"Stringing" Question

I have a .17HMR that is '"stringing" it's groups. What should I start checking first for this problem? I think "stringing" is the correct term....group is single file going away from the center......


Thanks, Tulley

[billc_sbio]

Yep, often heat related...

Sometimes, as the barrel heats up, it pushes against the stock and points in a (slightly) different direction.

However, barrels can move on their own from heating up. That depends on the barrel.

[jokester]

How long do you wait between shots? Like Bill mentioned, it could be a heat thing...

After it sits a few minutes, are your shots back on target, or do they continue to string?

-jokester

[StickFish]

First thing to check is if the barrel is free floated. Using a dollar bill, wrap it around the barrel and see if you can slide it all the way down between the barrel and the stock to the recoil lug. If you can't there is a high spot, sometimes those are designed in. If you can't make a little shim out of thick paper and place that where the recoil lug mates with the stock - recheck with the dollar bill. If it is now free floated - shoot again.

Vertical stringing can also be a sign that seating depth isn't correct for that load. Since you can't change that with a 17hmr, try a different load and see what happens.

[ORhunter]

All three previous replys give reason and solution. After finding the correct thickness of shim and eliminating the high spot, you'll need to bed the action so things won't change again in the future. This is something anyone can do so don't pay a smitty. Also seal the barrel channel by rubbing in some polyurethane or carnuba wax.

It a savage with the heavy barrel I wouldnt think heat would do it with the first 5 shots?

[ORhunter]

Yea, sounds unlikely.

Make sure all screws are tight......don't forget the scope.

[scottishsetter]

Wind? How far away to the target? How much in inches does it 'string'?
It's horizontal stringing right.

About 50 yards to the target...If up is North on the target the are heading North East away from center.

[billc_sbio]

Try this (I know, it will seem like it takes "forever") fire 1 shot, wait 5 min.

Then fire another. Repeat this 4-5 times and see IF your spaced out shots shoot to the SAME point (close enough for your satisfaction).

Then fire your 5-10 shots at the interval you were before.

This is just a "check" to see if your shots are really walking or something else is causing them to move in between shots.

My thinking is that if it's heat related, you'll see it "walk" when you fire them in rapid succession but NOT when there's a long time interval in between.

Other things, like something lose, a scope mount, or faulty scope, or Action Screws, especially on a bigger gun with some recoil could cause this.

But on a .17 rimfire, that's a little bit more of a "Hmm"?