Thread: clarification 7mmRm + ar2217 + hornady eldx 150g

The method of shooting a group with each powder charge and checking for groups is good. Just don't start that high because it will probably be time & effort wasted.

After determining the max powder charge that can be run before pressure signs, I would then drop back a few grains under that limit and begin loading multiples to test for grouping.
eg lets say we determined that the max powder charge in the particular rifle is 70gr. I would then load 5 rounds of each from 66 up to 70gr. 66, 66.5, 67, etc etc.

Lets just say that the 68gr was the most accurate out of those. Id then make up more variations around that mark but with smaller changes in powder charge. eg 67.8gr, 68gr, 68.2gr.
I would then pick the most accurate out of those, and if I was still not satisfied with grouping then I would make minor changes to the seating depth of the best shooting load.

If I was still not satisfied, Id change projectile. That is (one of) the processes to working up a very accurate load.

Originally Posted by ChrisW

The method of shooting a group with each powder charge and checking for groups is good. Just don't start that high because it will probably be time & effort wasted.

After determining the max powder charge that can be run before pressure signs, I would then drop back a few grains under that limit and begin loading multiples to test for grouping.
eg lets say we determined that the max powder charge in the particular rifle is 70gr. I would then load 5 rounds of each from 66 up to 70gr. 66, 66.5, 67, etc etc.

Lets just say that the 68gr was the most accurate out of those. Id then make up more variations around that mark but with smaller changes in powder charge. eg 67.8gr, 68gr, 68.2gr.
I would then pick the most accurate out of those, and if I was still not satisfied with grouping then I would make minor changes to the seating depth of the best shooting load.

If I was still not satisfied, Id change projectile. That is (one of) the processes to working up a very accurate load.

absolutly perfect! thanks chris.

I have a "range" i can test locally, but not in a controlled enviroment with seating etc. So the initial pressure test will be fine to do there.

once i have pulled the projectiles off those rounds, Can I reuse the projectiles? or are they now buggered? Also - I have had to order a new collet for the eldx range as a few of the 300wm rounds had a crease put around the ogive of the projectiles upon seating, again.. wil these be stuffed once they have this crease ?

You can still use the pulled projectiles. If you are using a collet type puller just don't clamp down on them too hard.

Maybe post a picture of the .300 projectiles, Id think they would be ok and the only detriment might be slightly reduced accuracy, but without seeing the damage its hard to really say.
I would generally use such damaged projectiles for fouling shots, sighters, even the pressure test as accuracy is of no concern; and use only non-damaged ones for the serious accuracy/group testing.

Originally Posted by ChrisW

You can still use the pulled projectiles. If you are using a collet type puller just don't clamp down on them too hard.

Maybe post a picture of the .300 projectiles, Id think they would be ok and the only detriment might be slightly reduced accuracy, but without seeing the damage its hard to really say.
I would generally use such damaged projectiles for fouling shots, sighters, even the pressure test as accuracy is of no concern; and use only non-damaged ones for the serious accuracy/group testing.

perfect, what a massive help. I have a Lyman magnum bullet puller on its way.
I have made myself a little bit of a plan if you wouldnt mind looking over it quickly? Also Are these powders ok for both of these ? Or would you or somone else recommend a different powder? From what i can tell 2217 is good for 7mmRm, and ok for the 300.

7mmRm
1x 150g hornady eldx + 64g ( min book amount )
1x 150g hornady eldx + 64.5g
1x 150g hornady eldx +65g
1x 150g hornady eldx +65.5g
1x 150g hornady eldx +66g
1x 150g hornady eldx +66.5g
1x 150g hornady eldx +67g
1x 150g hornady eldx +67.5g
1x 150g hornady eldx +68g
1x 150g hornady eldx +68.5g
1x 150g hornady eldx +69g
1x 150g hornady eldx +69.5g
1x 150g hornady eldx +70g
1x 150g hornady eldx +70.5g
1x 150g hornady eldx +71g
1x 150g hornady eldx +71.5g
1x 150g hornady eldx +72g ( max book amount )
1x 150g hornady eldx +72.5
1x 150g hornady eldx +73g


300WM
1x 178g hornady eldx + 76g ( min book amount )
1x 178g hornady eldx + 76.5g
1x 178g hornady eldx + 77g
1x 178g hornady eldx + 77.5g
1x 178g hornady eldx + 78g
1x 178g hornady eldx + 78.5g
1x 178g hornady eldx + 79g
1x 178g hornady eldx + 79.5g
1x 178g hornady eldx + 80g
1x 178g hornady eldx + 80.5g
1x 178g hornady eldx + 81g
1x 178g hornady eldx + 81.5g
1x 178g hornady eldx + 82g
1x 178g hornady eldx + 82.5g
1x 178g hornady eldx + 83g ( max book amount )
1x 178g hornady eldx + 83.5g
1x 178g hornady eldx + 84g


And fire each round, Over the Chrono , record the speed aswell as look for pressure signs. Then once pressure signs are apparent, Drop back to the previous load.

Next step : Once I have figured out the correct pressure range for my setup eg.70g for the 150g 7mmRm, then load 5 of each of 67g, 67.5g, 68gm 68.5g, 69g, 69.5g, 70g.

Next Step : Once fired, Choose the recipe with the best grouping , eg. 68.5g , and load up 3x rounds of 68.1g, 68.3g, 68.4g, 68.5g, 68.7g, 68.8g ?

If im still not getting any good accuracy then I need to switch projectiles or powder ?

"Next Step : Once fired, Choose the recipe with the best grouping , eg. 68.5g , and load up 3x rounds of 68.1g, 68.3g, 68.4g, 68.5g, 68.7g, 68.8g ?"

Yes you could load 5 of each of those powder charges (or however many you want) if you wanted to be thorough about it. I think when you start getting into .1 and .2gr increments (on a large capacity case like a magnum) its time to move to seating depth tests as we are looking "resistant" loads with a big velocity flat spot where .1 or even .2gr shouldn't make any meaningful difference. More on that below.

In regards to shooting the pressure test over the chrono - if you can do that it gives you a much more accurate starting point for your development.
If you can identify flat spots in velocity, where additions of powder result in minimal changes in velocity - then those are the places to start your load development around.

I previously described doing it without the chrono, but with a chorno instead of doing a run from (example) 64gr up to 70gr then picking the best and going from there, I would only make loads around the areas where there were minimal changes in velocity.
Ideally you want to focus your efforts around areas where velocity remains stable over a fairly wide powder change. This makes for a very resistant load. ie if you got a bit sloppy with your powder charges or your scale deviates by a little bit, it wont really make a difference as you are looking to work within a wide "node"

See this thread in particular my post where I did a pressure test as I describe, and identified flat spots in velocity in which to focus my future development. Note that for example from 69 to 70gr velocity only changed by 21fps across a whole grains addition of powder, and by comparison to other places in the test this is a definite flat spot...that means in theory as long as im anywhere in between those charge weights, velocity should be consistent and so this should make for a very resistant load.

https://www.nzhuntingandshooting.co....55/index3.html

In cartridges of .30-06 or 7mm mag size I would only load in 1 grain increments for your ladder test. Look for the cluster of 2 or more shots from successive loads and then work on the variables of seating depth and possibly fine tuning the powder charge. 5 or 6 rounds max should do the job.

Anecdotal data and manuals will tell you about where you want to be with a given powder and projectile. But you need to work up to this with your ladder test to be safe first off and confirm the load velocity and accuracy node is the same for your rifle.