Thread: 75gr Amax 223, UPDATE

So I loaded up 7 different powder charges, 2 bullets of each and shot two ladder tests.
Loaded up from 23.0-25.4gr in 0.4gr increments. I Loaded them 0.015" off the lands. Was going to do 0.010" but my land testing method showed some consistency but showed a spread of values a full 0.006" so opted for slightly further away.

Targets were shot at 263 yards in little or no wind.
I believe the test went well-ish. I determined that these bullets will stabilize in my rifle and that the seating depth can't be too far off.
But I have a problem knowing what shot is what load. It was to far for my x16 scope to pick up each shot, and the holes aren't in a 100% obvious vertical line.
I knew this was a problem and heard of multiple sources using highlighters on the projectiles to see what shot was what, but none of the high lighter transposed onto the target grrrr.

I have attached images of the two ladders I shot.
I transferred both sets of holes on to one sheet of paper and thankfully what I assume are groups 4, 5 and 6 are pretty close together. Even if I haven't assumed each shot correctly I think that area of the target is close enough I can assume my assumption is good enough to do further testing. The shots from these 3 groups had a total spread of about 2", so hopefully this is a good sign.

Will do 4 rounds of 6 different loads from 24.0-25.0gr in 0.2gr increments.
Hopefully today.

The first ladder test I ever tried I did at 100 Yards (working up a different load) and put every shot on top of each other.
This second attempt was more successful, but a spotting scope would've been more helpful!

Note: I actually loaded the bullets at 0.016" off the lands as I wound my seating die a tad to far (promise I haven't been rough every other part of the process).

@Beetroot

I too had the issue of seeing which shot was which from long distances however I easily solved this problem.

I positioned my video camera near the target, off to one side and about 30 meters back to ensure it didn't get hit, set it on record, then retired to the shooting position to shoot the test.

After shooting the test it is an easy matter to replay the video and mark up your target accordingly.


Cheers
Pete

You're going about it all wrong, the easiest way to test your loads is to shoot 3 shot groups at separate aiming marks I use adhesive 20mm stickers on a piece of cardboard big enough to take the all the groups,
then you can compare each group with the others to narrow down the best powder charge start at 100 m/yrds once you have the best powder charge fine tune it by shooting 5 shot groups varying the load .1 grain
you should hit a sweet spot were a .5 grain either side has no change on the size of the group, then move the target to 200 m/yrds and shoot 5 5 shot groups to get an average,
The ladder test is best done at a 300 m/yrds or longer and with 2 people there is not enough difference in velocity at close range to separate the shots.

I would suggest following the above post for the next phase however I wouldn't say you were wrong in doing our ladder test, it's a good quick way of showing where pressure issues are found so you can operate with confidence when doing your groups, in terms of the order finding the best load, I have had ladder tests that printed a wide range of shots on top of each other the. Could t replicate it with groups... Frustrating...
Regardless, if you fire groups with the charge range you have loaded as described above you will have your load confirmed pretty quickly

I gave up on the ladder test for selecting optimal loads because it necessitates shooting at longer ranges in order to seperate the groups.

So I also test at shorter ranges using a target for each charge weight as shown below


This target is produced automatically as part of the load database I keep in a spreadsheet for each load I do.

I can also print it blank for general use, as well as vary the actual spot on the centre.
It's designed for a4 pages , two of which side by side fit nicely onto a real estate agents open home sign


Tim

I decided to give the ladder test a second go, based on what I read on what I perceived as reputable websites (not just forums).
The thought of using less reloading components sounded nice.

I tested the loads made up and was some what successful.
All but one load shot under .9moa, one was under .6moa and one under .5moa. Sadly the two good groups were separated by the worst group of the lot.
As I had it in .2gr increments I will choose the two best loads and load up 5 rounds of each and then a 5 rounds .1gr higher and lower and see how it goes.

At first I was hoping to not spend too much on the whole load work up, but considering load development is the most I tend to get to shoot in one sitting, I don't mind if it costs a tad more.
If the two good groups I shot weren't flukes (which I don't think they were) I'll be pretty stoked as I will (hopefully) have a .5moa load doing over 2800fps from my factory sporter weight Tikka with no mods. So fingers are crossed!

At the risk of starting an ocw vs ladder test debate .... Have you considered trying ocw ?

Http://optimalchargeweight.embarqspace.com


Tim

Another method to get you close is using a chrony. ie when your velocity spread is minimal that seems fairly close.

Originally Posted by kiwi39

At the risk of starting an ocw vs ladder test debate .... Have you considered trying ocw ?

Http://optimalchargeweight.embarqspace.com


Tim

this is what i use ocw.

Originally Posted by Mauser308

To me, there seems to be a lot of variables there that haven't been nailed down or something else that isn't working right.

If the best two groups are separated by the worst group, either the groups should have all been good or there was two flukey good groups or one shooter's error crap one. If it was me, I would go and find a nice wind-free shooting area and try out the load around the point of the bad group and verify that for consistency. It may be that the projectile/powder combo you are using just won't work repeatably in your rifle and you haven't got enough data yet to prove or disprove that.

What is the limiting factor for your seating depth, magazine length or rifling/lead? Might be worthwhile rolling up another test of what looked like a good grouping powder charge and try four seating depths of 3-shot groups and just verify if there is any trend showing there...

I have been seating the projectiles to .015" off the lands.
I was very confused like you said, that the two best groups were separated by the worst.

My loads I were testing were .2gr different (24.4, 24.6 24.8). I was going to load up more lots that were 24.3-24.9 in .1gr intervals and see if it was shooter error the one bad group or if there is something funny going on. Hopefully the results will show up as some sort of OCW test and I'll have a load sorted.