The Accurate Reloading Forums THE ACCURATE RELOADING.COM FORUMS Guns, Politics, Gunsmithing & Reloading Reloading Difference from lot to lot of IMR powderGo | New | Find | Notify | Tools | Reply | |
| Difference from lot to lot of IMR powder | Login/Join |
| One of Us |
I have been loading IMR 4350 for my 6.5x55 SM and found 46.1 grs to be a great load. I have been loading out of 1 lb. cans and needed more. When I loaded the next group of rounds, I started getting pressure marks and sticky cases, also the velocity went up 30 fps. I only shot a few rounds and pulled the rest of bullets. Is it common to have that big of a difference between lots of powder? A while back I did have a problem with one lb. of IMR4350 that showed a decrease in velocity of 150 fps. I thought that was a "fluke", but now I don't have much confidence in that powder any longer. Also, when chronographed the ES was high (don't remember the exact figure..over 30). Is this common for IMR powders and what other powder for the 6.5 would you recommend? | ||
|
| one of us |
It's not surprising for alliant powders either. I've had good luck with hodgdon powder and would say that if I4350 has been working then H4350 would be good. What I've been trying to do is go to a gun shop when I know I'll need powder and check the lot numbers I make sure there are a few pounds of the same number there. I'll buy a pound of powder and if it shoots good I'll go back the next day and pick up another 2-3 of the same lot number. As another note. We have a really good local competitive shooter that shoots nationally. He has converted to V V powders...saysthey are the most consistant he's ever seen. | |||
|
one of us |
there are some diffrences from lot to lot. I usually try to buy 3,4, 5 pounds from the same lot. Really should work back up when you change. just in case you do experience diffrences as you have. | |||
|
| One of Us |
If you have a scale that can measure in grams and a reliable container marked in cubic centimeters (like the Lee dippers) nothing could be easier than measuring the density of the powder you buy. Just weigh a level dipper of powder and divide the weight by the volume and you'll get the % of density as compared to the standard (pure water) which is 1. Once you have your % you just label your can and the next time you can compare densities, which you have found out can vary quite a bit from lot to lot. an example: 2.2cc of powder that weighs 1.98 grams = 90% You'll need to measure and calculate at least 3 times to get a fairly accurate % especially if you are not experienced with dippers. The proper way to use a dipper is described in Richard Lee's "Modern Reloading" a book worth having. Dividing ounces and grains does not work easily. +1 for the metric system....... I have been told that powder manufacturers set their own standards within an industry wide tolerance for powder density. Powder makers then may allow as much as a 16% variance in density from lot to lot. Winchester used to say they allowed a 10% variation and the Finns claim only a 5% difference, I have been told. I learned about this when I was having trouble with a trap load using a new can of Red Dot. Apparently I had been lucky for years and never encountered a big density difference before that one. On investigation, my can of Red Dot was indeed 16% lighter than the one I had been using. This made a big difference in the load. This was not news to a gunsmith friend, who gave me an even better reason for always checking density than the one I already had figured out for my self. He said that a 16% variation can work both ways. That is to say, if my first can had been 16% heavy and the second can 16% light, I could have wound up with a 32% difference!!!! This would have been perfectly ok with the powder maker. I think most powder makers try to maintain closer tolerances than that, but I have seen proof that they do not always succeed. I doubt that it would be good for the bottom line to throw out an entire run of 16% off powder. So I check mine If the enemy is in range, so are you. - Infantry manual | |||
|
One of Us |
I have found Varget in my 6.5X55SM works Great! By chance do you reload/shoot in extreme weather/temp changes like myself? If you do Hodgton makes good "Extreme" powders! So that would be a good point to look at. Our 6.5X55's work great with slow burning powders. If you go to there web page you can pull up there powders and loading page. Its great! I always triple check all my loads personally because of the differences in powders weights from book to book. I trust the powder companies the most with there load date due to th  e fact that they are the ones making them. So to me it only makes sense that they test there powders more.www.Hodgton.com I will dig out my favorite loads for you for my swede. It has been in the shop now for the last few months getting work done. Myself I always start as low as possible to start working up. Loading cast is just as fun too! Best Of Luck! Keep me posted! PM me if you wish to compare notes! Disabled Vet(non-combat) - US Army NRA LIFE MEMBER Hunter, trapper, machinest, gamer, angler, and all around do it your selfer. Build my own CNC router from scratch. I installed the hight wrong. My hight moves but the rails blocks 3/4 of the hight..... | |||
|
| One of Us |
