powder lot# variances

elkhunter11 · #1 07-03-2009, 08:54 PM

After using an old lot of IMR 4831 to develop a load for a new rifle I settled on 59gr which produced 3070fps.Since the old lot of powder was nearly used up,I bought three more cans of IMR4831.Before loading any large amount of rounds,I decided to compare the new lot# of powder to the old lot#.I loaded up five rounds with each lot# both using 59gr.I fired all ten rounds over the chronograph,and the old lot of powder was averaging 3060fps,while the new lot# was averaging 3165fps.It is not unusual to see differences of 25fps to 50fps between lot#s,but 105fps is much more than I am used to seeing.

When you change lot#s of powder,do you just keep loading rounds with your old recipe,or do you actually compare both lot#s first?

Pathfinder76 · #2 07-03-2009, 09:56 PM

I compare lot #'s with a chronograph always, and buy in bulk. I'm curious to know if your old lot of IMR 4831 was pre Hodgdon?

elkhunter11 · #3 07-03-2009, 10:05 PM

The old lot is still in the metal can,I am guessing about 10 years old.The best thing is that there are no pressure signs at all,and there is no measurable case web expansion.I do however need to shoot a few groups to verify the accuracy with the new lot.

Pathfinder76 · #4 07-03-2009, 10:11 PM

Interesting.

elkhunter11 · #5 07-03-2009, 10:20 PM

Obviously the load using the old lot was very mild.

Pathfinder76 · #6 07-03-2009, 10:25 PM

Were you seeing case web expansion with the original load?

elkhunter11 · #7 07-03-2009, 10:41 PM

None at all.The 59gr load grouped well,and was only 1 grain below the maximum load,so I stopped there.I likely could have added another grain or two and still been very safe.

Pathfinder76 · #8 07-04-2009, 02:00 PM

I'm curious to see what you find with temp sensitivity.

elkhunter11 · #9 07-04-2009, 02:44 PM

I shot some groups this morning and the groups opened up to around 1".I backed off the powder charge by a grain,and shot two groups right around 5/8".I will load up some more rounds at 58gr and shoot a few more groups tomorrow to be sure.

Sheepcrazyguy · #10 07-06-2009, 09:00 AM

I have a 308 Norma Mag that I've stopped using. Several years ago i used IMR 4350 and 165 Hornady's and shot a 1" group constantly at 100 yards. I used up the first can of powder and loaded up another batch of bullets from a new can and the group was gone. I've tried everything possible that I can think of and can't get a decent group from it. I've shot a couple hundred rounds trying to get it shooting good. Probably have it down to 3" now. I've stopped using it because of this. SCG

Booner Sniper · #11 07-06-2009, 09:48 AM

Sheepcrazyguy,
what kind of rifle is your Norma in? Have you tried IMR 7828, that's what I have found to work the best in my new one I had made. In my old one I used IMR 4350 but couldn't get what I wanted in the new one.

Sheepcrazyguy · #12 07-06-2009, 11:10 AM

Quote:

Originally Posted by Booner Sniper

Sheepcrazyguy,
what kind of rifle is your Norma in? Have you tried IMR 7828, that's what I have found to work the best in my new one I had made. In my old one I used IMR 4350 but couldn't get what I wanted in the new one.

Mine is a Voere? Not sure I spelled that right. Mauser 98 action and a thin barrel. Can't remember the exact name of it. Laufstal 3? Or some thing like that. Haven't looked at the old girl for a few years. Awesome cartridge. have thought about rebarrelling but have too many guns to choose from already. I did try IMR 7828 also, never could get that 1" group back though. Thanks for the info though. SCG

Dick284 · #13 07-06-2009, 11:41 AM

Quote:

Originally Posted by Sheepcrazyguy

I have a 308 Norma Mag that I've stopped using. Several years ago i used IMR 4350 and 165 Hornady's and shot a 1" group constantly at 100 yards. I used up the first can of powder and loaded up another batch of bullets from a new can and the group was gone. I've tried everything possible that I can think of and can't get a decent group from it. I've shot a couple hundred rounds trying to get it shooting good. Probably have it down to 3" now. I've stopped using it because of this. SCG

Did you try getting the copper fouling out of your rifle?
Also how is the bedding?

