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June 25, 2011, 01:48 PM | #1 |
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Join Date: October 10, 2010
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just got into reloading. finally. need help
im shooting lead at this point and have unique load data for 9mm and 45acp. when i look at .308 loads, it doesnt show anything for unique. i already know the bullet cant be used in full loads, so i am fine with a reduced load.
ive read that you could use about 10g of unique for a light plinking load. what do you guys use for light loads, if any for unique powder? i cast 160 gr bullets for the 308. |
June 25, 2011, 01:57 PM | #2 |
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9 grains of Unique is Rocky Raab's universal .30 cal plinking load, though he goes up to 10 grains in the longer .30-06 and magnum cases. 9 will work fine for you.
You also have the option of loading with Trail Boss to keep the case better filled for the most consistent ignition and MV. Plus it burns cleaner than about anything else ever made. 70% to 100% full up to the bullet base, but not compressed. Those are IMR's instructions.
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June 25, 2011, 02:10 PM | #3 |
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would 9gr be on the low or upper end load data? i only can shoot up to 100 yards. if its on the low end how much more could i add? what are the velocities?
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June 25, 2011, 03:23 PM | #4 |
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That's a light plinking load. With your bullet weight, it's probably in the 1300-1400 fps range from a 24" barrel. About 15,000 psi. How much more you can take depends on how hard your bullets are? They'll strip or start leading before you get to maximum safe pressure with Unique. 12 grains will get you to 24,000 psi and 1600 fps. 13 grains to 27,000 psi and 1700 fps. It's all very approximate because case capacities vary with the brand, but you'll be plenty safe within that range. If you want to shoot faster, then it'll be time for really hard bullets and a different powder. IMR 4227, perhaps. 27 grains of 4227 will give the same peak pressure as 13 grains of unique, but the extra gas it makes will bump velocity to the 2100 fps range.
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June 25, 2011, 03:32 PM | #5 |
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Join Date: January 24, 2009
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Thanks for asking
The conventional wisdom is, "If you can't find a loading manual printed by a reputable publisher that lists a bullet/powder combination, don't load it."
What you are contemplating is developing a load from scratch. Something that conventional wisdom says should be done by a ballistics laboratory (where they have instruments for measuring pressure and velocity and they don't mind occasionally blowing up a firearm and also have blast shields and other safety measures). The typical handloader should not do it. That's the bad news. The good news: Unique is a fairly fast powder and is forgiving of light loads (where slow-burning powders are definitely NOT). A handloader paying attention to all the various factors can push the performance envelope (with caution) if taking proper precautions (basically being your own lab). To my mind, doing what you contemplate, your greatest risk is getting a bullet that does not leave the barrel. The next bullet, encountering a barrel obstruction, may do damage to your gun, to you and to bystanders. To mitigate that potential would involve at the minimum, a chronograph. If you get inconsistent velocity or velocity below 500 fps, I would suspect that some time or other you will have a bullet fail to leave the barrel. Also, you should keep an eye on the brass. If it has soot on the outsides, it is likely because there is not enough pressure inside the case to cause the case to expand enough to seal against the chamber walls. Those are only two of the things one should be aware of when developing new loads in unharted (unpublished) territory. Here's my advice. Email or call the makers of Unique and ask them their advice. It seems to me that this particular quest (low velocity lead bullets using a fast powder) is not particularly dangerous, as these things go. But I definitely would not try it without a chronograph. As a side note: When I taught my friend to reload for his 500 S&W, I suggested Trail Boss powder. It occupies a lot of volume for the energy released. Difficult to make a double charge or a missed charge with Trail Boss. We loaded a bunch of 350 grain slugs that clocked 700 fps. So now, one of his favorite loads for the 500 is a 1,000 fps (thinking 700-800 is too low a pressure for reliability). Lesson: Get a chronograph. Regards, Lost Sheep |
June 25, 2011, 03:38 PM | #6 |
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The Unique loads, though, have been tried and published in other places than the usual load manuals. Rocky Raab's written about it. The NECO firelapping manual includes quite a number of Unque recipes for bottleneck cases, .308 included. So this isn't new turf, really.
If you want to locate more such data, try searching for sub-sonic loads and catsneeze loads here and at castboolits.com.
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