12-23-2020, 07:39 PM
400's will do fine for a bolt gun.
On a separate note, I think I will weigh in on the discussion concerning es/sd of load sets developed by handloaders.
The typical sampling and standard deviation, etc, activities concern some existing universe of components, and taking some random sample of those to look for data such as mean, median, std deviation etc. The larger the sample, the more accurate your findings, in general. This would also apply to factory ammo bought as those boxes of rounds are indeed samples of some larger universe -- which presumably one could continue to buy and shoot -- a competitor who finds one such lot for his rifle, usually goes back and buys a lot of that lot#. And this type of random testing is/was also used appropriately in several of my multi-million $$ nuclear regulatory projects, where we were engaged in verifying adequate nuclear safety/licensing of large scale plants, for protecting the health and safety of the public.
For handloaders, however, the issue is a bit different; not totally but somewhat, let me explain what I mean.
I can't speak for every loader but for, say, a relatively conscientious one that is attempting to find accurate loads for his/her rifle. In this case, es/sd plays a part in the load's performance but also has partly to do with the process and various error factors of the loader's routine.
Example: take uniformly sized and re-sized cases, uniform primers (same lot), a single bullet of some percentage consistency (0.3 gr/100 or so), a single lot of powder, an overall length (+/-0.003 for example) or OAL, all within some manner of tolerances, and powder that is weighed and held to, say, +/- 0.1 gr accuracy (out of say 30 grs) of the powder scale. All of those variables have some small % of variability, so if a load, say, exits the muzzle at a consistent node/MV/angle/etc, then one can say such a load could be accurate in one's rifle. As long as you can continue to produce this load with that process and those tolerances, then its performance will be in accordance with the % deviations of the variables listed above... some of which won't have a discernable amount of MV delta, but some will. In those cases, comparing one set of cartridge load combo "A" against a differing set of combo "B" (ie, increasing powder charges for example), one can use es/sd of those load sets as an indicator of potential accuracy. [Certainly more load sets of equal combo are better than a single one.]
In my case I would estimate that, in somewhere up to about 95% of my "good-node-accurate-loads" the resulting MV data remains tightly within an MV range and I would say, I have a good load and the es/sd's also are very good. I can verify that load over several sets of it, over different days at fairly consistent environmental conditions (I shoot at a temp-controlled indoor range).
I'm not a competition shooter so I can't take it to that level, but in my shooting and load development, I am confident that when I find such a load for one of my rifles, every time I have loaded back up that combo, it shoots just like the initial sets I had, with not equal but definitely closely agreeing, es/sd/accuracy/poi etc results.
So I think as loaders we can make a case for using our es/sd values as guides to finding that accurate load, BUT it begins with a boringly consistent and accurate reloading technique.
Therefore, I do think there is a useful case for these in our load development efforts.
On a separate note, I think I will weigh in on the discussion concerning es/sd of load sets developed by handloaders.
The typical sampling and standard deviation, etc, activities concern some existing universe of components, and taking some random sample of those to look for data such as mean, median, std deviation etc. The larger the sample, the more accurate your findings, in general. This would also apply to factory ammo bought as those boxes of rounds are indeed samples of some larger universe -- which presumably one could continue to buy and shoot -- a competitor who finds one such lot for his rifle, usually goes back and buys a lot of that lot#. And this type of random testing is/was also used appropriately in several of my multi-million $$ nuclear regulatory projects, where we were engaged in verifying adequate nuclear safety/licensing of large scale plants, for protecting the health and safety of the public.
For handloaders, however, the issue is a bit different; not totally but somewhat, let me explain what I mean.
I can't speak for every loader but for, say, a relatively conscientious one that is attempting to find accurate loads for his/her rifle. In this case, es/sd plays a part in the load's performance but also has partly to do with the process and various error factors of the loader's routine.
Example: take uniformly sized and re-sized cases, uniform primers (same lot), a single bullet of some percentage consistency (0.3 gr/100 or so), a single lot of powder, an overall length (+/-0.003 for example) or OAL, all within some manner of tolerances, and powder that is weighed and held to, say, +/- 0.1 gr accuracy (out of say 30 grs) of the powder scale. All of those variables have some small % of variability, so if a load, say, exits the muzzle at a consistent node/MV/angle/etc, then one can say such a load could be accurate in one's rifle. As long as you can continue to produce this load with that process and those tolerances, then its performance will be in accordance with the % deviations of the variables listed above... some of which won't have a discernable amount of MV delta, but some will. In those cases, comparing one set of cartridge load combo "A" against a differing set of combo "B" (ie, increasing powder charges for example), one can use es/sd of those load sets as an indicator of potential accuracy. [Certainly more load sets of equal combo are better than a single one.]
In my case I would estimate that, in somewhere up to about 95% of my "good-node-accurate-loads" the resulting MV data remains tightly within an MV range and I would say, I have a good load and the es/sd's also are very good. I can verify that load over several sets of it, over different days at fairly consistent environmental conditions (I shoot at a temp-controlled indoor range).
I'm not a competition shooter so I can't take it to that level, but in my shooting and load development, I am confident that when I find such a load for one of my rifles, every time I have loaded back up that combo, it shoots just like the initial sets I had, with not equal but definitely closely agreeing, es/sd/accuracy/poi etc results.
So I think as loaders we can make a case for using our es/sd values as guides to finding that accurate load, BUT it begins with a boringly consistent and accurate reloading technique.
Therefore, I do think there is a useful case for these in our load development efforts.
"Down the floor, out the door, Go Brandon Go!!!!!"