The quest for the perfect load.
Ok today I'm going to talk about how to find the perfect powder charge utilizing the ladder test method.
First start with published loads never use a load you find on the internet or a buddies load, it could be catastrophic in your particular rifle.
Ok so what we are looking for is a good node, an area in which a few bullets group well.
Here's how we do it, first find a load for your cartridge, for this example lets say 50gr of powder, what we will do is load cases with the particular bullet and primer you will be using, and set to saami coal specs, we will then charge bullets as follows.
48/48.5/49/49.5/50/50.5/51/51.5/52/52.5/53/53.5/54/54.5/55
You can start lower and go higher, but this is a good reference, as you start getting into higher powder charges remember to check for pressure signs. Now take some magic markers and paint the bullets because the paint will transfer to the target letting you know which bullet hit where on the target (log what charge with what color and keep it in proper order. Very important) for this many bullets I would use black, blue, purple, green, red, yellow.
Now there will be more than one bullet with the same color so we repeat the colors in order so if 48gr is black then 51gr will be black again, we need this space in powder loads so not to be confused later.
Ok now set a target preferably 18"+ in height no closer than 200yds, 300 is better, steady your gun in a shooting rest (this is important, it has to remain steady) center your scope on the target (I prefer a piece of cardboard 24-36" tall with a 1" black dot in the middle) load the bullets one a time allowing 15-30sec between shots. What will happen is the holes will form a vertical string (don't worry bout side to side as this is caused by the wind and is not important) what you will notice is gaps between the holes going up, but there will be a group of 2-3 holes very close together and perhaps more than one grouping. So now you say " well there is a black hole at the bottom but up here there is also a black hole next to blue and purple, what charge is it" as the powder increases the bullets climb, it's the second black hole so it is the second cartridge that had a black bullet (make sense?).
Ok so let's say charges of 53/53.5/54 grouped the tightest.
( I take it this far you may not, your decision if you want to break it down to .1gr increments) now do the same test again but this time break it down by .1gr increments, look for the tightest group. Let's say 53.4/53.5/53.6.
Then load up 3-5 rounds in each load and see which produces the best group, I'll take that load and move to the next stage.
Now you're wondering about seating depth, refer to an older post (budget oal gauge) I find the oal for my chamber and load 3-5 cartridges per oal using this method .020 short of oal (jumping.), exactly at oal (often called kissing) and .015 longer than oal (called jamming).
Then I see which group is tightest, let's say jumping had the best group then I will load 3-5 rounds at .025/.020/.015/.010 shorter than oal.
After that you should have the most accurate powder/primer/bullet/case combo for that rifle, if you change something, different brass, bullet, etc you will need to tune it again, but not as extensively.
It will take approximately 75 cartridges, but you will be producing excellent groups.
Comment with any questions you may have. Thank you.
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