Ultra Big Bore's by B&M Definition is any caliber over .510 caliber.
We have some experience here with Ultra Bores, however, we do not own any. Ultra Bores require very large, heavy, long, and cumbersome in my opinion platforms, or rifles. These are a long way from the short and handy DGR I prefer. Most folks have the "Mine is Bigger Than Yours" syndrome with these.
The one exception to this rule is my good friend Sam Rose. Sam loves his double rifles, and his favorite double rifle is his 577 NE guns. These are big guns, and heavy, but Sam puts his to good effect, and we have done a lot with his various 577s here. 577 NE is actually .585 caliber.
I have never been impressed at all with Ultra Bore performance in the field. In fact, I have watched and heard of more failures of Ultra Bores, on buffalo and Elephant than you can count. Actual performance in the field has been "dismal" at best......
Until.................
In the early days of our Bullet Research here, Sam brought one of his MIGHTY 577s down to do some testing. It was going to be a very interesting day. I had little to ZERO experience with Doubles, much less the mighty touted 577 NE.
In those days Sam was still shooting the old Woodleigh Round Nose solids. Solids play a MAJOR role when hunting large Dangerous Game. Many of you probably don't know a lot about solids, and how or when they need to be applied. But here, we believe very very strongly in the use of solids for many areas of hunting, and not only for large dangerous game, such as buffalo or elephant, but in many areas Good, and "Properly" designed solids have a use in all sorts of game fields, that you may not have thought about.
But in .585 caliber, good solids were not designed until very recently. Everyone just relied upon the very few that were available, mostly from Woodleigh being the old standby. And, as we learned, the major cause of the problems associated with many failures of solids in most all areas.
Having already been working hard with solid technology, Sam was going to get an introduction to this. I had one Ultra Bore here at some point before Sam came down. It was a 600 OverKill, .620 caliber. Performance was dismal in that thing. Terminal Performance. I have two boxes for Terminal Performance Tests, both capable of being filled with 65 inches of Wet Print Material.
Wet Print is NOT Animal tissue, nor is it trying to simulate Animal Tissue. It is a cheap, and consistent medium in which we can test various bullets, with everything being the same. We take extreme pains to make sure of this. What we do know, 100% fact, is that Bullet Behavior in this Wet Print test Medium is exactly the same, as bullet behavior in animal tissue. What you get in the test, is what you get in the field, of course one has to take into account "Bone" in animal tissue, that disturbs the process somewhat.
There are actually two of these boxes, and when we test properly designed big bore solids, both boxes have to be lined up back to back to catch some of these.......
Sam was concerned, but I assured him we would not need or require two boxes to catch the Round Nose .585 caliber solids. Just not going to happen..........
As you see below, the big 750 gr Round Nose only went to 14 inches straight, before it took a turn hitting bottom of the box and scooting along to 36 inches max. Remember, ONLY STRAIGHT LINE PENETRATION counts with solids. If it veers off course, from the point it veers and turns, that is no longer VIABLE penetration....... You might as well MISS completely.
OMG This set Sam on Fire! Sam is extremely talented, has a Lathe and can do damn near anything. Sam was instrumental from this point on in our Solid Bullet Study, and our Endeavor to discover The Perfect Solid. In the end, We accomplished this, but it was many 1000s of rounds, 1000s of bullet fired and a tremendous effort that was put forth, and I am talking several sessions a week testing various designs.....
Barnes at the time was headed in the right direction with their Flat Nose Designs, as you see here, a hell of a big difference in Straight Line Penetration.......
After much work, much testing of various Factors involved with Terminal Penetration of Solids, which include the following........
Factors Involving Solid Straight Line Penetration & Depth of Penetration
#1 Meplat Percentage of Caliber
#2 Nose Profile
#3 Construction & Material
#4 Nose Projection
#5 Radius Edge of Meplat
Above Factors are in Bullet Design
#6 Velocity
#7 Barrel Twist Rate
#8 Sectional Density
The basic BBW #13 Solids were designed................
Other factors that we were working on, were Bearing Surface, this had a tremendous effect on Double Rifles in particular with "Barrel Strain"...... reducing bearing surface made these bullets perfectly safe to use in Double rifles, without having barrels separate. It also reduces pressures overall, allowing you to gain more with less pressure.
