December 27, 2006, 05:24 PM | #1 |
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Interesting discrepancy
When I looked at the IMR 3031 powder in 3 of my manuals I noticed that in the newest one (The Lee 2nd edition) has a starting load that's higher then the Max load was in one of my other manuals.
Here's how they read for a 150 gr jacketed bullet for a 30-30 rifle. IMR 3031 Start 29.5 Max 31.1 ........ Lee Second Edition IMR 3031 Start 26.5 Max 28.5 ........ Lyman 47th Edition IMR 3031 Start 26.5 Max 29.5 ........ Metallic Cartridge Reloading (old one) I wonder how many other discrepancies are in various manuals that you guys might have? |
December 27, 2006, 06:13 PM | #2 |
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Different philosophy re> compressed loads. My vintage (1st?) Lee’s 3031 loads for the 30-30/110gr has loads up to 5 grains over what other sources publish. Lee would publish compressed loads, while others sources cut the loads off at the case volume (after bullet seating). Win’s Ball Powder Pamphlet were more conservative, cutting off at 98% case volume.
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December 27, 2006, 06:56 PM | #3 |
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compressed loads are'nt the only reason though.bullet types and other components also contribute.i've seen differences like that in about every caliber for other manuels.thats why your supposed to work your load up from minimum.
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December 27, 2006, 07:35 PM | #4 |
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I think the first thing you need to know is that every firearm is different. You can take 10 Remington 700s in 223 or any other manufacturer and cartridge, load the same exact load and run it through all of the rifles and each will chronograph differently. Then there is the bearing differences between the manufacturers bullets. Not all .308 150 gr bullets have the same bearing surface on the rifling which will make one brand/design faster than another or allow more powder to be used before peak pressures are reached. The loading manuals are a guide, not an absolute. I have several rifles that I am way over max in the printed manuals yet have zero signs of any pressure. I have a 6.5x 06 that I can't even get close to max with the printed data and pressure signs abound. That's why the manuals always state to reduce the max loads by 10% and start up if you are looking for max speed. Brass can make a difference, some brands are heavier walled than others and the interior dimensions of the case are slightly smaller but critical to the pressure curve. There is no one data manual that is going to have the same results as another. That's why reloading is so much fun- all the variables. And besides, if it was easy, anybody could do it.
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December 28, 2006, 01:30 PM | #5 |
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Are we safe in assuming that all the manuals are of approximately the same age? Powder formulations change over the years.
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December 28, 2006, 02:03 PM | #6 |
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The Lee book reprints IMR data. You might figure they made the powder, they know what to do with it. But you ought to see what they said in 1990, woo, boy.
Lyman runs their own test lab; I dunno about Metallic Cartridge Reloading. True, components, barrels, interpretation, and lawyer lingo change from brand to brand and year to year. But I have an old article discussing the particularly great variation in .30-30 data. Nobody could figure out why two shops could start with the same nominal cartridge and come up with such widely different loads. |
December 29, 2006, 06:28 AM | #7 | |
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Not critical. Just interesting
Quote:
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December 29, 2006, 08:47 AM | #8 |
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I just worked up a load for my 30-30 using H4895 and some old 150g Hornady bullets. The Speer 13 lists 31g as max while Lee and Hodgdon both list 34g as a max compressed load. 34g didn't turn out to be compressed much at all and no pressure signs as far as I can tell either. Chronographed right at 2300fps out of my old gun so that's what I'm sticking with.
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December 29, 2006, 11:48 AM | #9 |
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Are we safe in assuming that all the manuals are of approximately the same age? Powder formulations change over the years.
Please correct me if I’m wrong, but I was under the impression that if the powder manufacturers changed the recipe, they changed the name too. As all this was a safety concern to prevent KABOOMs when someone uses granddaddy’s manual from the wayback days. ~z
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December 29, 2006, 12:34 PM | #10 | |
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Quote:
Hodgdon started out selling H4895 that was really DuPont IMR4895 military surplus. When that ran out, they went to ICI in Scotland and had powder of the same nominal burning rate made in a different plant, probably with differences in equipment and materials. Then they changed suppliers to ADI in Australia where they use still different manufacturing processes and materials. Still call it H4895, though. In the meanwhile, DuPont brought out commercial IMR4895 but then shifted production to Canada, in a different plant with different "recipe." So there have been five different "recipes" for 4895, all different enough that it is best to use the right company and vintage data for loading. Alliant powders are the same brands and designations established by Hercules but they are not made in the same plant or with the same formulation. |
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January 2, 2007, 12:14 PM | #11 |
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I've noted the same variations for IMR 4064 in 22-250...Theres a 2.3 gr. spread among different manuals. I chose to use IMR's data which was the hottest. Like someone else said, it's their company, they know the powder, and I figured the data on THIER website is probably the most recent...I've recently switched to benchmark because I needed a faster burning powder to get better performance out of my 55 gr. bullets. I'm not knocking the powder or IMR...It was just something my gun likes better.
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January 2, 2007, 02:26 PM | #12 |
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Lots.
Every "max" and "min" load for every cartridge will vary from source to source. |
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