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Old May 5, 2013, 02:37 PM   #1
sculls711
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newbie help

I am new to reloading and have some very, very basic questions. I hope someone on this forum has the patience to help. So, here goes.

I am loading .40 S&W 180gr. using Accurate #7. If I go to the Speer handbook, it calls for a start charge of 8.6gr, not to exceed 9.4 gr. However, the accurate data page calls for a start charge of 7.7 gr. not to exceed 8.5 gr. I would think that the Accurate page would me more...acccurate, but I wonder why there is such a discrepancy in the data. Any thoughts?

Also, I am puzzled by another, what I consider, strange set of data. All of the following are using AA#7 powder. For a 180 gr. bullet, AA calls for a starting load of 7.7 gr. For a 165 gr. bullet, it calls for a starting charge of 8.4 gr. And for a 155 gr. bullet, it calls for a starting charge of 8.4 gr. So, you need a larger charge to push a lighter bullet? Just seems wrong to me. What am I missing? I would love to get educated.

Thanks for the help.
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Old May 5, 2013, 03:17 PM   #2
Misssissippi Dave
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The difference in the amount of powder can easily be the result of a different bullet with the same weight or how deep you seat the bullet. How hard the bullet is can also be a factor. There normally is a big difference in the amount of powder used between lead/plated and jacketed bullets. Some references are more on the cautious side as well.

Think of it this way when you see the need for more powder with a lighter bullet. The time a bullet is in the barrel while gas is expanding is a shorter time than it is for a heavier bullet. You need a little more power to create gas in a shorter time. You will see this more with certain types of powder with a give burn rate compared to others. There seems to be certain exception to many general observations.

A cronograph is often used by reloaders to determine how fast a bullet is going at a given distance. They can also see how much variation there is from one test round to the next. You can also see when a powder is spiking by measuring the speed. They can be used for a lot more but this seems to be the things referenced most often. It seems this is one of the best tools available to develope loads. When you don't know just what published bullet you can find compares the best to the bullet you are wanting to load, a cronograph is quite useful. It is something to think about getting one day.
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Old May 5, 2013, 03:51 PM   #3
g.willikers
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When comparing load data from different sources, make sure you really are comparing apples to apples.
Two bullets of the same weight might require very different amounts of powder.
They may be of different shapes and lengths and take up different amounts of case volume.
Even when loaded to the same cartridge over all length.
For example, check the load data between say a lead semi wadcutter and that of a full metal jacket, both of the same weight, and sticking out of the case the same amount.
The load data will be very different for the two.
This might be the reason for your confusion.
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Old May 5, 2013, 06:29 PM   #4
Shootest
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Quote:
Also, I am puzzled by another, what I consider, strange set of data. All of the following are using AA#7 powder. For a 180 gr. bullet, AA calls for a starting load of 7.7 gr. For a 165 gr. bullet, it calls for a starting charge of 8.4 gr. And for a 155 gr. bullet, it calls for a starting charge of 8.4 gr. So, you need a larger charge to push a lighter bullet? Just seems wrong to me. What am I missing? I would love to get educated.
Generally speaking, It is more difficult to get a heavier bullet moving, thus in order to keep pressure within safe limits, less powder is used.
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Old May 5, 2013, 07:17 PM   #5
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Along the same lines as g. wilikers, also check you manuals to see what pistol was used to test each load. If, for example, one company used a 4" Glock and another used a 5" 1911 and still a third used a sealed test barrel they will get diffrent data for the same bullet/primer/powder combo. For MOST powders, start at the minimum and work up slowly - not more than 0.2 grains at a time - and watch for pressure signs. You might look at the primers being used, too, since some burn hotter than others and will, therefore, raise pressure faster. Hope this helps.
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Old May 5, 2013, 07:22 PM   #6
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Look at what they are using for seating depth. Most times in a high pressure hand gun round if a lighter load is listed there is a shorter length listed. (That means do not seat shorter than that. Longer is fine.) With the bullet seated deeper less powder is used to get the higher pressure.

I also say when it doubt start with the lower listed load, and carefuly work up. Shoot them slow, and if needed check the barrel to make sure the bullet is not stuck there. Rarely have I seen a hand gun load for semiauto shoot best when at max load. Most of mine shoot best on upper end of the midrange loads.
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Old May 5, 2013, 10:01 PM   #7
sculls711
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Thanks

Thanks all. Most helpful.
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Old May 5, 2013, 10:31 PM   #8
Misssissippi Dave
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Most of my loads also tend to be between lower to upper mid range. I also normally don't use the slowest powders. Slower powders will let you load to higher speeds. Higher speeds don't always give you better accuracy.
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Old May 7, 2013, 07:51 AM   #9
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bullets are NOT all the same

First, let your bullet be the guide.

I suggest starting at the LOWEST published charge weight regardless. Working upward in .2g increments can help keep you safe.
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