Ladder Testing and Loads

[coues7]

I've gotten everything loaded up to do a ladder test and wanted to get some input before I proceed. I'm shooting a GAP 300WM 1:10 twist 26" Bartlein Barrel using 190gr SMK's. I've loaded up 10 rounds of each of the following loads using RL22:

72.2gr
72.5gr
72.8gr
73.0gr
73.2gr
73.4gr
73.6gr

I'm using Redding Type-s bushing dies with the 0.335 bushing. My reasoning was two 5 shot groups to verify each load. Have I loaded to much? Am I headed in the right direction?

Thanks,

Scott

 

[Bugholes]

Re: Ladder Testing and Loads

I would load 3 or 4 of each charge only. If you load at home, its better to have an extra round when youre testing. You might need to clean the barrel between groups and need a fouler round or you could double with another shooter, pull a shot, whatever. Better off to take the press to the range, load two rounds at a time and shoot. if the holes arent touching (or pretty close to it) then just keep moving along through your testing

 

[ChadTRG42]

Re: Ladder Testing and Loads

That's a lot of ammo to test, but you'll be fine. You will need to watch for pressure somewhere just above 73 grains. I'd shoot 1 group of each charge, and see what you get, and keep the other group as a back up. What brass are you running? If it's Win or Nosler, then these charges are ok. If it's RWS or a mil spec case, it will fine pressure sooner. You should now how it shoots within 3 rounds. The rest, just pull the bullets and reuse.

 

[Swan]

Re: Ladder Testing and Loads

Ignore the ladder test BS. Just throw some paper up at 300yds, maybe 400yds, and shoot some 5rd groups of each charge. You will be done in an hour and know exactly what your gun likes.

Ladder tests are for the overly bored and confirm nothing a good OCW can't do in less time and energy.

 

[coues7]

Re: Ladder Testing and Loads

Chad,

I'm using once fired Federal cases from the original FGMM I shot. I know it's not the best but I had them on hand.

Swan,

I guess I may be a little confused between the OCW and the ladder. Either way I need to get this custom gun to shoot!

 

[vman]

Re: Ladder Testing and Loads

coues7, sounds like your good to go BUT yeh you loaded way too much.

Have you already confirmed your rifles max?

If not, not to worry.

I would do the following.

1) set up target at 300 yards
2) use a few 72.2grainers to get you on paper at that distance.
3) begin by firing 1 shot from each load at the SAME POINT OF AIM on the bottom of target. Take notes as you go along observes point of impact and pressure signs
4) when you find your node(s) your good to go.

you have what I consider, small increments in powder charges so you should get yourself right on that node, compared to those using 0.5gr increments.

Remember, a ladder test is not concerned with horizontal spread, only vertical.

You could go out and shoot groups, but groups are not what your after. Your concern is finding the most consistant load with the least amount of vertical spread and the least amount of muzzle velocity variation.

The ladder test is simple and helps to determine one of the "easier" variables to deal with in long range shooting, which is bullet drop.

Its a shame wind isnt as easy to deal with!

 

[Headgear]

Re: Ladder Testing and Loads

When you do the ladder test, do you shoot one round of each charge at a different target and then go back through for the second round at each target and so on? Or do you shoot all of the rounds of a certain charge and then move on to the next charge and shoot all of them? I've read pros and cons of doing both ways

I have never had much luck doing ladder tests either round robin or shooting all at once. It was interesting to me that such a little change in the charge could have such a big impact on vertical POI, but other than that I haven't ever seen big dramatic grouping effects. If memory serves, are you not looking for about three charges that give you a group that is as close together to each other than all of the rest? If that is the case, I always had a hard time picking out those three.

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Remember, a ladder test is not concerned with horizontal spread, only vertical.</div></div>

Why only vertical? I thought that in doing a ladder test you are trying to determine the charge that allows the bullet to leave the crown at exactly the same time that the shock wave, vibration is back at the receiver end of the barrel so it can not disturb the bullet as much as it exits the barrel? If that is true, could it not have as much effect horizontally as vertically?

