Ran another ladder still can’t seem to find a clear path forward

[Justice1327]

It is a hunting rifle. This is also the second bullet I have tried first was 190 Berger and I couldn't seem to get it either. I have developed other loads for different rifles and either got lucky or something. Never had this much trouble. Do you have a recommendation for a seating depth test. My plan was to start at lands and work back .003 at a time

How far off the lands are you now? If around.015-.020 you can jump in increments of .020 or .030. Ex: you are .020 off now, next 3 shots are .040 off, then .060 off until you get to .120. Start with the shortest cartridges first. Then work your way down the increments and note when the grouping starts to come together. If they come together between 40 and 60 and not 60 to 80 or 100 or 120, then you know you can Start working at .005 increments between 40 and 60 until your group closes up. Only need to shoot 3 shots at each increment. Never saw a group get smaller with more shots.

 

[Wolf76]

Ok, so this is a real question not being a wiseguy, how do you know which is a safe charge weight to do the seating test with. Sort of a chicken and egg situation. If the shooter is starting from scratch how can he know the selected charge weight for the seating depth test is ok in his/her rifle? but if they work up a charge weight from min to max then test seating depth at the charge that showed the most promise then they also know the charge is good in their rifle.

Just pick a middle of the road charge. Almost no risk of overpressure even when jammed. Start with intervals of distance off the lands..5,15, 30, 45 off etc. Would start further off for monos. Shoot three shot groups at 200. You'll see something really standout, even if it sucks. Then tweak it in 5 thousandths and watch the harmonics. You'll hone it down in a few sessions. The reward is half the equation is effectively solved.

 

[GuroChris]

Just pick a middle of the road charge. Almost no risk of overpressure even when jammed. Start with intervals of distance off the lands..5,15, 30, 45 off etc. Would start further off for monos. Shoot three shot groups at 200. You'll see something really standout, even if it sucks. Then tweak it in 5 thousandths and watch the harmonics. You'll hone it down in a few sessions. The reward is half the equation is effectively solved.

OK, I'll try it. I'm going to get started on some load development for next year pretty soon. I assume that since I'm working with mag length as a hard stop that this method will work the same just start at mag length and go from there instead of lands.

 

[Bob Wright]

A ladder is simply a 10 shot group looking for 2 or 3 to land in a cluster vertically, possibly another cluster, higher or lower.. Also shot over a chronograph to verify a flat in velocity. This isn't what I expected to see, which appears to be an OCW target of sorts. It should be shot at 300 yards approximately.
Once you find a cluster or velocity flat, your development would then shift to seating depth test in that velocity/cluster node.
Then, start tweaking powder charges in that node in .2 increments, from low node speed to high node.

 

[Randy dawson]

How far off the lands are you now? If around.015-.020 you can jump in increments of .020 or .030. Ex: you are .020 off now, next 3 shots are .040 off, then .060 off until you get to .120. Start with the longest cartridges first. Then work your way down the increments and note when the grouping starts to come together. If they come together between 40 and 60 and not 60 to 80 or 100 or 120, then you know you can Start working at .005 increments between 40 and 60 until your group closes up. Only need to shoot 3 shots at each increment. Never saw a group get smaller with more shots.

I am .020 off as of now. Is there any reason to try at the lands as well? Most rifles I have are limited to mag length. This one happens to be able to set at lands and still fit in the mag

 

[Randy dawson]

A ladder is simply a 10 shot group looking for 2 or 3 to land in a cluster vertically, possibly another cluster, higher or lower.. Also shot over a chronograph to verify a flat in velocity. This isn't what I expected to see, which appears to be an OCW target of sorts. It should be shot at 300 yards approximately.
Once you find a cluster or velocity flat, your development would then shift to seating depth test in that velocity/cluster node.
Then, start tweaking powder charges in that node in .2 increments, from low node speed to high node.

Yes I know it's not truly a ladder test. But I ran that one as well the other day. Im just trying to figure it all out. Just learning as I go.

 

[sedancowboy]

I would go back in .020 or .025 increments. I would not go closer to the lands if a hunting rifle. You do not need to do .003 increments that is way too small to find a node. If your seating depth is so sensitive as to need .003 to tune then you are not in a node in my opinion. in my 338 LM example I found accuracy at .050 off the lands which turned out to be max mag length.

