Disaster with Barnes TSX in 257 Weatherby

In your photo, I don't see anything truly key-holing, but they may be yawing (still a stability issue).


Don't worry about the ballistic coefficients. They have far more to do with a bullet's flight characteristics, than stability. And, a bullet's shape affects the BC more than length alone.


Unrelated to the OP, but related to your last post....
Note how Sierra quotes multiple BCs for their bullets.
That's because G1 ballistic coefficients actually change significantly in flight (as velocity changes). And, the standard G1 model doesn't apply well to modern boat tail designs.

Because of this, manufacturers have to decide what BC to use. Some use the highest BC the bullet is likely to achieve. And, some are more conservative and use an average of the expected velocities to get their BC.
Without knowing what velocity is used to calculate the listed BC from any given company, comparing G1 BCs of different bullets really doesn't do much good unless they're significantly different (like a .273 vs a .426).

Most precision bullet makers will also list the G7 BCs for their bullets. The G7 model is much better suited to modern boat tail bullet designs, and allows for more precise ballistics calculations. But... G7 BCs are much lower for any given bullet, than the same bullet's G1 BC. So, "main stream" manufacturers are hesitant to start listing G7 BCs for their bullets. They don't want people getting confused and thinking the lower G7 BC is representative of the older standard of the G1 BCs.
Here's an article, if you want more information. (It also has representations of the G1 and G7 standard projectiles.)
 
Don't worry about the ballistic coefficients. They have far more to do with a bullet's flight characteristics, than stability.
Click to expand...

Sorry to belabor this, but if bullet stability is not a function of BC, what is it a function of? Is there some minimum muzzle velocity for any given bullet and barrel length/twist? Are we "doomed" to learn about each bullet's stability with each gun by trial and error; hopefully not...

Thanks for the useful presentation of BC data. I knew Berger gave G7-BCs but I've not been able to make comparative use of it (other than between Berger bullets) as no other bullet manufacturers give the same data.
 
Ballistic Coefficients are a numerical representation of how closely a projectile's in-flight performance conforms to that of the "standard projectile". So, as mentioned earlier, that's generally the G1 standard projectile.

A Ballistic Coefficient represent a bullet's resistance to aerodynamic drag.
Having an approximation of that factor allows one to calculate fairly precise trajectories for a given velocity.

That's pretty much it. BCs just tell you how well the bullet will resist aerodynamic drag, in relation to the "standard projectile".


When we're talking about stability, we're referring to rotational stability: A bullet rotating in a manner that is stable and predictable, around its long axis.
A rotational velocity that is too low may not keep the bullet stable on that axis; and a rotational velocity that is too high can magnify small balance imperfections in the bullet, causing it to also be unstable.
(If you rotate them really fast (like 350,000 rpm), they can self-destruct before they reach the target.)

By saying your rifle is not stabilizing the Barnes 115 gr TSX, we're referring to them having a low rotational velocity. They just aren't spinning fast enough to remain stable in flight. To fix that, you must increase velocity, or the barrel twist rate. Since replacing your barrel probably isn't on your to-do list, increasing the powder charge for more velocity is the better solution (if you can do so).

If you can't find a powder that will get you enough velocity to stabilize that bullet in your rifle, you have two choices: 1. Forget about that bullet. 2. Rebarrel the rifle with a faster twist rate.
(I would opt for #1.)


If I was in your position, I would:
Give away the rest of the bullets, if it was a box of 50.
Increase the load, to try to make these work, if you bought 100 or more.
And use the 80 gr TTSX (or 100 gr TSX - the heaviest I would go) if you want to try a different Barnes bullet.
 
Barnes manual loading data for their 115gr TSX in a 257 Wby start load is 66gr/H-1000 @3073fps and max load of 72gr/H-1000 @ 3287fps.

If you look at Hodgdon data they list the Barnes 115gr XFB start load of 67gr/H-1000 and max of 71gr/H-1000 both list the Fed 215 primer.

you already had this post from

mrawesome22 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.
 
Barnes manual loading data for their 115gr TSX in a 257 Wby start load is 66gr/H-1000 @3073fps and max load of 72gr/H-1000 @ 3287fps.
Click to expand...

