Measuring rim thickness, worth it or not

manitou210

manitou210

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Measuring rims of different ammo some surprises. your thoughts
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SK Rifle Match had two that would not fire very thin rims, the rest measured quite good, 2 to 3K.my two rifles did just okay, my friends 54 really likes this ammo

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The Midas + Are one of my favorite ammo in my two Remington target guns, best 100 yard target
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.389"
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This old Lapua Midas M is the best ammo I have used they measure all the same wish the still made this stuff have about
1500 left, my Rem 540xr loves it 10 shot group under 1/2 "
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The Center x measured very good, bought a brick its shoots just okay in my guns, not in class of Midas + or M
some shooters having good results at club

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Got these from Tesro last week going to try them at 200y they are about 30 fps than above ammo could be okay?
They measured very good.
 
Tried it a long time ago.

My conclusion were
- From a given lot, there were no noticeable (to me) change in the POI between rounds of different rim thickness
- It's a time consuming process. I could make better use of my time 1) working out 2) shooting 3) earning $ to buy higher quality ammo

I was using a slider rim thickness gauge.

One interesting thing I noticed, is using cheap ammunition (Winchester/Remington/or the Russian stuff we used to be able to get)
- There would be a variation on the rim thickness, on the same cartridge, depending which way you put the writing on the back.
- The way you loaded the round in, would affect the POI up or down. I guess the "tinner" side of the cartridge probably had less priming compound, affecting how the powder was burned. Now that I think of it, it would have been interesting to use a chrono and compare velocity...
 
I found rim thickness to be a partial player in the accuracy game, I sorted base to driving band with the G3 MK II Pro ogive comparator and found the results on paper were more eye opening then that of just sorting by rim thickness. The 3rd process in my sorting is breaking down all my sub groups by weight.
I managed to make SK rifle match run alongside eley match by sorting it, at a cost of about half it's not a bad gig if you have the time and desire to sort it, but as the cost of the ammo goes up so does the consistency in those 3 things and sorting becomes more of a mute point
 
sillymike said:
One interesting thing I noticed, is using cheap ammunition (Winchester/Remington/or the Russian stuff we used to be able to get)
- There would be a variation on the rim thickness, on the same cartridge, depending which way you put the writing on the back.
Click to expand...

I also tried it with cheap ammo, it made a difference, got better grouping and no odd flyers, I agree it's a time consuming process...
 
On RFC there is periodic discussion of the question of sorting by rim thickness and by weight. There is even a sticky on it. In the thread that was made a sticky, a shooter compiled a great deal of data based on results from sorting by rim thickness, but four years later he deleted that data and replaced it with the following words: "I have finally come to the realization that data is meaningless. All one has to say is "Sorting improved my groups" or "Sorting improved my scores" or "Sorting improved consistency" and no amount of data, graphs or charts will ever change anyone's mind. I have now convinced my self that sorting does nothing to improve precision and that is enough. To that end all data has been deleted.

The consensus on RFC, for what it's worth, is that sorting doesn't make a difference, at least one that's worth the effort. Elsewhere, it's claimed that decades ago sorting used to be more common because rim thickness varied more back then. There don't seem to be many (any?) top ARA shooters sorting by rim thickness.
 
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