Load development VLD's

elktaker

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So I am awaiting my new barrel and trying to figure out how to load develop Berger VLD's. My old barrel did not allow me to reach the lands so I just shot groups at max coal with different powders.

This is a 7mm WSM with a short throat so my VLD's will touch the lands at magazine length. I am shooting 168 Berger VLD's with Norma MRP.

I currently only have 8 cases (20 more waiting to fireform). I loaded 8 the following for a short break in/test pressure.

2 of each:
62, 62.5, 63, 63.5 (I be chronographing all of these and check for pressure)

Hopefully this will get me on paper and zero-ed at 100 yd. Then I will CoW Fireform the 20 case (270wsm) I have and give the barrel a good cleaning.

My question is when I start developing a load should I pick a charge say 63.7gr (-.5gr published max) and start with distance from COAL?

or should I pick a standard COAL and vary charges?

(Barrel is a 3 groove Pacnor 28" and it will be lots of steel/paper shooting but purpose is hunting big game)
 

elktaker

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Thank

So start OCW style (.020 off lands) then do seating depth.

Might stretch it to 200 instead of 100 to help interpret it a little better.
 

coyotezapper

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Thank

So start OCW style (.020 off lands) then do seating depth.

Might stretch it to 200 instead of 100 to help interpret it a little better.

Don't confuse this with OCW, they are similar but not the same. I go to 1000 yards or transsonic after the 100 yard testing and have never had a problem and this is for BC validation purposes only. Groups that are good at 100 are good at 1000 if done right. Pay attention to vertical and velocity - you will see the flat spot - node.
 

elktaker

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Don't confuse this with OCW, they are similar but not the same. I go to 1000 yards or transsonic after the 100 yard testing and have never had a problem and this is for BC validation purposes only. Groups that are good at 100 are good at 1000 if done right. Pay attention to vertical and velocity - you will see the flat spot - node.

What is the difference other than range from an OCW? Are you selecting the best group the same by finding groups that have similar impact/velocities? Then picking in the middle of that node.

Barrel was suppose to be finished yesterday, but I have my doubt. Read a few reviews of Pacnor saying it will be done then barrel is done 2 months later. Fingers crossed, next week I will have a barrel.
 

coyotezapper

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What is the difference other than range from an OCW? Are you selecting the best group the same by finding groups that have similar impact/velocities? Then picking in the middle of that node.

Barrel was suppose to be finished yesterday, but I have my doubt. Read a few reviews of Pacnor saying it will be done then barrel is done 2 months later. Fingers crossed, next week I will have a barrel.

Yes, you have the general idea but read the entire thread to understand it entirely. First step is to find powder charge and then fine tune with seating depth. While finding powder charge / flat spot ignore group size, look at vertical and velocities only.
 

elktaker

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Yes, you have the general idea but read the entire thread to understand it entirely. First step is to find powder charge and then fine tune with seating depth. While finding powder charge / flat spot ignore group size, look at vertical and velocities only.

Thanks, I understand that I am looking for a node were the charges are giving close to the same velocity and vertical spread ("flat spot"). To give me a sweet spot that always for temp change and human error in powder to have less affect than just picking the best group. Then I will get into seating depth and fine tuning the charge to find the top and bottom of the node as explained in the forum.

I am just not sure how it differs from OCW for the first groups other than the range (or maybe I have been doing a modified version of OCW development).
 

Mikecr

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There is a key flaw in OCW: It leaves you assuming initial seating depth, while focusing purely on powder. This is a carry-over from the origins 'incremental load development', and 'ladder testing', that do this as well.

Powder is actually the fine adjustment to grouping, seating is the coarse adjustment.
As with anything else, we should adjust coarse first, followed by fine adjustment.
That means:
1- Berger's seating testing
2- Powder testing(ILD, Ladder, OCW, etc.)
3- Fine adjustment of seating -to shape grouping(without collapsing your powder results)
 

elktaker

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There is a key flaw in OCW: It leaves you assuming initial seating depth, while focusing purely on powder. This is a carry-over from the origins 'incremental load development', and 'ladder testing', that do this as well.

Powder is actually the fine adjustment to grouping, seating is the coarse adjustment.
As with anything else, we should adjust coarse first, followed by fine adjustment.
That means:
1- Berger's seating testing
2- Powder testing(ILD, Ladder, OCW, etc.)
3- Fine adjustment of seating -to shape grouping(without collapsing your powder results)

Okay so I should start with Seating (the other forum linked by coyotezapper starts with powder then seating then back to fine powder).

So should I just load rounds .5 below published max. That would be 62.7 gr of Norma MRP for the Beger's seating test.

(I will check pressure signs during sight in up to published max)

Then I will do OCW and fine tune like you suggest.
 

Mikecr

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I do my best to test away from any expected powder tune. This way I'm seeing the affects of seating, and not seating combined with coming out of powder tune. Seating is enough of an abstract on it's own.

The folks thinking start with powder then seating then back to fine powder, have it backwards. They're thinking powder is the coarse adjustment, and seating is fine.
But when you do an ACTUAL seating test, you'll see groups open/close/open more than ANY amount of powder change can cause.
And with this, best seating as determined through actual testing, holds, even with powder changes(as in different powders).

Put another way; if you're seating is not best, no matter what you do otherwise your gun will not be shooting it's best. It can only shoot the potential that bad seating allows.
 

FearNoWind

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Powder is actually the fine adjustment ... seating is the coarse adjustment.
.. we should adjust coarse first, followed by fine adjustment.

That means:
1- Berger's seating testing
2- Powder testing(ILD, Ladder, OCW, etc.)
3- Fine adjustment of seating -to shape grouping(without collapsing your powder results)

I agree (I'm a recent convert) that there needs to be a "best of show" seating depth established early in the process using a moderate powder charge before we begin testing for optimum powder quantities. But we still end up tweaking the seating depth as the final step. If we schedule seating depth as the "fine adjustment" to shape grouping then seating is not the coarse adjustment. We can't have it both ways Mike.
 

Mikecr

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Berger's full seating test is first. This is coarse.

When I say "Fine adjustment of seating" (last) I'm talking tweaking a couple thou at a time both ways over a window of ~10thou max.
I suspect this is what most people actually do instead of full seating testing, and probably where they latched onto the notion of seating being fine.
That is, they guess initial seating rather than finding best. Then they work powder, then they tweak seating a bit. This is shaping without reason to be anywhere near best seating to begin.
They could get lucky. That's not me(I'm not lucky).
 
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