I've read so much about doing these accuracy tests I can't keep it all straight but I don't remember hearing that the only effect that you would be concerned with is vertical. I am not trying to be a jerk, I am pretty new to all of this and I want to understand.

 

[coues7]

Re: Ladder Testing and Loads

In reality I guess I'm confused between OCW and ladder....and my 35p won't be here until Christmas.

 

[SPAK]

Re: Ladder Testing and Loads

OCW is really 3 ladder tests done in one shooting session if that makes sense. Only it was designed to be done at short range and without the necessity of a chronograph. It works by isolating a series of charges that produce a similar poi on the target. Not necessarily the smallest group.

here's a link to what OCW is. It will probably explain it better than I will: http://optimalchargeweight.embarqspace.com/

I like to run a pressure test and my ladder test simultaneously at 330 yards (Furthest I can go at local range). Note where I find my pressure signs and where my "probable" accuracy nodes are. Then I'll run an OCW test at 100 yards with those charges of the accuracy node to confirm. All my shots are over a chrony. Might be overkill, but it works for me.

There is the variable of chronograph error, so really my deciding factor is how they shoot down range...Having said that, your oehler 35p is probably the best one out there to have.

In the end I can take a charge in my accuracy node usually + or - .2gr and still group within 1 MOA.

 

[ChadTRG42]

Re: Ladder Testing and Loads

There's 3 methods out there for developing a load:

1) standard ladder test- load 4 or 5 rounds of the same charge weight, and increase the charge weight slightly for each of the following groups, until you find a sweet spot or reach max pressure.

2) OCW- or optical charge weight.

3) revised method of a ladder test with 1 round at a given charge weight, and increasing the charge by a small amount 1 round at a time.

I use the tried and true #1 method, since you can complete this in 1 range session. With a little research, you can figure out where you need to start, and usually end to find a good load.

 

[Supersubes]

Re: Ladder Testing and Loads

I think three is sufficient for each charge weight. Shooting round robin is the only way to account for varying barrel heat and shooter induced errors.

I also shoot over a chrono. It is amazing how such wide range of charge weights have the same poi. With my .308, .260, and 6.5l, the node ended up being about a grain. I shoot at 530 yards for the test. I throw charges from the measure now...trying to hold .1 grain charge variances is such a huge waste of time.

 

[vman]

Re: Ladder Testing and Loads

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Headgear</div><div class="ubbcode-body">

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Remember, a ladder test is not concerned with horizontal spread, only vertical.</div></div>

Why only vertical? I thought that in doing a ladder test you are trying to determine the charge that allows the bullet to leave the crown at exactly the same time that the shock wave, vibration is back at the receiver end of the barrel so it can not disturb the bullet as much as it exits the barrel? If that is true, could it not have as much effect horizontally as vertically?

</div></div>

The vertical component relates the optimal pressure and harmonics which is what the ladder test aims to confirm. Note, that loads in a node should have the least amount of muzzle velocity variation and MV is what is the main factor is concerning vertical variation. Its the factor that we can aim to control the most.

The horizontal component that is of the main concern to shooters is wind. There are others such as spin drift etc, but these variables tend to be measurable and easily defined.

Therefore when you perform a ladder test, if two shots have similar vertical, but a few inches apart in horizontal you disregard this, as this is wind, a component which has nothing to do with muzzle velocity.

 

[Headgear]

Re: Ladder Testing and Loads

Thanks Vman. Sorry to the OP, I didn't mean to ask so many on your thread. I get carried away.

 

[jmtyndall]

Re: Ladder Testing and Loads

I know some people say the ladder test isn't statistically valid, but if you follow the method laid out in the sticky's here, then it is still less rounds than OCW and gets the same results. The first ladder gives you a node, you run the second ladder to confirm results from the first, then you run 5 round groups. You pretty much triple test the node to ensure it's the right load range.

