Ladder test. 300 yds is plenty. Look for the vertical grouping. With moa hunting rifles I have done the test at 100 yds. With a really accurate long range rifle you need to stretch it out. Pick a good well known bullet and powder combination. Think H4350 and a 140 gr eldm in 6.5 creedmore. Run your ladder in .3 or .5 gr based on case capacity. The accuracy node will be easy to spot.
Ladder or OCW... what will tell me more?
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mwkelso
Well-Known Member
After you find the accuracy node using .3 or .5 increments, do you dial the node in even tighter with .1 increments? Or switch focus to seating depth?
I just ran a ladder test this last weekend on a .270 that had it's best with 51.5gr of h4350, and shot 1.25moa. The closest to that was 51gr with a 2moa group. Everything else ranged from 2.5 to 4 moa.
In a true ladder I'm not shooting groups. I'm loading 10-15 rounds from min to max or slightly above. 1 round each .3-.5 apart depending on case size. Shoot the same target and find where 2-3 shots cluster vertically.
This is going to be your node. Typically if you have a good bullet powder combo your node is going to be .9-1.5 grains apart. I would then load in the middle of the node for groups. Maybe go up or down a little. Idea is to be close to the middle so you dont fall out of the node. Then I would do a seating depth ladder. Same principle you just vary the seating depth. For longer range shooting I would take a load that grouped worse than another as long as the vertical spread is close.
This is going to be your node. Typically if you have a good bullet powder combo your node is going to be .9-1.5 grains apart. I would then load in the middle of the node for groups. Maybe go up or down a little. Idea is to be close to the middle so you dont fall out of the node. Then I would do a seating depth ladder. Same principle you just vary the seating depth. For longer range shooting I would take a load that grouped worse than another as long as the vertical spread is close.
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I don't mean to hijack a question intended for someone else, but speaking from personal experience I would've recommended that you adjust a .270 in .3 gr. powder increments. I have used the OCW numerous times, and am a big proponent. I typically adjust in .5 gr. powder increments for magnum cartridges and .3 gr. increments for non magnum cartridges. It never ceases to amaze me when a rifle moves from a scatter node to an accuracy node. The only hesitancy I have in recommending you move on to the next step (seating depth tuning) is usually with an OCW test you'd like to see the OCW load yield an MOA or better result in a "good shooting" rifle (your 1.25 MOA is just slightly outside that). But, you're relatively close so you could probably move on to the next step if your pressed for time or resources.
However, if it's feasible I'd suggest you run to the range with the following loads of H4350: 51.7 gr. (4 loads), 51.5 gr. (5 loads), and 51.3 gr. (4 loads). Take a shot every 3 to 5 minutes (careful not to heat the barrel up to much). I like to take two fouling shots, hence the reason for the 5 loads of 51.5 gr. I'd bring an extra load of the 51.7 and 51.3 grains just in case (that's the reason for the 4 loads of those). Since you will only be testing 3 loads I'd personally also bring those identical loads with a different primer, and just see what happens.
Once I've identified the accuracy node I use Erik Stecker's (Berger Bullets President and chief ballistician) suggested seating depth method - this process has never failed me. Here's a link to that method:
https://bergerbullets.com/getting-the-best-precision-and-accuracy-from-vld-bullets-in-your-rifle/
After running your OCW and seating depth tests, you will typically find a "clear winner". I hope this helps. Let me know how things go for you, I'm very interested.
In the photo above charge weights 5-7 grouped in about 1/2". Thats .9 grain difference in powder. I just picked the middle load. So with 9 shots on target I found a decent load. Now granted this was a well known bullet powder combination for this rifle. I started doing this during the great component shortage. If I had loaded 3-5 rounds each for group testing it would have taken 27-45 rounds. The long range target guys have been doing this for years. Vertical is the killer for those guys and a long range hunter as well.
Heres the problem I have with a load that goes from sugar to crap over 1/2 grain of powder. 1/2 grain is what 30-50 fps. Maybe less in some cases. You can lose that much velocity with some powders on a really cold day. Now your 1 moa load is 2 moa or whatever. The node is too small.
Since they are already loaded, I'd shoot those 3 shot groups at 300yds. It will teach you plenty.
That said, I prefer a 2x shot ladder at 500 to show if it likes the bullet and nodes. Either way, good luck. Many ways to figure out a good load
That said, I prefer a 2x shot ladder at 500 to show if it likes the bullet and nodes. Either way, good luck. Many ways to figure out a good load
25WSM
Well-Known Member
I shoot 1000 yd compatition and need the best tunes I can get. I use the Satterlee method with a ladder done at same time. I can tell you from experience that the two shot at the same time gives the same info repeatedly. Meaning the velocity flat spots are also the best vertical on the paper. I always use the Satterlee method to get my node and then fine tune from there. Saves lots of ammo. When I get it shooting best I still have to do 1000 yard ladder test to fine tune the vertical. The most accurate load you get at 100 yards or 300 yards will absolutely not be the most accurate at 1000 yards. I recommend doing a ladder at the max range you plan to shoot. As an example I have a 6.5 creed that will shoot zeros at 100 yards. But that load shoots 10 inches at 1000. My 1000 yard tune has shot 10 shot groups at 1000 yards in the 3s. But that load won't even break half inch at 100 yards. My 300 wsm is exactly the same way. The guys at the 1000 yard range will all tell you that tuning at any other distance is a waste of time. I know everyone wants to say they have a quarter in gun but that load is not going to be your friend at long range.
Shep
Shep
I would love to be there next to you at the range to see much bigger groups at 100 than at 1000 relationally. I don't shoot at 100, so that still confuses me.
25WSM
Well-Known Member
I live in western PA and shoot at Williamsport. Your always welcome to come.
Shep
Shep
I need to make it out there. BR style isn't my cup of tea, but still impressive numbers posted. Really shows which cartridges are inherently accurate
