Home Forums Reloading Big Game Rifles Why would a rifle suddenly hate a load?

- Tikka T3
- 6.5x55


Why would a rifle suddenly hate a load, that used to shoot great? Gun shot like crap last couple times with the VLD's.

1.) I cleaned it, and checked all hardware. Still shot like crap.

2.) I swapped scopes...still shot like crap.

3.) Tried a different load I worked up in the past, with 130 Accubonds, and it shot unreal. What gives?

(the Accubond groups were not a freak occurence.) Even when the barrel was hot, it was shooting them under an inch at 100. The gun used to like both loads, but now it refuses to eat VLD's.

My rifle used to love VLD's:



This is how it shoots VLD's now:


130 Accubonds:

Different lot of bullets or powder?????????

Not knowing the time span of "then" & now...........but I do believe Berger made some bullet changes in the last couple of years, not completely positive, just IIRC.

MM

Same components...

I even loaded up some fresh loads thinking I screwed something up.

It loves the Accubonds, and that is fine with me. I am just baffled by all this. On a side note, other than this gun, I have yet to find a gun that likes VLD's.

Some more possibilities would be:

1. Difference in sizing techniques but I would assume you sized cases for both loads the same.

2. Difference in temperature at which the loads were shot. I found that a difference in 0.5 gr. of powder either way in a 300 Win. Mag. made a huge difference in resultant accuracy so, difference in temperatures could make a difference as well.

3. It's possible you have some barrel erosion in the throat area so the bullet isn't as close to the lands as it was when the load was initially worked up. The Bergers may be a bit picky in this regards.

I, by the way, have a couple of barrels that like VLDs quite well but more that do better with other bullets.

I was wondering if it had something to do with the throat, but this rifle only has about 300 rounds down the tube. I just can't imagine a lowly Swede eating a throat that quick.

Have you thought about copper buildup in the barrel?

How often was it grouping as well as #1? Did it do that day after day or was it only under a certain set of conditions: weather... temperature, wind, wind direction, etc on a given day? Was it also sometimes throwing one out? (I'm wondering if that bullet is actually very stable or if it's always been marginal.)

Some loads seem to be "there" at a very specific sweet spot, a specific combination of conditions. Other loads, perhaps never quite as "perfect" shooting, seem to work very well but are less affected by slight variations in the myriad of variables. I may be crazy, but I prefer the latter. I wonder if your VLD load is one of the former?

Most loads will have two "sweet spots", one for the powder charge and one for seating. But, thinking of them as a "spot" is often misleading. Actually, they are, or should be, moderately wide ranges in which small variations make no difference. Properly loading into the middle of the powder or seating range provides a load that can tolerate some variation with little or no effect. Improperly loading, that is at the ragged edge of the proper window for each, makes our reloads loads quirky.

I find that an unnoticible powder range is often .3 to .5 gr. wide, depending on cartridge size. The seating window often runs from .010" to .015", depending on bore size. ANY variations inside those ranges means nothing to my average accuracy. Loading on the edge of those ranges drove me crazy until I figured out what was going on.

If you've checked the mechanical possibilities, ie scope, stock touching, etc, have you done a through cleaning of the barrel with an aggressive copper cleaner?
I don't think that slight changes in powder lot or bullet lot would cause that dramatic a difference in bullet group. The stock touching the barrel would; a loose scope mount would, have you taken off the mounting system for the scope and put it back on??
Did the group degradation happen overnight or was it a gradual thing?

Check bullet seating depth with the VLD`s. I think you will find you need to move out. Some rifles are extreamly finicky with VLD`s.
The difference in ogive between the two bullets will give you a clue.

How many rounds would you say have been shot down the barrel.

I only ask because I have had guns that would not shoot a particualar load and after 300-400 rounds down the tube I tried the same load and the gun shot ended up liking it alot. If a little barrel wear can cause a not so good load to become accurate then there is no reason to believe it couldn't make a good load go bad.

Just a thought.

I believe I am just past the 300 mark on round count.

This gun comes with a long throat, so I was never able to touch the lands if I wanted to. If it means moving the seating depth further out, I am pretty much out of luck.

Just a thought. This exact thing happened to me. My problem was that by brass was wore out. To many reloadings. I loaded up some fresh, out of the bag brass, and that baby shot awesome again. Maybe worth a try?

I have seen the same thing--except that the old brass was rejuvenated by annealing.

Thanks. Guess I will try annealing, or I even have some virgin brass. I am using Lapua brass.

Wonder if switching to the newer brass will now make the Accubonds shoot like crap instead? ha

"annealing the brass made the rifle shoot better"...... that's anew one on me.