Fluted Barrels / Vertical Stringing

[Brian in Montana]

I'm still relatively new to handloading, but I've done some great work with my .308 and 7mm08. This past summer I bought a Weatherby Vanguard Wilderness in .270 win. I haven't experimented with it as much as the others yet, but I am having some trouble finding a load as accurate as with the other 2. I always shoot 5 shot groups, but I seem to get some vertical stringing, in a general sense with the .270, where that's never been a problem with the others.

So a theory I have is the difference in barrels. The 7mm08 is a Remington 700 (not floated, but the barrel is pretty solid, the way Remington makes them). The .308 is a T3X lite (free-floated barrel, not fluted). The .270 is a light weight, fluted barrel that is not free floated. I'm guessing that the less steel in the barrel, coupled with the contact points in the stock, makes it a little more susceptible to vertical stringing and other inaccuracies as the barrel heats up.

Make sense? Anyway I'm going to try just shooting 3 shot groups with my next load tests, let it cool more, and see what difference that makes.

 

[88man]

Maybe your over heating it a bit?? Sounds bad but I would have been surprised if the tikka T3x didn't shoot well.
1. What is your seating depth of the lands in the 7-08 & 308? I guess the vanguard has the freebore?
2. Have you tried increasing and decreasing powder charges by .2grn? and charting? Even trying another powder.
3. What bullet are you shooting?

 

[Brian in Montana]

Yes, the Tikka shoots great and I have 3 different loads for it that are MOA or better. In the Vanguard Wilderness, the .270, I've tried several different powders and bullets - mostly Accubonds and Federal TBT's. The best I've done so far is with 140grn TBT and H4831sc, pretty accurate. I'd hunt with it, but my goal for this rifle is fast , flat shooting, 130grn bullets. I've varried the charges a lot, starting with .2gr ladder tests and shooting test groups based on the flat spots (this has worked well in the past). My next bullet will be 130grn Hornady Interbonds. My 7mm08 shoots the heck out of those.

Not giving up on this rifle yet, but I was wondering if anyone has seen a similar thing with a fluted, non-free-floated barrel.

 

[VikingsGuy]

Not giving up on this rifle yet, but I was wondering if anyone has seen a similar thing with a fluted, non-free-floated barrel.

A few thoughts. First, I would definitely free float the barrel. Second, if I am getting low velocity SDs over 5 shots, and solid consistent 3 shot groups in the first 3 shots off a cold barrel in a hunting rifle I wouldn't worry about a little stringing in 4th and 5th hot barrel shots as you only need the first few in a true hunting situation. Third, I try to leave 5 minutes between shots if I am picky about my groups with a sporter weight barrel.

 

[ShadowFast1]

There's a good article about vertical stringing: HERE

I think the same thing can happen in a non-fluted, heavy barreled, free floated rifle. The fluting process can also cause stress in the barrel which could produce stringing as the barrel warms up. Some barrel companies try to steer people away from fluting for that reason.

If you can't tune the rifle or load such that it gets rid of the stringing that's ok. You still have a solid, lightweight rifle that will be plenty accurate for hunting. Just keep in mind how your impact changes as you take follow up shots.

 

[cahunter805]

I agree with above. Free float the barrel and see what happens. The factory stock is well built and should float quite easily. You can also skim bed the action.
The Weatherby wilderness has a very light profile barrel also. Give plenty of time between shots if doing 5 shot groups.
H4831SC or RL19 are great powders in the 270win.

 

[Brian in Montana]

I'm a little reluctant to go and do my own free-float job on a light-weight stock like that. I'm sure I could do it, but I've read sometimes the stock has contact points on the barrel simply because its not rigid enough on its own; too flexible on recoil, which can cause its own accuracy problems. I don't know if that's the case with the Vanguard Wilderness or not. I'd probably just replace the stock if I decided that's the way to go.

 

[Brian in Montana]

A few thoughts. First, I would definitely free float the barrel. Second, if I am getting low velocity SDs over 5 shots, and solid consistent 3 shot groups in the first 3 shots off a cold barrel in a hunting rifle I wouldn't worry about a little stringing in 4th and 5th hot barrel shots as you only need the first few in a true hunting situation. Third, I try to leave 5 minutes between shots if I am picky about my groups with a sporter weight barrel.