 

[Alan Griffith]

Re: Ladder Testing and Loads

I've been using ladders to develop loads for about a decade. Absolutely love it. It got even better when I discovered Jason Baney's article over on 6mmbr.com

http://www.6mmbr.com/laddertest.html

The following is a step by step I put together to develop my 130 Berger VLD load for my Surgeon in 6.5x47 L.

LR Ladder
Stage 1: Establish Maximum Pressure like a Ladder @ practical distance of 100 - 500 yds (10-rds)
1. Fireform new brass in 1% increments/.4 gr increases
2. Color code bullets w/ Red/Green/Blue/Black
3. Foulers/sighters are loaded @ lowest charge
4. Spot initial rounds if possible via spotting scope

Stage 2: Define Accuracy Window
1. Fired @ 300-500+ yds
2. Work from max downward
3. .3 gr incremental increase
4. Load 3 shots each, 6-10 charges, and shoot Round Robin (30-rds)
5. Color code bullet ogives
6. Shoot up, down, up
7. Load/shoot 10 sighter/folulers


Seating depth test
1. Load 3 shots for each seating depth of something chosen from Accuracy window and shoot (15 rds)
2. Shoot 3 shot groups, Round Robin, on different aim points
3. 300-500 yds


Stage 3: Confirm best load
1. Load and shoot 3 shot groups, Round Robin, (15 record shots)
2. .2 gr increments
3. Color code bullet ogives
4. Start .1 gr below and .1 gr above Accuracy Window
5. 300-500 yds


Stage 4: Fine-tune variables
1. Load and shoot 3-round Ladders, tuning seating depth, primers, neck tension
2. 1000 yds

This is my 1000 yd ladder, 5-shots each powder charge, .2 gr increase. It's not dark enough to see the colors but they are there.

In 70-100 rds I had my load for my 6.5x47. I've been shooting it for about 10 months now. When I ran out of my 8 lb jug of H4350 and started a new one, I contacted Hodgdon with both lot #'s and the advised on how much I would need to increase my powder charge to equal the old lot. All I had to do was play a little bit with the powder charge, increasing it .55 gr and my accuracy, ES and SD came right back with an added bonus of 60 fps extra. This with .079" throat loss with 900+ rounds down the tube, not cleaning the barrel in over 700+ rounds. Accuracy is still 3/4 MOA and better with single digit SD's.

Alan

 

[coues7]

Re: Ladder Testing and Loads

GSSP, you got me kinda of confused. On Stage 2, since you said start with max in step 2 did you mean decrease by 0.3gr increments? Can you explain Stage 2 a little more.....you got a lot going on there.

 

[Alan Griffith]

Re: Ladder Testing and Loads

Coues7,

It's been 10 months since I put this thing together. Please, try reading Jason's article and you might see what I was trying to say. If not, ask again, and I'll see if I can answer your question.

Alan

 

[cali_tz]

Re: Ladder Testing and Loads

I started working with the ladder concept, and instead I found it's much easier to shoot groups at different targets on the same paper, logging velocities from the chron. The problem I found is that too many of the bullets are clumping together on the 'ladder' and it gets to be a mess. Large paper targets that have 4 'zeros' on one 14x14 inch piece of paper seem to be a far more useful way of finding the right load.

BTW, this whole harmonic node concept is interesting. I haven't yet read an explanation of just where in the barrel mechanical vibration is this mythical node. If the barrel is in constant motion, which it would absolutely be until some short time after the bullet leaves the barrel, then where is the 'node' ? I suspect there is a magical combo of powder, bullet, seating depth, primer that performs best for each instantiation of a rifle make. But the solid technical reasons for that I still have not seen.

 

[Alan Griffith]

Re: Ladder Testing and Loads

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: cali_tz</div><div class="ubbcode-body">The problem I found is that too many of the bullets are clumping together on the 'ladder' and it gets to be a mess. </div></div>

Two things:

1. Shoot further away so the "mess" spreads out a bit.

2. Mark the bullet ogives with different colored permanent marks so it will leave a colored rings on the bullet hole.

Alan

 

[Supersubes]

Re: Ladder Testing and Loads

I shoot on a white poster board like paper with a single aim point using the sharpie marked bullets like GSSP, works like a charm.