I took the following from the Barnes website for this bullet and H1000: Starting Load 63.5 (3101) and Max Load 67.5 (3243). That's quite different from 66/72. I would think boosting the load from 63.5 to 72 (13%) might give enough of a velocity increase to stabilize the bullet. nmbrinkman says his Tikka T3 does very well with this bullet using H4831. He doesn't say what his load is (min or max) but I believe H1000 has about the same burn rate as H4831.

It's pretty clear now that this bullet needs more "umph" for my barrel. I would never have thought that different barrels for the same caliber would have different "umph" requirements but I guess they do.

I think, as in the old closing of Dragnet, "This case (on this bullet in my barrel) is closed"!

I just wish we could establish some direction as to which bullet shape might be most likely to be better stabilized in my barrel without needing max loads.

Thanks everyone.
 
It's pretty clear now that this bullet needs more "umph" for my barrel. I would never have thought that different barrels for the same caliber would have different "umph" requirements but I guess they do.
Click to expand...

They absolutely do. That's why there are different rifling twist rates.

There is no "right" number for a cartridge and any choice is a trade-off.

Lower numbers (1:8 being lower than 1:12) will spin bullets faster, higher numbers spin bullets slower.

Lower numbers also provide more resistance to the accelerating bullet and so produce lower muzzle velocities.

Lower numbers will stabilize heavier bullets but might over-spin light bullets.

Higher numbers give slightly higher velocity but might not stabilize heavier bullets.

It's important to note that we take a few liberties in our choice of words in this discussion. We say "heavier" and it's generally true but as you've found the real issue is length. The reason your gun will stabilize a 117gr Sierra but not the 115gr Barnes is because the traditional jacketed lead construction of the Sierra is heavier per length than is the solid copper Barnes bullet. In other words, the Barnes is longer to reach the same weight.

I just wish we could establish some direction as to which bullet shape might be most likely to be better stabilized in my barrel without needing max loads.
Click to expand...

You can. There are plenty of bullet stability calculators in the internet. They're not absolutely accurate but they provide a good idea. I've found that they seem to be less accurate with smaller diameter bullets. They tend to be pessimistic, saying that a bullet won't be stable when it actually will. On the plus side, if it says you are stable, you can pretty well bet on it.

Here's one:
http://www.jbmballistics.com/cgi-bin/jbmstab-5.1.cgi

Inputing your data, I get a low 1.xx stability factor, which is in the border region. If your velocity is significantly slower and/or you mismeasured the twist rate, you would be (and obviously are) unstable.
 
I just wish we could establish some direction as to which bullet shape might be most likely to be better stabilized in my barrel without needing max loads
Click to expand...
Use a shorter bullet.

I've always had good results with the Sierra GameKing 117 gr spitzer BT.
Click to expand...

Use that, or any lead core flat base bullet.
 
FLChinook, I just checked Barnes site and your right on what your using as to what I have in their manual plus the 90gr and 100gr loading data is different.

The test rifle they used a Wiseman 24" long barrel 1/10 twist.

When I work up a load I never do it over a chronograph and that's just me but on the Wby's I do. the 257 Wby I had build with the 115gr TSX I got max Barnes velocity 2gr under max using IMR-7828ssc and if it was me I'd use that powder over H-1000.
 
Call Barnes and talk w/ Randy and see what load he suggests. Explain the problem to him and he will fix it. Might want to pull those loads as the Barnes aint cheap.
 
Sorry to belabor this, but if bullet stability is not a function of BC, what is it a function of?
Click to expand...

No stability is not a function of BC, BC is a function of the bullets shape. Long skinny pointed bullets will have a higher BC than short blunt fat ones, to put it (ultra) simply.

Is there some minimum muzzle velocity for any given bullet and barrel length/twist? Are we "doomed" to learn about each bullet's stability with each gun by trial and error; hopefully not...
Click to expand...

Yes, but generally not by YOUR trial and error. Most of the work has been done for you, its in your loading manual, if you dont see a bullet weight listed, thats because its not right for the "normal" twist fort he caliber, BUT, you have to keep in mind that, #1 copper bullets introduce a new variable (long for weight). and, #2, The whole twist rate/stability thing is, to quote capt. barbossa, "more what you'd call "guidelines" than actual rules"........ That is, not ALL .257 WBY rifles with a 1in10 twist will shoot that bullet poorly. As anyone who is into guns eventually finds out, each gun is an individual as far as what it shoots good and what it shoots poorly. Its possible the next rifle off the assembly line after yours shoots 115gr barns TSX into super tight groups. (its also possible it shoots them just as poorly)

For the most part, you wont go wrong following conventional wisdom as far as bullet weight/twist, but there are always exceptions, (monolithic hunting bullets being one of them). Some rifles with "to slow" twist rates will stabilize "to heavy" (long) bullets, while some rifles with "correct" twist rates wont stabilize "correct for twist" bullets..... And even when the twist and bullet length are perfectly matched, sometimes your gun just plane wont like a bullet/powder/primer/brass combo.... we just have to keep plugging along till we find one our gun likes...
 
we just have to keep plugging along till we find one our gun likes...
Click to expand...

