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Posted: 8/18/2008 6:08:24 PM EDT
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So I had an "Oh Sh!&t" moment earlier today when looking at my manuals...I just started reloading, and based my first recipe off of the Sierra 2005 manual for my .38 SPL rounds... I'm using 158 grain Montana Gold Bullet CMJ (?) bullets (with cannelure, of course) in once-fired brass with WSP primers over 6.8 grains of AA no. 5; the Sierra manual said that 6.6 grains was the minimum, with 7.4 being the max load; giving me a very comfortable margin for error (i've never seen my 650 throw more than 7.0, and that's only when it's been shaken a little when clearing a malfunction; generally if there's any deviation it's to 6.9 grains). After loading up a 100 rounds I stopped by the range on my way back from work last week and did some quick shooting; the rounds functioned fine in my Taurus .357 Tracker (which I specifically loaded the .38s for, it's the only revolver I have). The primers kind of looked flat to me (maybe a sign of high pressure) but when I compared them to factory once-fired rounds they looked the same. Then I look in my hornady manual (while looking for a suitable .45 ACP powder) and notice that they list the max. load for AA no. 5 as being 6.4!! I double checked my Sierra manual just to make sure I hadn't misunderstood....so there's obviously a HUGE difference between the two manuals on what is acceptable for these rounds. The Sierra says that 6.8 will only push them to 800fps; the Hornady says 6.4 will push them to the same velocity. And they have a full 1.0 grain difference in max loads... So what're your thoughts on this? I just can't understand why there would be such a discrepancy... |
No discrepancy involved. Sierra Manual uses Sierra bullets. Hornady Manual uses Hornady bullets. Did you use the exact same case brand with the exact same primer choice? 6.0gr to 7.0gr. of AA-5 is a fair +P load, depending upon your choice in components. You want a factory duplication, right? Start low and work up. Buy a chronograph. |
| I wondered the same thing. My Sierra manual is different than my other 3 manuals by about 2 or 3 grains. Usually lower than the others. I have a friend with an older manual and they all have a higher max charge than the new books. I wonder if the safety margin is getting bigger, and the reloading companies are trying to play it safe. |
The joke on Sierra is, is that their legal counsel wrote the manual. I'M NOT SUGGESTING YOU DO THIS!!! However, you could probably jack most loads up by a few grains and be safe, vis-a-vis the Sierra V manual. Chris |
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My Hornady manual lists a 6.5 gn of W231 as a max charge for .45 200 gn LSWC while my Lee says 5.5 gn. That was a fun surprise when I loaded up a bunch of .45 at 5.5 gn as a starting charge using my Hornady manual. Only later did I find out that the Lee manual was different. The rounds all worked fine, but they were definitely hot. I wouldn't want to shoot a 6.5 gn charge for more then a few rounds, if it was even safe for the gun to shoot. |
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You are always going to have discrepancies between loading manuals since each company uses their own brass/bullets combo for the most part. It's always a good practice when you load based on a particular manual is to start with the listed minimum charge and work your way up in small increments. When I load with new receipe, I only load 20 rounds for semi auto rifles or pistols. With revolvers I only load 12 rounds. I test not only for function but for velocity. |
As mentioned, because of different components, lots of powder (especially true with AA#5), barrels, chambers etc. there are differences in the charge weight - BUT NOT THE VELOCITY OBTAINED!. If you have a chronograph you can use 800 fps as a goal and quit when you reach that velocity, regardless of charge weight, and know that you have a load with the same pressures as those the manuals achieved despite any charge weight discrepancies. This is because velocity is the by-product of pressure, so a chronograph can, albeit indirectly, give you an insight into pressure being developed by a given load. You don't need to push the load until pressure signs are shown on the brass/primer to find your load velocity/pressure goal (in this case 800 fps.) If pressure signs occur before the book(s) (hopefully more than 1 source) velocity is obtained, you need to back off because your components/gun give greater pressure than standard. However this is very unlikely. One must pay attention to barrel length factors, and chronographing similar factory ammo will be a terrific aid in knowing what velocity YOUR handgun gets with factory pressure rounds. So using a chronograph really simplifies load work-up in cases like this and eliminates "guess-timation."
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