 

[clmayfield]

Re: Ladder Testing and Loads

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: cali_tz</div><div class="ubbcode-body">
BTW, this whole harmonic node concept is interesting. I haven't yet read an explanation of just where in the barrel mechanical vibration is this mythical node. If the barrel is in constant motion, which it would absolutely be until some short time after the bullet leaves the barrel, then where is the 'node' ? I suspect there is a magical combo of powder, bullet, seating depth, primer that performs best for each instantiation of a rifle make. But the solid technical reasons for that I still have not seen.</div></div>

Here is further reading on barrel harmonic theory: http://varmintal.net/amode.htm

And here is a second theory, acoustical shock wave theory:
http://www.the-long-family.com/optimal%20barrel%20time.htm

Actually, saying that you want the bullet to exit when the barrel is at a node is not exactly right. In wave theory, a node is the point at which the wave is midway between the crest and trough. If you think of the barrel moving up and down during a shot, you actually want the muzzle to be either at the crest (top of the wave) or at the trough (bottom of the wave). If you are in the middle, or the node of the wave, the muzzle is actually moving the fastest. If the bullet exits the muzzle a split second earlier or later, the difference in direction is large. If you think of the muzzle going to the top of the wave, for instance, it has to go all the way up, slow down, stop, and reverse direction. If the bullet leaves the muzzle a split second earlier or later the muzzle will not have moved quites as much.

All that said, people generally use the term "accuracy node" to indicate a charge that creates better accuracy for the rifle. So we might as well use the standard term.

The "shock wave" theory is kind of interesting. It says that a large wave hits the muzzle at generally the same time every time. When you are developing your load, you want to time the bullet to leave the muzzle before the shock wave hits.

All of this is theory. What we know in practice is that different loads shoot better than others. Why it is this way can be important in the development of things such as barrel tuners, and can be interesting. But really, we just know that load development works.

 

[vman]

Re: Ladder Testing and Loads

Its an interesting concept, this whole optimal barrel time, harmonics etc...

I dont think its fully understood, but the intentions are all good and the end outcome which is what we are really interested in.

 

[ChadTRG42]

Re: Ladder Testing and Loads

I've recently started reading about this "ladder test" method of 1 round for each powder charge. I do not fully understand it. For example, I can work up a load, generally, in 25 rounds (5 groups of 5 rounds each) in one range session. Most of the time, I can see in 3 rounds that one (or more) of the powder charges will not work, so I have 2 rounds left over to pull the bullet. If it takes me, say 25 rounds or less in 1 range session, and this 1 round each ladder method takes 50-100 rounds and numerous range trips, what's the benefit of this method? Does it get you to the same place as other load development methods- I don't know? Has anyone tried both methods at the same time, and did both methods produce the same "sweet spot" powder charge? I'm not dogging this method. I'm simply inquiring on more information to see what the differences are.

For what I see, there is plenty of information available to the reloader to have a good starting and ending point (min and max) for powder charges for a given bullet. There is normally a better or optimum powder to choose for a given caliber/bullet combo. Normally there are several "sweet spots" or nodes for a given powder and bullet combo. Most shooters want the fastest load that shoots the best, so you load near the maximum charge weights. So, the lower charge weights would only help to give you information that you don't need, since you are looking for higher velocity than the starting loads.
Please enlighten me!

 

[vman]

Re: Ladder Testing and Loads

Chad, technically speaking the ladder test should take less.

I could in theory load up 10 rounds and go out and do a ladder.
3 of them will be sighters/foulers and 7 of them will be incrememntal loads.

The only reason I load more I so that I can perform the ladder test more than once... So i will do it twice in one range session with 20 rounds. I take that info home and look at what is my node.

I then come back next range trip with a few more loaded in that node and then confirm everything.

