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Posted: 3/15/2015 5:59:15 PM EDT
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I've been loading for over 30 years and have loaded everything from .223 to 416 Rigby. I've shot competitively everything from IDPA to 1000 yard benchrest.
So in my years of loading, I've come to accept that not every powder charge is going to be exactly the same. My Dillon powder measure will vary +/- 0.2 grain and even my Lyman DPS 1200 Electronic scale will vary +/- 0.1 grain. Loading some .223 today and I was using my Lyman with some extruded powder (doesn't meter well in the Dillon). I accepted 25.5 to 25.6 grains on the scale. I haven't seemed to have any issues accuracy or otherwise. I'd be interested to see if some of you other handloaders have a similar tolerance, or if you tolerate no variance at all. Thanks in advance. |
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Depends....
On the 600 yard loads, I get picky. With the 80 SMK, RE-15, Rem 7 1/2, I try to keep the two sigma range 0.1 grain. At the 300 yard line and down, 5 times that much does not break the x-ring. Maybe even more would work, but it isn't hard to charge within 0.5 grain two sigma. |
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My Dillon measure throws an average charge of 24.0 gr using Varget with SD = 0.12 gr. Even with that variability, it loads shoot 1/2 MOA at 200 yards.
Is that accurate enough? It is not an idle or rhetorical question. How accurate you want to be will factor into how accurate your charges need to be. IMO, within reason, it is a small factor but it is a factor. |
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I have found that a "good" load will tolerate +/- 1gr easy and still be accurate as far as groups go. But of course velocity will change so down range the drop will open up the group vertically.
I found this out by being lazy. As most know a Uniflow does not throw stick powder very well. One day I had no time to trickle before High Power Silhouette rifle practice so I just used the Uniflow without trickling. I did a few test throws and most were within +/- 1gr. My load could easily tolerate this without being hot so I went with it. There were some that were VERY crunchy, I threw these back in the hopper. At the range I shot a group at 200 meters and they were very close to MOA accurate. I later shot groups at 100 yards and they were not much different than my match ammo group wise at 100 yards. If you think about all the things that can effect pressure it makes a lot of sense to develop loads that can tolerate a little pressure difference and still be accurate. If I had a load that opened up to twice the size group with only a +/- .5gr change in charge weight I would be looking for a better recipe. Motor1 |
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Rifle Loads.
I try and work up an accuracy load that has about a .5 grain swing. Here is what I mean. The two best 10 shot groups were 25.5gr and 26gr. I settled on 25.8gr for my accuracy load. When I dump my powder charge, I will remain well within the accuracy "node" with a +/- .2 grain swing. 
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Quoted: Rifle Loads. I try and work up an accuracy load that has about a .5 grain swing. Here is what I mean. The two best 10 shot groups were 25.5gr and 26gr. I settled on 25.8gr for my accuracy load. When I dump my powder charge, I will remain well within the accuracy "node" with a +/- .2 grain swing. http://i2.photobucket.com/albums/y17/steve4102/300BAR.jpg Knowing how well it'll do in the worst case is a lot more useful to me than knowing what it'll do under ideal conditions. |
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