Best generic load dev video I’ve seen.

[huntnful]

Pressure ladders for groups basically tell the whole story of that bullet, powder & velocity, in conjunction with the precision capabilities. They work great and are super simple. I don’t do anything else anymore.


Here’s a similar one I just did myself the other day.





If the ladder looks like shit, it likely just shoot like shit no matter what.

If it groups into a decent cluster for the amount of shots taken, pick whatever charge is in the middle of the cluster and below pressure. Literally that simple.

 

[Muledeerfanatic]

Basically what I do
Then do some depth test
I don't try too hard
Works out fine

 

[hdc77]

Im in this bandwagon as well, I usually pick a seating depth .020 off lands, and do the powder ladder, it target sucks I try a different bullet. This happens rarely with Bergers. This is a 12 shot ladder group with a 260 AI and 140 HT.

 

[Quicksilver]

100%, usually shows itself pretty early if the rifle likes the combo or not. Just got done battling a rifle through 3 different powder combos but my buddy was convinced he had to shoot a certain bullet. Went to a known accurate powder that wasn’t a speed demon and it shot like .75moa over 2gr of powder. Narrow it down and I shot a .185moa group at 450yds. Instant difference compared to the other pressure tests, I knew it was going to shoot.

 

[huntnful]

Im in this bandwagon as well, I usually pick a seating depth .020 off lands, and do the powder ladder, it target sucks I try a different bullet. This happens rarely with Bergers. This is a 12 shot ladder group with a 260 AI and 140 HT.

Beautiful!

100%, usually shows itself pretty early if the rifle likes the combo or not. Just got done battling a rifle through 3 different powder combos but my buddy was convinced he had to shoot a certain bullet. Went to a known accurate powder that wasn’t a speed demon and it shot like .75moa over 2gr of powder. Narrow it down and I shot a .185moa group at 450yds. Instant difference compared to the other pressure tests, I knew it was going to shoot.

Yeah that’s a perfect example for sure. If you’re dead set on a bullet, better have a few powders on hand to test.

 

[OverInfinite]

I've taken this concept and applied it to my 5 shot group loads and it pretty much sums them up the short way. I have two rifles that I need to load test for, and I will be trying this method.

 

[doc holiday13]

I find it interesting so many people choose their starting point as a measurement off the lands and not just loading a bullet to SAAMI spec or Manufacturers spec. Not saying its wrong and I do understand that chambers are cut differently because reamers change with use, but i would speculate that starting with the SAAMI spec would likely get you a lot closer to the perfect seating depth

My last 2 load devs have started with using the SAAMI OAL spec for a bullet and accuracy was spot on

 

[OverInfinite]

I find it interesting so many people choose their starting point as a measurement off the lands and not just loading a bullet to SAAMI spec or Manufacturers spec. Not saying its wrong and I do understand that chambers are cut differently because reamers change with use, but i would speculate that starting with the SAAMI spec would likely get you a lot closer to the perfect seating depth

My last 2 load devs have started with using the SAAMI OAL spec for a bullet and accuracy was spot on

I think this is dependent highly on the cartridge. like all my 6.5CM's have ended up within 0.050" of SAAMI. where as my 284Win and 22-250 are pretty much limited by brass surface bearing and i am still not touching the lands. The only reason I pull them out is to get more powder in them.

 

[Chris in TN]

I will say that as a kid I saw older shooters legit obsess over 'load development' and often they'd shoot dozens if not hundreds of rounds in a completely willy-nilly fashion (or so I say based on what we know now) and I am soooooo glad we don't have to jump through those hoops anymore. Start with good components, use good procedures, fire in a good barrel, and have realistic expectations, and life is just so much easier.

I find it interesting so many people choose their starting point as a measurement off the lands and not just loading a bullet to SAAMI spec or Manufacturers spec. Not saying its wrong and I do understand that chambers are cut differently because reamers change with use, but i would speculate that starting with the SAAMI spec would likely get you a lot closer to the perfect seating depth

My last 2 load devs have started with using the SAAMI OAL spec for a bullet and accuracy was spot on

I realize that there's a difference between posting a link and making a coherent argument. But I'm gonna be lazy and post this link - because it does make a pretty coherent argument, at least one that has convinced me, not that I'm some gauge of wisdom.

Anyway: https://precisionrifleblog.com/2020/04/05/bullet-jump-load-development-data/

I think it boils down to this: The bullet's depth in the case (or, SAAMI specs) has a fairly small (and predictable) impact on the physics of what happens in the case, when the round is fired. But the same metric also has a much larger relationship to the lands in terms of jump distance, and that seems to have a larger impact on other aspects of the shot.

I'm not smart enough or patient enough to test such things so I just take the word of guys who have, and try to start near that 0.060" off the lands realm. It works thus far, for me.

 

[huntnful]

I find it interesting so many people choose their starting point as a measurement off the lands and not just loading a bullet to SAAMI spec or Manufacturers spec. Not saying its wrong and I do understand that chambers are cut differently because reamers change with use, but i would speculate that starting with the SAAMI spec would likely get you a lot closer to the perfect seating depth

My last 2 load devs have started with using the SAAMI OAL spec for a bullet and accuracy was spot on

I see your point for sure, but with just trying a bunch of different bullets, and also inconsistency from bullet lots, I prefer to have a consistent baseline starting point with a certain distance from the lands, not a certain cartridge COAL.

 

[doc holiday13]

I see your point for sure, but with just trying a bunch of different bullets, and also inconsistency from bullet lots, I prefer to have a consistent baseline starting point with a certain distance from the lands, not a certain cartridge COAL.

