7mm load development

[Rhunter2]

The best method I have found is the OCW (optimal charge weight) method for my 7mm Rem Mag, and all other calibers. It was started by Dan Newberry years ago. What you are doing is similar, except I shoot round robin like Dan does, and 100 yards is just fine. Two minutes between shots, and take a few fouling shots before you begin. I usually use 5 to 6 different charges, hence 5 - 6 targets. I also use QuickLOAD and a LabRadar. This way I can document everything I need accurately, especially the true burn rate of my H1000 at a given temperature while at the range. I don't get hung up on extreme spread and standard deviation anymore, and just go with what I see on target. You will find your optimal charge weight, it just takes time.

I didn't do the round robin but I don't believe my conditions changed much, if at all. I also think that the barrel should have been similar heat due to letting it cool frequently. I took a couple of three shot groups (68.2,68.5,68.8 @ 69.4, 69.7, and 70) and found the center of these groups. These two had the closest points of impact and each measured about 1.4". I believe that the Newberry method says to focus on those that group through different charge weights.

 

[Radhimself]

The 162's and 180's eld-m/x will stabilize FINE in a 1-9.25/9.5 twist

 

[Radhimself]

Seat that 162eld-x .3 off the lands and try H4831sc with a cci 250 primer

My sweet spot was at 67grn in Nos brass

 

[barefoot1]

Wow you stole my thunder Radhimself!
H4831sc 168 grn Interlocks and 162 grn ELDx's have also been outstanding for me.

 

[WalksLikeADeer]

Seat that 162eld-x .3 off the lands and try H4831sc with a cci 250 primer

My sweet spot was at 67grn in Nos brass

Did you mean 0.030" off the lands?

 

[RockZ]

The 69.4 to 69.7 range has very uniform velocities .The one shot at 3072 could be that piece of brass...use it for foulers.
Try 69.5 and do a seating depth test at 100yds. With the low ES and SD you should get at 69.5gr .it should make a great long range load.
You just need to dial it in. A seating depth test starting at .010" off the lands should do it. I've done it with loads just like you are dealing with for many many rifles and get them shooting in the same hole!

 

[Rhunter2]

The 69.4 to 69.7 range has very uniform velocities .The one shot at 3072 could be that piece of brass...use it for foulers.
Try 69.5 and do a seating depth test at 100yds. With the low ES and SD you should get at 69.5gr .it should make a great long range load.
You just need to dial it in. A seating depth test starting at .010" off the lands should do it. I've done it with loads just like you are dealing with for many many rifles and get them shooting in the same hole!

That is the way I was leaning. I think I might grab the 68.2 and do the same. All shells were seated .010 off for this test. Is it best to move out by .005 and how far out do you go?

 

[Hoppsing55]

Loaded some shells for my 7 rem mag. Loaded 3 shells in each group, increasing charge by .3 grains. Shots were at 200 yards. Had one load that had an sd of 0 and two with 4.04. Unfortunately these loads weren't close to one another. Load with 0 sd had one of the lowest vertical spreads but the group stunk. Had one group that shows a .9" group at 200 with a lowers vertical spread but the sd is almost 25. I don't see a clear path here. Any suggestions? I can load targets but there are 10 separate targets so I loaded the data instead.

Drop your low end node down a little. Maybe start at 67.1 / H1000 / under the 162 eldx.

 

[RockZ]

This a great start:
http://www.longrangehunting.com/thr...-from-berger-vld-bullets-in-your-rifle.40204/

 

[RockZ]

I do something similar but I load all of mine at .010" off and bring a portable press and do the seating depth test at the range.If you have to load at home I would only load 3 per seating depth and do them in .020" increments.all the way to .120 off. I shoot two and if they are not touching I go on to the next one. If a depth shoots a one hole group..I stop there. The 3rd one is for pulled shots or to confirm results so for the most part I shoot 2 shot groups until I find something interesting.

 

[RockZ]

After the first round if I don't get a one hole group I'll take the best one and fine tune it .
If two consecutive seating depths are shooting well I'll start at the midpoint of those.

 

[Shootin4fun]

I admit to being skeptical of the value of 3-shot groups. I haven't discussed this with a lot of accuracy nuts, but one friend who is pretty much an accuracy nut is satisfied with 3 shots while another insists on 5-shot groups to establish a useful baseline. I tend toward the latter. I wonder, if you were to load up five rounds each of 67.6, 67.9 and 68.2, would you collect a more instructive data set? At the very least, you would see if there is a random shot that creeps in somewhere.

Yup IMHO, 3 shot groups during initial load dev are mainly good for looking for pressure signs and getting a basic idea of where you are in velocity. You need at least 1 sample of at least 5 to get meaningful stats. Now of course if you shoot a lot of 3 shot groups, and they're the same size and same relative POI, then OK that means something. If I shoot 2 groups of 5 and see a pattern, it's likely real. Shooter inconsistency also can throw off your interpretation of a 3 shot group.

 

[Shootin4fun]

The best method I have found is the OCW (optimal charge weight) method for my 7mm Rem Mag, and all other calibers. It was started by Dan Newberry years ago. What you are doing is similar, except I shoot round robin like Dan does, and 100 yards is just fine. Two minutes between shots, and take a few fouling shots before you begin. I usually use 5 to 6 different charges, hence 5 - 6 targets. I also use QuickLOAD and a LabRadar. This way I can document everything I need accurately, especially the true burn rate of my H1000 at a given temperature while at the range. I don't get hung up on extreme spread and standard deviation anymore, and just go with what I see on target. You will find your optimal charge weight, it just takes time.

I factor in the OCW method, but don't shoot round robin because Magneto speed doesn't allow returning to a string. Once you hit a OCW, you can make fairly significant component changes and have the results be constant. I have loads where if I change the primer AND case, with no difference in POI. Example would be Lapua brass/small primer vs. Hornady brass and LR primer in a 6.5 CM.

 

[drborsos]

I factor in the OCW method, but don't shoot round robin because Magneto speed doesn't allow returning to a string. Once you hit a OCW, you can make fairly significant component changes and have the results be constant. I have loads where if I change the primer AND case, with no difference in POI. Example would be Lapua brass/small primer vs. Hornady brass and LR primer in a 6.5 CM.

I don't use my MagnetoSpeed when doing OCW, only when I want to know the velocity for the ambient temperature, etc. The MagnetoSpeed shifts my POI and can act like a tuning device. Then I can calculate the burn rate of my powder with QuickLOAD and be safe with pressure.