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I've got a question about projectiles and powder throws. I've got some Winchester Power Points, 64 grain .224 diameter. I'm running them in an AR. My reloading manual only lists three powders for this bullet weight, one of which I have. These are:

Accurate 2520
Accurate 2460
Accurate 2230

I have the 2460 and it's okay, I'm not anywhere near max yet and may wind up sticking with this powder.

But while there's not much data out there on the 64 grain PP, there are beaucoup powders and data listed for the 63 grain Sierra bullet.

Is one grain of bullet weight going to make an appreciable difference?

I'm usually not ever near a max load, unless it just proves to be the most accurate which I've found to rarely be the case. Usually near max but almost never max. I've done all of my reloading to date with 7.5x55 Swiss and .308 Winchester in bolt guns. What think you guys?

Paul
 

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With only 1-2 grain difference there should be no problems transposing the load data. Just start at the minimum and work your way up. Sierra's load data for .308, 150-155 gr. are together in their load book.

Glenn
 

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Discussion Starter · #3 ·
With only 1-2 grain difference there should be no problems transposing the load data. Just start at the minimum and work your way up. Sierra's load data for .308, 150-155 gr. are together in their load book.

Glenn
Thanks Glenn. I didn't think it would be a problem but I wanted to make sure.

Paul
 

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its not just the bullet weight that is a concern. you also are dealing with different bullet profiles . even 2 bullets of the same exact weight can have different max powder charges because they have different amounts of bearing surface. i personally dont care for the practice, but if your going to substitue bullets, work your load up from the starting point in the load data.
 

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its not just the bullet weight that is a concern. you also are dealing with different bullet profiles . even 2 bullets of the same exact weight can have different max powder charges because they have different amounts of bearing surface. i personally dont care for the practice, but if your going to substitue bullets, work your load up from the starting point in the load data.
+1 probably the most missed issue. Not ALL bullets are created equally! lenght,bc and ogive should always be considered as well as base.
 

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1 grain in weight is not going to make a difference, safety-wise. Bearing surface can, but the chances of the bearing surface of 2 bullets off by 1 grain in weight being measurably different will be negligible for a bullet that light.

Dont sweat it. One reloading manual's max charge weight could easily be another reloading manual's medium charge weight. They are never consistent because the environment and equipment used to test will never be consistent.. There is no "National Department of Charge Weight Standards", so to speak...

BC and Ogive will have no bearing on the the charge weight you use, only on the flight characteristics of the bullet after it exits the muzzle, and bullets with a different form factor and BC will behave differently downrange even if fired at the same muzzle velocity..

So if the question is whether you will be safe using load data from a load that uses a bullet that is 1 grain less in weight is, essentially, yes, you will be safe. If the question is whether the two different bullets will fly the same, is another matter, and probably they will not, but that does have to do with BC and form factor and not so much the weight in this particular instance...
 
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