VELOCITY AND STABILITY! Velocity and stability are linked together also, not just twist rates as both these tests the twist rates are the same at 1:14 for 458 B&M and 458 Lott. Buffalo just reposted this above but I am going to post the bullets again. In the same rifle, 458 B&M a 500 Barnes Banded FN at a muzzle velocity of 1815 fps and 22 yd Impact at 1780 fps gave straight line penetration thru 62 inches of test medium! Now we drop that velocity to 1490 fps and impacts at 1450 fps we do not have consistent stability. Total penetration nearly the same at 52 and 53 inches, but both bullets veering off course at 35 and 42 inches. Even if stable penetration would not have went further than 52-55 inches at this velocity.


Michael

Not much to say about this! Speaks for itself!

quote:

Originally posted by someoldguy:

quote:

Is this bullet slightly bent too?

It does look bent! There appears to be a slight curvature towards the base.

Glenn and RIP

NO not bent, just the camera, it's dead straight. No fear, I check all of them to see if they are bent or messed up in any way, I will report that and show that if it is. This is just the camera is all.

Michael

One thing I wish to mention, and mostly for those who just don't happen to think about it. Especially with all the solids we have been testing on this thread you will see at times some varying penetration depths, even side by side, and also varying STRAIGHT LINE PENETRATION Depths as we see above with the 458 B&M. This is not an inconsistency with the test medium, this is UNSTABLE BULLETS--that do not have any CONSISTENCY. If it's unstable for whatever reason, there is no consistency to what it might do in the medium. Stability is the issue, not the consistency of the mix. There will only be a small difference in a medium inconsistency of a couple of inches from one box to another.

FYI

Michael

quote:

Originally posted by buffalo:

quote:

Originally posted by michael458:
Tomorrow time permitted I will do us a 458 test again, with the 500 Barnes Banded Solid, with two boxes together, and one at very low velocity as buffalo suggests. Should be interesting to get, as I like buffalo, believe that this bullet is about as good as it gets for intended mission!
Michael

Hope you get the time you need soon Michael.. I am waiting very unpatiently..

Well Buffalo, now I am waiting! It's done, so now what?
Michael

quote:

NO not bent, just the camera, it's dead straight. No fear, I check all of them to see if they are bent or messed up in any way, I will report that and show that if it is. This is just the camera is all.

I guess it's a good thing it wasn't bent. Shooting a bent bullet probably wouldn't be too good for your barrel.
About the 286 grain 9.3 bullet:
We can't blame the test media either because it's been pretty well consistent. Twist rate has been right, meplat has been right. Velocity and bullet length, about what you'd expect.
Am I ready to throw in the towel? Oh, hell no! I love mysteries!

quote:

Originally posted by michael458:

quote:

Originally posted by buffalo:

quote:

Originally posted by michael458:
Tomorrow time permitted I will do us a 458 test again, with the 500 Barnes Banded Solid, with two boxes together, and one at very low velocity as buffalo suggests. Should be interesting to get, as I like buffalo, believe that this bullet is about as good as it gets for intended mission!
Michael

Hope you get the time you need soon Michael.. I am waiting very unpatiently..

Well Buffalo, now I am waiting! It's done, so now what?
Michael

Hmmmmmm!!! Now I am thinking...
Well done Michael

What was the velocity of the 458 Lott Michael?

By the engraving looks like a 12 twist.

Michael.

I am thinking about that 320 Woodleigh FMJ 9,3 bullet. Amazing performance. Wonder why it performed so much better than f.ex. the 550 grs Woodleigh .458 bullet..?
I almost tend to believe that these very long 9,3 and 6,5mm bullets behaved like arrows.. Long and the tail prevented them from veering off course..
But to test that in the 458 - I mean to get such a long for caliber 458 bullets - would demand a FMJ bullet of at least a 1000 grs and a super fast rate of twist.... Not possible..
I dont know what to suggest right now...

quote:

Originally posted by boom stick:
What was the velocity of the 458 Lott Michael?