A good load should have little muzzle velocity variation between rounds. Its as simple as that. If you want to verify this compare the MV on shots within your node to a string of shots on a load not near your node. You will notice the MV to be inconsistant or less predictable.

Consistent MV means consistent bullet drop which leaves us to deal with much more difficult issues like the wind.

 

[clmayfield]

Re: Ladder Testing and Loads

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ChadTRG42</div><div class="ubbcode-body">If it takes me, say 25 rounds or less in 1 range session, and this 1 round each ladder method takes 50-100 rounds and numerous range trips, what's the benefit of this method? Does it get you to the same place as other load development methods- I don't know?
</div></div>

First of all, a ladder should take 20 rounds or fewer. Some run 2 ladders, which doubles that. The advantages are:

1) The efficiency. Sure, you can shortcut the process by only testing near max load, but you can similarly cut out the bottom of the ladder if you want to fire fewer rounds. The OCW does a nice trick of firing the low charges in large intervals as sighters and then tightening up the load intervals near max, which is a good idea.

2) The robustness of the result. If you shoot five different loads and choose the tightest group, you have a load that works best of the five you tested that day. Now what happens when temps change? Or if there are other factors that change ever so slightly. The ladder finds those charge weights where verticals are relatively insensitive to different charges. In other words, if you are off by 0.2 gr, the bullets pretty much have the same POI. And theoretically, if other environmental factors, such as temperatures change, it won't throw your load into chaos.

OCW works a little bit differently, but it has this "robustness" feature as well. If your load groups well even if it is overcharged or undercharged by .2 gr, chances are, that load is going to shoot well no matter what. And if its verticals are the same as an interval less powder and an interval more powder, then chances are that you have a really robust load.

For the ladder test or the OCW, I still think it makes sense to find a couple of sweet spots and load those up and see what shoots better. Yes, it is an extra range trip, but what you are gaining is a very robust load, which is a good thing.

The other thing that I would like to point out is that, yes, you can skip the lower weight charges because most people like to go to max load, but what if you skip a really nice sweet spot? If someone is willing to give up really tight grouping for 35 fps of MV, then yes, it makes sense to skip. I think it is nice to know what you are trading off.

 

[Nefariousd]

Re: Ladder Testing and Loads

Did My ladders using the 6BR article as a guide, worked well. Shot it at 695 yards-ish

 

[vman]

Re: Ladder Testing and Loads

Generally the further out you go the better the information you get back to determine what truly performs well out far.

If your going out past 300 yards, chances are your keen on shooting well at longer range shots. So why not take the time and effort with a little bit of prep work to come up with something that works well in your rifle.

Groups to me have less use in determining a nice node with consistent MV. I say this because you might pull off a fluke 5 shot group OR you may shoot a group the reads well but forget it grouping up, not horizontal.

Il put it into perspective. Say you shoot 2 different groups at 300 yards. One group using 46gr of varget shoots a 1.5" tall group. The other group using 46.5gr of varget shoots a 1.5" wide group at 300 yards.

The group size is the same, so which one do you go for? If you say you would go for the one thats 1.5" wide your simply using the technique a ladder test looks to define, but instead applying it to a group shoot.

If you go for the group thats 1.5" tall, you have mislead yourself into believing this is a "good node" because the results look appealing because the wind didnt play havoc... but we are not interested in wind in this test, only drop.

 

[jmtyndall]

Re: Ladder Testing and Loads

Thats a good point. The ocw guys say a ladder test could be off because a fluke shot lands near the previuos, but with. Ladder the node should be 3-4intervals wide usually. Thats a small chance of 4flukes in a row. By that arguement ocw could also produce "fluke" groups just as easily as a ladder could

 

[vman]

Re: Ladder Testing and Loads

Optimal charge weight (OCW) and ladder ultimately look for the exact same thing.

The only difference really is in the eyes of the person pulling the trigger.

Guys that understand the workings of a ladder realise they are looking for a window of "like" muzzle velocities via the vertical travel of multiple charges over the same distance at the same point of aim.

