I was reminded today of the alternative technique for developing rifle
loads whereby instead of throwing groups downrange, you instead fire one
shot at each load (starting well under hot load of course) and watch the
vertical stringing. At the point when stringing diminishes to next to
zero you've got your optimum pressure/velocity and you then affect group
size by working the load overall length/seating depth?

Somewhere I've got a link to a better explanation and I'll look for that
now.

Here is a link for that procedure, it may be the one you are referring to:

http://home.snafu.de/l.moeller/Laddertest.htm#Laddertest

I have not tried it, but intend to do so sometime.

~Holmes

Well done Holmes!

That's the one and I'm going to save it and print it now!

Basically they are playing with barrel viberations and it probably won't work on a properly bedded rifle...vertical stringing is caused by velocity and bedding combined...All in all its a pretty worhless skematical publication that, like so many things, is worded so that its hard to contradict but is of little value aftwer you wash it.... IMHO....

That's the one objection that I have toward Mr. Atkinson ... it is hard to get him to really speak about what's on his mind! Tom Purdom

You'll get enough deviation one load to the next that any vertical stringing will be somewhat inconsistent. Variations in load will affect barrel harmonics too, as suggested here. A "one shot group" is not a group at all . . . It's a single shot, and doesn't provide any sort of sample size validity.

The best way to work up a load is with a chronograph. You can get a reconditioned Chrony (brand) for about $45.00 that will give you WAY more data than any vertical string scheme.

The other problem with technique is that you change the loads in 1/2 grain increments and your looking for impact variation based on that 1/2 grain. That kinda assumes absolutely zero holding error by the shooter. That is kinda tough to do.

Keep it coming guys - I ask questions when I want to learn from the wisdom of others.

Chronograph? Yes, I have one and really really don't like testing new loads without it. Groups are fine but I want to know about velocity and pressure.

Avoiding zero shift with half grain load increments? Is that be why the original article suggests doing this test further out than 100 metres - at 200 or 300? That way, any vertical variation is likely to be (1) magnified over the same effect at 100, (2) certainly likely to be more visible from the firing point and (3) by the same token less likely to be attributable to operator error.

Tempting in theory but I still don't buy the one-shot approach, long distance shooting notwithstanding (if vertical stringing is magnified at distance, so will aiming errors all the same). No, 3-shot groups would be more significative but then, we might as well shoot for groups, like we do since eons. My mind stays open but I remain to be convinced there's something rounder than the wheel...

PS.
Pete, fellow Roedeer hunter, have you read about the astronomical blunder I committed last night (cf. big game hunting topic) ?

I do a charge progession of 1% and shoot three shot groups. If you can get them all on paper without changing the sights, you get the easiest comparison.

The best of all worlds is when the smallest group is at the center of a cluster of consecutive small groups that are also close together on the target. Then you know the load is very insensitive and self-compensating at that charge weight.

How much vertical stringing you get with a charge increase depends on a lot of variables. Each rifle is a law unto itself. But it's important to hold the rifle as you will in use. Laying it on the bags and letting it free recoil will give you much different results than pulling it firmly into the shoulder and gripping the forearm.

Some rifles are also very sensitive to whether the magazine is fully loaded or not. Test it as you will use it, even though this does not give you the smallest "benchrest" groups.

Don

Andre - what are you like? I think I've probably been guilty of shooting the wrong fox when through the scope I've been able to see one which my lamping buddy hasn't been able to see - or he's been focussed on a different one.