Solid & FMJ Bullets
Solid & FMJ Bullets
Since developing the .500 caliber cartridges, I have been an avid student of solid and FMJ bullets. I needed a good solid for the 50 B&M to do accomplish the missions I had set forth for these rifles and cartridges, which means elephant, hippo, and buffalo. This led to a vigorous study that continues nearly on a weekly basis here. The first outing for the 50 B&M in it's prototype stage took me to South Africa where I was testing many of the available bullets in .500 caliber in the field. We had quickly put together a little round nose brass solid that weighed a tad over 400 grs. While I had tested all the bullets before leaving in the test medium, I had paid little attention to the little solid. I intended to only backup shots with it while testing expanding bullets. All the bullets I tested performed exactly as expected, with the exception of the round nose solid, which was a miserable failure, veering off course on a regular basis, even turning 90 degrees in an eland. I was astounded at this poor performance, and knew I had a big job ahead of me trying to get the right bullet that would track straight, deep, and true!
It took 5-6 generations of bullet design to get a proper solid that would do the job in the 50 B&M and the 500 MDM. It was the 510 gr Flat Nose copper made by Lehigh bullets that was used to great success on elephant and buffalo in 2007.
This 510 Copper Solid was only the beginning however. The strive for excellence was not over by any stretch. By 2008 myself and test partner Sam Rose embarked upon a great journey to find the "Perfect Solid", which eventually led to the BBW#13 Solid. Now made exclusively by Cutting Edge Bullets.
BBW#13 Solid
It was a long journey to get to the last Generation of the BBW#13 Solid you see above. Along the way many things were discovered about how solids penetrate and why. A set of "Factors" was discovered that effected straight line penetration & depth of penetration. There are now 8 Major Factors that contribute to Success of a properly designed solid.
1.....Meplat Percentage of Caliber
2.....Nose Profile
3.....Construction & Material
4.....Nose Projection in Front of First band.
5.....Radius Edge of Meplat
Above Factors All Inclusive of Bullet Design Alone
6.....Velocity
7.....Twist Rate
8.....Sectional Density
Each one of these factors can and do come into play during terminal performance of a solid or FMJ bullet. More discussed below about these factors.
Traditionally solids have been limited to use by most hunters for the really big thick skinned dangerous game, elephant, buffalo, hippo. My traditional load out for buffalo was always a premium expanding bullet up front for the first shot, then followed by solids behind that. Thinking back on my first field outing with the prototype 50 B&M in South Africa, backing up the expanding bullets with a solid for plains game, zebra, wildebeast, eland and such, I decided that this was not a bad idea to incorporate solids in all such hunts. Never being one to shoot the first shot, then wait and see what happens, it just made good sense to me that one would back up the first shot with followup shots when needed to make sure game was taken and not lost. It also made good sense to me that if one did not drop the animal at the shot then most of the time one is faced with an animal that is moving away from the shooter, presenting a very long terminal distance that most expanding bullets would not be able to make that journey to the vitals, a good solid can do this.
So today solids have become very important to my hunting and shooting style, and are used on every hunt in which I embark upon! Just like hunting buffalo, expanding bullet up front, followed by solids. It just might save an expensive follow up should something go wrong, as it does in the field all too often! Regardless of the game hunted, I have solids backing me up, and this has proven to be successful for me on every endeavor.
There are many many reasons to have a good solid where you can put your hands on it, regardless of caliber or cartridge! And NO REASON AT ALL, NOT TO HAVE ONE!
All Solids are not created Equal
Meplat Size
Meplat Size is of utmost importance. This we express the measurement as a percentage of caliber. What we have learned is that in most all cases during terminal penetration a flat nose solid can in fact stabilize itself during terminal penetration, if the meplat size is large enough. What is the right size meplat? 65% or better of caliber is stable in most all situations. The very best of flat nose profiles the meplat sizes run from 65% to 75% of caliber. We did a test to determine proper meplat size. If you look at that you begin to see how different meplat sizes work and stabilize.
There are other factors that effect what size meplat one must use, one important issue is that of feed and function of your particular rifle. I use all Winchester M70 actions. These actions work well, depending on the caliber, with meplats up to 70% depending on nose profile also. Of course in a single shot or double rifle, meplat size is not an issue. Should one have to drop below 65% meplat for feed and function, I would suggest some gunsmith work on the rifle other than the compromise of the bullet and it's stability during terminal penetration.
As Meplat size drops below 65% of caliber it becomes less stable, and other factors begin to become even more important, Velocity and Twist Rates can make a big difference at that point. Neither of these factors can overcome meplat size, however faster twist rates and higher velocity can increase stability to a point. Once meplat size drops below 55% of caliber neither twist rate nor velocity can do much for you at that point, and the bullet becomes unpredictable.
Meplat size larger than 70% continues to be extremely stable during penetration, but depth of penetration becomes less as meplat size is increased because of more surface area up front.
Nose Profile
Once a Solid Projectile begins Terminals, the "Nose" does the Driving! The Bullet becomes a "Front End Drive" vehicle. The Nose is responsible for how the bullet performs at that point.
First one must have the right nose profile. Right out the gate, a round nose solid or FMJ is at the bottom of the list in straight line performance. While they work better in the field than in the test medium, the potential for them to veer off course in animal tissue is there and they do this on occasion, I have seen it, other hunters have seen it, It Happens! A round nose solid is just not stable during terminal penetration, end of story.
A Properly designed Flat Nose Profile is not only successful in the test medium, but it is successful in the field as well.