This to me is the most important factor.

The moment people start talking groups they start thinking smaller is better, which is most cases is true but a group has both a Y and an X axis, and unless you know how to read which of the groups is actually telling you the optimal charge with most consistant MV, theres a chance you may get it wrong.

 

[vman]

Re: Ladder Testing and Loads

Check out this image i just made to help explain.

Say i was doing an OCW test and these two groups had me confused.

I would go with group A because i has the least amount of vertical dispersion, even tho group B in general looks like a nicer small group, it in fact has more vertical travel and therefore an indicator of a less consistent muzzle velocity then group A.

 

[Headgear]

Re: Ladder Testing and Loads

Vman, How exactly do you go about doing a ladder test start to finish? I have been doing the OCW and have not trusted the results. You may have already posted the procedure or Your procedure but I missed it if you did. I only have access to a 200 yard range nearby. Hope that is long enough.

Thanks

 

[ChadTRG42]

Re: Ladder Testing and Loads

Ok, seeing the above data, here's my thoughts. When I load 5 groups (A-E) of 5 rounds each, I shoot each one of them for group size over a chrono. I normally test loads at 300 yards. Most often there will be about 2 groups of the 5 that stand out for accuracy and low ES. When shooting these 5 test groups, you can see a pattern form. For example, Load A might be very tight and have a faily low ES. Then Load B would open up some (either horizontally or vertically, or randomly round), and have higher ES. Then Load C will be similar to load B. Then Load D will start to tighten back up, and then Load E will be nice and tight, and give you the lowest ES out of the 5. Load E would be your sweet spot load. Loads B and C may not be the sweet spot load, but it may group horizontal or vertical. Often I will see groups string horizontally or vertically before or after a sweet spot. (Now, a horizontal string needs to have any called fliers, that would have pulled a round right or left anyway.) So, picking groups based on it stringing horizontally could easily not be the sweet spot load. It could <span style="text-decoration: underline">almost</span> be the sweet spot load, but you wouldn't know it until you shot 5 or more rounds of the same charge just above and below that charge (which would be an old school method of load work up).

Also, when shooting all these groups, you can see a pattern on the target on where each group prints in relation to the other loads. Like this ladder test, most sweet spot loads print near the same spot as the groups before and after it.

So, when loading 5 groups of 5 rounds each with the old school method of load work up, I take into account many variables to decide on the sweet spot load. The top 2 would be the smallest group and low ES (maybe not the lowest ES, but low). It must print as consistantly closest to the point of aim as possible for each shot, hence the tightest group. Low ES will minimize your vertical stringing at long range. Looking into all these variables when shooting multiple test loads will tell me which load will be the best one for this rifle. I still don't see how this "ladder test" of 1 round each, then testing multiple groups anyway, can be any faster or tell you any more information than what you would find out doing the old school method of load work.

 

[cali_tz]

Re: Ladder Testing and Loads

I don't know what the old school method is, but instead of this ladder approach which seeks to identify loads that minimize vertical dispersion, why not just shoot each load group at a different target on the paper, and see which groups better, both vertically and horizontally. If there is anything to barrel harmonics, then why would there ONLY be vertical vibration... there would also be lateral vibration.

I agree about going out farther, say to 300 to 400 yards. My comment about the vertical ladder bunching into a mess was likely because I was too close at 200 yards.

But nonetheless, makes more sense to me to get a huge 4x4 ft sheet of paper at 300 to 400 yards, put a bunch of paper targets on top of that and shoot each load at a different paper bullseye. Alot easier to keep track, and forget about coloring the ogives of the bullets.

