*really puzzled* do lots of the same powder varies "a lot"?

[Jicko]

I loaded 2 boxes of 50 rounds of:
- 43.0gr RL15
- 175SMK
- FED210M (same lot)
- FC once-fired, FL sized, trimmed brass
- Seat to ~2.85"

In between Box1 and Box2, I calibrated my electronic dispenser and scale.

At the end, when i chrono them (i did at least 15 rounds per box), there is consistantly a 50fps between my Box1 and Box2. Box1 is SLOWER by 50fps than Box2. And within each box, the ES and SD is really tight.

I thought that my scale must be off, hence the powder throw is different.

I pulled 1 round from each box last nite. To my surprise, the slower box's round has 43.0gr, while the faster box's round has 42.8gr!!!

Now, as I my really puzzled, I did opened up a new 5lb jug of RL15..... so the ONLY potential reason is that this new jug is somehow "hotter" than my last one....

Any ideas????

Now I am really puzzled.... HOW can 42.8gr be FASTER than 43.0gr?

[Sunwolf]

Brass weight the same?COL the same?

[Stockton]

Actually what your describing falls into the category when using different lots. But of the same lot and a faster rate with less powder is reason for suspicion. Take a closer look into your equipment and your techniques(ie..brass,bullet,COAL,weight,etc). Same powder and same lot already ensures possible powder issues that i know of.

[Jicko]

Once fired FC brass, FL sized, trimmed, they weight close enough.

Same bullet from the same lot.

Same FED210M from the same lot.

Bullets seated with Redding Competition Seating die, COAL statistically the same between the 2 boxes.

All the dies are from Redding... using RCBS single stage press... not junky Lee die + Lee press....

The tight ES/SD within the same box ruled out that the setup has any huge variation. ES = ~15fps. SD = 5-10

Even tho I only pulled 1 rounds from each box, I did weight the remaining rounds in each of the box. The aveage overall weight different between the box 1 and box 2 is 0.17gr(box 1 heavier, the slower box is heavier!!).... and that also kind of correlate with my 43.0 vs 42.8 findings.

[30Cal]

I've seen a lot worse variation from surplus powder, but 50fps is not THAT huge.

[rksimple]

I haven't had lots vary that much with Rl15. But with Varget, yes.

[Ahhnother8]

Have not used RL15, but have likely used 10 different lot numbers of Varget, and they are all different. I have five different jugs of Varget open right now, and am not happy with any of them, so borrowed a jug from a friend. Had to do this in 2007 also. Some are hot, and some are not. Some are finicky, and some are not. It's just like changing lot numbers of ANY component, you have to go back and test again. When you find something that you like, buy it ALL!!

Lane

[Pthfndr]

Have not used RL15....

Lane

Well there's your problem

[Bruce3]

i found that going between bottles of HP38 that there was a change of .3 grains, it use to throw 4.6 EXACTLY but now throws 4.9 grains

[Jicko]

Talked to Alliant today.

They said that it is possible to have variation lot to lot. And it is just "not possible", in their own words, to make powders identical from lot to lot.

So, just need to check the velocity when u are changing LOT.

Hmmm... now I have to keep track of my LOT.... d@mn it....

[gunboat]

I think the important thing is not the velocity difference but where they hit the target --

[rksimple]

I think the important thing is not the velocity difference but where they hit the target --

The two are closely intertwined. Predicting where the bullet will impact is a function of velocity (among other things). Its much more critical the further you shoot. So the important thing IS the velocity difference so one can properly predict impact. Unless of course, hitting the target in as few rounds as possible is not a goal.

[Ahhnother8]

Talked to Alliant today.

They said that it is possible to have variation lot to lot. And it is just "not possible", in their own words, to make powders identical from lot to lot.

So, just need to check the velocity when u are changing LOT.

Hmmm... now I have to keep track of my LOT.... d@mn it....

Now for the REALLY BAD news. It can/does vary WITHIN a given lot. Whatcha gonna do now?

Lane

[rksimple]

Now for the REALLY BAD news. It can/does vary WITHIN a given lot. Whatcha gonna do now?

Lane

Buy 100 punds of the stuff, mix it all together, and hope for the best!

100 lbs would last you...what...9 months?