Range Day - 7mm RM

TackDriver284 · Apr 12, 2017

Side note, H1000 is too slow to use with light bullets, it works best with heavier bullets. Try a faster powder like RL 19, RL 22, IMR 4350

Darkhorse · Apr 12, 2017

I would work your seating depth first to find a node. Changing your seating depth can move your POI on the target as well as tightening up the group.
I choose the bullet and powder I want to use, and the charge weight. Then I do pressure testing to be sure the load is safe in my rifle. After that it's mostly fine tuning the seating depth until I get a load I'm happy with.
If you work with charge weights then you change the velocity and when the bullet exits the barrel. You are looking for a node.
If you work with seating depth you change where the bullet exits the barrel. You are still looking for a node.
I might be wrong but that's the way I see it.

boomer68 · Apr 13, 2017

Darkhorse: That's what I'm thinking as well. Seating depth is the key. I have a Hornady OAL tool, but have to pick up a 7RM case.

hereinaz · Apr 13, 2017

Darkhorse":1482hiup said:
I would work your seating depth first to find a node. Changing your seating depth can move your POI on the target as well as tightening up the group.
I choose the bullet and powder I want to use, and the charge weight. Then I do pressure testing to be sure the load is safe in my rifle. After that it's mostly fine tuning the seating depth until I get a load I'm happy with.
If you work with charge weights then you change the velocity and when the bullet exits the barrel. You are looking for a node.
If you work with seating depth you change where the bullet exits the barrel. You are still looking for a node.
I might be wrong but that's the way I see it.

Darkhorse, you are right on finding a node for any particular charge by adjusting seating depth. I do that as my second step after the OCW test, to "accurize" the load.

You are just cutting out out the load development step that looks for a charge weight, and going to accuracy. You will hit great loads that way too.

Some reloaders get confused thinking the OCW test is to look for accuracy. Maybe that is what got the OP. So, if OP wants to go right to accuracy, your test is the best bet. Many loads have been found without it.

OCW test is done first to "optimize" the charge weight of powder that will be most resilient/flexible to changes in pressure as a result of factors like variances in case capacity, temperature, under/over charges, even going as far as brass and primer changes in some instances.

The ladder test is similar to OCW, in that it looks for powder charges that provide similar velocity by measuring/comparing drop at distances like 200+ yards. The OCW measures/compares the POI of groups instead of drop.

For either the ladder or OCW test, the objective is finding the charge weight of powder that is least sensitive to the variables of loading. In OCW lingo, the charge is "optimized". It won't necessarily be accurate yet. That is what confused me most trying to learn this stuff.

The ladder test is rarely mistaken as an accuracy test because no "groups" are shot. But I think because reloaders shoot groups in the OCW test, people focus on "accuracy" of the individual groups instead of imagining as if the center point of each group were one bullet hole and finding the "OCW node"...

OCW node doesn't always correlate to an accurate load, because accuracy is affected by the jump/jam. Consequently, the next step in load development after the OCW test is to "accurize" the optimal charge weight by following steps like Darkhorse mentioned to accurize the load.

And, as I said above, my "OCW" test put me onto an Optimal Charge Weight, but my jump was too short. So, I tested bullet seating like Darkhorse, and shrunk my groups that started from just over MOA down to shooting a .5 MOA group at 200 yards. I am a rookie shooter and this was my first ever time reloading and doing the OCW test. May have been luck, but I attribute any luck to following the system.

Hope that is what OP was looking for.

Sent from my SM-G920V using Tapatalk

Darkhorse · Apr 13, 2017

boomer68":2u8yhy4v said:
Darkhorse: That's what I'm thinking as well. Seating depth is the key. I have a Hornady OAL tool, but have to pick up a 7RM case.

boomer, if you have a set of Hornady bullet comparators then you don't need a extra 7mm case. Just look for the one that has .280 stamped on the side and attach it to the sliding anvil on your calipers. Then squeeze the other anvil tight against the gauge and adjust the dial to read "0". With a dummy case find the distance to where the bullet contacts the rifling and write that number down.
I record my seating depth as "Distance to lands", any changes in seating I reference from this number.
Was that confusing?

pharmseller · Apr 13, 2017

I use the Nosler max load of 72 grains of MagPro and 160 Accubonds for 3,000 fps and great accuracy, OAL 3.245". This load shoots sub-MOA in 2 Tikka rifles.

P

Darkhorse · May 1, 2017

hereinaz":14h3pxv8 said:
Not sure your skill, but I know that my groups have shrunk more because I learned to be a better shooter, than because I have better ammo... Big factors, I leveled my reticle on my scope, I put on a bubble to prevent cant, learned to load my bipod, I got better trigger control, I have better breathing, I use more consistent form behind the rifle, I find natural point of aim, etc.

To all that, I am grateful for forums like this. Before, I think I traded away a great shooting gun, because I didn't really know how to shoot...

You have hit the nail squarely on the head. All those things you mentioned should be practised until they become second nature. Muscle memory if you will.
One thing I've noticed over the years is only a few will put in the time to really become a good shot. Even bench skills are mostly mediocre. No telling how many accurate rifles have been sold or traded off because the shooter couldn't get MOA out of it.
One thing for sure, if the shooter can't shoot a 1/2" group then no matter how accurate the rifle is it will never shoot a 1/2" group.
Just keep doing what your doing and things will go your way before long.

sask boy · May 2, 2017

I have loaded for 2 different 7mm mags for many years and I am now loading one of them with 168gr ABLRs & RL22 it is accurate but I believe with a little adjusting in the OAL it could even get better.
The load for the other 7mm mag is 160gr. ABs and IMR4350 and it has shot very accurately in every rifle I have ever loaded it in

.

Blessings,
Dan