I've heard that VV powders are really good. I haven't tried any yet but as soon as I can find a source I'll pick some up. Right now I can't find any powders. How much of this stuff are people going to hoard? There has to be an end in sight. I may have to give up shooting for a while if this keeps up. I haven't seen Fed 210's on the shelf for some time now. | |||
|
| One of Us |
I'm not sure how much you are allowed to keep before you run afoul of the local fire marshall. It might be worthwhile to have a chat with him. Mine happens to be a fellow BR shooter and most understanding. I have not had a difference of density over 5% with any of the dozens of cans of N-133 or N135 I've used. Lately I have begun using N-540 and there was zero difference in the two cans I bought even though they were made a year apart. Vihtavuori actually puts the date - to the day-- that the powder was made--on the can. If the enemy is in range, so are you. - Infantry manual | |||
|
| One of Us |
If anyone is having extreme pressure differences from lot too lot of powders in any brand name . You have the ability to call in the LOT# and have them decipher manufacturing Date and Facility while reporting your discrepancies . Please remember if your EXCEEDING any published DATA per cartridge they won't give you the time of day !. Also some powders that retailers sell have set for extended periods of time and may have gone through excessive Heat and Cold cycles . Loading and shooting in these excesses can also account for a variable in FPS as well as Pressure spikes . My rule is Buy Large , my other rule is Mix half cans with Full cans of EXACTLY the same Brand and Number of Powder . Reseal properly store and use up one container first , then repeat process . It limits problems . Changing Primers bullets will or can account for variables also . | |||
|
| One of Us |
PS ; Local news a few days back had a story concerning Tire purchasing . Seems as though some unlucky folks purchased tires from a local shop , they had an accident about two months later . An investigation reveals the tires sold were manufactured in 1994 or 1995 !. As most people don't ever bother to look at the DOT coding just because you buy them in 2009 doesn't mean it was manufactured then !!!. Be Smart Be Aware ... | |||
|
| One of Us |
Thanks for the input. I would appreciate any info you can give on your loads and what works for you. I do hunt in extreme weather/temp variations (varmints in the summer/deer and elk in the winter). I have heard that Hodgdon Extreme powders are great. | |||
|
| One of Us |
This past fall I had good luck with Varget, I needed to work on my groups but was good for a worn pitted barrel. I think I needed to up the powder charges. But its at the smith getting reworked. Disabled Vet(non-combat) - US Army NRA LIFE MEMBER Hunter, trapper, machinest, gamer, angler, and all around do it your selfer. Build my own CNC router from scratch. I installed the hight wrong. My hight moves but the rails blocks 3/4 of the hight..... | |||
|
| One of Us |
It's quite common, and not a fluke at all.
Using the same charge weight of an old and new lot of IMR 4350, I once had velocity drop 200 fps.
There's no reason for that at all. I think the problem you've having is indicative of buying powder one small can at a time, and then skipping a necessary step in safe handloading procedures when changing lots. No two lots of any canister grade propellant are the same. There's almost always a difference in density. As the reloading manuals say, when you run out of an old lot, and buy a new one, you're changing a component. You need to reduce the charge and work back up with the new lot. Having to ladder back up over the chronograph to get back to where you were with the old lot each time you change wastes a lot of time, powder, and bullets if you're buying small amounts of powder. That's why buying mutiple cans of the same lot number at the same time, or a large canister, is the best approach. Many rifle shooters skip the step of redeveloping between lots. Single barrel shooters can often get away with it because, although it's there, the difference is more difficult to see with a single barrel. Not so with the double rifles I load for. The regulation of double rifles, generally, is dependent on matching the velocity and bullet weight of the load it was regulated with, and they're often very sensitive to changes in velocity. Due to variation in density between lots, in order to maintain perfect regulation, it's necessary to adjust the charge of each new lot of the same powder in order to achieve the same velocity with the same bullet. I have one double that loves IMR 4350, and I've used that powder exclusively in it for 20 years. The charge weight for the same velocity and regulation with the same 300 grain bullet has bounced back and forth between 51 and 57 grains for the different lots of 4350 I've shot up in it over the years. If your rifle likes IMR 4350, then the answer isn't to change propellants. Just work back up properly between lots, and buy larger quantities of it to reduce the necessity of doing so. ------------------------------------ "Serious rifles have two barrels, everything else just burns gunpowder." | |||
|
| One of Us |
This is very good to know! Disabled Vet(non-combat) - US Army NRA LIFE MEMBER Hunter, trapper, machinest, gamer, angler, and all around do it your selfer. Build my own CNC router from scratch. I installed the hight wrong. My hight moves but the rails blocks 3/4 of the hight..... | |||
|
One of Us |
