We have photographs of three recovered bullets, presumably all from the same box, that were fired into the body of a bear in three successive shots. All three bullets failed in an identical manner.

I would think that these bullets were for some reason too hard. Better quality control practices should have resulted in the rejection of these bullets.

I would certainly not hunt using ammunition loaded with any of the bullets from the same box or lot as these. But based on this evidence, neither would I condemn as inherently defective all bullets of the same or similar design.

The quality control question is very troubling, however. Copper is apparently far less forgiving than lead.

quote:

Originally posted by jorge:
Angle of incidence: A fixed number in degrees of the angle between the wing's chord and the longitudinal axis of an aircraft.

Angle of attack: The angle between the wing's chord and the relative airflow in flight.

Explain how that translates into bullet performance as bullets have no wings. Angle of incidence I can sort of understand but AOA? I'm all ears. jorge

Jorge, its at the bottom of the webpage Gerard provided the link for...



Cheers,
Canuck

I shouldn't say anything here as I haven't got to the TSXs yet. I don't shoot lots with the .308 hunting loads. I use cheaper handloads or milsurp. But I have been using old X's and now blue meanies in 150 gr middle of the road velocities, in my Sako FS .308. NEVER have I collected a bullet from a whitetail and NEVER have I had a failure! The deer almost always are DRT. A few times recently I went with the cheap Remington factory 200 gr in the 358 winchester. Again not applicable. Now I will be using the 9.3 286 gr Prvi bullets. I don't know if I will get to the TXSs. This condemnation of them still sounds premature to me. Yes, there was a problem but RB will gladly apologize and give you a replacement if the alloy was bad. His company is growing for a reason. They exhaustively test and hunt with their own bullets. Sounds like a most wonderful job to me. Go for a new box of bullets and test them on some hogs. See if you can find peace with that. Good luck. Packy

quote:

Originally posted by AaroninUtah:
Without any more information, I would have to call bullshit on the whole thing.

I cannot see anymore than two groves on the bullets, so it is an old Springfield military rifle in 30-06?

If it penciled in, you sure wouldn't have recovered the bullets in the lungs. They would have been gone forever.



I think we need more information to come up with any conclusive conclusion.

Aaron

I thought it was just me but I cant see more than 2 groves either

might be a 1917 or p14 with a .311 bore 2 grove bbl opened up to 300 or just an 06 still not sure its not a bbl bulett powder combo problem

hope he finds out and lets us know I love a good mystery solved

Jorge,

quote:

Angle of attack: The angle between the wing's chord and the relative airflow in flight.

One could replace the wording like this: Angle of attack: The angle between the wing's chord (the longitudinal axis of the bullet) and the relative airflow in flight (the flight path of the bullet). While angle of incidence means only one thing (the angle at which the the path of the bullet intersects with the surface on which it impacts), the angle of attack can be caused by two entirely different problems with a bullet in flight.

A bullet with too much gyroscopic stability will not "nose over" on the far side of the trajectory bow. Eventually it flies, spinning in a stable manner around it's axis, but with the nose constantly above the flight path, like the bottom bullet in the illustration.

On the other hand, with too little gyroscopic stability, the bullet yaws around the flight path with the nose and base centre both describing a circle around the flight path. At the moment of striking, the angle of attack could be with the nose of the bullet above, below or to the side of the flight path, depending on where it is on the circle around the flight path. The result, when the bullet strikes the target, remains the same as in the first case, because the centre of gravity of the bullet is offset from the centre of pressure on the nose of the bullet. When the CG and the centre of pressure are aligned on the flight path, all is well. When offset either side of the flight path, regardless of why, bad things happen. The yaw caused by low gyroscopic stability is a slow "wobble" and usually changes in frequency over the duration of the flight.

There is another "wobble" the bullet is subjected to but it differs from the one described above. This is caused by non concentricity of the bullet and is at a high frequency (bullet rotation speed). Turned bullets generally do not suffer from CG offset problems, it is the domain of the multiple material bullet, be it a lead core in copper jacket, or some other combination of two or three different materials. This is not important with terminal ballistics, it just causes gray hairs with accuracy and grouping.

quote:

Originally posted by AaroninUtah:
I cannot see anymore than two groves on the bullets, so it is an old Springfield military rifle in 30-06?

