behind in the barrel that could foul it up?

I doubt it. I shot 5 1/2 moa groups at 100, 1 1/4 moa group at 200, 1 1/2 moa group at 400, and a 3/5 moa group at 600 shortly after firing sharpie-colored bullets from my rifle. If you're really worried about it, just color above the ogive so no sharpie color touches the rifling.

All group sizes are estimates from memory; pics can be provided upon request