 

[Bob Wright]

Yes I know it's not truly a ladder test. But I ran that one as well the other day. Im just trying to figure it all out. Just learning as I go.

Just sharing that you are conflating different tests and getting unreadable/confusing results.
Simplify it, since you know that you apparently are not seeing pressure (right?), so go back to the middle of your powder charge working upwards in .5 gr increments until you see primers getting a bit flatter or an extractor swipe, stiffer bolt. At 300 yards, you'll see the node(s) and can verify the velocity flats over a chrono. Right now, you don't have good data.
I'll run three different ladders with changes in primers or powder just to test velocities.
Not everyone agrees with one way of doing it as you can imagine.

 

[Justice1327]

I am .020 off as of now. Is there any reason to try at the lands as well? Most rifles I have are limited to mag length. This one happens to be able to set at lands and still fit in the mag

Depends on if the bullet has a tangent or secant ogive. The secant section ogivec reduces drag i.e. higher BC; however, the tangent ogive makes the bullet easier to tune, i.e. less sensitive to seating depth positioning.
I just completed development for a 243. Started at .020 off the lands. Took an average for several pwdrs from 8 sources ( books & pwdr company web sites) From that average we pick the most dense load and went down 1 full gr. ( if average was 38.5...we started at 37.5) from here we loaded 2 rds in .3 gr increments ( 37.5, 37.8, 38.1 etc) until we saw pressure signs ( crater in primers, slightly flattened primers or stiff bolt lift) documented all velocities on a spreadsheet, put that into a scatter chart, and then looked for a flat spot or a window. Also looked for low es,sd. Nearly always in that flat spot. Then we loaded 2rds in .1grain increments from the lowest pwdr charge to the highest charge w/in that flat spot (lowest was 38.6 /highest was 39.1) (38.6, 38.7, 38.8, 38.9, 39.0,39.1). This allows us to find the sill or sweet spot. In our case it was 38.75 . We then went out and shot for groups using the seating depth method I previously mentioned. We started with the shortest and went up in length. You do this so when you find the groups you like, you simply seat the longer rds to that depth.
clean the gun, especially the carbon, after each 10 rds and dont let your barrel get too hot or too cold. Fire 2-3 fouling shots before each testing.
Factory action, Model 70 w/ Shilen match brl, 22", Mag sporter profile, bedded action and trigger set at 2.5 lbs: 90gr ELDX, 3105fps, .63"grp at 100yds and we called it a day.

 

[redleg1013]

Shot is wind less than 10 mph. From a bench with sand bags. Last group on bottom left was sighting a different rifle. But they are in order left to right, top to bottom. Starting lowest charge working to highest. 4 min between shots for barrel to cool. Started with a clean barrel

Your load is between 72.5 and 73.5
Re-shoot with finer resolution (0.2 gr) and do a seating depth test.

 

[vancewalker007]

If you average the last 4 rows there looks like a node lurking in the following powder load span. I've never been able to clearly narrow a velocity jump with .5 gr changes. I always use 0.2gr jumps. Just a suggestion, it seems to work for me. For hunting I'd try to nail down one in this higher region because its going to give the best wind performance. Elevation is a no brainer any more with all the tools available. But wind is tough and anything you can do to minimize it makes it better.

Was 75.5gr your max because a smidge more was pressuring out?

75​

75.2​

75.4​

75.6​

 

[GrayCreed]

Shot is wind less than 10 mph. From a bench with sand bags. Last group on bottom left was sighting a different rifle. But they are in order left to right, top to bottom. Starting lowest charge working to highest. 4 min between shots for barrel to cool. Started with a clean barrel

Your shoulder must be killing you

 

[JPro7mm]

Definitely pick the lowest ES and SD then play with seating depth. I thought my rifle would not shoot Barnes Match Burners. Was .020" off lands and could not get better than 1.25 MOA. Picked the lowest ES load and shrunk groups to .3 MOA once I got to .090" off lands.

 

[PowellSixO]

Do a seating depth run on the 8-1, 8-2, 8-3, and 8-4 load. That will clean right up.