There are 4 grooves.

quote:

If the bullets tumbled, it sure would have caused considerable damage and no compaints would be heard. If two tumbled in the animal, were they shot out of a rifle with the correct twist rate?

After reading Gerard and Canuck's comments I have no doubt the bullet tumbled. They must have caused a lot of damage because the grizzly bear gave away rather quickly.

I have been contacted by Barnes X and I am trying to put more information together. I will keep you al updated.

To Gerard, and Alf, as you both seem to share the same point of view...

HV's are no different to lead core and cup designs in "the forming of petals as the bullet expands is very important" and that they all need "that the nose of the bullet opens far enough to allow enough shortening of the bullet for better stability in tissue."

And this I do not understand. I always thought that a long, spinning, javelin would be much more prone to traveling head on than a short one.

And here is a picture for Gerard. My last shot with the custom made 112gr HV Alvaro's bullets. Was taken at 150 yards with my little 6,5x57R and weighed 155lbs.



And another question for Gerard, please. In what does Lutz Möller's KJG bullets resemble or differ from the HV's?

Regards to everybody.

Montero

Thank you montero, I will place the photo on our Gallery page. The penetration requirements in air differ greatly from that which is required to penetrate soft solids. In air the gyroscopic stability of the bullet is selected to overcome the tendency of the base heavy bullet to tumble in flight. In tissue this is not possible and the bullet must be designed to change shape on impact, to accommodate a different set of parameters, in order to proceed in a predictable manner. Once the bullet is "flying" in tissue, spin stabilisation no longer works and the bullet answers to the laws of centre of pressure, centre of gravity, stagnation pressure, shoulder stabilisation, overturning moments and moments of inertia.

You have a PM.

Noted Gerard and I get your explanation, Canuck's picture clarified it a bit more. Cheers, jorge

A 6.5x57R that weighs 155 pounds!?!

Good God man, you must be built like Arnold Schwarzenager if you can hunt with that thing!!!!!!!!!!!!!!!!!

to minimize recoil, I must say...

the post looked a little heated, so I though some leveity was in order

Montero, Nice pig.

Like I stated before,if you shoot the bullet from an improper barrel it will strike the target sideways.It's just common shooting sense.Unlike many I did not need Gerard to explain anything to me or anyone to tell me TSX bullets are no good because they tumble.I suggest you look at the size of the holes the bullets make on the target paper and go with the rifle/bullet combo that makes the smallest holes.

quote:

Originally posted by shootaway:
Like I stated before,if you shoot the bullet from an improper barrel it will strike the target sideways.It's just common shooting sense.Unlike many I did not need Gerard to explain anything to me or anyone to tell me TSX bullets are no good because they tumble.I suggest you look at the size of the holes the bullets make on the target paper and go with the rifle/bullet combo that makes the smallest holes.

TSX shoot great on paper but often tumble when they hit the animal becasue they are too long for a standard twist barrel. So either go at least 10% lighter in bullet weigh or go with a faster twist barrel.

500 grains,wouldn't they not shoot good on paper, especially at longer distances if they were not stable? TSX bullets are accurate in medium bore calibers but I have not tried them in big bore calibers with standard twists.

Not to be a PITA, but define bullet failure, I doubt that they were recovered from a live Grizzly.
mr

quote:

Some advice: Using a 285gr mono in a 9.3x62 is a misapplication of the bullet. You are putting the blame of the failure on the bullet, where it is the choice of bullet that is at fault. Fifteen years ago we did not know any better and a lot of development has been done since. I can tell you with total confidence that, if you took that shot with a 230gr (or thereabouts) expanding mono, terminal performance would have amazed you. There is no doubt in my mind that GSC hollow points bring a measure of reliability to the table that cannot be equalled by a jacketed lead bullet.