By the engraving looks like a 12 twist.

around 2200 f/s muzzle and around 2150 f/s impact. Twist was 1-14"

Sorry Boomy - my name was not Michael

quote:

Originally posted by boom stick:
What was the velocity of the 458 Lott Michael?

By the engraving looks like a 12 twist.

Boomy

Today was running it a tad low, just over 2200 fps.

Michael

quote:

Originally posted by buffalo:
Michael.

I am thinking about that 320 Woodleigh FMJ 9,3 bullet. Amazing performance. Wonder why it performed so much better than f.ex. the 550 grs Woodleigh .458 bullet..?
I almost tend to believe that these very long 9,3 and 6,5mm bullets behaved like arrows.. Long and the tail prevented them from veering off course..
But to test that in the 458 - I mean to get such a long for caliber 458 bullets - would demand a FMJ bullet of at least a 1000 grs and a super fast rate of twist.... Not possible..
I dont know what to suggest right now...

I think yes, long for caliber is a factor, but not to be discounted is the nose profile of the 9.3, far different than the round of the 458.

M

quote:

Originally posted by buffalo:
Sorry Boomy - my name was not Michael

Makes no difference! Part of the team!

Is there any ANY real reason to have anything slower than a one in 12 twist for modern rifles?
even a 1% increase in pressure is a great trade off for straight line penetration.

I see no real argument for a slow twist except nostalgia and twist nostalgia means nothing if you are looking at hunting big critters.

Sorry, brain fart. was wanting to know the twist. the velocity was posted.
so seems 14 is ok with these bullets but I'd like at least a 12 twist. 10 twist will be just fine for my rifles. My 470 is a 10 twist. works great! helova pig killer with 400 grain speer gold dots @ 2400 fps. Never recovered a bullet.

quote:

Originally posted by boom stick:
Is there any ANY real reason to have anything slower than a one in 12 twist for modern rifles?
even a 1% increase in pressure is a great trade off for straight line penetration.

I see no real argument for a slow twist except nostalgia and twist nostalgia means nothing if you are looking at hunting big critters.

Boomy

Again, I am certainly not a twist expert by no means. But for what we are talking about I can think of a reason to have anything slower than 1:12. I say 1:12 or 1:10 for myself.

Now the only reason I can think of for a slow twist like 1:18 or slower is nostalgia and tradition and that is what they have always been, but also for cast bullets I understand too fast can cause them to skid! So for cast bullets I think they like the slow twists to keep the bullet from skidding. Other than that I don't know!

RIP may be able to add some to that, but that's my take.

M

quote:

Micheal,

The plot thickens ... that one FN bullet can perform, but not another one !!!

Observation:

This bullet performed badly ... and this in an acceptable twist rate. A mere 14 inches of penetration at an impact velocity of 2528 fps (similar as if shot in a 9,3 x 64 mm). Perhaps this bullet should be shot through another barrel with the same twist rate. If it yields much better penetration, then we can't blame the twist. Then barrel behaviour needs to be considered as giving different yaw angles, which is currently being ignored. Obviously if some bullets are "dud" bullets (not being uniform/identical) in the pack, then we will see variation, even failure. A bullet like this with a FN profile should perform better.

The theory says:

A high SF is not synonymous with small yaw angles for a start. A high spin rate will unmask any flaw in asymmetry in the mass of a spinning bullet, the faster the spin the greater the effect of asymmetry. Unfortunately over-spin is a problem in that it influences the ability of the bullet to dynamically stabilize, it also has an effect on downrange tractability, i.e. yaw angle. In terms of Gyro stability (SF value) a bullet can have a large angle of attack, but still be gyroscopically stable. The angle of attack at impact implies that the long axis of the bullet is sitting at an angle to the direction of it's forward motion, however small we think it might be, but it is there, and it may just play a greater role than we might think in respect of in-target stability.