Thanks. I probably could get the Barnes TSXs to work by changing powders and increasing loads. But, to be honest, my heart isn't in it anymore. I only have about 20 of the bullets left and I'm going to just give them away :D

Opening Day is only 4 days away now and time is fleeting. I know, I should have planned ahead more..:(

All the bullet makers have excellent call support. I called Sierra today because I have Sierra bullets. I told him what powders were in my larder; he chose the one he felt would do best with my GameKing 117's. I loaded a batch with his recommended load and then another batch at the max recommended load. Off to the range I went...

The recommended load gave me 0.7" three shot groups and the max load gave 1.3" groups. I'm now set for OD. I can experiment with other bullets and loads after my freezer is full of venison..:D

Thanks again for everyone's help. I have learned a HUGE amount from this thread!
 
good luck! our season ended sunday.... we saw 5-8 deer and a moose in the first 2 days, then the weather turned and we didnt see anything but tracks from then on :mad:
 
Hmm, poor choice of a title, this is not a disaster.

A disaster would be a blown up gun.

Merely a minor problem to be sorted out or just give up and go with something else.
 
Barnes website lists 1/9 or faster for that bullet.
Click to expand...
Barnes isn't always consistent with their twist rates.
The bullet is listed as needing a 1:9" twist or faster, but the load data is all based on a 1:10" twist barrel (with no notes about a recommended twist).
 
Hmm, poor choice of a title, this is not a disaster.
Click to expand...

The point of exaggerated word-usage is well taken... We all are very sympathetic and concerned about the many folks affected by the true disasters associated with the recent storms.
 
I also had a new Zeiss 4.5-14 50 scope with Leupold rings on my previously-installed Leupold one-piece base.
Click to expand...

I think I found your problem; see the quote below.

A guy had a keyholing problem a while ago on another forum with his remington in 308. He racked his brain along with everyone else who offered up a possible reason for it. In the end it turned out that his scope was so far out that the bullets were actually hitting the ground in front of the target and skipping to the target.
Click to expand...
http://w.snipershide.com/forum/ubbthreads.php?ubb=showflat&Number=2444749


I had a similar problem where it appeared my friend's rifle was keyholing but in reality it was an issue with scope adjustment.
 
dont forget

Don't forget that if you have a marginally stable load and the temperature drops significantly, your stability may go right out the window. Temperatures below freezing can start the problem all over again.
 
Barnes TTSX Keyholing in 257 Roberts

I have three 257 Roberts rifles that I am hand loading for. I tried some Barnes TSX FB bullets in 115Gr and this is the first time I ever experienced key holing while shooting from my Nosler Trophy Grade rifle (1/10 twist). These were loaded with 40g of IMR 4831 and OAL was 2.80. I shot the same load from my Savage 257 Roberts (also 1/10 twist) and no key holing (though poor grouping). After trying about 6 different load combinations I found a load that shoots 3/4" or better in all three rifles. That load is the 100 GR Barnes TTSX BT (with the blue tip) with 42g of RL19 at OAL 2.80. I also got similar accuracy using the 100GR Nosler ballistic hunting tip with 40g of IMR 4350.

I have not tested in the Winchester yet but am hoping the 100 GR Barnes TTSX BT with the 42g RL19 may be my go-to load for all 3 rifles.

When you combine all the possible combinations of bullets and powders and then add the factor of 3 different rifles, this stuff can drive you insane.

I wanted to post this in the event that it helps somebody looking for a Roberts load and also, cause the key holing was a whole new experience for me that I don't want to repeat.
 
If you look at the stability/twist calcs for that bullet, you need
at least a 1:9 for it to function at any reasonable velocity --
-- even for a Weatherby. ;)
 
You must log in or register to reply here.
Back
Top