The question in this thread is not about bullet mass or velocity. The two .308 TSX bullets were shot from a 300 Win Mag at 60 and 90 yards distance. So the velocity was high enough to cause expansion of the bullet under normal circumstances. It was stated that the bear was hit broadside, and the shots were properly placed in the lung heart area, so no bones were encountered that could have deflected the bullet - so, the angle was not oblique. In fact the one bullet showed signs of wanting to open up. Furthermore the writer says ... "The shooter does not recall any unusual recoil that could made us suspect a deficient load" So it was not a squib load. It also had nothing to do with twist. I would venture to say that it was an annealing problem and that could be tested very easily if the bullet was returned to Barnes. Perhaps the bullets got plugged, but that is strange as that should actually happen before the bullets struck, as one respondent commented. The failure to open up happened with 3 bullets in succession. Perhaps this batch of bullets had somehow a smaller hole punched into them. The fact that the bullets did not exit indicates that they must have been destabilized in target, tumbled and was found on the off side of the animal. The rest of the bullets in the box could very easily be tested under lab conditions and the mystery will be solved, I am sure.

But then Gerard comes along and makes an interesting statement ... "Using a 285gr mono in a 9.3x62 is a misapplication of the bullet." I take isssue with that. The bullet is not too long for a 9,3x62 mm chambered rifle, as it has a long throat by design, and the twist is adequate to stabilize a mono bullet. I did a test with a 286 gr Brass turned solid with a smallish flat meplat (SF = 1.86), and it penetrates straight. Bearing in mind that the specific gravity of Brass is lower than Copper, so it is a tad longer. 286-gr Woodleigh steel-jacketed Solids have been used for decades with success. Gerard says the choice of a 285 gr mono is at fault and a ligher bullet of 230 grains (or thereabouts) would have amazed us. This is jumping to another aspect and has nothing to do with these TSX bullets that did not open up. Also most controlled expanding bullets such as Swift A-Frame's, NF's and Rhino's are very reliable and effective killers and little wonder that they are so popular.

Warrior

quote:

Originally posted by Warrior:
The failure to open up happened with 3 bullets in succession. The rest of the bullets in the box could very easily be tested under lab conditions and the mystery will be solved, I am sure.

Warrior

After re-reading this whole thread, I believe that is the key to the problem, not the construction type of the bullet. The probability of three failures in a row smells more of a batch/QC problem to me.

I'm going to admit I've jumped around this thread a bit. I will say from years of experience with the barnes bullet that it DID NOT IMPACT STRAIGHT ON with the target. If it had it would either be opened up or it would not have been recovered. Since it did not open up but yet had enough drag going through the animal as to be recovered it had to be going through at a terrifically bad angle.....ie: mostly sideways.

Chris/Warrior/Truvelloshooter,

quote:

It also had nothing to do with twist.

It has everything to do with twist. Look at the photos. Both bullets are bent. Monos bend when they tumble on impact and this is caused by a large angle of attack. There are only two reasons for a large angle of attack on impact. The bullet touched something in flight that caused it to start yawing, or the twist rate of the rifle is too slow for the chosen bullet. With three bullets in succession it is unlikely that something was hit in flight. This leaves the twist rate of the rifle.



Looking at the photo of the engraving I would bet on a twist rate of about 1:13" and this is too slow for a mono bullet this long. A much better result would have been obtained with a 150gr bullet. Maybe Montero could ask for a measurement of the twist rate of the rifle.

quote:

The fact that the bullets did not exit indicates that they must have been destabilized in target, tumbled and was found on the off side of the animal.

And mono bullets do this when............?

quote:

But then Gerard comes along

and not long after you show up with your agenda in tow.

quote:

and makes an interesting statement ... "Using a 285gr mono in a 9.3x62 is a misapplication of the bullet." I take isssue with that.

What else is new? There is the agenda and you have not mentioned your favourite bullet in quite a while now.

quote:

The bullet is not too long for a 9,3x62 mm chambered rifle, as it has a long throat by design, and the twist is adequate to stabilize a mono bullet.

