First Ladder test results. 7RM IMR-4350 A-Max 162

[AJ Peacock]

Well, Although the wind was horrible (0-10mph from the left right, downrange and uprange). But I did the ladder anyway, figuring I was already at the range. It was 26 degrees and a foot of snow that I had to trudge through since I couldn't drive to the 200yd targets. While I was at the range, I didn't think I had any good data, since it seemed the shots were all over (shooting 5 different targets, so I wouldn't have to walk down and back so many times to mark the shots).

Range was only 200yds, but I think I got some good data anyway. Here is a picture/graph that tells the whole story.
I decided that a good way to look at the data would be to plot the velocity spread as well as the Vertical spread for every 3 shot string. For example the spread between shot #1 and #2 was added to the spread between shot #2 and #3. That is the spread that was graphed for shot #2.



I ignored the horizontal spread due to the poor conditions.

edited to add : Shot #2 closed tight so I removed it and it had land marks on it. So it was seated a little long which probably explains its higher velocity as well as its higher vertical spread.

Comments?

Don

 

[papa45]

I presume you fired 15 rounds total. I also presume your "vertical spread" means point of impact for each shot relative to the same point of aim. If that is the case, then you seem to have a node point between shots 7, 8 and 9, which would be your sweet spot.

 

[AJ Peacock]

[ QUOTE ]
I presume you fired 15 rounds total. I also presume your "vertical spread" means point of impact for each shot relative to the same point of aim. If that is the case, then you seem to have a node point between shots 7, 8 and 9, which would be your sweet spot.

[/ QUOTE ]

You presume correctly with regard to the vertical spread measurement.

Actually, 17 shots to give me 15 data points for the spreads. I'll probably look into a node around 12-13 as well, as 12-13-14 basically hit VERY close to each other (.3MOA vertical spread), even though 14 jumped up in velocity a bunch which made the upper graph look bad.

My measured velocities were quite a bit lower than what was listed in the manuals, but I'm sure the 26 degree temperature had something to do with that. I also left the rifle and ammo out for 2 hours prior to going to the range, so everything would be consistent start to finish.

Shot #0 velocity was 2612 Shot #16 velocity was 2855

Also, since #6 was against the lands, I'll probably try the next loads .001" deeper so all the loads will definitely be off the lands. These loads were probably nearly touching the lands, which I've read is not the 'best' place to be, due to the exact problem I experienced.

Don

 

[Blacktail2]

The node I see when looking at the data is 4-5-6.The reason for this is an E.S. of 23 between the 3 shots.I would load up 57.3grs and give that a try.

 

[AJ Peacock]

[ QUOTE ]
The node I see when looking at the data is 4-5-6.The reason for this is an E.S. of 23 between the 3 shots.I would load up 57.3grs and give that a try.

[/ QUOTE ]

Yes, you are right. That is the node I was looking at. I think there may be a second around 13.

Don