Disaster with Barnes TSX in 257 Weatherby

F

FLChinook

New member
I tried the Barnes TSX 25 cal., 115 gr flat base, in my .257 Weatherby today. I also had a new Zeiss 4.5-14 50 scope with Leupold rings on my previously-installed Leupold one-piece base.

Powder was 63.5 gr of H1000 and brass was once-fired Weatherby (Norma).

I think the only variables were the new scope, new rings and Barnes bullets.

I sighted in using some year-old reloads made up of the same brass and 117 gr Sierra GameKing bullets (63 gr of H4831). Adjustments to the scope were exactly as expected (4 clicks = 1 inch in any direction at 100 yds). Finally, I shot two 3-short groups with the Sierras at 50 yards (point of impact .5" high)

Then I moved to the Barnes at 100 yards.

The first bullet missed the target entirely. I shifted back to 50 yards and more or less hit the bullseye. Back to 100 yards - another miss. I'm scratching my head in dismay.

Finally, I came back to 50 yards and shot 6 of the Barnes and got a spread from 4" at 7:30 to 2" at 10:30. Clearly, the shot at 7:30 would have missed the 100 yard target.

There was a guy shooting next to me who was a gunsmith and he very kindly took a look at the gun/scope. He could find nothing wrong. He suggested that since the Barnes are sold copper, maybe they have to make them slightly smaller (sold copper not being able to "squeeze" down a barrel as easily as a lead-based bullet).

I just miked the two bullets (Barnes and Sierra). The difference is not measurable by my non-digital mike and tired eyes but after setting the mike on the Sierra, the Barnes IS slightly smaller. Not enough for me to mike the difference but enough to feel a wiggle.

Does anyone have any idea what could be happening?

Thanks
 
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Failure to stabilize is my first guess
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I would say so also. Solid copper bullets are lighter than lead bullets so they have to be longer to make weight.

Try some lighter weight jacketed bullets which would be quite a bit shorter and see if the problem goes away.

I wonder what the rifling twist in your barrel is also. It may be a 1 in 12 twist which would be for shorter bullets.
 
Ah.
The keyholing is the key info. You're not stabilizing.
Don't worry about accuracy, continue to work up the charge until they stabilize, if they do, then worry about accuracy above that point.
 
Your measurements were probably correct.

If you put a precision mic on the different bands and body segments of Barnes' solid copper bullets, you'll find that most are tapered or wasp-wasted (depending on the design).
I'd like to say it's so the bullets can handle the various bore dimensions seen in factory rifles, without causing excessive pressure in the tighter bores. .....but I don't really know if it's intentional, or just a byproduct (mild defect) of their manufacturing process. :rolleyes:
 
Don't worry about accuracy, continue to work up the charge until they stabilize, if they do, then worry about accuracy above that point.
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I don't have the time nor inclination to try and sort out this problem. Just let me re-ask the question: Can failure to stabilize produce 12 moa patterns at 50 yards? That seems quite incredible :rolleyes:
 
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It pretty well must have, since that what you were getting. What other explanation is there?

It shouldn't take any more time than any other load work up. Shoot your rounds. They'll either stabilize as you approach max or they won't. If they don't, you have an inaccurate load. If they do and you're happy with the accuracy, you're golden.
Should be just like any other load work up.
 
I've always had good results with the Sierra GameKing 117 gr spitzer BT. Do you think Nosler's Ballistic Tip 115 would do as good or better?

What's your favorite powder for these two bullets?
 
Can failure to stabilize produce 13 moa patterns at 50 yards? That seems quite incredible
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Absolutely. If you are getting keyholes, the bullets are tumbling end over end in flight. Did you ever shoot pennies out of a slingshot? They curve all over the place. Similar effect when you have a tumbling bullet. I had some 45 Colt loads that were tumbling on me earlier this year. At 30 yds, I had bullets hitting 10 feet from each other. One bullet hit five feet to the right of my target, then another one hit a good five feet to the left. So when they are tumbling, there's no telling where they will go.

In my case, I tried a different powder and the problem went away. The tumblers shot perfectly fine out of a different gun however. It may not fix your problem, but it may not hurt to try a different powder.
 
My .25-06 (Tikka T3) is a 1:10 as well. The 115 Barnes FBs are the most accurate bullet I've loaded. Sub MOA @ 100 yds. I can't imagine the 06 Remington can stabilize it but the weatherby can't. Maybe try H4831. That's what I use.
 
Here's picture of the target. I initially thought there was only 1 keyhole but clearly all but maybe 2 are keyholed. My powder charge was at the suggested starting amount but the max is only 4 grains higher. Would such a small increase turn around this unbelievable effect?

This was at 50 yards...

257 Weatherby Barnes TSX Keyholes.jpeg
 
Is the rifle a Weatherby?

If so, they have extreme freebore which will also help with low velocity with a starting load.

Get a chronograph and get them up to speed.
 
My .25-06 (Tikka T3) is a 1:10 as well. The 115 Barnes FBs are the most accurate bullet I've loaded. Sub MOA @ 100 yds. I can't imagine the 06 Remington can stabilize it but the weatherby can't. Maybe try H4831. That's what I use.
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I know a lot of people have great success with this bullet which is why I'm so surprised. H4831 and H1000 are both slow-burning powders and somewhat similar.

If increasing the velocity is the answer, then what will happen to the bullet downrange when the velocity reduces? Will it start out stable and keyhole at longer distances?

I am so tempted to abandon it altogether and go back to my GameKings or maybe try Nosler BTs...

My reloading books do not give me data on the Nosler :rolleyes:
 
Is the rifle a Weatherby?
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Yes, it's a Mark V, one with a "blued" SS barrel that came from the Saco Maine plant in 1999.

I see some shooters at the range with chronographs but I would prefer not to have one... can't I rely on the reloading tables?
 
Absolutely not. Without a chronograph, it is anybody's guess.

My best guess is with that huge freebore and minimum load, you are getting extremely low pressure and velocity, thus the keyholing and poor accuracy.
 
Why don't I see this with other bullets?
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My guess is your particular problem is because lead free bullets are longer for their weight. They may be 115gr, but their length will be longer than a "normal" 115gr bullet, and contrary to what many think, its length, not weight which determines if a bullet will stabilize with a given twist rate.

I bet the 100gr TSX would shoot much better, as its length is more in line with what a 115gr conventional bullet would be....
 
Is the tendency to keyhole a function of Ballistic Coefficient?

Here's the BCs:

Barnes TSX 100 .336
Barnes TSX 115 .335

Sierra GameKing 100 .355 (vel>2800)
Sierra GameKing 100 .310 (vel<1600)
Sierra GameKing 100 .333 (vel>between)

Sierra GameKing 117 .410 (vel>2500)
Sierra GameKing 117 .403 (vel>1800)
Sierra GameKing 117 .370 (vel>between)

Nosler Ballistic Tip 100 .393
Nosler Ballistic Tip 115 .453

Nosler Partition 100 .377
Nosler Partition 115 .389
Nosler Partition 120 .391

Berger VLD Hunting 115 .466

It's interesting that the Barnes TSX bullets of different weights have almost the same BC. Every other bullet I've checked has a larger BC for increasing bullet weight.

The Nosler Ballistic Tip seems to have a better BC than the Partition; almost as good as the Berger...

I don't think Bergers would work will with my gun (if it has "huge freebore") as Berger recommends lengthening a round to where the bullet almost touches the lands. That would be hard to do in my case.

It's interesting that Sierra gives different BC values for different velocities; slower is not better :mad:
 
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