Actually the twist is too slow. You do not learn at all, do you? 400 Nitro Express reported a failure with that weight mono in a 9.3, Jagter reported one with a bronze solid of that weight in a 9.3, I have seen two and you say your sample of one did not fail. What does this tell us? Sometimes it works and sometimes it does not. The reason for this borderline performance is.............?

quote:

286-gr Woodleigh steel-jacketed Solids have been used for decades with success. Also most controlled expanding bullets such as Swift A-Frame's, NF's and Rhino's are very reliable and effective killers and little wonder that they are so popular.

Of course these bullets are bi-metal bullets and they are s-h-o-r-t-e-r so they require less t-w-i-s-t r-a-t-e and they work well in a slow caliber like a 9.3x62.

Hey, at last you found a vehicle to mention your fave bullet in a mono bullet thread!.

quote:

Gerard says the choice of a 285 gr mono is at fault and a ligher bullet of 230 grains (or thereabouts) would have amazed us. This is jumping to another aspect and has nothing to do with these TSX bullets that did not open up.

Yes, it is that bullet length / twist rate thing that you have been wresteling with for the last six or so years and amazingly, still fail to understand. It is less of a jump than your hop to bi-metal bullets, hoping no one would notice.


Kraky,

/

Gerard,

You have a PM.

Montero

The standard twist rate for the 300 Win Mag is 1-in-10" and most factory made rifles would come that way. Being 30% off for a 1-in-13" really stretches normal production tolerances and is not that likely, but the remote possibility exists. If the barrel is indeed so much slower, then tumbling incidence would surely be greater. The 180 grain Barnes TSX bullet is in fact a tad shorter than the previous Barnes-X BT bullet that worked so well here in SA (35.26 mm vs 35.31 mm). The bullet is not too long for the standard twist rate, unless the Barnes people are so out of touch with reality. Be that as it may, the measuring of the twist rate is a good start in the process of elimination. The next step is to critically examine the hardness of the copper and if the hole configuration is as it should be. Barnes tested this design and would not have made the changes if they thought it was not an improvement. Until this is done, we are just speculating on the balance of probabilities. I would suspect the bullet was not annealed to the right level, but remain open for any other logical possibility.

Coming back to the 9,3 x 62 mm. The 9,3 was designed to shoot 286 grain bullets and its long throat accommodates 286 gr mono metal bullets very well. Both the Barnes Solid RN (35.05 mm) and the X-version (38.1mm) works otherwise Barnes would not offer them. See the Man Magnum article (2005) where the 286 gr Barnes-X bullet (SF = 1.35) was used to kill a buffalo. I have not tried the 286 gr Barnes Solid as yet, but other people have and they have not complained (in case you doubt it, please contact Gregor Woods and he can provide you with more names). I have used the 250 grain X-version (34.1 mm) and Rhino's 286 grainer (34.2 mm) with super results. A-Square also makes a 286 grain Mono RN bullet and that is their only offering in a Solid, and I doubt that they believe it is a misapplication. This in no way subtracts from the virtues of a 230 gr HV bullet.

On 1 Sep 2005 I said the following about the 286 gr custom turned bullet ... "The design is exclusively the brainchild of the owner of the firm and not mine. Again I am just a user of a fine bullet with proven excellent field results. These bullets have been tested by many other users, including the owner and all his other friends. So I can assure you the testing stretches far far beyond the three that I fired into a wetpack that you use as justification to bolster your weak argument." Of all his solid bullets, he singles this one out as one that his friends rave about. This bronze solid cuts the paper beautifully and go straight through my wetpacks never to be found. Since then I shot 3 Blesbuck with the sole purpose to get minimum meat damage. No turning or tumbling; only straight penetration. This 286 gr bronze solid (SG = 8.78) is 34.4 mm long, with a medium sized (4.4 mm) flat meplat ... It works like a charm. I like the angle of the crimping groove in particular, as it is so easy on the neck of the case and it sort of clicks in just nicely behind a 90 degree stop of the groove - the best I groove I have ever seen. Its CG-point is as close to the middle as possible, and surely adds to its in-target stability.

