[chrism]

Well, had to do some errands in town today, and decided to try out a few new loads with the rifles - the range in Grand Rapids is 200yds, which is the distance I like to sight in at.
First up is a 260 rem, did some load developing earlier and found this load - but wanted to try it out again just to verify that it grouped as good second time around - found it with OCW gig, which makes me a believer in that method! 44gr h4350, lapua 123 scenarios...say no more!
2nd up was my new/old gun, an older m70 action that was turned into an exotic build - Manners t5 stock, m70 action, and Shilen 5.5 match barrel, 325 wsm caliber - am just starting the development/barrel break in on this beast, so stay tuned!!! This round was 62gr h4350 with a 200 NAB, just above the min book load...


Here is the range, setting up the 260...

then I just about shit when I walked up to the target - I could see that they were close thru the scope, but was smiling from ear to ear when I got close and saw with my own eyes! Thats a 5 shot, 200yd group! the one 'flyer' must have been shot the instant that mosquito bit me...lol!

Then it was Mr 325's turn - here is the beast - the loads were on the light side, but they still let you know that this was a big gun...

for the start of load development, this looks promising - again, 5 shots, 200yds

That was my afternoon!

 

[Riggs]

Looks like you're just about ready.

 

[snomad]

I am scratching my head; what is an OCW gig? Nice shooting BTW.

 

[chrism]

OCW, Optimal Charge Weight - you load up a bunch of rounds with varying powder capacity (say 3rnds each of 5-8 charge weights- shoot the different loads in sequence at different targets, and look for the loads that have the same point of impact - that means that is what your gun likes.
Another way to do it is to shoot all these loads at 100yds at same target, and watch the shots go for horizontal to vertical, the junction of the two is your sweet spot.

As an example, the pic above with the 325 shows horizontal stringing - seeing that I will bump up the charge a wee bit at a time (say 62, 62.5, 63, 63.5, 64, 64.5, 65grains) until it starts to go vertical - then repeat, and note where the change in impact from H to V is - provided there are no pressure signs, this will be my MAX go-to load for that gun.

 

[Riggs]

You can also get horizontal stringing as the barrel warms up, if there's unequal forend pressure on the sides of the barrel. That's one of the reasons I like free floating my barrels.

 

[snomad]

Some call that a ladder test. Finding the best nodes and fine tuning around those. Another variation of this test is to load single cartridges .2 or .3 grains apart from min to max. Shoot these at the same target. The loads that seem to group the same spots without continuing to climb the target are your nodes. Fine tune with .1 increments around those nodes to find the best load/s. Of course observing for pressure signs along the way. Some say to play with distance to the lands with a safe loading first and then tune the charge weight. With a lot of hunting rifles you can't get close enough to the lands before you run out of mag room. Another interesting thing is that some loads may group better at longer range due to bullet stabilization. Check those loads of yours at 100 yards to see how and where they group.