ladder test, strange results?

[jmtyndall]

The upward stringing is what should be there, but what's with all the stringing up to the right. This was shot at 300 with bipod and rear bag. Thinking that those 155's look awful good. Gonna focus my next tests in the 45.5-47.0gr range with the 155's. Considering that weight range grouped a hair under 2".

I can post chrono data in the morning, I took all the info down today.

I'm shooting a savage 10, with a super sniper 16x, with burris rings and mounts, factory tupperware stock. When I just shoot (not workup) it doesn't do this so I don't think it's barrel heating. Wind was 3-5mph to the right with berms on the sides of the range, so essentially nothing. I checked all the rings and mounts, they were tight, but I gave em a little more torque just in case there was an issue there. Any ideas? Do I just have a strange gun? haha

Edit:
Not sure if it's helpful, but here's chrono data. Temp was about 45-50* with some cloud cover. Chrono 7-10yards from the muzzle

175SMK:
42.0-2530
42.5-2583
43.0-2594
43.5-2635
44.0-2704
44.5-2699
45.0-2737
45.5-2721
46.0-2760
46.5-2777
Didn't have any real pressure signs, but decided it would be prudent to stop there.

155SMK:
44.0-2699
44.5-2695
45.0-2743
45.5-2789
46.0-2818
46.5-2842
47.0-2842 (I suspect this is a bad reading, but chrono was flashing duplicate, so I wrote it)
47.5-2892
48.0-2917
48.5-2920
Again, not real pressure signs, but decided it would be a good idea to stop here

155 Scenar H4895:
43.0-2789
43.5-2825
44.0-4861
44.5-2879
45.0-4892
45.5-2917
46.0-2930
Here I got a bolt lift that was noticeably heavy. Primers were a little flat, but nothing extreme, either way, I stopped the ladder test there, as it was a sign I was getting into toasty loads, and I like my hands and face the way they are.

 

[XTR]

Re: ladder test, strange results?

There is no rule that says your barrel's resonance has to be up and down.

I shot a test lot of 150 GMX bullets last week that shot a full 2" right of my Sierra Pro Hunters in my hunting 308. I'm sure it was something similar.

That or there is something loose.

 

[jmtyndall]

Re: ladder test, strange results?

So you think I should move on to the next step and compare the bullet impacts with the least direct vertical spread?

Now that I've mad sure everything's tight, run from a ladder in .3gr increments across what appears to be nodes now, to confirm the ladders?

 

[badbot]

Re: ladder test, strange results?

since it is a savage loosen the barrel nut and rotate the barrel 45 degrees counter clockwise. re do test and report results

 

[jmtyndall]

Re: ladder test, strange results?

Can't decide if that was a joke or not.

Would be an interesting idea if it worked or I had any headspace to play with. I'm pretty much at the minimum so that's out.

I have a 3rd ladder from 155 scenars, but my camera died, so I can't tell the order they hit, however it shows trending up and right also. I'm thinking a loose anything would produce a more random dispersion. Barrel heating may have been an issue, but I checked the video and the closest two shots were 45 seconds apart, most were about a minute and some change, so I don't think that's an issue.

I'm going to load up 175s from 43.2-45.3gr and then some 155's from 45.2-47.3, that should take me outside of what appears to be the nodes. Also going to load up 10 sighters/foulers square in the middle of those windows, and try to keep the time between shots to about 30 seconds. I'll record it again, and see if I get the same trend.

 

[vman]

Re: ladder test, strange results?

If your ladder results are confusing you, but you have chrony results to go with it, investigate the regions that have similar muzzle velocities.

With the 175 SMK look between 44.0 to 45.5. Maybe load up at smaller increments and try an OCW group test at 200-300 yards.

Im not familiar with using H4895, so I wont comment on the 155 results. If you used the same powder for both i find it odd that the sierra and lapuas showed very different pressure signs.

 

[Nefariousd]

Re: ladder test, strange results?

FWIW I think you need to shoot farther. My savage 308 at 300 stacks in 3-4 Grains (yes grains)in like 12-14 inches at most, so it's not as easy to discern trends. When I push out over 500 it becomes pretty clear where the nodes are.

What is the barrel length 24 or 26?

 

[jmtyndall]

Re: ladder test, strange results?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: vman</div><div class="ubbcode-body">If your ladder results are confusing you, but you have chrony results to go with it, investigate the regions that have similar muzzle velocities.

With the 175 SMK look between 44.0 to 45.5. Maybe load up at smaller increments and try an OCW group test at 200-300 yards.