What I've done in the past is shoot 5-shot groups based on the the flat spots in a (velocity) ladder test. If one groups well, I follow up with 5 or maybe 10 more of the same over the Magnetospeed and calculate average, extreme spread, and standard deviation. I haven't really done that with the .270 because I've never quite got a 5 shot group as small as I like it. I'll switch to initial 3 shot groups after the ladder test, and give the barrel more time to cool. Ill keep my 3rd step the same for the velocity data - its good to know how consistent your load is.

 

[kiwi hunter]

my understanding of vertical stringing is the bedding,,light weight plastic stocks that you can twist are a cheap option

 

[cahunter805]

I'm a little reluctant to go and do my own free-float job on a light-weight stock like that. I'm sure I could do it, but I've read sometimes the stock has contact points on the barrel simply because its not rigid enough on its own; too flexible on recoil, which can cause its own accuracy problems. I don't know if that's the case with the Vanguard Wilderness or not. I'd probably just replace the stock if I decided that's the way to go.

The Factory Wilderness stock is a carbon fiber hand laid stock and has an aluminum bedding block. It’s a great solid stock and not a cheap plastic stock.
Removing the pressure points and free floating the barrel is easy. Wrap some sandpaper around an undersized deep well socket of appropriate size and sand the points down. Keep working until the points are gone and there is no contact on the barrel all the way to the chamber end.

 

[HandgunHunter]

When the gun is fired the barrel heats up and expands.
This can put pressure on the stock since it’s not free floated and change harmonics.

krieger is the only barrel maker that comes to mind that contours and flutes prior to cutting the bore.
If work is done on the outside of the barrel after the bore is cut it is “possible” to endure stress which will be affected by heat and worst case cause the bore to actually expand.

 

[Fire_9]

I say float it and see what happens. If that doesn’t fix it, sell it and buy something else....

 

[Wilderness_56587]

I was looking at getting my howa barrel fluted and then re-cerokoted, to cut a little weight and I like the way it looks.

Should I not do this after reading this? Right now it shoots great.

 

[HandgunHunter]

I was looking at getting my howa barrel fluted and then re-cerokoted, to cut a little weight and I like the way it looks.

Should I not do this after reading this? Right now it shoots great.

Fluting a barrel after the boring process has some risks. Depends on the quality of the smith doing the work.

weight savings on a sporter weight will be minimal as in a couple ounces.

 

[Wilderness_56587]

Fluting a barrel after the boring process has some risks. Depends on the quality of the smith doing the work.

weight savings on a sporter weight will be minimal as in a couple ounces.

https://www.longriflesinc.com/collections/gunsmithing-services/products/gunsmithing-services-barrel-fluting?variant=11249278465

This is what I was going to go with in the spiral, anyone have experience with them?

 

[HandgunHunter]

https://www.longriflesinc.com/collections/gunsmithing-services/products/gunsmithing-services-barrel-fluting?variant=11249278465

This is what I was going to go with in the spiral, anyone have experience with them?

I am sure it will look nice. Weight reduction will still just be a couple ounces.

If the barrel is button rifled I would not do it.

 

[HandgunHunter]

Those pictures show it on a varmint weight barrel. Your flutes will be well under 1/16” deep.
guessing you are doing it to a sporter weight gun.

 

[Wilderness_56587]

Those pictures show it on a varmint weight barrel. Your flutes will be well under 1/16” deep.
guessing you are doing it to a sporter weight gun.

Yes Sporter weight not a Heavy Bull Barrel

 

[Fire_9]

Yes Sporter weight not a Heavy Bull Barrel

Don’t do it. There are far better ways to shave a few ounces

 

[VikingsGuy]

Should I not do this after reading this? Right now it shoots great.

I like to tinker, but once I get a rifle that “shoots great”, then I like to leave it alone. Better to tinker with one that doesn’t shoot great and make it better.