 

[ChadTRG42]

Re: Ladder Testing and Loads

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: cali_tz</div><div class="ubbcode-body">But nonetheless, makes more sense to me to get a huge 4x4 ft sheet of paper at 300 to 400 yards, put a bunch of paper targets on top of that and shoot each load at a different paper bullseye. Alot easier to keep track, and forget about coloring the ogives of the bullets. </div></div>
This is exactly what I do. I use large, white paper backers with targets on them to shoot each group. It is fairly easy to keep track of. I log all info in my log book with the target and chrono info after each group, and where the group impacted on the target.
Old school ladder load dev. method is simply several groups of 3-5 rounds increasing in powder charge, til you find the best load.

 

[cali_tz]

Re: Ladder Testing and Loads

xactly Chad, that makes alot of sense. btw, your 338LM prices are amazingly low, compared to $4-5 each for new Hornady 338LM ammo in 20rd boxes.

Can you load Lapua bullets too?

 

[ChadTRG42]

Re: Ladder Testing and Loads

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: cali_tz</div><div class="ubbcode-body">xactly Chad, that makes alot of sense. btw, your 338LM prices are amazingly low, compared to $4-5 each for new Hornady 338LM ammo in 20rd boxes.

Can you load Lapua bullets too? </div></div>
Yes. If they make a .338 bullet, I can load it. I've been doing some of the new Barnes 265 and 285 grain Tipped TSX for some hunting friends. Those are pretty nice, too!

 

[Emouse]

Re: Ladder Testing and Loads

not cleaning the barrel in over 700 rnds??

WTF?

 

[Goldbeachman]

Re: Ladder Testing and Loads

Yeah really, 700 rounds. You really shouldn't overclean the barrel like that. Last time I read Frank's (Lowlight's) comments about cleaning, in this thread here he said: "We ( well, he, I just watched ) had to clean Jacob's AW last week, we estimate the rifle had about 1500 to 1900 rounds down the tube between cleanings. Used by 3 separate people during 3 different classes, besides himself, so the exact number is a bit sketchy at this point, but accuracy definitely started to fall off so it was cleaned.

Went back to sub-.5MOA after a bit of Iosso and 5 or so patches."

Personally, I'm not so big on cleaning anymore....

 

[Alan Griffith]

Re: Ladder Testing and Loads

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: vman</div><div class="ubbcode-body">Check out this image i just made to help explain.

Say i was doing an OCW test and these two groups had me confused.

I would go with group A because i has the least amount of vertical dispersion, even tho group B in general looks like a nicer small group, it in fact has more vertical travel and therefore an indicator of a less consistent muzzle velocity then group A.

</div></div>

Below is a somewhat real life example of VMAN's example.

A new lightweight 6.5x47 Lapua I took delivery of last month shot these two 300 yd ladders about 10 days back.

The first was with the 140 Accubond and Rel 17 covering a 5-1/2 gr spread in .5 gr increments. Normally I wouldn't do .5 increments but my main goal was a pressure ladder followed by an accuracy ladder. You can see a vertical spread of nearly 6+" by a 6" horizontal spread.

The next ladder was with the same 5-1/2 gr Rel 17 charge but with the Berger 140 VLD. It's vertical spread was about 2" and 3" horizontal spread if I don't include #3. Needless to say, I got very excited with this one.

I then loaded up some rounds that were between #9 and #10 and shot them @ 600 yds. I had a good 5-11 mph wind from my 4. Not really paying too much attention to the wind, I shot the following group which had an extreme spread of ES of 28 and SD of 9. As you can see I've only a 2.5" vertical at 600 yds. That would equate to about 4.16" @ 1000 yds; pretty decent!

So, if you count the 10 break-in loads I shot, the two 12 rounds ladders and 8 additional 600 yd check rounds, a total of 42 rounds, I've got a decent hunting/target load. If I want, I can fine tune @ 600-1000 yds to fine tune seating depth and/or primer changes.

Alan

 

[vman]

Re: Ladder Testing and Loads

Alan my friend you just hit the nail on the head.

Prime example of minimal rounds fired with maximum knowledge gained about the charges your rifle likes.

Those results are sweet.

I think the key factor that people dont understand regarding ladder testing, is that the wind (horizontal movement) counts for jack shit.

Those results are nice!