ladder test results, need opinions

[SICARIO]

So I did my first ladder test.

Bullet:178gr hornady BTHP
Powder: Re15, 35-44 gr in 1gr increments.
Primer: CCI
Distance: 100yrds

Everything was fired at the middle, where the two pages meet. From what I can see, 37gr is a good place to focus on. 43 and 44 gr caused my bolt to not lock back, so I'll probably stay 42 and under.

Am I on the right track?

 

[30SMK]

Re: ladder test results, need opinions

Ok well I would would say that for a more accurate ladder test you should probably move out further than 100 yards. I do most of mine at 300 yards and if I had 600 at my daily disposal I would do it at that. I would also go with smaller increments than 1 gr steps. I usually do 1/2 gr increments and then fine tune from there. Honestly you should be seeing better grouping at your accuracy nodes than what you are showing. I usually shoot 20 rounds over a 10 grain spread and in that I will typically find 2-3 accuracy nodes where I have at least 3 shots **clustering together**.

What type of rifle are you shooting?

I would say that you should stay away from any loads that cause you bolt to stick too bad or show other pressure signs.

 

[SICARIO]

Re: ladder test results, need opinions

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 30SMK</div><div class="ubbcode-body">Ok well I would would say that for a more accurate ladder test you should probably move out further than 100 yards. I do most of mine at 300 yards and if I had 600 at my daily disposal I would do it at that. I would also go with smaller increments than 1 gr steps. I usually do 1/2 gr increments and then fine tune from there. Honestly you should be seeing better grouping at your accuracy nodes than what you are showing. I usually shoot 20 rounds over a 10 grain spread and in that I will typically find 2-3 accuracy nodes where I have at least 3 shots keyholing.

What type of rifle are you shooting?

I would say that you should stay away from any loads that cause you bolt to stick too bad or show other pressure signs.
</div></div>

Thanks for the info.

The rifle is a Mega Maten w/ a Fulton 18.5" chrome lined barrel.

As far as the distance goes, I only have 100yrds readily available.

I purposefully shot some of the rounds to the left or right so it would be easy to see where it hit.

There weren't any pressure signs, but I was shooting with an empty mag, so the bolt locked back after each shot, but the 43 and 44 gr shot didn't lock back (not sure what that indicates).

Should I do another ladder test with a smaller increment of powder differences?

 

[2clicks]

Re: ladder test results, need opinions

100 yrds is a little short for a ladder test imho. At 600 the accuracy window becomes very clear and the windage is a not a contributing factor. Hope you can find a longer test range to benefit your efforts.

 

[NoFail]

Re: ladder test results, need opinions

If you only have 100 yards then you should use the OCW method to find your nodes, IMO. Works for me.

http://optimalchargeweight.embarqspace.com/

 

[trailrider121]

Re: ladder test results, need opinions

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: NoFail</div><div class="ubbcode-body">If you only have 100 yards then you should use the OCW method to find your nodes, IMO. Works for me.

http://optimalchargeweight.embarqspace.com/ </div></div>

+1 for above.

 

[Teggy1]

Re: ladder test results, need opinions

NoFail is right, OCW, and use smaller charge increments. 300 really is the min. IMHO for ladder test. I think 30SMK means clustering, not keyholing for the accuracy nodes. Keyholing generally referred to as the bullet hitting the target sideways.

 

[Deadshot2]

Re: ladder test results, need opinions

I may be FOS but aren't 39 and 40 darn near at the same level vertically?

When I see this I usually work my loads around this type of grouping. I'd be inclined to try a spread of loads starting at 39 and ending at 40 using small increments like .2 or .3 gr. You might also find something interesting around 44 gr.

Notice how those three loads deliver the bullet to almost the same vertical point.

I agree with those that suggest longer distances for ladder tests but if this were one of my load developments I would be real interested in the three charge wieghts I mentioned.

FWIW, my rifle shoots the lights out with 41 gr RL-15 using the same bullet but that's in a bolt action.

 

[jbailey]

Re: ladder test results, need opinions

How does this rifle shoot groups at 100yds? Reason I'm asking is because the photo has a TON of scatter in it, MUCH MUCH more than I would expect at 100yds even across the range of charge weights tested, indicating that there is potentially a problem somewhere else in the system. You need to be able to shoot 0.50moa at or better at 100yds before than of this other stuff matters.

I have done 100yd ladder tests just to see what was up and the bullets were all going into, or very close to, the same hole.

 

[SICARIO]

Re: ladder test results, need opinions

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: JamesBailey</div><div class="ubbcode-body">How does this rifle shoot groups at 100yds? Reason I'm asking is because the photo has a TON of scatter in it, MUCH MUCH more than I would expect at 100yds even across the range of charge weights tested, indicating that there is potentially a problem somewhere else in the system. You need to be able to shoot 0.50moa at or better at 100yds before than of this other stuff matters.

I have done 100yd ladder tests just to see what was up and the bullets were all going into, or very close to, the same hole. </div></div>

The left to right was done on purpose since there would be a bit of overlap otherwise. I shoot MOA or Sub MOA with my 168gr amax at the same distance.

I guess my understanding of a ladder test is that rounds that hit higher are leaving the barrel when it's at it's peak oscillation, and therefore most consistent. There does seem to be a significant difference between 36-38 gr. though.

My plan was to do a large variation to hone in on a more specific area, and then .2 or .1 gr increments in either direction of the higher shot. I may be way off, but that was my understanding.

 

[jbailey]

Re: ladder test results, need opinions

Yes, your thinking on ladder test is correct, but it is VERY strange that oscillations would cause 3" of vertical dispersion at 100. At 300yds yes, but no way at 100.

I would redo, using the OCW method as linked above. Hopefully this improve the results AND give you better data to make load decision on.