Help with a 243 AI please

[1shot]

I'm having trouble getting a 243 AI to shoot. It's a 31.5" Brux barrel, light Palma contour with 81 rounds down it. Chambering done by Greg at Kelbly's. Twist rate is 1-7.75. Brass is Lapua fire formed. Neck clearance is .2655 on a .269 chamber with .002 neck tension. So far I have tried Berger 105 hybrids, 115 Berger VLD bullets. H-4831sc, RL-26, N-560 and N-160. Wolf LR and CCI br-2 primers.
All testing is done from the bench at 100 yds over a chronograph.
So far, no load combination has shown any indication of wanting to shoot, and no load have less than a 20 fps variation, and groups are 1"+ at best for 5 shots.
Any thoughts as to what may be going on?
thanks,

Lloyd

 

['Freak]

How many groups were fired using the same components and only evenly incrementing up charge weight?

 

[1shot]

Several, depending on charge weight. I try and never change more than one variable at a time.

 

[Geno C]

You've changed 8 variables in 81 rounds. It's hard to pin something down changing that much. Is this all with formed brass?

 

[1shot]

'Freak,
I would test a powder in .5gr. increments, then switch primers, then seating depth. never changed more than one variable at a time.
Geno C,

Good question, I should have elaborated more on my original post. All the testing was done with the same 10 pieces of brass previously fire formed to this chamber. I grouped them into two groups and labeled them 1-5 and A-E. They stay in their lots and are fired in the same order for each test. I know that the Hybrids like a jump so I started with .015 off. The VLD's like a mild jam so I started with .015 into the lands.
When I changed primers, I made no other changes. Regardless, the rifle shoots patterns, not groups. I will check all my torque setting to see if I missed something to eliminate that variable as well.
BTW, My 100 yd. range is only about 70' from my reloading bench, so shoot and tune is real easy for me.


Thanks,

Lloyd

 

[Geno C]

How many are you loading at each charge? With only one bullet and primer your at 20 rounds per powder, throw in 2 bullets and you're at 10 rounds per bullet per powder. Throw in the 2 primers and you're at 5 per powder per bullet per primer...

I know sometimes you can just tell when something isn't going to shoot but I'm having a hard time following the procedure you've taken to rule out a combination?

Have you cleaned the barrel? Any break in done to iron out the thoat? I have plenty of barrels that didn't settle down on velocity until they were close to 100 round down them.

In any event, try some H1000 with the vlds .010 into the lands with any primer. Load to max pressure and back off to the highest node. I've yet to find a 243ai that won't shoot this combination. Anything is possible though

 

[Terry Altom]

That's understandable concern. 1 MOA from a 243 AI isn't what you'd expect to see.

The barrel is still "young", so I'd pick a powder and run a very methodical test. Stick with one bullet, one primer. I'd suggest the hybrids at .020" jump. That is often spoken well of.

Shoot four or five shot groups. Don't count a bad shot on your part or a heavy wind switch against the load. If I know a bad shot was me, which I can usually know as soon as the shot goes off, I don't count that against the load. Just gotta be honest with yourself and let the load data speak for itself.

Can you possibly shoot 200 yards? .5 grain might be a bit wide. I would try .3 grains. I think the best first decision is to pick a seating depth and run a power charge ladder or pick a power charge and run a seating depth ladder. Apple or oranges. I usually pick a seating depth and run a power charge test. Just my preference.

I'm sure you know very well what you're doing, but it never hurts bounce ideas off others.

And, post some pics of targets..we all love looking at targets.

Terry

 

[hunter686]

This is going to be controversial... But have you made sure rings/base are locked in? Shooting patterns sounds like it could a "shift" somewhere.

 

[BoydAllen]

I would check your scope bases and rings, change scopes and check your bedding with a dial indicator. While checking bases check to see if any of the screws are bottomed.

 

[hunter686]

I would check your scope bases and rings, change scopes and check your bedding with a dial indicator. While checking bases check to see if any of the screws are bottomed.

Beat you too it Boyd

 

[1shot]

To all,
I'll try and hit all of the very valid suggestions you guys have provided.
1. I checked all screws, bolts, duct tape joints etc. and only one of the eight ring screws were less tight than all the others. The receiver is a Panda with a Davidson rail, so no chance of a loose rail here.
2.The bedding was checked and the receiver was re-installed, very tight fit with no issues. This was my Palma rifle and was more accurate that the driver most of the time. The only thing I changed is the barrel, which is installed properly and tight.
3. I can only get 100 yds. without taking a drive, then I go straight to 1,000. If a load won't shoot sub .3 at 100 with ES in the low teens or single digits at 100, it sure won't perform at 1,000.
I have swallowed my pride and posted the "groups" (I use that term loosely) for all of you to laugh at! I purposely don't have the data on the groups themselves.
Thanks,

Lloyd

 

[jvw2008]

Check the crown VERY closely and scope the bore if you haven't already.

 

[LHSmith]

"Scopes- the Weakest Link" Ratigan wrote a whole chapter on this in Extreme Rifle Accuracy.

 

[GeorgeS3]

How does gun shoot with virgin brass?

 

[1shot]

To update the progress of this issue:
1. The scope was changed out with no improvement.
2. Virgin brass after neck turning shoots as poorly as previously fired brass.
3. The only constant is that the barrel shoot it's best (.4 moa) for 5-10 shots after cleaning, then begins to open up dramatically.
Cleaning the rifle and shooting it the next session provides similar results. The barrel is now on it's way back to the mfg. for inspection.

Thanks,

Lloyd

 

[6MMsteve]

have you verified the twist rate?

 

[1shot]

Yes, 1-7.75"

 

[MrMajestic]

Have you tried a flatbase bullet? Does the bore copper up out towards the muzzle?

 

[1shot]

MrMajestic,
I have not tried FB bullets as I only shoot 600 & 1K, sling and coat. The barrel doesn't copper at all, but I shoot moly coated bullets.
Thanks,

Lloyd

 

[1shot]

All,
It seems sometimes someone post a problem and asks for help, then we never hear what the end result was. In my case, it turned out to be the barrel that Brux replaced it immediately. I told them of everything I had done that I previously posted on here. The combination of groups getting big after 5-10 rounds and that I was using 2.5-4 gr. more powder to achieve the same velocity was what turned the light on for me. Loose bore!! As soon as it started to warm up, the groups got big and the ES went off the chart.
Thanks to all the responded with possible solutions.

Lloyd