There are four possible causes for dispersion as related to twist. They are, static or bullet imbalance, yaw in the barrel, dynamic imbalance (which occurs when the bullet's axis of inertia is not in line with its angle of form), and insufficient stability (SF). The effects of the first three factors can be lessened by decreasing the twist rate. The fourth one, insufficient stability, is reduced by increasing the twist. Dynamic stability, depends on geometric properties of the bullet and flow field properties and cannot be influenced by barrel parameters. So the SF value on its own is therefore not the only and absolute value that governs stability.

Back to the poor performance of the 286gr Barnes Banded FN

The question that arises is one of uniformity of this batch of Barnes Banded FN's, and then secondly as I have mentioned, to shoot these bullets through another barrel as a check to see if there is a marriage between this bullet and your barrel versus another barrel. Some barrels just do not like certain bullets as funny as this may sound. Not just an imbalance that is created inside the barrel, but also how it brakes away from the muzzle. The flow field around this bullet (perhaps uneven pressure grooves) may in fact cause a dynamic instability.

Warrior

Cast bullets should be made somewhat hard to prevent overexpansion so no reason there for a slow twist.

As for the 9.3 286 Barnes Banded, it was shot in a 9.3X62 in an early test last fall, and it gave pretty much the same results, it was terrible. It made it to 25 inches but had veered off course seriously then too.

I don't think there is much you can do with this bullet and it's the nose profile, too small a meplat to stabilize. I can see no other reason, there may be, but that's my simple answer, for it's poor showing.

Boomy

Don't think you will ever get a cast hard enough not to skid in a faster twist, if you push it. And if you get it too hard, then it's brittle, too soft, skids, I think it's best to leave the cast for the cast bullet rifles and the handguns that can utilize them, for us and what we do, make them proper solids! Probably what we ned to keep in mind is to not try and teach a cat to bark, and a dog to meow!

Michael

Will the (in)famous spread sheet be posted soon?

Thanks

Well, IBT, that's a good question! I can do photos, but really don't know how to do a spreadsheet?

I am sending a new addition to RIP and Jim, I am sure they probably can! Or can someone tell me how?

Michael

Mike

If you are out there lurking about how about STAMP the 470 500 NorthForks, the meplat and see what you measure on it for me!

M

Holy Cow! For some reason I went back to Page 1 and just was looking over it, two things struck me, first I wish the range was as clean and neat as it was in those photos on page 1! Second, this is page 46! That's unbelievable to have come that far in a short time as this has been, or seems to be, and we have not stopped at all! Who's having fun? I am! Also I found some primers the other day! And I am not telling anyone where either! I was down to less than 3000 Federal 215s! I found some 215 Match primers, was not so sure about them, so got 2000 of them and tested several known loads in the different B&Ms and 500 MDM. Zero difference, so I got another 5000 of them! Should be good for a year or so I suppose! Page 46? Wow. OK, just random BS.
Michael

carts are carts but what makes a diff is all the stuff discussed here on this thread. Bullet profile, construction, velocity, twist ect.
Excited to see how the S&H bullets from Jay do in your test medium. Don't forget witness cards!
And make sure nothing of value is behind the bullet box
Can someone bring a BMG to test them at 3,000 fps?

quote:

About the 286 grain 9.3 bullet:

I still keep noticing this bullet appears really long. Might the twist rate not actually be fast enough to stabilize this bullet, since it's a mid-bore instead of a big bore? I'm not suggesting you go with a different twist because I'm pretty sure that rebarreling would get expensive quickly. It's just a thought.

Since the 6.5's have a very fast twist, I'm thinking that something faster than 1:12" would make that 286 grain do better. Something around 1:10 or even slightly faster.

Someold guy,

Are you saying the 12" twist is fine for the Wdl RN FMJ giving deep penetration, but not fine for for the FN Barnes Banded Solid? Before it was the oppsosite that RN's needed more twist?

