Looking for opinions reading a ladder test

[KevinBaker]

I've been trying to diagnose some issues concerning inconsistencies with my F/TR results for the last few months, which may be me, the load, my equipment.....etc. I decided to shoot this ladder test today which would cover the charge that I've been running. This is a 185 Juggernaut along with Varget, Lapua Palma brass, and a Federal 205 primer. For test purposes, they were all loaded .015" jumped. The lower results were shot lowest to highest charge, and the upper was shot the opposite with cool down period in between.

Thoughts?

 

[Dos XX]

What distance was that shot at? It looks like 44.5 and 44.7 might be something. Any velocity info?

In general, a 185 Juggernaut at approx 2750 fps and somewhere between .010 and .020 off will usually shoot. I was usually at .020 off.

 

[KevinBaker]

What distance was that shot at? It looks like 44.5 and 44.7 might be something. Any velocity info?

In general, a 185 Juggernaut at approx 2750 fps and somewhere between .010 and .020 off will usually shoot. I was usually at .020 off.

Sorry, i forgot to include that.....It was shot at 600 yards. I chrono'd this charge span back in June, and I ended up using 44.8 at an average of 2764 fps. That being said, this ladder test backs that data up. This load however, has been inconsistent for me. Sometimes it's good, and others it opens up with shots way out of the group (vertical).

I'm trying to eliminate one thing at a time, but i keep coming back to my bipod. It's a Duplin, and i had a really hard time holding elevation with it last weekend. It has some "slop" in the elevation adjustment that i've learned when adjusting should come down below desired point of aim, and then back up to hold tension on it. I swear it's moving during my string though.

 

[GlennK]

Eliminate the uncertainty of the bipod and repeat ladder....see if it duplicates. Or increase distance and magnify the spread....Just my opinion

 

[Dos XX]

Can you try a front rest to eliminate the bipod variable? At the least, try a different bipod?

 

[lawman29]

Do you have a portable wind flag (the small bench rest type)? The top target looks like a left-right wind came up. I've had that happen with a ladder test due to impatience (see photo.....) As Dos XX stated use a regular front rest to eliminate variables... You just want to test the load.

 

[dirtworks5]

Not always but most generally vertical will come from the operator of the trigger!
Happy Shooting
Vern

 

[6BRinNZ]

I'm not sure about the primer but varget is a common powder for that combination.
What verification do you use for seating depth? I have had a load go from inconsistent to hammering just by relooking at seating depth.

 

[KevinBaker]

Thanks for the replies. I do have a backup bipod that I can use to repeat the test with. I will usually test for seating depth using the same methods as the ladder test. It seems that this bullet isn't very picky to seating though, so I'll try the bipod first and see what happens.

lawman29, I was under the impression that when shooting a ladder test that you need not worry about using wind flags because you are trying to find the node based on the tightest vertical grouping?

Thanks again for all of the replies.

 

[jsthntn247]

That's very little vertical across the entire powder charge at 600 for a 308 off a bipod. I'd take 44.8 and shoot 5 shot groups at 5, 10, and .015 off at 600 yards. I'd take the best seating depth of those and shoot 44.5, 44.8, and 45.1 and see which powder charge shot best. Try and shoot them at daylight when the wind is lowest.

 

[lawman29]

when shooting a ladder test that you need not worry about using wind flags because you are trying to find the node based on the tightest vertical grouping?

Kevin there is a vertical component for wind effects (no matter the direction), so subtle changes in wind direction can effect your results. Also, you mentioned letting the barrel cool down between the two tests, don't need to do that. When I go to the range to test, I first shoot several rounds to warm the barrel up and foul if it is clean.

 

[seymour fish]

Kevin there is a vertical component for wind effects (no matter the direction), so subtle changes in wind direction can effect your results. Also, you mentioned letting the barrel cool down between the two tests, don't need to do that. When I go to the range to test, I first shoot several rounds to warm the barrel up and foul if it is clean.

Decent mid to upper 44 range. Seating depth brings it in, or go to H 4895