Powder lot to lot variations?

[AZmark]

These questions have probably already been asked a thousand times....

Just how much variation is there between the same powder but different lots?

Would there be any variation between H4831 and H4831sc other than lot#?

Does anyone mix different lots of the same powder when you get down to the bottom of the can you're using and there's not enough to reload say 20 cartridges?

 

[209jones]

No issues with using blended lots, just recheck the load with the blended lots to see how much change you get, if any. With H4831 you are likely using 55-75gr, never hurts to try some 1gr lower and up to maybe .5 higher. Industry used to claim a +/-5% variance on lots, not sure if they still do. Not supposed to be any difference between any of the SC or SSC and the originals in Hodgdon's lineup, but, the variance on lots still applies.

 

[6.5 forever]

I have had success adjusting the powder charge to match velocity of my current load.

 

[243winxb]

Powder Lot Variations: A Case Study with H4831 - Hodgdon Extreme​

Open PDF The problem with mixing/blending different lots, 1 powder lot may end up being a recall.
Buy 8 pounds at a time, same lot. New lots, work up the loading again.

 

[WV Hitman]

For all my hunting handloads the past 50+ years in all my handguns, especially the ones I use for 400-500 yards kills I've seen no difference in point of aim or group sizes in lot to lot changes based on over 19,000 kills of groundhogs, deer, bears, western US game, and a lot of African animals.
I imagine the extremely long range rifle shooters may have different experiences.

 

[6.5 forever]

For all my hunting handloads the past 50+ years in all my handguns, especially the ones I use for 400-500 yards kills I've seen no difference in point of aim or group sizes in lot to lot changes based on over 19,000 kills of groundhogs, deer, bears, western US game, and a lot of African animals.
I imagine the extremely long range rifle shooters may have different experiences.

Out here in the west, 1000+ yard rifle shooting at milk jugs and softball targets requires extreme accuracy. Every detail matters.

I can't disagree with your experience on handguns. I have no experience with those.

 

[SKWERLZ]

I always assume a new lot of powder needs to be carefully confirmed.

 

[6.5 forever]

Powder Lot Variations: A Case Study with H4831 - Hodgdon Extreme​

Open PDF The problem with mixing/blending different lots, 1 powder lot may end up being a recall.
Buy 8 pounds at a time, same lot. New lots, work up the loading again.

Very interesting. Thanks for posting.

 

[K22]

Powder Lot Variations: A Case Study with H4831 - Hodgdon Extreme​

Open PDF The problem with mixing/blending different lots, 1 powder lot may end up being a recall.
Buy 8 pounds at a time, same lot. New lots, work up the loading again.

I never thought about that in all years that I have loaded and blended lots. Something to chew on for sure. Thanks for the insight. It seems like there is always something new to learn. Good job!

 

[JFrank]

A while back I ran out of one lot number of H4895 that ran about 2930 with 31.0 gr in the bra .
The next lot ran over 3000 at 31gr. Now I watch lot numbers carefully and do not mix them for a comp gun.
I will mix left overs from similar speed lots for plinking or varmint control.

 

[Pirate69]

When I compare GRT powder burn rate data (and predicted velocity) to actual measured velocity, sometimes I see a significant difference in predicted velocity and the corrected burn rate.

I found the following on the net. Take it for what you think it is worth.

1–5% difference in burn rate is common between lots of the same powder.

In some cases, especially with older or reformulated powders, up to 10% variation has been documented.

This can translate to 20–50 fps velocity shifts or 10,000+ psi pressure changes, depending on the cartridge and load density.

Real-World Testing Insights
• Ballistic labs often test multiple lots and publish comparative data. For example:
• One test with Varget showed a 40 fps spread across three lots in .308 Win.
• Another with H4350 revealed pressure differences of 8,000 psi between lots in a magnum cartridge.

 

[Ackman]

In the test I ran many years ago, there was very large change from lot to lot. The rifle a Sako, 6BR Hart barrel, 14 twist, 0 freebore. Did a direct comparison, same load- 58 VMax and AA2230 powder....old vs. newer comparison. . A1lb bottle I'd had around for awhile, and a new keg. Shooting one group with the new stuff, then below it, same load with the earlier sruff. Quite a difference.....bit of a surprise.. The keg 35.0 load is what I shoot in that rifle. At 3855 a 58VMax is very effective on pd's and chucks.

*****The 55 BlitzKing and a little more powder is good for over 3900 and .120"grouping. These are hot loads and ok in my rifle, but may not be ok in yours. So be aware of that and use caution working up.

 

[209jones]

I can relate to the caution about a recall lot, I ran into IMR4320 years ago, before the internet existed, found out a few months later in an recall ad in a magazine. Have never heard of a recall on any version of 4831, I've blended original and H4831, no issues, AA9 and RL22, H4350, no issues, slight powder chg change. That news gets out PDQ these days, only recent ones I'm aware of at present are IMR4007ssc, AA4350 and some older lots of L'il Gun, That's over about 15 yrs I can think of, I'd still treat L'il Gun as sketchy. All that said, can always shoot some of the new stuff first to do a quick pressure test with it, and if its OK, blend the other stuff in, by the sounds of it, OP doesn't have much, but, will still likely have to do a tiny ladder test around his original load.

 

[Texas Solo]

Depends on the powder.
I've found huge differences in various lots of Varget.

 

[Steve Donlon]

I got a pound of IMR 4064 for some 150gr bullets in a 30-06. It was so hot that I just threw it away. I was glad it was only a pound. It was scary hot, didn't want anything to do with it. That was years ago.

 

[markm87]

Depends on the powder.
I've found huge differences in various lots of Varget.

We used to shoot a ton of Varget in 308, and it seemed like every new 8 lb jug gave up a little more velocity.

When I first started shooting 308 long range I screwed myself by buying 1 lb of Varget at a time. I was chasing my ass all the time trying to get good 1000 yard dope. I'd heard of lot variations, but didn't think it could be that big of a deal. Wrong.

My biggest lot swing was on 308 using IMR 4064. I had a loss of over 100 fps. One of the jugs smelled like Vick Vapor rub. Really odd.

 

[Murray Brook]

Years ago shooting H-450 in my 270 Weatherby mag I had a 5gr difference from one lot to another. I was very fortunate I went from the fast lot to the slower one. Had it been the other way around I may have been in trouble

 

[searcher]

The highest variation I can recall seeing between lots of the same powder was around 90 FPS. I typically buy a number of pounds (or jugs) of the same lot, and it can be years (or even a decade) before I need to buy more of the same type. When I do, I try to run completely through my old powder and tend to not mix it in with new powder as I don't want the small amount of my old powder to contaminate my new powder down the road due to age, even though that is unlikely. If I go from one jug to another with the same lot of powder, I will blend it into the new jug - as they are the same age and lot, though the moisture content may be different due to the old jug being exposed to air more often from repeated openings. I just be sure to roll the jug around a lot to get it mixed in really well. When starting on a new jug of a different lot number, I always back off the load a grain or so if my load was anywhere near being warm. I chrono the loads to see what the difference was, as well.

 

[Orr89rocz]

Had an old H1000 can that required 63 grs to get 2723 fps. New can 63 gr shot 2840. I had to reduce 2.5 grains to get back to original load velocity and accuracy and it didnt shoot as tight

I got a new batch of reloder 23 thats much slower than my old batch. 1-1.5 gr more to get closer to original velocity

It can be significant