Just something to think about.
And that makes me think there is still something else.
The pendulum cannot swing this way.

Warrior

quote:

Are you saying the 12" twist is fine for the Wdl RN FMJ giving deep penetration, but not fine for for the FN Barnes Banded Solid? Before it was the oppsosite that RN's needed more twist?

Just something to think about.
And that makes me think there is still something else.
The pendulum cannot swing this way.

It's called grasping at straws, Warrior.


I'm starting to think there *is* something else, but I still think about bullet length needing a faster twist for stability. I don't have any measurements but it *appears* to me that the Barnes bullet is somewhat longer than the FMJ, even though the SD is lower. This might account for the great performance of the FMJ and the crappy penetration of the FN.

But if this isn't true, I'll have to come up with another handful of straws.

quote:

Originally posted by michael458:
Mike

If you are out there lurking about how about STAMP the 470 500 NorthForks, the meplat and see what you measure on it for me!

M

.335 Stamped and measured under a magnifying glass.

And this response started page 47.

Hope to continue testing this weekend.

Mike

Thanks, as I calculate that is basically 71% meplat for caliber! There is reason for me asking, as Jim collected 83% meplat from their website or other information? I will let him elaborate that. If so, how is that measured? Now stamping is a good idea and it's certainly the only way I can get a proper measurement, but I wonder if stamping leaves something out, that should be counted???? I don't know. Some meplats are sharper than others, some slightly rounded at the edges.

Meplat is a damn hard thing to measure, at least for me!

I am getting tempted to drag out one of the Capsticks and do some work with it in the next week or two, might look at that today!

Michael

Michael,
Had a great time meeting the mad scientist and shooting with you. I think you drank the most beer. You surely have a great range and it is the cleanest place I've ever seen. Learned a lot about what bullets do from you and very impressed with all that you have done and posted. I thought I was a big bore gun nutt but I think you may have me beat. Yes I like those Model 70's but still love my double rifles. Got to bring some to your range for you to try out. I shot my 500 B&M SS some and it is a sweet little rifle. After shooting the other B&M's I'm afraid that there will be some of those in my collection also. I guess you never have enough guns. It surely is an addiction.

Sam

I checked it again. Used black ink and stamped it on white paper. Measured .335-.336

83% equals .393 and that is the measurement at the edge of the bevel (which is slightly rounded)on the side of the bullet.

Large meplats are often the source of feeding problems. One must find ways to overcome this and the obvious answer is below. Observe two FN bullets with meplats larger than 93%.



Pictures courtesy of Andy and RIP.

quote:

Originally posted by Gerard:
Large meplats are often the source of feeding problems. One must find ways to overcome this and the obvious answer is below. Observe two FN bullets with meplats larger than 90%.

Gerard

I know where this is going! Best get behind the couch before the rocks hit you!

Yes, I see what you are saying for sure. At what velocity are you getting this effect? I think not low 2100-2300 fps! Not a bad concept I think, but hard to control????? I don't know. Velocity being the key.

Thanks--excellent point!

Michael

quote:

Originally posted by Mike70560:
I checked it again. Used black ink and stamped it on white paper. Measured .335-.336

83% equals .393 and that is the measurement at the edge of the bevel (which is slightly rounded)on the side of the bullet.

Mike

While I am not convinced that STAMPING is the proper exact way to measure meplat, I feel we are loosing something on some of them, North Fork being an excellent example. But since currently I don't have a better way to do it, nor can think of one, for the purposes of our discussions here we will stay with that method I think for consistency sake! I know everyone will not remember this, some might not even pay it any attention, but I think if we keep this in mind when we speak of % of meplat this method may serve consistency best. At least until we get some method that is better or more consistent, and more precise. No I have not forgot who come up with this, Thank You Glenn!