For all the above reasons I believe we cannot just make a blanket statement that a 285/6 gr mono is a misapplication. Many people have had success with it and failures are most probably far and in between. And as long as I am having success with it, I will be using this beautifully made custom-turned bronze solid.

Warrior

quote:

Originally posted by Gerard:
Chris/Warrior/Truvelloshooter,

quote:

It also had nothing to do with twist.

It has everything to do with twist. Look at the photos. Both bullets are bent. Monos bend when they tumble on impact and this is caused by a large angle of attack. There are only two reasons for a large angle of attack on impact. The bullet touched something in flight that caused it to start yawing, or the twist rate of the rifle is too slow for the chosen bullet. With three bullets in succession it is unlikely that something was hit in flight. This leaves the twist rate of the rifle.



Looking at the photo of the engraving I would bet on a twist rate of about 1:13" and this is too slow for a mono bullet this long. A much better result would have been obtained with a 150gr bullet. Maybe Montero could ask for a measurement of the twist rate of the rifle.

quote:

The fact that the bullets did not exit indicates that they must have been destabilized in target, tumbled and was found on the off side of the animal.

And mono bullets do this when............?

quote:

But then Gerard comes along

and not long after you show up with your agenda in tow.

quote:

and makes an interesting statement ... "Using a 285gr mono in a 9.3x62 is a misapplication of the bullet." I take isssue with that.

What else is new? There is the agenda and you have not mentioned your favourite bullet in quite a while now.

quote:

The bullet is not too long for a 9,3x62 mm chambered rifle, as it has a long throat by design, and the twist is adequate to stabilize a mono bullet.

Actually the twist is too slow. You do not learn at all, do you? 400 Nitro Express reported a failure with that weight mono in a 9.3, Jagter reported one with a bronze solid of that weight in a 9.3, I have seen two and you say your sample of one did not fail. What does this tell us? Sometimes it works and sometimes it does not. The reason for this borderline performance is.............?

quote:

286-gr Woodleigh steel-jacketed Solids have been used for decades with success. Also most controlled expanding bullets such as Swift A-Frame's, NF's and Rhino's are very reliable and effective killers and little wonder that they are so popular.

Of course these bullets are bi-metal bullets and they are s-h-o-r-t-e-r so they require less t-w-i-s-t r-a-t-e and they work well in a slow caliber like a 9.3x62.

Hey, at last you found a vehicle to mention your fave bullet in a mono bullet thread!.

quote:

Gerard says the choice of a 285 gr mono is at fault and a ligher bullet of 230 grains (or thereabouts) would have amazed us. This is jumping to another aspect and has nothing to do with these TSX bullets that did not open up.

Yes, it is that bullet length / twist rate thing that you have been wresteling with for the last six or so years and amazingly, still fail to understand. It is less of a jump than your hop to bi-metal bullets, hoping no one would notice.


Kraky,

Makes perfect sense to me....

I for one am glad to see you wiegh in on these topics.....

Alf,your example proves the marginal stability theroy in my opion.....

Keyholing would explain the whole thing.

I have had 200 gr TSX's keyhole and with the same load/velocity the 200 gr Accubonds did not. This was in a 30-06 and I did not want to try to push the TSX's faster because of pressure concerns.

ALF,

Barnes doesn't seem to list a 130gr TSX for the 8mm. I'm assuming a typo and you actually meant 180gr.

The reason I bring up is that an 8mm 130gr bullet would be very short and should be much easier to stabilize, even at 2800fps.

Alf,
I agree with jwp475. Slowing down a marginally stable bullet will reduce the gyroscopic stability and will bring on a case of the tumbles. Drop to a 160gr mono and see that rifle perk up.

Chris/Warrior/Truvelloshooter

quote:

The standard twist rate for the 300 Win Mag is 1-in-10" and most factory made rifles would come that way.

