Rifle test loads

[cwall64]

It has been a while since I worked up any rifle loads (20 - 30 years) and was curious as to what steps (in grains/tenths of grains) most used to step up the loads in testing? With pistol loads I have typically used 0.2 grain increments. I am still kicking myself for buying an AR, but having fun shooting it, so I thought I would start loading for it...

[nbkky71]

For rifles I usually go in increments of .3 grains.

[igolfat8]

.2 grain increments for me.

[adamge]

I was surprised how .2grain increments would show large changes in group sizes. So I wouldn't want to go more than .3.

[lwink]

Depending how from scratch I'm starting -- on a new gun in a new caliber for me I'll start with bigger jumps looking for pressure signs -- oftentimes .7 or even 1.0 grains on some of the long action calibers. Once I establish an upper limit where I start seeing pressure signs I'll back down accordingly and will do .2 grain increments (usually 3 -5 different ones). I've also gotten in the habit of loading 4 of each so I can do 3 shot groups and if I pull one I'm still able to see a group. I felt I was using a lot of extra components when I always loaded 5 for each test load, but I also have a bench 20 feet from my door so It was easy to go back and forth if I really needed to. Basically by these two methods I'm trying to find the hottest possible accuracy node for that rifle, and all this comes with seating depth tests as well as that makes a big pressure difference.

If I am starting with a caliber I'm familiar with (or has good proven data) like 6mm BR or something and have a known chamber cut and throat length I'll go ahead and start on someone else's foundation and use just a .2 or .3 grain step, and in my bench guns once I find the best spot I'll fill in the gaps with every .1 grain just so I make sure I've maxed out the accuracy. At that point though it can change a tenth or three every lot of powder and I don't think this forum is really a bench style reloading one.

[cwall64]

Depending how from scratch I'm starting -- on a new gun in a new caliber for me I'll start with bigger jumps looking for pressure signs -- oftentimes .7 or even 1.0 grains on some of the long action calibers. Once I establish an upper limit where I start seeing pressure signs I'll back down accordingly and will do .2 grain increments (usually 3 -5 different ones). I've also gotten in the habit of loading 4 of each so I can do 3 shot groups and if I pull one I'm still able to see a group. I felt I was using a lot of extra components when I always loaded 5 for each test load, but I also have a bench 20 feet from my door so It was easy to go back and forth if I really needed to. Basically by these two methods I'm trying to find the hottest possible accuracy node for that rifle, and all this comes with seating depth tests as well as that makes a big pressure difference.

If I am starting with a caliber I'm familiar with (or has good proven data) like 6mm BR or something and have a known chamber cut and throat length I'll go ahead and start on someone else's foundation and use just a .2 or .3 grain step, and in my bench guns once I find the best spot I'll fill in the gaps with every .1 grain just so I make sure I've maxed out the accuracy. At that point though it can change a tenth or three every lot of powder and I don't think this forum is really a bench style reloading one.

I like your approach! I was reading somewhere else where it was recommended to take the difference between min and max load, divide by 4, round down that number to the tenths of a grain and then start with min and work up by the number you arrived at. This allows you to take 4 larger equal steps (5 test loads) and once you find a good large step, work within that range to narrow down your "perfect" load...

This is for an AR-15 platform, but gun is garrenteed 3/4 MOA at 100 yards - Hornady Match 75 grain BTHP ammo did much better than that in reality (5 shots touching/one big hole @ 100 yards) in the first time out. If I can match the performance of that ammo i'll be extremely happy!

Edited August 21, 2015 by cwall64