Michael

quote:

Originally posted by srose:
Michael,
Had a great time meeting the mad scientist and shooting with you. I think you drank the most beer. You surely have a great range and it is the cleanest place I've ever seen. Learned a lot about what bullets do from you and very impressed with all that you have done and posted. I thought I was a big bore gun nutt but I think you may have me beat. Yes I like those Model 70's but still love my double rifles. Got to bring some to your range for you to try out. I shot my 500 B&M SS some and it is a sweet little rifle. After shooting the other B&M's I'm afraid that there will be some of those in my collection also. I guess you never have enough guns. It surely is an addiction.

Sam

Sam

Excellent that you have come out from lurking in the shadows to join us---WELCOME!

Thanks for the kind words, it was a pleasure to have you here! Glad you got to shooting the little 50, it's loads of fun, damn effective for it's size too.

One can never have too many! Yes my man, bring the big doubles down and we will do some test work with them and see what they are made of! Should be a hoot! Look very much forward to when you can plan another visit! I will be sure and have more beer on hand! If not, hell we will just fall in on some Goose!

Thanks again.

Michael

Doc M,
The .395-caliber/340-grain GSC FN "prototype"
I can vouch for.


That one smacked the IWBB at about 2700 fps from a 1:12" twist:
8" of water + 1" of plywood + 1" of air in series of ten 10" deep compartments.
Started off at 2725 fps and impacted at 25 yards.
Went to about 69.5" or 70" of penetration in the bowels of the IWB (Texas Heart Shot buffalo simulation).
It stayed perfectly straight until the end.
Imbedding in that 7th plywood wall, drained 7 buckets of water.
IIRC, that is, will check the old file ...

The corner radius on the meplat is good for feeding.
Not getting too big with the unfired meplat is good for feeding.
GSC and North Fork copper is tough enough for elephant skulls.
S&H brass is even tougher.

I think you are stuck with just measuring the flat of the meplat, excluding the rounded corner radius of the nose.
Using the stamping technique suggested to you by Glenn:
Only the flat is working in shoulder-stabilizing the bullet.


The bigger the meplat, the more stable for straight line penetration.
At some point meplat size increases resistance enough to decrease penetration.
That might be tissue/test-medium and velocity dependent.
Faster twist can only help.

I will study a way to post your spread sheet whenever I can.

A clickable link at some web site might work, but I do not know how to do that:

www.DocMterminalballistics.com ???

I will chop up the table and scan to enlarge all the segments and try to photobucket it in some legible format.

Hmm, just 47 pages so far. . . .
I knew this thread was gunna go nowhere. . . . .

Nothin but a bunch of very informative info, based on nothin but a bunch of tested facts!

Yup, just as I thought; it'll never get off the ground!

RIP

I think measuring the flats by stamp is our method, as long as no one forgets and keeps that in mind. Gives us consistent measurements to go by.

Twist really has become a very important factor in this! Far more than I thought possible.

I will also check the spread sheet and how to get it posted, or a link to it. I have a buddy that has a website and he can post it I think, he has other things about the B&M Rifles over there, so I am sure he could do this too. I will check that and could link it maybe.

I will check some other things too with photobucket, might could convert it to a jpeg? I don't know?



DWright

I was thinking about you this morning and wondering where you have been? About the thread, yeah, who would have thought it? But here we are. I suppose some folks are very upset that it has continued, don't you suspect? The truth is out there!



I almost feel guilty I have nothing to report! Sorry! After Saturday and a tad bit yesterday it's burned me out for a couple of days. Also I had some other shooting to do that needed doing, some load development on the 50 B&MSA, that semi thing I have! Folks are asking, so I have to get moving on it and try some things. I can tell you this, hows a 300 Hornady, .500 cal in the semi at 2500 fps? I figure that beats the other 50 thing? Have to look, I can't recall!

Oh and hey see my little photo under the name? Yeah, figured out how to do that today too!

Anyway, gotta get back to it!
Later
Michael