I was getting back into the reloading bench for my Springfield M21 rifle several weeks ago, took some time off because of work the last few weeks. In any case, I started breaking in the rifle with PMC M80 surplus and eventually some cheapo match loads using the new fired brass and some Speer 168 grain match bullets. Even after I accidentally set the OAL shorter than intended by a casual error, the rifle was shooting 3/4 MOA about 60% of the time in ten round groups (my declining ability and penchant for weak off bipod shooting instead of bench make up most of the 40% remainder), and I was excited for what the rifle might be capable of. Finally got a big box of 175 grain Sierra OTMK and was excited, hoping the bigger bullets would do even better in the 1:10 Douglas. This time I double checked and made sure the OAL was 2.810.
The end result was 2 MOA. I'll admit in hindsight that work fatigue might have played a larger role in the poor performance than I would like to admit, but even when I was calling my shots dead on there was no denying that the accuracy of the cartridge was inferior to the 168 grain Speer. Now, I know that the real answer is to sit down and load a great big batch of bullets with different powder charges and OAL to hunt down the problem properly, the whole incident got me thinking about an issue, especially after asking the good folks at the M14 forum what they thought the problem might be.
Besides the load being a bit too hot for barrel harmonics (the load was perfectly safe for the rifle), they said they would seat the 175 OTMK even further, to the absolute maximum the M14 magazine will allow. Others talked about how they didn't always get good results with high BC heavy bullets. With the bullet shape, this makes sense, and then I thought back to my lead bullet casting and all the literature I read on that subject. That the old Lyman experts talked about general lead bullet design, what worked not only with lead alloys but also what works in loose free bores in rifles and throats of revolvers; that flat nose and big dull round nose are forgiving and generally will work in anything where a spitzer is problematic to nearly impossible to make accurate.
So, after a long winded introduction to the question, is there really a correlation between "dumb" bullets of older and simpler design and forgiveness in throats, that they might be more forgiving with OAL differences? Are modern "smart" bullets of modern and advanced design, meant to maximize BC for a bullet weight, less forgiving with OAL, and potentially more problematic in loose guns? Am I making excuses for bad handloading and shooting, on the wrong track, or is there some truth in this long winded observation?
The end result was 2 MOA. I'll admit in hindsight that work fatigue might have played a larger role in the poor performance than I would like to admit, but even when I was calling my shots dead on there was no denying that the accuracy of the cartridge was inferior to the 168 grain Speer. Now, I know that the real answer is to sit down and load a great big batch of bullets with different powder charges and OAL to hunt down the problem properly, the whole incident got me thinking about an issue, especially after asking the good folks at the M14 forum what they thought the problem might be.
Besides the load being a bit too hot for barrel harmonics (the load was perfectly safe for the rifle), they said they would seat the 175 OTMK even further, to the absolute maximum the M14 magazine will allow. Others talked about how they didn't always get good results with high BC heavy bullets. With the bullet shape, this makes sense, and then I thought back to my lead bullet casting and all the literature I read on that subject. That the old Lyman experts talked about general lead bullet design, what worked not only with lead alloys but also what works in loose free bores in rifles and throats of revolvers; that flat nose and big dull round nose are forgiving and generally will work in anything where a spitzer is problematic to nearly impossible to make accurate.
So, after a long winded introduction to the question, is there really a correlation between "dumb" bullets of older and simpler design and forgiveness in throats, that they might be more forgiving with OAL differences? Are modern "smart" bullets of modern and advanced design, meant to maximize BC for a bullet weight, less forgiving with OAL, and potentially more problematic in loose guns? Am I making excuses for bad handloading and shooting, on the wrong track, or is there some truth in this long winded observation?
