Fine Tuning a Load

[Winston]

Hi Folks,

Sorry to keep badgering you all with rookie questions, but this forum is gold for a relatively inexperienced shooter in a rural area.

I've put about 1000 230 grain hybrids through my 308 barrel on my Hall B. About 250 of those were what I thought was working up a load, but it was probably as much my learning how to shoot the rifle (it seems to want fairly strong shoulder pressure when shooting from a rest). I'm a reasonably consistent 59 shooter, with a handful of 60s, but centres are often lost to elevation.

Skip forward to last weekend when I shot my first club comp with a SEB joypod courtesy of Jason Mayers. Off the bipod the rifle is a totally different beast and seems to prefer almost free recoil. I managed a hatrick of 60s, but my centre count was low (60.2, 60.6, 60.3) and I seemed to be placing shots at the top and the bottom of the six ring, like I was from a rest.

I figure now that I have a better handle on how the rifle behaves, it might be worth looking at tweaking my load. It's currently 44.0gr of 09 under a 230gr Hybrid with a hard jam. I'm getting 2370fps with an es of 15 at worst.

I seem to remember reading a post by williada about shooting 3 different seating depths for varying powder charges in a grid layout.

My question is what seating depth increments should i try (currently on a 15 thou jam) and what powder increments should I try?

Any help would be much appreciated.

Thanks gentlemen,

Alex

[Brad Y]

Winston

5 shot groups at 0.3 over and under your charge to see how big the node is might be enough. You might want to even go 0.6 over and under if pressure issues aren't appearing. It may give you better results either end and then you know where you stand for a final powder charge. Then you can play around with seating depth to fine tune further. Do you powder test with your current seating depth, if it's working which it sounds like it is. You can do the same with seating depth so you know your window where the gun will work in that regard too. It will all give you data to know what to load for various conditions and stages of a prize shoot in regards to barrel wear. There is more I believe to this regarding compensation tune and nodal tune but I hope my response is possibly a little easier to understand.

Of course you could just have one load and run a variable tuner but that opens another can of worms to learn and be proficient with. But it's more than possible and Rod Davies is a perfect example of it.

I feel that these days when learning barrels, calibers and tuning loads in rifles that the first barrel is almost for free. Use it to work out how it goes in and out of tune, learn from mistakes and move forward to new barrels with the knowledge you have gained. It's taken me two barrels to figure out how I use my 284 shehane now am onto my third fourth and soon to hopefully be my fifth with good success.