Pressure signs

[243winxb]

Hodgdon- EXTREME CONDITIONS 0 to 125 degrees. Has to make a difference with ANY POWDER.

Lot to lot consistency would seem to be a bigger issue?

Hodgdon said-

LOT CONSISTENCY
Hodgdon goes through painstaking measures to ensure that all powder is consistent from
lot to lot.

• Sep 19, 2017 from "unclenick"
Hodgdon says they keep the burn rate to ±3% for the Extreme line of powders and ±5% for the IMR line

post #8 https://www.shootersforum.com/threads/h4831-lot-ot-lot-variations.186113/

Google "hodgdon h4831 difference in velocity different lots" Old 2012 info.

So, from the slowest lot to fastest is 6% & 10% as of 2017. If you worked up to maximum with the slowest lot and a new lot is 10% faster, your over pressure.

 

[Mike Matteson]

I am aware of powder lots there is a burning rate change or can be. The extreme conditions needs to be watched very closely too. As I stated before, I ran into this problem in around 2000 with IMR 4350 & IMR 4831. Blow a primer out of case, and bolt was very hard to open. H4350sc had been out about that time I believe. Read up in the H4350 and changed over and never looked back. I hunt in weather temp. from +100 to -20 degree. I can't have the extreme change on how the powder is going to react. I do use W760 powder, and beginning to chart the difference in change in temperature. I haven't had any problems with W760 yet and used it in 100 degree and in 30 degree weather. I will this winter see how the w760 hold in velocity in in the colder temperature. The W760 load was develop in the warmer weather. The one thing I would like to see all powder companies have a chart on extreme conditions with their powders. I do weight all my cases. Have found that the heavier case that chamber pressure do change. I do load above what the reloading manuals call out for in developing a load. I don't just come up with a load and use it in different rifles. Each rifle that I load for is on it's own chart for loading. I do own more than one rifles in the same caliber, and load for other rifles that are the same cartridge.

 

[rsnell]

Nosler developed their loading data using Winchester large rifle primers and lists the accuracy load as 43 grains of varget. That does not mean your rifles will find 43 grains of varget as the most accurate load but primers do make a difference. How much is the bullet jump?

 

[BoomFlop]

My jump is .1055 to lands, which was determined by seating depth test.

 

[Mike Matteson]

Varget is rated at 8 on the Extreme Velocity Spread. So weather doesn't effect the powder much being hot or cold. I never have used Varget powder, but I going to look into it.