HollowPoint
12-27-2018, 05:07 PM
I recently reverted my rebarreled and rechambered K31 Swiss rifle back to it's native 7.5x55 Swiss cartridge. I still had the original barrel so it was a simple matter of putting it back on.
This rifle in its' original configuration was a tack driver as far as military surplus rifles go. I've posted photos of my two hundred yard targets here before. One target in particular showed a cluster of a little under an inch and a half. This was done with a scope mounted but my 100 yard groups were about the same using peep sights.
My problem was that after re-installing the factory barrel I was unable to get those groups I was once getting with the same loads. At the very least I expected to have to tweak them after reinstalling that factory barrel but I just couldn't get those groups to tighten any more than two and a half or three inches at a hundred yards; and this was using the same charge weights and bullets/components as before.
I've been using the same RCBS powder scale for years. This is what I used to load all of my guns with the exception of my occasional use of an old Lee Powder scale and a short time when I bought and started using one of those Lyman digital powder dispensers. I quit using it because the powder charges it was dropping never matched the weights that my RCBS scale was registering.
Out of frustration of not being able to tighten up my K31 groups I took that digital scale out of the storage closet and blew the dust off of it. I also had one of those cheap Harbor-Freight digital postal scales on hand as a cross reference. I was determined to figure out what was going on with my previously accurate loads no longer being accurate so, I used the calibrating weight that came with the Lyman digital scale and proceeded to test each of my scales. Lo-N-Behold, it was the RCBS analog scale that has been off all of these years. With the lighter charge weights it was off by a bit over .5 grains. The heavier the charge weight, the more it was off. And I couldn't have been luckier than to find this out before my next range session.
I had loaded up a batch of OCW test loads for my 6.5x55 Swede and I had planned on testing up to the maximum loads in the Nosler load book. My RCBS scale at the listed maximum load was off by a bit over 1.5 grains. That's over 1.5 grains over maximum. (KaaBoom)
There have been other time when I reloaded ammo that had been previously proven to be very accurate out of the same rifles and the accuracy just wasn't there. I had just chalked it up to me having a bad shooting day. In addition to the RCBS analog scale I had also use one of those cheap Lee analog powder scales from way back when I first started reloading . I see now that no powder scale can be completely trusted unless or until they've been cross referenced with other powder scales to confirm their accuracy.
I fiddled around with my RCBS analog powder scale until I finally got it calibrated with both my digital powder scales. It took some doing. I had to take some weight off of that little sliding thingy on the beam and then slowly add it back on until all three scales were able to mimic one another. I'll probably quit using the old Lee powder scale all together. So, I took apart all that previously loaded ammo and re-did it so that now it all falls in line.
Now I have to go back and take apart at least one of all of my previously loaded accuracy loads for my .223, .303, K31, .45, 9mm and my 380. Fortunately, I still have some of those loaded accuracy loads so that I can take one of each apart and just weigh the powder charges to at least get me close to the updated charge weights. I'm not to worried about the handgun loads, those were all loaded light; it's those rifle loads that I need to check.
Have any of you guys ever checked the weights that your go-to powder scales are giving you against any other powder scales to see if they are giving you accurate measurements? For me, it's been at least thirty years. All this time I had just assumed that because it was a brand name scale, it was giving me accurate readings.
HollowPoint
This rifle in its' original configuration was a tack driver as far as military surplus rifles go. I've posted photos of my two hundred yard targets here before. One target in particular showed a cluster of a little under an inch and a half. This was done with a scope mounted but my 100 yard groups were about the same using peep sights.
My problem was that after re-installing the factory barrel I was unable to get those groups I was once getting with the same loads. At the very least I expected to have to tweak them after reinstalling that factory barrel but I just couldn't get those groups to tighten any more than two and a half or three inches at a hundred yards; and this was using the same charge weights and bullets/components as before.
I've been using the same RCBS powder scale for years. This is what I used to load all of my guns with the exception of my occasional use of an old Lee Powder scale and a short time when I bought and started using one of those Lyman digital powder dispensers. I quit using it because the powder charges it was dropping never matched the weights that my RCBS scale was registering.
Out of frustration of not being able to tighten up my K31 groups I took that digital scale out of the storage closet and blew the dust off of it. I also had one of those cheap Harbor-Freight digital postal scales on hand as a cross reference. I was determined to figure out what was going on with my previously accurate loads no longer being accurate so, I used the calibrating weight that came with the Lyman digital scale and proceeded to test each of my scales. Lo-N-Behold, it was the RCBS analog scale that has been off all of these years. With the lighter charge weights it was off by a bit over .5 grains. The heavier the charge weight, the more it was off. And I couldn't have been luckier than to find this out before my next range session.
I had loaded up a batch of OCW test loads for my 6.5x55 Swede and I had planned on testing up to the maximum loads in the Nosler load book. My RCBS scale at the listed maximum load was off by a bit over 1.5 grains. That's over 1.5 grains over maximum. (KaaBoom)
There have been other time when I reloaded ammo that had been previously proven to be very accurate out of the same rifles and the accuracy just wasn't there. I had just chalked it up to me having a bad shooting day. In addition to the RCBS analog scale I had also use one of those cheap Lee analog powder scales from way back when I first started reloading . I see now that no powder scale can be completely trusted unless or until they've been cross referenced with other powder scales to confirm their accuracy.
I fiddled around with my RCBS analog powder scale until I finally got it calibrated with both my digital powder scales. It took some doing. I had to take some weight off of that little sliding thingy on the beam and then slowly add it back on until all three scales were able to mimic one another. I'll probably quit using the old Lee powder scale all together. So, I took apart all that previously loaded ammo and re-did it so that now it all falls in line.
Now I have to go back and take apart at least one of all of my previously loaded accuracy loads for my .223, .303, K31, .45, 9mm and my 380. Fortunately, I still have some of those loaded accuracy loads so that I can take one of each apart and just weigh the powder charges to at least get me close to the updated charge weights. I'm not to worried about the handgun loads, those were all loaded light; it's those rifle loads that I need to check.
Have any of you guys ever checked the weights that your go-to powder scales are giving you against any other powder scales to see if they are giving you accurate measurements? For me, it's been at least thirty years. All this time I had just assumed that because it was a brand name scale, it was giving me accurate readings.
HollowPoint