Recently, at an F-Class competition, several competitors stated with great confidence that their .308 barrels were 1:13". A couple were measured and found to be 1:12". I had a Schultz and Larsen rifle in the shop some years ago. It was stamped 1:10" and I wondered what on earth one would do with a 7mm that slow. On measuring it, it was found to be 1:11.5!!?? With practical hunting competitions gaining popularity, I measured 10 or 12 rifles so far this year. About half are not what they are supposed to be and one was so far off, the owner had it rebarreled straight away. He had trouble with it since buying it used several years ago. Wonder why the previous owner sold it? Obviously you have not measured many rifles with proper equipment. Running a tight patch or brush down the bore is a fast way to get the wrong information. Try something based on fact some time instead of sucking that thumb.

quote:

Coming back to the 9,3 x 62 mm. The 9,3 was designed to shoot 286 grain bullets and its long throat accommodates 286 gr mono metal bullets very well.

It was designed around 286gr jacketed lead bullets. Just because 286gr monos fit, does not mean that they are the the right length. You sure are muddy on the bullet length / barrel twist thing.

quote:

See the Man Magnum article (2005) where the 286 gr Barnes-X bullet (SF = 1.35) was used to kill a buffalo.

See the posts by 400 Nitro Express and Jagter where 286gr monos failed. Do you really think that, if you repeat something often enough, it turns to fact?

quote:

I have used the 250 grain X-version (34.1 mm) and Rhino's 286 grainer (34.2 mm) with super results.

Probably because they are shorter than 286gr monos. Is it not incredible how you confirm time and time again that you have no grasp on this twist/length thing?

You should stop

quote:

This bronze solid cuts the paper beautifully and go straight through my wetpacks never to be found.

Try building wetpacks with more depth.

quote:

Since then I shot 3 Blesbuck with the sole purpose to get minimum meat damage. No turning or tumbling; only straight penetration.

You figure that shooting a blesbuck proves the bullet for Cape Buff? How do you know they did not tumble? Did you recover any or are you stating as fact what you think should have happened? Par for the course.

Here is a photo showing the custom turned bronze solid on the extreme right:

Pic 1: 300 gr Swift A-Frame
Pic 2: 300 gr Rhino
Pic 3: 286 gr Custom Solid

I do not have to dream about straight penetration nor all the other users, we know they go straight and after all the the vitals show a clean path, there is no quessing.

Gerard,

I am sure you are dying to see another picture of a performing Rhino bullet and since you have asked me about my favourite bullet, I will share it with you. But very important it is also Hanke Hudson's favourite buffalo bullet - here is why:

Hanke Hudson are using 400 gr .416" Rhino Softs.
He shot a Blue Wildebeest at 80 paces and retrieved the bullet.
The muzzle velocity was 2,320 fps. The bullet penetrated completely.
It retained a mass of 394 grains or 98.5% and the bullet mushroomed as expected.
The expanded diameter measured 21 mm.

I am a firm believer that we need nothing more than 2,100 fps IMPACT VELOCITY on game. Typically at this velocity most premium controlled expansion bullets will exhibit its best weight retention ratio and widest mushroom without the loss of petals. The bigger the hole through the heart, the quicker the animal will drop . Once the threshold strength of a particular bullet type is exceeded, it starts to break down. Velocity is only the tool to get the bullet there. When the bullet gets there, it must perform as expected and this is a function of staying inside the threshold strength limits of the bullet - a bullet construction issue.

Heavy for caliber bullets (high SD bullets) just work better on big game such as buffalo, as they smash the heaviest of bones easier due to higher momentum levels. Bullet mass is far less critical (progressively so) as we cascade down to smaller game. What I mean is, we do not need a 400 grain bullet to shoot a Blue Wildebeest, I have done it quite effectively with 160 grain Rhino bullets in a 7x57 mm.

Mr. Hudson, a PH, can be contacted at VLT Arms at 012-333-0171/2 (Pretoria, RSA).

quote:

Do you really think that, if you repeat something often enough, it turns to fact?