I certainly do understand that different bullets will sit differently. On my 25 creed I loaded hornady 134's according to the spec called out in the drawing provided by hornady, then when I loaded some sierra 135's i set the bullet seating to have the same jump as the hornady because the hornady bullets were shooting great

 

[RME]

Maybe I missed this being mentioned already but what distance are these groups being shot at?

 

[ckt3]

Kinda seems like playing in the noise to me, but maybe I'm missing the point. In the video he steps up 0.3 gr increments in his ladder for a composite 10 shot group with a single shot at each charge. You could just shoot 10 shots at the midpoint charge weight and call it a day, especially if you're doing all this testing at 100 yards. Consider the stacked tolerances across the powder manufacturing, the powder measure, the other variables in each loaded cartridge, the expected velocity, the chronograph's velocity measurement, the expected dispersion, and the human shooting error. Then on top of that you have an n of 1 at each charge. And how much vertical dispersion is even expected at 100 yards given such small changes?

I think the signal on the POI delta at each charge weight is ~= 0. That is not to say the exercise is valueless, rather, you are essentially just measuring the POI for the average charge weight across that group at a modest statistical power, and any interpetation beyond that seems fanciful.

 

[huntnful]

Maybe I missed this being mentioned already but what distance are these groups being shot at?

100 yards.

You can shoot them at any reasonable distance though. Some guys shoot them at 600 yards to look for a vertical “node” between charge weights, but that’s above my pay grade lol

 

[huntnful]

Kinda seems like playing in the noise to me, but maybe I'm missing the point. In the video he steps up 0.3 gr increments in his ladder for a composite 10 shot group with a single shot at each charge. You could just shoot 10 shots at the midpoint charge weight and call it a day, especially if you're doing all this testing at 100 yards. Consider the stacked tolerances across the powder manufacturing, the powder measure, the other variables in each loaded cartridge, the expected velocity, the chronograph's velocity measurement, the expected dispersion, and the human shooting error. Then on top of that you have an n of 1 at each charge. And how much vertical dispersion is even expected at 100 yards given such small changes?

I think the signal on the POI delta at each charge weight is ~= 0. That is not to say the exercise is valueless, rather, you are essentially just measuring the POI for the average charge weight across that group at a modest statistical power, and any interpetation beyond that seems fanciful.

When you’re testing a new bullet and new powder in a new chamber or new barrel, you don’t know where the middle charge weight is to begin with.

So this allows you to find the pressure of the current unknown system your testing, as well as the accuracy.

You’ll see in one of the test he only shot 7 rounds because he was getting into too much pressure. That happens often when you don’t really know where pressure is with that given combo. It sucks to load up a test and not even reach pressure, so I always load a few extra going higher than anticipated just in case.

If you actually do this test personally with a couple of powders, you can see A LOT of dispersion if the barrel doesn’t like a certain combo.

 

[wapitibob]

I shoot my ladder in 1gr increments, you know in a cpl minutes if the bullet/powder will shoot.

 

[ckt3]

When you’re testing a new bullet and new powder in a new chamber or new barrel, you don’t know where the middle charge weight is to begin with.

So this allows you to find the pressure of the current unknown system your testing, as well as the accuracy.

You’ll see in one of the test he only shot 7 rounds because he was getting into too much pressure. That happens often when you don’t really know where pressure is with that given combo. It sucks to load up a test and not even reach pressure, so I always load a few extra going higher than anticipated just in case.

If you actually do this test personally with a couple of powders, you can see A LOT of dispersion if the barrel doesn’t like a certain combo.

So the novelty he’s proposing is if you want to search for pressure with a ladder, put them all onto a composite group and you sort of get for free a group size measurement under some degree of variable conditions (?)

 

[TxhunterPRC]

So the novelty he’s proposing is if you want to search for pressure with a ladder, put them all onto a composite group and you sort of get for free a group size measurement under some degree of variable conditions (?)

Correct. I have done this for two barrels now and have had great results. One pressure ladder, load up 10 rounds of the charge I choose from the ladder and shoot it. 99% of the time its going to shoot good and stay consistent across time, weather, or whatever it may be. If you really want to confirm you can load up 5-10 rounds of charges, lets say .3g +/- what you want to run and they should shoot the same POI. A quick and easy way to tell if your barrel likes the combo you're putting though it.

For example, when I did this for my 25 creed, I had N555 and H4350 with Berger 135's. Both 10 shot ladders. The ladder for the N555 was ~1.2'' and the ladder for H4350 was ~.5''. Chose a charge that I liked with H4350 that gave me the velo I wanted and ran with it. I have tested above and below that charge and have roughly a grain of difference in charge weight that shoots the same POI.

 

[BBob]

but i would speculate that starting with the SAAMI spec would likely get you a lot closer to the perfect seating depth

Why? SAAMI freebore length specs are all over the map so why would loading to SAAMI be closer to perfect than picking a consistent off the lands measurement?

FWIW I’m not sure either way is the “perfect” way or if there is a “perfect” starting point

 

[wind gypsy]

I find it interesting so many people choose their starting point as a measurement off the lands and not just loading a bullet to SAAMI spec or Manufacturers spec. Not saying its wrong and I do understand that chambers are cut differently because reamers change with use, but i would speculate that starting with the SAAMI spec would likely get you a lot closer to the perfect seating depth

My last 2 load devs have started with using the SAAMI OAL spec for a bullet and accuracy was spot on

Not saying using saami doesn't work in many instances but it's not hard to have a rough idea of jump and go from there. Especially with non-recent cartridges, SAAMI is arbitrary to magazine lengths common in rifles decades ago and not at all tailored to a specific bullet. Seems silly to stuff a bullet deep in a case and jump a quarter inch to the lands because of a SAAMI spec.