Same powder, different lots

[Morgan321]

See picture below. New and old refers to different lot numbers of rl-19 powder. Previous ocw test with "old" lot showed no poi shift anywhere in the high 55 to low 56 grain charge. I was shooting 55.8 and tested these since the weather is getting cooler and I'm nearly out of the "old" lot of powder.

I can't help but feel I need to at least do a mini-ocw with the new lot to keep the group sizes down. I'm not very happy since I got 200rds worth of supplies and spent nearly 60 getting things straightened out. I'm going to use 1/2 of the second box of 100 to get back to where I was with the first lot!

Buts its OK in the end, I got 600rd worth of supplies all from one lot in the mail this week.

Anyway, different lots of powder for your viewing pleasure. Note that with the old lot all these charges would have identical group sizes and poi. In other words, the poi shift and group spread are all from the powder lot change.

 

[Morgan321]

Ps. Forgot I had some of 56.0 with the "old" lot. Picture below. This brass was twice fired, first pic was all once fired. Same day same conditions. This pic was shot first and I made an elevation adjustment before firing the first pic, so no poi to compare.

 

[BuzzBoss915]

I think you might want to work it up again? I'd back off two full grains, just to see what's going on. The quality control from lot to lot is usually pretty good. Lot to lot and year to year. It's a little like blending whisky, they make an effort to get it as close as possible, but I don't know if that includes actual blending. But when it goes out the door, the average shooter should not see very different performance...which is not to say it will be exact, but damned close. In other words, it is seldom you would have one lot acceptable and two different lots look that much worse. Generally, you can find some adjustment, a couple tenths more or less and you should be back in the ball park.

I have been using some of these powders for a very long time and I have never reached the point where I have to look for something else, because of accuracy concerns....all things being equal. This is not to say I have not tried some new product now and then, sometimes with a worthwhile improvement. But bailing out of a proven performer because of a variance in lot numbers, no, can't say that has ever happened. BB

 

[Rprecision]

To help diagnose do you have velocities for both ? That may help steer your load up or down back into your node

Just a thought

 

[Morgan321]

No idea on velocities. I wish!