New Powder lot ?

[savageshooter86]

If I have excellent load worked up and have to switch powder lot do I load to same velocity or re work entire load completely?

Thanks

 

[Jason Boersma]

Most will tell you to recheck your load, I have never worried about different lots of powder, just load and shoot

 

[Geno C]

If I have excellent load worked up and have to switch powder lot do I load to same velocity or re work entire load completely?

Thanks

I always mix my old stuff and new stuff together. Minimizes the variance a bit. But yes, if you want the most consistant load again you gotta drop the charge and work back up to where you are now. Varget over the years has given me some decent swings even after mixing.

 

[WyleWD]

I would suggest that you rework the powder charge using the same cases, primers, bullets, and seating depth. And especially if it is Varget. As Geno stated above I have seen some glaring lot to lot differences in it. JME. WD

 

[Ned Ludd]

You can check the velocity first with the new powder. If it's spot on that from the old Lot, you're GTG. The downside is that if the burn rate of the new Lot of powder is significantly different (i.e. faster), you might well be overpressure with the same charge weight. I've seen as much as a 75-100 fps difference between different Lots of the same powder. That is more than enough to alter the properties of the old load and create potential pressure issues trying to start with the new Lot of powder at the old charge weight. I typically reduce the charge weight by 2% with a new Lot of powder for safety reasons, then determine velocity. At that point, the reloading program Quickload is very useful tool for estimating what your velocity with the new Lot of powder will then be at the old charge weight. In my hands, even if the new Lot of powder has a significantly different burn rate from the old Lot, matching the [optimized] velocity of the old load with the new Lot of powder will get the load very close to where it was before.

 

[savageshooter86]

Yes it's varget. I'll keep everything same and drop charge and try to get back to velocity I am at now. Sucks to waste barrel to find out but needs to be done. load and barrel are hammering. Kind of makes me want to take off and save

 

[Berger.Fan222]

One advantage of keeping charges and pressures moderate is you can just start with the same load, check it, and see where you are without much risk of overpressure.

If you are already close to max, you really should drop down and work back up. We also leave containers open for a few days to acclimate to southern humidity. 43 grains of Varget from a newly opened container is a lot hotter than 43 grains of Varget left on the bench for 3 days in 50% relative humidity.

 

[The boogalorian]

I am starting a new lot of H4350 in a 6.5x47L. My loads were not showing any pressure signs (primers still rounded). Planned on loading the new powder at the same charge weight and checking avg velocity.
I see that most are referencing target above, any insight as to what I might expect with H4350?

 

[Berger.Fan222]

I am starting a new lot of H4350 in a 6.5x47L. My loads were not showing any pressure signs (primers still rounded). Planned on loading the new powder at the same charge weight and checking avg velocity.
I see that most are referencing target above, any insight as to what I might expect with H4350?

Most reloaders are not as good at recognizing signs of pressure as they think they are. If the old lot had you right at max, you may not see signs of pressure, but the new lot could put you over max.

So in addition to looking for pressure signs in the primer and brass, you should also consider if you are close to book max, what QuickLoad suggests your pressure is, and whether your velocity with the old lot suggests your pressure is close to max for your barrel length. Also, some bullets (solid copper usually) are much less forgiving of new lots of powder that are a bit faster.

I have a lot of experience with H4350, and I have not seen the lot-to-lot and other unexpected pressure issues that I have seen with Varget and Retumbo. But I am still more comfortable transitioning between lots for loads a couple grains below max than for loads right at max. What many reloaders think is max (from pressure signs) is probably 5000-10000 PSI above the SAAMI spec for max pressure.

 

[rardoin]

Yes it's varget. I'll keep everything same and drop charge and try to get back to velocity I am at now. Sucks to waste barrel to find out but needs to be done. load and barrel are hammering. Kind of makes me want to take off and save

I just load up a single cartridge of each charge weight starting at .4gr low then .2gr low then exactly at my known good load and fire over a chronograph...just takes 3 shots to know if you are in the same ballpark and where to begin load development IF needed. With RL-16 and RL-23 in two different cartridges I did not have to vary the charge weight with a new lot. With H4350 I had to increase the charge .2gr to keep the same velocity in one cartridge.

 

[mram10]

I was a load and shoot guy till I got a hot jug of h1000. Now I do a quick ladder for velocity and try to match while checking nodes again. Roughly 12 shots for insurance is worth it to me