ladder test or dot target for OCW

markc.mcconnell

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Minuteman
Feb 25, 2010
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Phoenix AZ
Good morning guys. I have a question about testing for optimal charge weight. I am load building .308 with Varget 175 SMK Win brass. When testing has anyone ever used a sheet of paper with 1" dots instead of doing a ladder. To be more descriptive; sight the rifle in and then shoot one round per dot. Any thoughts on this? thanks.
 
Re: ladder test or dot target for OCW

If i were doing an OCW I would place dots evenly on the paper... one dot for each different load. I would then mark them appropriately and then fire the rounds in a round robin sequence. For example, 43.0, 43.5, 44.0, 44.5, 45.0, 45.5 and then back again 43.0, 43.5, 44.0, 44.5, 45.0, 45.5... obviously with each different load you would shoot the appropriate dot target. I would look for the nicest group and also the flattest group.

If i were performing a ladder I would place one dot on the bottom of the paper and shoot a sighter to make sure you are on paper. I would then fire them in the following sequence, each time aiming at the same one dot on the bottom... 43.0, 43.5, 44.0, 44.5, 45.0, 45.5. I would look for shots that land in a similar horizontal place, and research more from there.

I like to develop loads at around 300 yards as a minimum. Allows me to determine which charge gives me the most consistent muzzle velocity, which in turn equates to similar bullet drop each time, more consistent ES and SD. These effects are often masked at short distances.
 
Re: ladder test or dot target for OCW

With a ladder you only load one round per charge weight but with the other do you load more than one round and if so how many per charge weight? I was thinking of only 1 with either test but maybe more would be better. Thanks for the reply.
 
Re: ladder test or dot target for OCW

Exactly. The ladder sorta saves you more ammo, and is my go to method of load development. It also forces you to focus on the one outcome really and that is what offers consistent muzzle velocity across the board.

OCW, can be a little misleading to some.
 
Re: ladder test or dot target for OCW

it's more ammo, but I do a combination of both. I do a ladder at 300 yards while doing pressure testing to see where my upper limit is.

Look sequence of charges that has the smallest vertical dispersion and then take those charges and load up 3 rounds of each and see how they print.

If they all have a similar point of impact I'll take the middle charge and choose that as my load. I'll play with seating depth if I'm not happy with the groups...Usually I don't have to.

All shots are over a chrono as well and the conditions are well documented for each session.
 
Re: ladder test or dot target for OCW

http://optimalchargeweight.embarqspace.com/

http://mikeswillowlake.com/Downloads/LadTestinst.pdf

http://www.6mmbr.com/laddertest.html

I prefer to do the Jason Baney method when I get the opportunity to shoot at longer ranges. I think it is a better compromise between the other two methods.

I do not see a reason why you couldnt do an OCW test just shooting at single dots. I would have 3 rows of dots with the differing charge weights. Shoot 1 round at each dot round robin for first row, then repeat x2. Compare POI between each sequential shots, then see if the pattern repeats 2 more times. I would shoot at least 3 rounds at each charge however. (I think you need to shoot ladders 3 times too for them to mean anything, IMO).
 
Re: ladder test or dot target for OCW

Good post!
3 weeks ago I started to do the same exact load for my 24inch barreled Savage.
What I did was this:
Did a 300yd ladder test one day being Very Very meticulous. That gave me a load range to work with. Which was the 43.5-45 grain range. The 43.5 was truly not needed as I wasn't truly happy with it's results on the ladder but I wanted to make sure.
I then loaded 5 rounds of these loads at .5g intervals.
Then it was back out to 300yds. 5 rounds of each load at its' own target. So that means I had 1 fouling target and then a single target for each load. That showed very very clearly what load the rifle liked. It happened to like the 44.5 the best. The grouping for that target was clearly much smaller than the other loads
Now my plan is to load 5 rounds of each 44.3, 44.5 and 44.7 and go to 300yds again.
All of these are being set to my chamber lengths as is eveything else just for my gun.
I don't think the 1in dots are going to help you. It's not what a ladder test is all about.
Save those dots for the OCW test!
Good luck let us know how it goes.
hope that makes sense...
T
 
Re: ladder test or dot target for OCW

good work rover31. If you have a chrony to shoot this over even better.

When you hit a node smack bang in the middle, you usually get consistent MV and a little forgiving area in regards to charge weight... a few kernels either side should not make a significant difference if your in the middle.
 
Re: ladder test or dot target for OCW

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: vman</div><div class="ubbcode-body">good work rover31. If you have a chrony to shoot this over even better. </div></div>

yes I do, crappy Chrono Master Beta. Chronos teach a lot.

The links provided above explain much better than I ever could, read them, print them out.

 
Re: ladder test or dot target for OCW

Please excuse my ignorance on this subject, I have a question.

If you have a good accurate load for a given distance what is the purpose to keep increasing the powder charge until there are signs of excessive pressure?

Isn't it true that you might have one load that works very good at a given distance and then another that works good at a different distance.
 
Re: ladder test or dot target for OCW

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: kwak</div><div class="ubbcode-body">Please excuse my ignorance on this subject, I have a question.

If you have a good accurate load for a given distance what is the purpose to keep increasing the powder charge until there are signs of excessive pressure?

Isn't it true that you might have one load that works very good at a given distance and then another that works good at a different distance.

</div></div>

There are two big factors when it comes to long range ballistics... to me those two factors are ballistic coefficient (BC) and muzzle velocity.

A bullet that travels fast has less lag time than a slow bullet... this is, the time taken to reach the target.

Say you then have two bullets with identical BC's but different muzzle velocities. Say you then shoot those two bullets out to 1, 000 yards. The faster bullet obviously hits first, and the slower hits last. Both have an identical BC but one of those bullets spent less time in flight towards the target, and in theory in a constant wind, will receive less time in the wind.

Its like comparing a 7mm-08, 7wsm, 7mm RM, and a 7mm RUM that all shoot a berger 180VLD. The 7mmRUM will have the advantage of speed over all of the other cartridges (at the expense of massive recoil and shorter barrel life).