Todays Test

[arcpest 6]

168gn A-max with TR140 COL 2.200"
41.5gns 2521 fps 1.239"
41.7gns 2488 fps .328"
41.9gns 2514 fps .300"
43.8gns 2666 fps .840"
44.0gns 2692 fps .471"
44.2gns 2717 fps .649"
45.7gns 2798 fps .505"
45.9gns 2802 fps .934"
46.1gns 2850 fps .468"
46.3gns 2827 fps .744"
46.5gns 2843 fps .775"
46.7gns 2841 fps .635"
46.9gns 2855 fps .529"
47.1gns 2861 fps .1.077"
I had another case with a fracture in the base but didn't separate this time.

Rick

[dicehorn 38]

Sorry, but I am assuming a 308.

 

I seem to recall that the purpose of you using a 168 gr A max was to extend your range out to 1000 yds?

 

If so, based on your various powder weights above, by my calculations (BC at .475) in order to keep your bullet above the speed of sound to maintain stability you are going to have to generate at least 2650 fps which from your figures suggests a starting load in the region of around 44 gr. As your above weights vary widely (.2 to over 1 gr) can I suggest perhaps now is the time to do the OCW test using 1/2 gr increments starting at 44 gr going up to 46.5 gr

 

I assume from your other post that the above were at 40 thou back - as they appear to be near the mark as far as an acceptable group is concerned, why not do the OCW test at say 20 thou for comparison purposes with the other targets that you have put together?

 

You state COL at 2.200" ?? seems pretty short for 308 - if I am assuming 308 to be correct

 

Peter

PS I know very little about 1000 yd shooting - my limit is around a paltry 500 yds!

[arcpest 6]

Hi Peter yes its .308 and the oal of 2.200" is with a comparator which is why it seems short.

I have been led to believe that I need to be hitting the 2900fps to be able to keep it above the sound barrier out to 1000 yards

I was going to run last nights test the OCW way but completely forgot once I set the crono up and started shooting so im going to make sure the next test will be run OCW

That was going to be my next test starting at 10 thou off then 15 thou ect.

According to my shooter app if I put in 2692fps which was the speed with 44gns of powder I will still be 1240fps at the 1000 yard mark which is still above the sound barrier.

 

Rick

[dicehorn 38]

AOL - ah that sounds better - you originally put COL !

 

Good luck with the OCW targets - You may want to make your own but if you want the one I made up - here it is

 

<a href="http://s438.photobucket.com/user/wyndog/media/OCWTARGET_zps7d2ab781.png.html" target="_blank"><img src="http://i438.photobucket.com/albums/qq101/wyndog/OCWTARGET_zps7d2ab781.png" border="0" alt=" photo OCWTARGET_zps7d2ab781.png"/></a>

 

If you decide to make your own it really is essential that you include the black lines - as in mine. If you line the black lines up with your crosshairs, it will ensure that you have the rifle in the same position each time ie you will not be canting the rifle which even at 100 yds can alter POI

 

Finally (if you have read and understood the concept of the OCW method) Each target paper with the 6 bulls will have the same distance from the lands - the only difference will be the powder weight for each bull you are firing at - once you find an acceptable group with a given powder that suits the harmonics of the barrel, only then do you alter the lands distance to fine tune the load.

[arcpest 6]

Hi thanks for that I will be using the OCW method when I get some more 155gn Lapua scenars iv already done the calculations for my powder of choice.

 

Rick

[arcpest 6]

Hi iv just loaded up my batch of rounds for my first try at the OCW method test for Wednesday, powder is TR140 bullets are 155gn Lapua scenars.

I will post my results on Wednesday so you can see how I did

 

Rick

[dicehorn 38]

Hi iv just loaded up my batch of rounds for my first try at the OCW method test for Wednesday, powder is TR140 bullets are 155gn Lapua scenars.

I will post my results on Wednesday so you can see how I did

 

Rick

Look forward to that as I have just done a OCW for a friends 308 using 168 gr A Max and N140 - one weight gave a .385" and another .392" so now fine tuning it with the lands distance.

[arcpest 6]

Hi that's a shame I don't have any 168gn A-max left! because I could have run a comparison between the 2 different powders to see how the velocity differs

 

Rick