Sheepcrazyguy · #14 07-06-2009, 12:48 PM

Quote:

Originally Posted by Dick284

Did you try getting the copper fouling out of your rifle?
Also how is the bedding?

Yes tried both of those. Still no change. I could try cleaning the copper fouling again though. What do you suggest I use? Like I said I've put several hundred rounds through trying to get it to group again. So another good cleaning may help. I haven't done anything with this gun for a few years so maybe it's time to try it again. Thanks

Dick284 · #15 07-06-2009, 12:58 PM

Quote:

Originally Posted by Sheepcrazyguy

Yes tried both of those. Still no change. I could try cleaning the copper fouling again though. What do you suggest I use? Like I said I've put several hundred rounds through trying to get it to group again. So another good cleaning may help. I haven't done anything with this gun for a few years so maybe it's time to try it again. Thanks

1st choice would be Wipe Out.
2nd choice would be either Barnes CR10, Butches Bore Shine, or Sweets 762.

I have to ask what did you use to clean it? Bronze brushes and Hoppes #9 or Nitro solvents do not do diddly for copper.

Did your patches come out blue or green?

Sheepcrazyguy · #16 07-06-2009, 01:09 PM

It's been so long now anything I said would probably be a guess. But here goes, I believe it was Barnes,probably copper brushes. That's mostly guessing on my part. I wouldn't mind hearing what you would recommend. Thanks.

Pathfinder76 · #17 07-06-2009, 01:17 PM

I'd say you've a screw loose.

Sheepcrazyguy · #18 07-06-2009, 01:42 PM

Quote:

Originally Posted by chuck

I'd say you've a screw loose.

I've been told worse than that. LOL But nope checked all of that too. I've tried everything I can think of on this and still the same. Hot loads, mild loads. Different powder,primers,bullets,cases,case length,scopes,glass bedding.The list goes on and on, but keep asking if you guys don't mind maybe I missed something. Maybe Dick 284 is right about the barrel not being clean enough but why when I shot the last round from the one can of powder to the next round out of the new can did things change? It wasn't a gradual change, it happened just like that from one 3 shot group to the next. Thanks for all the input guys.

Sheepcrazyguy · #19 07-06-2009, 01:43 PM

Sorry for stealing your thread elkhunter. Hope you don't mind

LongBomber · #20 07-06-2009, 03:31 PM

Shepcrazyguy - Silly question, but if your shooting a scoped rifle have you tried a different scope? I have had several scopes pack it in lately.

I have used a few different lots of 4831 in my 300wsm. I found I had to change the load a little up and down to keep the accuracy the same. I found that if I keep the velocity very close from lot to lot the accuracy was pretty similar. Now when I start a new powder lot I load one each of a few grains either side of my old load and fire them over the chrony looking for the velocity, then I try a few groups with the closest one. That seems to work well for me with this rifle at least.

Sheepcrazyguy · #21 07-06-2009, 03:46 PM

Quote:

Originally Posted by LongBomber

Shepcrazyguy - Silly question, but if your shooting a scoped rifle have you tried a different scope? I have had several scopes pack it in lately.

I have used a few different lots of 4831 in my 300wsm. I found I had to change the load a little up and down to keep the accuracy the same. I found that if I keep the velocity very close from lot to lot the accuracy was pretty similar. Now when I start a new powder lot I load one each of a few grains either side of my old load and fire them over the chrony looking for the velocity, then I try a few groups with the closest one. That seems to work well for me with this rifle at least.

Nope tried a different scope too and different weights of powder too. Checked all the screws in the bases when I had the scope off too. I didn't have a chrony at the time so I don't know what the original loads had for velocity. Good idea though. Thanks