Lot to lot velocity changes?

[rybe390]

Hey folks!

I just got back from a range trip that was meant to confirm zero and confirm Chrono data before a match this weekend with my 6.5 Grendel. I worked up a solid pet load and hope to run with it for a while.

Turns out, I was shooting 45fps slower than the last time I tested this load. Accuracy was a bit less than before but still shot well.

Do different lots of powder make this much of a difference that I can have a 50fps bump/drop? Or could it be 1x brass vs 2x brass this go round?

I do enjoy reloading, but I do not like constantly chasing. What can I do in my process to make sure I can have minimal "chasing" once I find a good load?

For reference: 6.5 Grendel, 123 eldm, 2.26 coal, 28gr IMR 8208 xbr, cci 450, hornady brass

 

[Airw4ves]

Someone once told me that he called Hodgdon to ask about a variation like yours and they said their tolerances are 50fps on either end of thier posted speeds. So a potential variance of 100fps. Although doubtful many will see that kind if a difference, it is commonly known that large differences in lot number will have different speeds.

Pretty much everyone I know follows the same rule. Find the powder you want, and buy as much of it as you can from the same lot. Now another option is that if you find say 8 x 1lb’rs of different lots, mix them all to make your own “lot”. I did this with an 8lb of H4350 and two 1lb bottles I had, and have had nothing but consistent velocities. Just be sure to seal it up tight and keep it in an appropriate climate since you’ll be breaking the factory seal.

 

[Sheldon N]

I just changed lots of XBR8208, 10 fps velocity difference so not too bad. I've seen worse with Varget.

Answer is to buy in bulk, get a couple 8lb jugs each time and work your way through them.

 

[dgheriani]

Yeah, Varget is bad for lot to lot variations, I've had a 50fps swings before. H4350 is better, never had much more than a 10-15fps swing. I always load 5 or 10rds with my current powder charge when I open a new 8lbs jug and compare side by side with ammo with powder for the old lot to see if the MVs match.

 

[Tx_Aggie]

I just changed lots of XBR8208, 10 fps velocity difference so not too bad. I've seen worse with Varget.

Answer is to buy in bulk, get a couple 8lb jugs each time and work your way through them.

^^^^This.

I've seen enough change in velocity from switching to a new lot of primers, bullets, powder, etc. to warrant buying everything in bulk.

It may require a little more outlay in money up front, but it's absolutely worth it to avoid the frustration of re-tuning a load every few hundred rounds. You'll also usually save some money in the long run buying all of your components in bulk.

 

[DrainTheSwamp]

I just got a new lot 8208 xbr and it’s 25 FPS faster than my old lot. Still shoots tight but the sd/es is higher so I’ll probably just lighten up the charge and slow it back down and see if it helps.

 

[Cayjotiethumper]

That's why I try and buy a large amount of powder at a time. I've had h4350 and Varget do that.