Ladder Test for finding powder charge

[Frequently Banned Troll]

Ever done that? Was it a good use of time?

I’m trying it for the first time this weekend. Two rifles, same caliber (6.5prx) 2 separate loads - every component is different. I’m hoping I can hone in on a good recipe in 2 times out shooting. Will see.

I’m going to shoot at 300m because parallax is that for the optics but will plot both impact and velocity.

 

[Nicoli7153]

I've done it for different bullets in my .308. Gave me a good understanding of pressure and velocity in that particular gun using different powders, primers and seating depth. Gave me a good idea what the gun likes/dislikes

 

[Wind Gypsy]

I've done ladder testing and used to do a lot of OCW testing, i dont believe i ever got to a position where either gave me particularly repeatable results that were clearly better in hunting rifles. I haven't messed with doing them beyond a 1 shot per charge weight ladder for velocity/pressure info in a while.

 

[Sheltowee]

I ladder test nearly all of my handloads and have found it to be an effective way to find the most efficient load in a given cartridge/projectile combination. For most cartridges in the .308/.30-06 class, I will start at about 92% of recommended max charge and work up 2% with 10 rounds at each step. If I'm not satisfied with velocity, SD or ES, I'll slowly work up past 100% of max. Gives me a decent idea as to ES/SD but true statisticians will tell you that it is too small of a sample size. Then, I'll select a given load balancing raw velocity with SD and ES.

I've found pretty significant variances between steps using this method. For instance, variance of 42% in SD, 40% in ES with the 25-6.5 load charted below.

25-6.5 PRC, 127gr. HHT, H4831sc, ADG brass, 2.830" COAL, 2.283" CBOL

	Average Velocity(fps)	Extreme Spread(fps)	Standard Deviation(fps)	Best 5-shot/3-shot group
Load 1	2709	46	21	--
Load 2	2735	25	8.9	--
Load 3	Chrono Failed	--	--	--
Load 4	2792	51	14.9	.805/.159
Load 5	2825	60	15.6	.755/332

25-6.5 PRC, 127gr. HHT, H4831sc, ADG brass, 2.830" COAL, 2.283" CBOL

	Average Velocity(fps)	Extreme Spread(fps)	Standard Deviation(fps)	Best 5-shot/3-shot group
Load 6	2887	45	14.1	1.064"/.468"
Load 7	2937	62	20.6	.573"/.342"
Load 8	2977	28	9.2	.487"/.284"
Load 9	2993	36	11.9	.810"/.389"

The method promoted by Hammer Bullets is to load a round or two, increasing in constant steps, stopping when you start to see pressure signs (cratered primer, heavy bolt lift, etc.), then back down a half grain or so. That is certainly faster but I don't love it for identifying the most efficient load.

 

[Ben Lamb]

I have a small star wars notebook in my range bag that has a little girl giving darth vader flowers that I keep all my ladder testing notes in, not some spreadsheet like a dork.

It's a great way to help find that accuracy node. I've done it with every rifle I reload for, except one 30-06 that shot my standard reload to about 3/4 inch. About to jump back into testing on a 7PRC. Brass & dies will be here Monday!

 

[Carl]

I'll use a ladder occasionally to find pressure and velocity for a new combination (usually loading at the range instead of at home).

I don't use them anymore to find accuracy, personally.

 

[Mallardsx2]