It has been proven that only a very few basic nose profiles are successful with any consistency, they are shown below. The Cutting Edge BBW#13 and North Fork profiles work the best. The older North Fork Profile has now been changed to a profile similar to the BBW#13 and made in copper.
New For 2012 the New North Fork Nose Profile. This is a vast improvement of the previous generation North Fork Solids.
The Barnes Banded Flat Nose Solid is, or I should say was, an excellent nose profile as well. It was the first flat nose solid that I used in the field, with excellent results. Barnes not only sold out the bullet business, but now has "sold out" shooters and hunters as well, not only by discontinuing several calibers of the excellent FN Barnes Banded and replacing with a round nose, but they are now on a smear campaign against the flat nose solids as a marketing scheme to sell more round nose solids. I will no longer support Barnes bullets as I see this act as a deceitful and malicious attack against performance for nothing more than marketing. With North Fork and Cutting Edge bullets on the market, there is no need for Barnes any longer regardless of their heinous actions against shooters.
Construction & Material
Construction of solid bullets is an important consideration. A poorly constructed bullet can be deformed when coming in contact with heavy bone material, limiting penetration, and causing the bullet to veer off course.
Nose Projection Above the top Band of Bullet
The last discovery concerning terminal penetration of solids was the "Nose Projection" in front of the first bands of the bullet.
Many BBW#13s were tested for various big bores, calibers, and cartridges. Most of these being designed for Bolt Action rifles. Cartridge length, magazine length played an important role in feed and function, and in the length of the "Nose Projection" out of the various cases. For the most part the length of the nose in front of the top bands was from .600 in the B&M Super Shorts, to .700 in the larger B&Ms and various other big bore cartridges.
However, for the lever action rifles that Nose Projection had to be much shorter, down to .450 or less, for it to work in most lever guns. For many 100s of tests I kept noticing that depth of penetration was considerably less than what I would have expected of the same weight or caliber bullet. Even tested at higher velocity in bolt rifle cartridges, there was no difference or little difference in depth of penetration. On average these shorter nose projections were given 25% less penetration than what I considered normal.
Finally it dawned on me what was happening. The light bulb came on!
One of the reasons a properly designed flat nose is successful is that upon terminal penetration in aqueous material, or animal tissue, is that the flat meplat creates a "Bubble" in which it rides in during penetration. Any disturbances in that bubble creates instability, or effects depth of penetration.
The Short Nose Projection was allowing the bubble to "Collapse" on the rear of the bullet, instead of behind the bullet, creating drag! Because the BBW#13 Solid has a proper 67% meplat, radius edge, and overall properly designed, it still remains stable even with a short nose projection, however, depth of penetration is effected because of the drag on the base of the bullet.
Since this discovery Nose Projection has become a very important factor in design. With bullets designed for Lever Actions, there is not much one can do on this front, other than understand the effects of Nose Projection.
Radius Edge Of Meplat
Early in the first generations of the BBW#13 we discovered that a sharp edge meplat penetrates "Less" than a more rounded edge, or radiused edge. A radius edge also increases stability in the last 10% of the bullets penetration.
The Factors Referenced Above Deal with Bullet Design
Velocity
Velocity can and does increase stability and depth of penetration with most solids. Again from the sample below you can see how twist rate, and added velocity increased the depth of penetration, and the stability.
Twist Rate
Twist rate comes seriously into play when working with a bullet of less than optimum meplat size. The faster the twist the better. For example you see in the Solid Meplat Test that a 60% meplat is trying hard to stabilize in a 1:12 Twist Rate, but just not quite there. Had a 1:10 twist rate barrel been available, a 60% meplat might have been stabilized better for terminal penetration.
Below you can see an example of how a faster Twist Rate can help stabilize a less than optimum meplat size for deeper, more stable penetration.
I must stress to you that twist rate really only becomes a factor if you are using a improper designed or smaller than 65% meplat solid. If you use proper designed 65% or better meplat Solids with either a BBW#13 Solid Profile, or the new North Fork Nose Profile, then a really fast twist big bore is not needed to terminally stabilize.
Sectional Density (SD)
SD is quickly becoming a moot point in most cases with the exception of comparing bullets of the exact same nose profile, meplat, velocity, and construction. All other factors being of more importance. An excellent example is to compare the SD of the 550 gr Woodleigh Round Nose FMJ at .374 to a 325 gr CEB #13 Solid with a SD of .221
Sectional Density will ONLY BE A FACTOR with two bullets that are exactly the same in every other Factor or aspect.
I predicted in 2008 that within 5 years all major manufacturers of solid bullets would have, and manufacture a flat nose solid of some variant. As far as I know, this has come true much faster than I expected. One must be aware however that all Solids are Not Created Equal---There are ones that do, and ones that don't. And all sorts of ones that are in between!
Below find some data on some of the solids that have been tested in various calibers and within caliber, various cartridges in some cases.
Solid Tests 510.pdf (PDF — 24 KB)
Solid Tests 500.pdf (PDF — 39 KB)
Solid Tests 470.pdf (PDF — 24 KB)
Solid Tests 458.pdf (PDF — 29 KB)
Solid Tests 366.pdf (PDF — 21 KB)
Solid Tests 416.pdf (PDF — 24 KB)
We continue to work on this and improve the performance of the cartridges based on the knowledge we have gained over the last few years. Solids will continue to play a major role in my every endeavor, thus new and improved designs for all of the cartridges/rifles are always being investigated and put to work.