Nothing matters except consistent impacts on target. Not the brand or price tag on the box. Not the es/sd. Nothing matters short of performance on target and there is no way of figuring out what ammo is better in your rifle than to test, either on your own or at a manufacturers test center. Simply paying more and hoping for better is actually statistically unlikely to equate to better groups. Thunderbolts and golden bucket of bullets and the like not withstanding.
I just returned from the Mesa test center. I was fortunate that they had 16 lots of CenterX and Midas to test. I was also fortunate that my rifle LOVED a particular lot of Center X. I was absolutely blown away at how much variation there was between the best lot and the worst. The worst being nearly 3x larger groups than the best. None of the Midas lots compared to the best two Center X lots.
Devan further proved that MV isn’t EVERYTHING. After testing. Confirming. And finally reconfirming the best lot, we strapped a Magnetospeed to my gun and compared impacts at 100m to their individual MV’s. One would assume that slower rounds would impact lower while faster ones impact higher. NOPE. Zero correlation between MV and impacts above or below an imaginary waterline. One would think that at some distance (150,200,250 yards or more) that MV and vertical impact would have to correlate and it might. But there is more to it. The BC of the bullets is poor and variable. Especially if the bullet is dinged, dented, scratched, or otherwise imperfect in any way. Perhaps even minutely. These are some of the variables that single shot bench-rest and, to some extent, controlled feed repeating rifles attempt to avoid.
The cliff’s notes takeaway message from the experts at the test center: There are huge differences in rimfire ammo. Test test test until you find a winner and then hopefully you can stock up on that one. If you are competing in the NRL/PRS game, it takes a lot of ammo to generate an accurate MV/temp table, dsf and MV calibrated ballistic curve(s). Doing all this with only one or two bricks of ammo only to have to start over again in a month or two makes for a lot of wasted time and ammo. Let the groups be your guide, not the es/sd. While poor es/sd will likely never shoot well, excellent es/sd is no guarantee in and of itself. Do not bother with weight or rim thickness sorting of ammo. When you weight sort, what component are you measuring? Powder? Lead? Brass? Primer compound? Who knows so don’t bother. In most all match chambers, the bullet is imprinting in the lands. In a match chamber, rim thickness will affect bolt closure effort, not headspace. This may not apply to looser, non match chambers.
This is the advice given to me from Lapua. YOUR mileage may vary.
CB
I just returned from the Mesa test center. I was fortunate that they had 16 lots of CenterX and Midas to test. I was also fortunate that my rifle LOVED a particular lot of Center X. I was absolutely blown away at how much variation there was between the best lot and the worst. The worst being nearly 3x larger groups than the best. None of the Midas lots compared to the best two Center X lots.
Devan further proved that MV isn’t EVERYTHING. After testing. Confirming. And finally reconfirming the best lot, we strapped a Magnetospeed to my gun and compared impacts at 100m to their individual MV’s. One would assume that slower rounds would impact lower while faster ones impact higher. NOPE. Zero correlation between MV and impacts above or below an imaginary waterline. One would think that at some distance (150,200,250 yards or more) that MV and vertical impact would have to correlate and it might. But there is more to it. The BC of the bullets is poor and variable. Especially if the bullet is dinged, dented, scratched, or otherwise imperfect in any way. Perhaps even minutely. These are some of the variables that single shot bench-rest and, to some extent, controlled feed repeating rifles attempt to avoid.
The cliff’s notes takeaway message from the experts at the test center: There are huge differences in rimfire ammo. Test test test until you find a winner and then hopefully you can stock up on that one. If you are competing in the NRL/PRS game, it takes a lot of ammo to generate an accurate MV/temp table, dsf and MV calibrated ballistic curve(s). Doing all this with only one or two bricks of ammo only to have to start over again in a month or two makes for a lot of wasted time and ammo. Let the groups be your guide, not the es/sd. While poor es/sd will likely never shoot well, excellent es/sd is no guarantee in and of itself. Do not bother with weight or rim thickness sorting of ammo. When you weight sort, what component are you measuring? Powder? Lead? Brass? Primer compound? Who knows so don’t bother. In most all match chambers, the bullet is imprinting in the lands. In a match chamber, rim thickness will affect bolt closure effort, not headspace. This may not apply to looser, non match chambers.
This is the advice given to me from Lapua. YOUR mileage may vary.
CB