Can anything be learned from this ladder?

[oldduc]

I have a couple 6XCs I've been shooting for a while but decided I wanted a Dasher. I rebarreled a Savage Model 12 F-Class 6.5-284 to Dasher with a 28", 7 twist, Criterion barrel. Bought hydroformed Lapua brass from Halls LR and fire formed it with cheapo bullets and Varget. Had my gunsmith (Mark Skaggs) bed the action and he recommended I try a load of 32gr of RL15 and 107SMKs. Didn't have time to work up anything else so I shot that for 600yd F-class for a while (avg. 197-9X). I ran out of 107s and since I have 500 Berger 105 Hybrids I looked here and saw what was being done and decided to try RL16 with them. Mulligan, I believe, suggested around 35gr RL16 so I loaded a ladder from 34.4 to 35.6 to see what might work. Its very hard for me to get to the range but today I was able to go shoot. Didn't have time to shoot 600yds and planned on a quick 200yd shoot. Even though it was only 67 degrees the mirage was so bad at 200 I couldn't use much scope power and the apparent target was moving about a half a minute. I brought the target in to 100yds and shot seven 3 shot groups with the 34.4 to 35.6gr RL16. The velocities ranged about 165fps over the loads and some grouped OK, but I'm not sure I really gained any useful info from all this. The barrel has near 300 rounds on it and seems to have settled down, at least. Not sure whether to buy some more 107s or try one of these loads at 600 during a practice match and see how it does. Do any of the RL16 Dasher shooters have any words of wisdom? Here's the target. Same point of aim, no scope changes, almost no vertical climb!? ~Gary

 

[Nature Boy]

In my opinion it looks like 35.0 - 35.2 is the node. Least amount of change in vertical compared to adjacent groups

 

[Boyd L.]

If 34.6 will repeat, it would be my choice at least until I stretched out the distance, which might suggest something else. It appears to have very consistent velocity if I’m reading your target correctly. For me that’s a good place to start.

 

[oldduc]

If 34.6 will repeat, it would be my choice at least until I stretched out the distance, which might suggest something else. It appears to have very consistent velocity if I’m reading your target correctly. For me that’s a good place to start.

Yeah, with a couple of exceptions, the velocities were pretty consistent for the 3 rounds in each group, but the 34.6 stayed together a little better. The velocity is a little slow, but it should work OK for 600yd.

As an aside, that 34.5 group shouldn't really be that bad. Just as I touched the trigger on the second round, some clown who was parked behind the firing line blew his horn and I jerked it.

I was pleased with the consistency of the powder and was really happy at how easy the gun cleaned up. I've read several folks who complained about how dirty RL16 is, but after shooting, it only took about 10 patches, after wet brushing, to get it clean. I've had to use 25-30 patches and brush twice to clean up RL15.

 

[oldduc]

In my opinion it looks like 35.0 - 35.2 is the node. Least amount of change in vertical compared to adjacent groups

Didn't mean to ignore you, got distracted. I agree that the group centers in that node have very similar vertical displacement, but I'm not too sure about the 30fps difference. The lower 34.4 - 34.6 node has a very small velocity difference by comparison, and it's hard to ignore that 0.142" 34.6 group (though that might be shite at 600). I might try both nodes with a seating depth ladder. I've got them just barely kissing the lands right now. Might be another week before I can get to the range again.

 

[Nature Boy]

The whole top row is relatively flat. I’d pick one of those and do a seating depth test

 

[JFrank]

I have a couple 6XCs I've been shooting for a while but decided I wanted a Dasher. I rebarreled a Savage Model 12 F-Class 6.5-284 to Dasher with a 28", 7 twist, Criterion barrel. Bought hydroformed Lapua brass from Halls LR and fire formed it with cheapo bullets and Varget. Had my gunsmith (Mark Skaggs) bed the action and he recommended I try a load of 32gr of RL15 and 107SMKs. Didn't have time to work up anything else so I shot that for 600yd F-class for a while (avg. 197-9X). I ran out of 107s and since I have 500 Berger 105 Hybrids I looked here and saw what was being done and decided to try RL16 with them. Mulligan, I believe, suggested around 35gr RL16 so I loaded a ladder from 34.4 to 35.6 to see what might work. Its very hard for me to get to the range but today I was able to go shoot. Didn't have time to shoot 600yds and planned on a quick 200yd shoot. Even though it was only 67 degrees the mirage was so bad at 200 I couldn't use much scope power and the apparent target was moving about a half a minute. I brought the target in to 100yds and shot seven 3 shot groups with the 34.4 to 35.6gr RL16. The velocities ranged about 165fps over the loads and some grouped OK, but I'm not sure I really gained any useful info from all this. The barrel has near 300 rounds on it and seems to have settled down, at least. Not sure whether to buy some more 107s or try one of these loads at 600 during a practice match and see how it does. Do any of the RL16 Dasher shooters have any words of wisdom? Here's the target. Same point of aim, no scope changes, almost no vertical climb!? ~Gary
View attachment 1070149

34.8 would be a place I'd look

 

[oldduc]

34.8 would be a place I'd look

It's pretty flat alright. If I get a chance to play with the seating depths, I'm beginning to think that maybe any of the top row loads can be made to shoot. I'm shooting a 600yd practice match tomorrow so I need to load up s bunch of one of these today. I usually use my LabRadar during the matches and that will help me see/compare how consistent the velocities are and how they compare to the target.
Just goes to show how inadequate 100 yard testing is for 600 yard shooting, I guess.

 

[JFrank]

It's pretty flat alright. If I get a chance to play with the seating depths, I'm beginning to think that maybe any of the top row loads can be made to shoot. I'm shooting a 600yd practice match tomorrow so I need to load up s bunch of one of these today. I usually use my LabRadar during the matches and that will help me see/compare how consistent the velocities are and how they compare to the target.
Just goes to show how inadequate 100 yard testing is for 600 yard shooting, I guess.

I'll take flat anyday

 

[Nature Boy]

Just goes to show how inadequate 100 yard testing is for 600 yard shooting, I guess.

I think it’s working pretty good for you. You’re looking at the batter in the pan and judging the cake before it’s baked

 

[oldduc]

34.8 would be a place I'd look

Well, I kinda chickened out and loaded the 34.6 "small group" load and shot a 600yd practice match this morning. Temp was 60ish with bright sun and the mirage was really bad with switching wind at 6-8mph. Shot a 198, but only 5 Xs. Ragglely looking "group". By the second relay, the air had warmed up and the mirage was better and the guy I was pulling target for shot 200-10x. I think I will try the 34.8 as suggested and play with the seating depth.