My only lot to lot experience has been with IMR-7828. I initially bought 2 lbs of it for my 338-378 Wby. As I was about to run out I bought two more pounds. the original 2 were of the same lot and the second 2 were the same but of a different lot. I finished up the original lot and then loaded just 3 cartridges of the second lot. I checked the velocity of several rounds of the original and then fired one of the second lot. The velocity was very close. I then fired the other two cartridges from the second lot and got an average that was right at what the original lot was. Until I do this one or two more times I can't say with certainty that this powder is VERY close lot to lot but I did like the initial results. By the way, we are talking about powder that was bought at two different stores seperated by a year and a half. I do also use this powder in my 257 Wby and found similar results even with the smaller case. Ken.... "The trouble with our liberal friends is not that they are ignorant, but that they know so much that isn't so. " - Ronald Reagan | |||
|
one of us |
This might be of interest to some as to differences in IMR powders. H Broemel is the author of Quik Load. http://www.24hourcampfire.com/...rch=true#Post2795026 ------------------------------------ The trouble with the Internet is that it's replacing masturbation as a leisure activity. ~Patrick Murray "Why shouldn`t truth be stranger then fiction? Fiction after all has to make sense." (Samual Clemens) "Saepe errans, numquam dubitans --Frequently in error, never in doubt". | |||
|
| One of Us |
H Broemel is absolutely correct. Even IF you are dealing with the same manufacturer (that does not mean the same "label") then there is always an acceptable lot to lot variation. That is why when you buy a new lot of powder and your load is top end you should always drop a bit and work back up. Real IMR powders vary about 3% +/- lot to lot in my pressure tests using 4250, 4895, 4227 and 4759. I do not know what the lot to lot variation is now that Hodgdon has taken over making and selling "IMR" powders but I suspect it to be close to the same. FYI; I have found the Hodgdon "Extreme" powders (H4895, Varget and H4831SC) to run about 2% variation lot to lot. All of my testing has been based on a comparison of weighed charges not volumetric measurement and pressures measured in real rifles using a M43 Oehler PBL. Someone posted the advice to "buy large and work up". That is very sage advise if you are loading at max or shooting a lot of one load. Saves a lot of time and componants not having to work up the loads all the time for each different lot of a powder you buy. Larry Gibson | |||
|
| One of Us |
That 3% +/- applies too ALL powders and manufactures !. Primers 2% +/- factor Even Match primers . Now move on too cases nobody knows what % of +/- factors into those . Least wise in 44 years of re loading and involvement in powder manufacture I've never heard any figure . Just talk around the cooler or bench . Most jacketed bullets are by far the most accurate component involved when building a cartridge !. | |||
|
| one of us |
Larry I agree with your thoughts on load reduction and work up when opening a new can of powder, but it seems to me Broemel is claiming IMR for the last 10 years has had more then one company maufacturing their powders for them. Most powders, although they have differances in the various lots, are made by one company only. St Marks for Winchester, or ADI for Hodgdons "extreem" powders for example. ------------------------------------ The trouble with the Internet is that it's replacing masturbation as a leisure activity. ~Patrick Murray "Why shouldn`t truth be stranger then fiction? Fiction after all has to make sense." (Samual Clemens) "Saepe errans, numquam dubitans --Frequently in error, never in doubt". | |||
|
| One of Us |
Back in the '80s I bought a couple of 1lb. cans of IMR4831. I already had a load worked up with the powder in the mid to slightly upper range. When I shot the first round, the primer blew-out and the bolt was very difficult to open. Had the brass face marks etc. Got brave and fired a second. Same thing. I was a novice at the time, so I loaded up the ammo, powder etc. and went to the gun shop where I bought the crap. The g-smith opened the powder can and poured a good bit of it in a bowl. After shaking the bowl around like a prospector, we found ball powder mixed in with the extruded. Since the ball powder was smaller in size it tended to fall to the bottom and was not readily visible. The gun shop owner/g-smith said he had seen that before. Since that day I have not bought another can of IMR powder until last week. Now after reading this it sounds like deja-vu all over again! "The right to bear arms" insures your right to freedom, free speech, religion, your choice of doctors, etc. ....etc. ....etc.... -----------------------------------one trillion seconds = 31,709 years------------------- | |||
|
one of us |
Powders do change composition & burn characteristics slightly from year to year, definitely from older powder lots (like 10 years). I love H4350 in my 260ai for 120-142gr bullets, about like the 6.5x55. LIFE IS NOT A SPECTATOR'S SPORT! | |||
|
| Powered by Social Strata |
 | Please Wait. Your request is being processed... |
|
The Accurate Reloading Forums THE ACCURATE RELOADING.COM FORUMS Guns, Politics, Gunsmithing & Reloading Reloading Difference from lot to lot of IMR powder
Visit our on-line store for AR Memorabilia