Apart from the two posts above having no relevance to the rest of the thread, I note that you never post pictures of bullets YOU recovered. Alway pictures of other hunter's bullets. Your bullets are unfired or recovered from wetpack and such. No pictures of animals YOU have shot. What is the problem, don't you have any? Have you actually hunted something other than paper and wetpack?

quote:

He shot a Blue Wildebeest at 80 paces and retrieved the bullet.
The muzzle velocity was 2,320 fps. The bullet penetrated completely.

Where did he retrieve it from if it penetrated completely? Do you read the stuff you write?

quote:

What I mean is, we do not need a 400 grain bullet to shoot a Blue Wildebeest, I have done it quite effectively with 160 grain Rhino bullets in a 7x57 mm.

Unless you post a picture, I will decline to take that as the truth. Actually, all that is needed is a 40gr HV in the right place.

Attie Janeke used 40 gr .224" GSC HV.
He shot a Black Wildebeest at 345 paces and did not retrieve the bullet.
The muzzle velocity was 4,200 fps. The bullet penetrated completely.
Mr. Janeke, a PH, can be contacted at the numbers on the web page linked above.

You enjoy hijacking threads dont you? Your forum manners are apalling and you are so transparent.

quote:

The bullet penetrated completely.
It retained a mass of 394 grains or 98.5% and the bullet mushroomed as expected.
The expanded diameter measured 21 mm.

How was the bullet recovered did it penetrate completely or was it still in the animal?

[Quote]
The bigger the hole through the heart, the quicker the animal will drop .[Quote]


I don't agree 100% with this statement,because once suffiecent damage has been done to bring the blodd pressure to zero then a larger wound will not cause the animal expire faster.....

/

That explains why it is tumbling at the lower speeds from your 6.5x68. It will do better in a 260Rem or a 264WM both of which have tighter twist than the 1:10" of the 6.5x68. You might get away with a 120gr mono but 110gr will be even better.

Here is another example of a Barnes-X bullet that did not open that was published some time ago:

Is that a Barnes it looks like one of those PMC copies. The PMC copies did not work well in a 308. Did you shoot this one?

Thanks, Alf!
And Gerard has noted the need for a faster twist for the slower velocity with the same bullet, to ensure the spin is fast enough for gyrostability through the air.
Very enlightening play with the gyroscope, Alf.

This is a beautiful example of why I use a 10" twist instead of a 15" twist in the 500 A-Square: 750-grain target bullets work well in a 15" twist 50 BMG at 2750 fps. For the same bullet at 2150 fps a twist of 10" to 12" is required.

Using more than enough twist for a hunting rifle used at less that 500 yards, is always a good idea. It is not a hindrance, in any manner, with getting better performance from the lighter weight FN solids and monometal softs at 2400 to 2500 fps.

It does seem most likely the culprit with the failure that started this thread was: SLOW TWIST

quote:

Originally posted by ALF:
Playing around with the Gyro

6.5 x 68
Rifle: Sauer 202 std CIP spec barrel
Brass: RWS
Primer; Fed 215 M
RL 19 65gr
Bullet B TSX 130 gr

Vel string: 3069/3044/3026
Range 105m



Now same rifle, same bullet, but different load

B TSX 130gr
H4350 55gr
Fed 215 M
String vel: 2808/2790/2778/2794/2782



This is 180 deg angle of attack
Everything remained the same, especially the rifle's twist rate and the bullet length, however the velocity was changed....... going to show there is more to Munks formula than just one or two variables

An interesting graph of the Gyro at work...... stability as determined by experiment in a wind tunnel. The solid coloured lines are for solid projectiles.



S = Stability factor
L/d = length to diam ratio

GERARD
so what twist would you recommend for a mono proj ...say a 180 gn tsx/in an 06 with a muzzle velocity of 2850 which is what im getting with Norma MRP
Daniel

quote:

Originally posted by Warrior:
Here is another example of a Barnes-X bullet that did not open that was published some time ago:

The tip on that one shows no indication that it impacted anything. Do you know where it came from?

Fjold,

I came across this bullet some time back, but can't remember the story anymore. Sorry.

Warrior