Stunk it up with my new 12FCV today :(

[Hedge]

Yup, it's a different game when you're looking for bug hole size groups. But, it's not just this caliber. Even match quality .22s will exhibit similar characteristics if the system isn't tuned. Think of it this way, you buy an off the shelf hunting rifle, put a decent scope on it and find it shoots a 3" group at 100 yds. Swap scopes, rings, different ammo...still 3", maybe a little more left and down. But, still around 3".

Now, pillar bed the barrel, free float it, change the trigger, tune the load, quality scope and mounts. Now, you're shooting 3" groups at 400 yds. You've changed the entire system but in doing so, each of the factors you've added play a larger role in accuracy.

[ThaDoubleJ]

I rechecked my torques today, I was way under 40 in/lb, now I'm at 36 (top of my screwdriver's range). I also found a lump in my stock at the forward most part and sanded it out, not sure if it was causing me any trouble, but I feel better about it.

[Hedge]

Bingo!
36 in/lb should be close enough. I've torqued mine to 30. You can experiment with the torque to tighten your groups.
Also, that lump in the stock may have been touching the barrel. That will have a big effect on your groups and consistency. If you ever want to see what effect it does have, once you get good, consistent groups, wedge a piece of cardboard or wood between the stock and barrel near the forend. Then, shoot for group. You'll see why barrels should be floated.

Anything touching the barrel during firing will affect barrel resonance. When the cartridge is fired, it sets up vibrations in the barrel. They're roughly sinusoidal so, the optimum time for a bullet to leave the muzzle is when the slope of barrel vibration curve is zero.
That's where timing the bullet launch with the proper load comes in. When you have variable barrel contact with the stock or other object, the barrel vibrations become inconsistent. Hence, your hits scatter all over the place.

There are devices you can attach to the barrel to dampen the vibrations, thus reducing shot deviation. But, they're clumsy and you have to readjust when you change loads. Much better to just find loads for each bullet you're using and re-zero your scope, IMHO.

[ThaDoubleJ]

Update: Screws at 36#, sanded that bump out of the stock, and switched from the WalMart bipod to the sand bags. Found out that hot barrels cause bad groups, bags are more steady than cheap bipods, and the gun will actually do 3/4 and 5/8 groups with both flavors of Hornady ammo. My POA/POI between the 32 and 40 also changed from 12" down and right to 2" up for the 32s with it zeroed for 40s. Overall, things are getting better, and although I've read about .3" groups from these guns, I'm not mad at all that I shot a 5/8 group with it. Best group I've ever put on paper.

[Hedge]

Glad to hear back from you. And nice to see your groups tightening up! You've brought that rifle a long way with just a few adjustments.
Sounds like you've learned alot in a short time. Good going!

Next step is getting into reloading and tuning a load. Then you'll see what that .204 can do.

[Hedge]

Thought you might be interested in seeing what a difference changing seating depth makes. Might be useful when you start reloading.

I'm experimenting with a different load using H4895 and 40gr. Vmax bullets. The thing about the Vmax is that it has a secant ogive. More efficient ballistically but sensitive to seating depth. These are .005" seating depth changes.

The numbers below the groups are reference numbers for me, only indicating relative changes in depth and don't really mean anything to anyone else. All loads were 26.4 gr. Chrono data is from 10 rounds fired at .060. All bullets had the same base to ogive (BTO) length.




I plan on working up some tests with the 39 gr SBK. That bullet is a tangent ogive and less sensitive to seating depth.

[jlc204]

I also found the 40 vmax to be very sensitive to seating depth. I couldn't believe how much difference .005 would make.