+/- 1/10th of a grain
- Thread starter ryanshaw44
- Start date
I've found that for smaller-capacity pistol cases, like .32S&W Long with 90gr wadcutters, 0.1 grain can make a difference. I shoot that cartridge in my Walther GSP (25-metre ISSF competition). There's a noticeable change in both recoil and impact on target between 1.8gr and 1.9gr HP38.
Pathfinder
CGN Ultra frequent flyer
- Location
- Northeast Ontario
I agree, in a big case...you will not notice.
What is most important is that you find the load that shoots the most accurately with the rifle and your choice of components and don't assume that max or near max velocity will always get you there.
That load combination will allow the bullet to exit the bore at the friendliest point of the barrels vibration cycle and you have a lot more latitude than +/- 1/10 of a grain that affect that vibration cycle than you would think.
http://optimalchargeweight.embarqspace.com/#/ocw-test-example/4529811475
That load combination will allow the bullet to exit the bore at the friendliest point of the barrels vibration cycle and you have a lot more latitude than +/- 1/10 of a grain that affect that vibration cycle than you would think.
http://optimalchargeweight.embarqspace.com/#/ocw-test-example/4529811475
Republic of Alberta
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I have seen bigger point of impact shifts and velocity differences from firing virgin brass vs once fired brass than you would ever see from +.1 of a grain in a 300 mag. Same thing with neck tension. There are other small things that make a way bigger difference than .1 of a grain.
It may be better to look at load increments in terms of percentages of the powder charge weight;
- in a 2.0 grain load .1 grain is 5%, for sure that will make a difference
- in a 40 grain load .1 grain is 0.25% probably only detectable in benchrest conditions
- in a 100 grain load .1 grain is .1% or one part in 1000, there are other factors, as mentioned above, that will give larger variations than this.
I use an increment of 1% in load development and drop it to 0.5% for fine tuning, which roughly translates to .5 grain (1%) and .25 (0.5%) increment in a 300 mag.
But in 38 special target loads the increment is .05 grain for the same percentage weight increment.
Charge density will also have an impact, loads of low charge density can be sensitive to small increments but this may have more to do with how the powder is laying in the case.
Dan
- in a 2.0 grain load .1 grain is 5%, for sure that will make a difference
- in a 40 grain load .1 grain is 0.25% probably only detectable in benchrest conditions
- in a 100 grain load .1 grain is .1% or one part in 1000, there are other factors, as mentioned above, that will give larger variations than this.
I use an increment of 1% in load development and drop it to 0.5% for fine tuning, which roughly translates to .5 grain (1%) and .25 (0.5%) increment in a 300 mag.
But in 38 special target loads the increment is .05 grain for the same percentage weight increment.
Charge density will also have an impact, loads of low charge density can be sensitive to small increments but this may have more to do with how the powder is laying in the case.
Dan
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rnbra-shooter
CGN Ultra frequent flyer
- Location
- New Brunswick
For a .308 target rifle (powder charges ~45 grains), I will happily use thrown powder charges out to 600 metres or yards, at any level of competition. In a box of 50 rounds, most charges will be within a 0.4 grain window (nominal charge weight +/- 0.2 grains), but over the whole 50 rounds there will be a 0.8 grain difference from the very lightest to the very heaviest.
If I have a very well tuned load for 1000 yard shooting, I will sometimes weigh each powder charge so that they are all within the same tenth of a grain reading. Do note the first part of the preceding sentence, "...a very well tuned load..."; I have found that unless you have a *correct* load, there is *no* benefit to be had from measuring each charge to a high level of accuracy.
In most circumstances I would be quite happy to shoot ammo loaded to +/- 0.1 grain at 1000 yards at any level of competition. And in some cases I would also be happy to shoot 1000 yards using ammo loaded to looser tolerances than this.
If I have a very well tuned load for 1000 yard shooting, I will sometimes weigh each powder charge so that they are all within the same tenth of a grain reading. Do note the first part of the preceding sentence, "...a very well tuned load..."; I have found that unless you have a *correct* load, there is *no* benefit to be had from measuring each charge to a high level of accuracy.
In most circumstances I would be quite happy to shoot ammo loaded to +/- 0.1 grain at 1000 yards at any level of competition. And in some cases I would also be happy to shoot 1000 yards using ammo loaded to looser tolerances than this.
If you are not weighing and sorting brass, 1-3 10ths will make less difference than the extremes of brass weight in a batch of 300 WM.
Your internal volumes will vary more than the equivalent of 1-3 10ths of powder.
Your internal volumes will vary more than the equivalent of 1-3 10ths of powder.
very good info here.
I was wondering this myself, as the hornady LNL auto dispensor/scale throws about +/- 0.1 grain.
so in the hierarchy of reloading variables:
powder choice
bullet weight
primer
times fired brass
neck tension
seating depth?
all matter more than 0.1 of a grain or powder?
I was wondering this myself, as the hornady LNL auto dispensor/scale throws about +/- 0.1 grain.
so in the hierarchy of reloading variables:
powder choice
bullet weight
primer
times fired brass
neck tension
seating depth?
all matter more than 0.1 of a grain or powder?
rnbra-shooter
CGN Ultra frequent flyer
- Location
- New Brunswick
@na1lb0hm, good idea to make a list of factors more important than a tenth of a grain of charge weight.
I might delete "times fired" from the list, because I haven't found it to be particularly important (though it can and probably does have a small effect on neck tension, which is correctly included in your list).
I'd replace "bullet weight" with "bullet choice".
You write "seating depth ?", you can remove the question mark; "seating depth" definitely belongs on the list.
I would add an important item to the list - "charge weight".
Probably also belonging on the list is "bullet straightness" (is the bullet seated reasonably straight, total indicated runout of no more than a few thou)
I might delete "times fired" from the list, because I haven't found it to be particularly important (though it can and probably does have a small effect on neck tension, which is correctly included in your list).
I'd replace "bullet weight" with "bullet choice".
You write "seating depth ?", you can remove the question mark; "seating depth" definitely belongs on the list.
I would add an important item to the list - "charge weight".
Probably also belonging on the list is "bullet straightness" (is the bullet seated reasonably straight, total indicated runout of no more than a few thou)
This is good info for sure. I have always worked up my final loads to the 1/10 of a grain in my 7mm mag and my 7X57.
Now I use 62.0 grains of IMR 4350 in my mag with a 140 grain bullet. When working up the load I found that 62 grains was as good as it could get and didn't start 1/10 grain increments.
However, when I was using RL22 I found that 1/10 of a grain did make a difference. I found the best load for my gun using a 145 speer was 67.3 grains. I can't remember now just how much better it was as compared to 67.4 or even 67.5 as I stopped using RL22 powder but I recall that there was a difference. Maybe the powder is a bit more picky ? or maybe my shooting was better when testing that load ?
Now I use 62.0 grains of IMR 4350 in my mag with a 140 grain bullet. When working up the load I found that 62 grains was as good as it could get and didn't start 1/10 grain increments.
However, when I was using RL22 I found that 1/10 of a grain did make a difference. I found the best load for my gun using a 145 speer was 67.3 grains. I can't remember now just how much better it was as compared to 67.4 or even 67.5 as I stopped using RL22 powder but I recall that there was a difference. Maybe the powder is a bit more picky ? or maybe my shooting was better when testing that load ?
