Lapua VS norma powder volume data

[noload]

Now I have this data and I don't know what to do with it. Through averaging the weight of a empty case and a water filled case (5 of ea.)(Norma vs lapua). I have found a Lupua case is bigger inside by 2 grains of water, which equals to 44 kernels of long grain 4831, or 1/27th of the total volume of power that I use for my 284S load.
The reason I did this is because the Lapua junky practice cases considerably out shot the Norma with the same load, and I'd like to adjust the air powder ratio in the norma cases to shoot the same as the Lapua.
It may very well be there is something else at play with the cases other than strictly powder/air volume ??
Any thoughts ??

 

[noload]

I hope your response is not: WOW this guys got too much time on his hands.......

 

[CatShooter]

Now I have this data and I don't know what to do with it. Through averaging the weight of a empty case and a water filled case (5 of ea.)(Norma vs lapua). I have found a Lupua case is bigger inside by 2 grains of water, which equals to 44 kernels of long grain 4831, or 1/27th of the total volume of power that I use for my 284S load.
The reason I did this is because the Lapua junky practice cases considerably out shot the Norma with the same load, and I'd like to adjust the air powder ratio in the norma cases to shoot the same as the Lapua.
It may very well be there is something else at play with the cases other than strictly powder/air volume ??
Any thoughts ??

"WOW this guy's got too much time on his hands.."

(Sorry, I couldnt' help it - the devil made me say it)

Your question is worded somewhat obtusely, but if I get the jist of it...

The only way to reduce the internal volume of cases (other than brazing some brass filler inside on the walls), is to seat the bullet deeper so the two internal volumes are equal.

But, of course, this means you surrender control of "jump and jam" with the Lapua cases

It would be much easier to develope two loads for the two different cases.

 

[mikecr]

How bout the flash holes?
Are cases same fire formed outer dimensions?

 

[noload]

Its a 284 shehane, powder I'm using is 4831 55.0 gn. Lapua case shoots .575" 6 shot group at 300. Norma case, same load, 4 shot group is 1.30 group, I trying to blame the poor performance of the Norma case on a difference of internal room. And was trying to figure out if I could mathematically come up with a different powder charge to make it shoot as good as the Lapua case.

 

[JamesnTN]

Try a faster burning powder using less powder will allow for more space in the case.

 

[DocBII]

noload,

Decrease the powder charge in the Norma cases, use a ladder test to determine how much. It's possible to use the 0.1 grain/grain of case weight adjustment, but I'd be reluctant to do this with different brands of brass.

HTH,
DocB

 

[Erik Cortina]

Is this the new .284 Win. Norma brass you are using?

 

[dmoran]

Adjust the charge to match the velocity and they will produce near equal performance - IME
Donovan

 

[noload]

Not the New norma Eric. This is formed from 6.5x284. I did reduce the charge from 55.3 to 54.8 and it gave me a good Vertical of .750" at 600yd ( 5 shots ). I have to run it thru the crony now and verify that group a few more times before I make it my control load.

 

[Erik Cortina]

I agree with the others, adjust charge to compensate for difference in brass internal capacity.