Im not familiar with using H4895, so I wont comment on the 155 results. If you used the same powder for both i find it odd that the sierra and lapuas showed very different pressure signs.
</div></div>
I may add an additional load to the 175s second test to catch the 45.5gr load, since I currently loaded 43.2-45.3 by .3gr increments.

Should I focus on the one with more vertical, or be more concerned with the muzzle velocities?

The Sierra 155 was shot with Varget. The Lapuas were the only ones shot with H4895, and showed significantly higher velocity. I suspect if I went a half grain higher with the Sierra's I'd get the same sticky bolt lift.


<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Nefariousd</div><div class="ubbcode-body">FWIW I think you need to shoot farther. My savage 308 at 300 stacks in 3-4 Grains (yes grains)in like 12-14 inches at most, so it's not as easy to discern trends. When I push out over 500 it becomes pretty clear where the nodes are.

What is the barrel length 24 or 26?

</div></div>
Shooting a 24" barrel. I wish mine would have spread 14". The 175's covered 4.5grains in the test, and I'm looking at 6" dead vertical, 10 inches measured down the angle. The problem with going further is that my local range only goes to 300, except when a group rents the 1000 range. When they shoot, they don't have enough time for me to get a whole ladder off before they move to a further distance.

 

[vman]

Re: ladder test, strange results?

300 yards should be ok... Just make sure your bench set up is rock solid and/or your shooting form and poa is the same with every shot.

If you have the tools, or have a friend that does, check the runout on your loaded rounds as that can be a cause for fliers, scattering and general confusion... but this may not be the case always

Try using varget with the scenars, you will be suprised.

Im currently on 46.3gr Varget and had 3 shots go through one ragged hole at 300 yards the other day. As always theres a flier that f***s my shit up and the group went to 3 inches. BAH! Mind you i dont weigh my cases, projectiles or check for run out. Chances are if i did all of this that group would have been much nicer.

If the ladder is confusing you, take a small test group of a few different charge weights and shoot groups at 300 with them. Chances are the one that produces muzzle velocities with the least SD and ES will rounds showing in the same horizontal plane... ie, wind may push them side to side, but they will either form a tiny group, or form a line running horizontal.

If you have the bullets hitting and scattering upwards, this is indicative of inconsitent muzzle velocity therefore the different speeds place them at different heights.

As stated before, the more range you can do this the more obvious the results become.

 

[jmtyndall]

Re: ladder test, strange results?

I had a buddy check a couple rounds. One had zero runout, and two others had around .001 it looked like. He said it was less, but idk how to read the damn gauge haha.

That's another thing I didn't do, weigh cases, measure bearing blah blah. I just can't shoot that well yet. If todays ladder is not more revealing than the last one, I will just pick a few rounds in the areas that look good and OCW them over a chrono. Should I do that at 100 or 300?

I'm wondering if my shooting form had something to do with this. The rifle was pretty much level, but I wasn't preloading the bipod like I usually do. just had 3 sandbags on the rifle to keep it pointed at POA. Then once I had it sitting and pointed right, I was just the trigger on it.

 

[TORCHRIDER]

Re: ladder test, strange results?

Sandbags on the rifle? Where exactly? Don't put any pressure on the barrel as that will cause all sorts of issues. Are you shooting from a bi-pod because that is how you intend to shoot the gun? Otherwise I have always gotten my best groups by shooting off a rest and bag. If shooting off a bipod, you may want to stick a frisbee under it so the bipod can move freely instead of catching on the bench.

 

[vman]

Re: ladder test, strange results?

To clear things up, if your shooting form is not solid, your results may not be solid either.

You want as little (none at all) shooter error as possible. Any error that might change the impact of the bullet is a no no.

If your intending to use this rifle with a bipod I recomend using that. Sit straight behind the rifle, exactly behind it, read up on natural point of aim and get that sorted, shoulder the rifle the same each time and load the bipod. Keep a sandbag on the rear and make sure your aiming exactly at the same point of aim every time. Lastly, gently squeeze the trigger every time.

Any errors you add just make the results confusing and you might miss a node due to one or two bad consecutive shots.

300 yards is better than 100. At 100 yards the differences in drop arent all that apparent, but 300, they show up a little more.

 

[jmtyndall]

Re: ladder test, strange results?

That's how I shot this. Two bags under the butt of the rifle(I got too tall of a bipod, and one behind it to keep it all settled. Didn't load the bipod though.

I do intend to shoot from a bipod. Each shot I looked through the scope to insure the POA was where I intended, if it wasn't, I moved the rifle and bags until it was. The only part of the rifle I touched was the stock with my cheek to make sure the POA was still good, and the trigger. The rest was MUCH more solid that I am.