New barrel installed

[sako6br]

Finally after a year and a half of waiting and procrastinating I got around to installing my new barrel. This barrel is 6" longer and has a 1:10 tw vs a 1:12 tw.
It is a 6mm, 4 groove cut rifled MacLennan.
Because I used my own reamer I was able to duplicate the exact same chamber as the old barrel and thus was able utilize some loads from last year as well as some new loads that were loaded this morning.
I looked into this Ladder testing which has been mentioned here a few times so I loaded 3 loads varying the powder charge 0.5gr for ea. (29.5, 30.0 & 30.5)
Because 30gr & a 75gr V-max was my pet load from last year, I wanted to stay around that.
So the target was posted at 150 yds (my range length) and I sighted in with some old rounds from last year. For this exercise I paid no attention to the breeze which was about 5mph and I alternated through each group one shot at a time.
So as we can easily see... my pet load from the old barrel is still king.

The lower group is from leftover old rounds from last year. Two were 75 gr V-max and the third was a Berger 68gr. (all with 30 gr H4895)

Next, I need to find a load for some 90gr. Scenar bullets as well as trying some 87gr V-max for that ground hog that's waaaaay out there.

 

[Obtunded]

If you have the facilities, ladder testing works better at distances of 300M or greater, and load in .1 grain increments. I don't have much experience with 75 grain bullets, but a .5 grain jump can miss an accurate node entirely with 105's (and most other cartridges with less than 40 grain charges)

I discussed this with Jerry Teo once and he uses to rounds per charge and I like that idea.

Your gun shows real promise

 

[mmattockx]

Jerry's article on his version of ladder testing:

http://www.longrangehunting.com/articles/reloading-load-tuning-1.php

Mark

 

[sako6br]

In other words, I should try another test. One at 29.8gr, 30.0 & 30.2gr. After that, a third test with 0.1gr intervals.
Sound right?

 

[sako6br]

After reading that article by Jerry Teo I noticed the center (30.0gr) is rotated clocwise slightly. The others are almost exactly 1" left and 1" high.
Do not include the lower group in this test.

 

[mmattockx]

In other words, I should try another test. One at 29.8gr, 30.0 & 30.2gr. After that, a third test with 0.1gr intervals.
Sound right?

I am no expert on ladder testing, but from Jerry's article, I would say that is where he would go to nail down the node. I think the 0.2gr increments would be fine enough to find the sweet spot.

Mark