Reloading Practices

Target accuracy is down to .02 grains now. For plinking +-.1 grain is great ammo and .2 is still very good. A standard high quality measure will serve you well.

AJC1 said:

Target accuracy is down to .02 grains now. For plinking +-.1 grain is great ammo and .2 is still very good. A standard high quality measure will serve you well.

Click to expand...

I agree. If you practice with a good powder measure you should be able to achieve plus or minus 1/10 grain with most ball or flake powders. Just sit down with your measure and scale and throw and measure 40 or 50 charges. When you get comfortable with the results go to loading ammo.

There's a lot of variables.

For my 3Gun and training ammo I use standard (hopefully Hornady) 62grn FMJ and thrown charges of TAC or CFE .223. From my Dillon I get about a .1-.2 grain deviation, that combination gives me slightly over 1MOA for 5 shots at 100 and an SD in the low 20's with mixed range pick-up brass. Perfectly acceptable out to 300 yds on an 8" plate, which is about the max distance, min tgt size at my 3Gun club.

I just finished a couple months ago working up a load for me new SPR build that clones the MK262A1 load with a 77 grain Sierra OTM with thrown charges of TAC from my Harrell's. That load out of that gun is solid 3/4MOA, low .10s in SD. The other differences are they're all loaded in PMC brass that's been annealed and trimmed to the same length with match primers.

"Plinking" is still such a broad term that I have a tough time answering this. What kind of "plinking" accuracy are you looking for? Are you just wanting to ring a 10" gong at 150? Are you actually going to be looking for good grouping?

For me, if I am loading straight blasting ammo that I don't concern myself so much with accuracy on, but more on practicing good fundamentals with regards to handling the rifle, I don't care if I have a full grain of difference between the bottom end charge and the top end(my powder measure normally throws +/- 0.2 grains, so I typically end up between 26.8 grains and 27.2 grains, with 80% or so being between 26.9 and 27.1, making that wide of an "acceptable" range a moot point). As long as I am hitting my 6" gong at 100, I am happy. I think people SEVERELY overestimate the difference a small variation in charge weight is going to make on plinking ammo.

Just for kicks, I just checked my load testing targets, and most of them are showing about 1 to 1.5 inches of elevation change in the estimated center of the groups at 100 yards over the difference of 2-3 grains of powder. That is 2 to 3 whole grains, and it changed the impact at 100 yards by less than 2 inches. Even if we extrapolate that to 150 and add 50% to those sizes, we are still talking under a 3 inch difference between 2.5 whole grains of powder difference. Now, if you are talking about the same powder, and assuming that you are only going to be getting a single grain spread, lets cut that size down to 40% of that 3 inches, and you should expect about a 1.25" elevation change between top and bottom. Chances are, your powder measure is going to be throwing much better than a 1 grain variation(most are typically +/- 0.2 or 0.3 grains, meaning around a half grain from lowest to highest), meaning it should be even smaller. If yours is like my uniflow or the one that came with my mark 7, you will probably see about the same variation I do. Are you really going to sweat a difference of less than 2 inches at 150 yards? I know I sure won't unless I am going for precision shooting, in which case I am weighing every charge to within 0.01 grains difference.

Next, no matter how precise and consistent your powder charges are, there will ALWAYS be some inherent amount of inaccuracy in the ammo, just based on the primers, the brass, and the bullets. Since you said it is plinking ammo, I highly doubt you are going through the process of weighing all your cases to find the ones closest in case weight/volume(at best, you might be separating them by headstamp and MAYBE by year), or weighing the bullets to find the ones closest to each other in weight. All of those things are going to add up to some spread in your groups, but shouldn't really be any bother for plinking ammo.

Long story short, throw 10 charges with your powder measure dialed in where you want it. Make sure they are consistently within whatever you consider an acceptable range(for me, that is 1 grain from low to high), and also within safe limits. After that, start loading and check a charge every 10 to 20 rounds if you want that extra peace of mind. A half a grain high or low isn't going to be the end of the world unless you are already loading at the max load. Hell, you probably won't even notice that high or low charge.

Anything more than .2 or so would bother me even for plinking ammo. Match ammo I generally trickle up and shoot for no more than .05 variation. Using a ball powder, even an inexpensive measure like the Lee PPM will hit 0.5gr variation or less. I load all of my bulk (plinking) ammo and also my short-course match ammo with ball powder such as BL-C(2) or H335 in a Lee PPM because it's quick and plenty accurate.

For my general plinking ammo I use a powder that meter to ±0.1gr or less. This is normally a small flake or ball powder. Extruded is at a min twice that. My bench ammo is loaded as precise as I can get it ±0.02gr (GP250).

In my opinion, if you do a proper load workup, your load will be tolerant of small changes in charge amount. In other words, the velocity won’t change much within a certain charge range. Even so, at 150 yards, a small change in velocity won’t result in much vertical dispersion due to bullet drop, I would be more worried about the effect of barrel harmonics and finding a good node. For plinking ammo at that distance, I would not be concerned with variations of +/- 0.3gn. I would also look for the accuracy node at the lower end of the charge range, and use flat-based bullets.

I get 0.05gn variation on my redding 10-x powder throw as verified by my Gemtech scale.

With stick powder in rifles I have to trickle, though.

Toprudder said:

In my opinion, if you do a proper load workup, your load will be tolerant of small changes in charge amount. In other words, the velocity won’t change much within a certain charge range.

Click to expand...

That's my theory as well. Once I have the load dialed in, I don't bother worrying about deviations from the powder drop... for plinking ammos. I trickle up any other rifle rounds that are meant for accuracy, or if I'm working near the top of the load data (which isn't often.) Some powders drop better than others, however. With the exception of H335, I'm a big IMR man, so I have to make sure the drop is set right by dropping 10 test charges and scale them before moving on with the loading.

Doing the math... say you are working with an established load of 43.5grn IMR4895 for your .308 loads. A 1% difference in charge weight is .43grn (half a grain.) If you are working in middle of the road loads you would probably still be OK (at 43.9grn,) but if you were working towards the top... not so much. I would hope whatever powder drop you are using wouldn't have a variance over .5%, let alone 1% ...but the only way to find out is to test drop.