We worked with two bands, one top, one bottom, and this 3 band version two top and one bottom. In the end, we settled for 3 bands at the top, with one at the bottom. This allowed more versatility in seating the bullet in different cases at different depths. 4 Band pressure and barrel strain was no more than 2-3 bands. But if you went above 4 bands you started increasing both. No, accuracy with these bullets has no bearing. They are hole for hole if you do your part........
And here, you see a difference in penetration, this is mostly because of the Larger Size Meplat........
Sam was excited about his increased performance, and it was not long before he left for Africa with his 577 NE and some brand new bullets to test..... Sam was the first individual to use the New BBW#13 Solids on elephant and buffalo. When he left, I told him he was carrying the Most Effective 577 NE that had ever seen the African Continent. I was right....... He was extremely successful on both buffalo and elephant. The bullets had performed even better than we expected.
Now the Ultra Bores had proper bullets............. we are seeing success now with 600 NE, 577 NE and the various 600 OverKills that are out there.........
Below is a friend that used his 600 NE on elephant .................
Of course, with proper bullets.....
Sam still hunts with his 577 NE, but learning all we have from our test work, Sam took the weight down from 750 gr Solids and 700 gr Raptors, to 650 gr Solids and 600 Gr Raptors. Velocity can be increased, along with Terminal Performance with these in Double Rifles.
Sam has used this for many a buffalo and several elephants.........
Next up is the mighty 600 Overkill, here is a preview of this..............
We have some experience here with Ultra Bores, however, we do not own any. Ultra Bores require very large, heavy, long, and cumbersome in my opinion platforms, or rifles. These are a long way from the short and handy DGR I prefer. Most folks have the "Mine is Bigger Than Yours" syndrome with these.
The one exception to this rule is my good friend Sam Rose. Sam loves his double rifles, and his favorite double rifle is his 577 NE guns. These are big guns, and heavy, but Sam puts his to good effect, and we have done a lot with his various 577s here. 577 NE is actually .585 caliber.
I have never been impressed at all with Ultra Bore performance in the field. In fact, I have watched and heard of more failures of Ultra Bores, on buffalo and Elephant than you can count. Actual performance in the field has been "dismal" at best......
Until.................
In the early days of our Bullet Research here, Sam brought one of his MIGHTY 577s down to do some testing. It was going to be a very interesting day. I had little to ZERO experience with Doubles, much less the mighty touted 577 NE.
In those days Sam was still shooting the old Woodleigh Round Nose solids. Solids play a MAJOR role when hunting large Dangerous Game. Many of you probably don't know a lot about solids, and how or when they need to be applied. But here, we believe very very strongly in the use of solids for many areas of hunting, and not only for large dangerous game, such as buffalo or elephant, but in many areas Good, and "Properly" designed solids have a use in all sorts of game fields, that you may not have thought about.
But in .585 caliber, good solids were not designed until very recently. Everyone just relied upon the very few that were available, mostly from Woodleigh being the old standby. And, as we learned, the major cause of the problems associated with many failures of solids in most all areas.
Having already been working hard with solid technology, Sam was going to get an introduction to this. I had one Ultra Bore here at some point before Sam came down. It was a 600 OverKill, .620 caliber. Performance was dismal in that thing. Terminal Performance. I have two boxes for Terminal Performance Tests, both capable of being filled with 65 inches of Wet Print Material.
Wet Print is NOT Animal tissue, nor is it trying to simulate Animal Tissue. It is a cheap, and consistent medium in which we can test various bullets, with everything being the same. We take extreme pains to make sure of this. What we do know, 100% fact, is that Bullet Behavior in this Wet Print test Medium is exactly the same, as bullet behavior in animal tissue. What you get in the test, is what you get in the field, of course one has to take into account "Bone" in animal tissue, that disturbs the process somewhat.
There are actually two of these boxes, and when we test properly designed big bore solids, both boxes have to be lined up back to back to catch some of these.......
Sam was concerned, but I assured him we would not need or require two boxes to catch the Round Nose .585 caliber solids. Just not going to happen..........
As you see below, the big 750 gr Round Nose only went to 14 inches straight, before it took a turn hitting bottom of the box and scooting along to 36 inches max. Remember, ONLY STRAIGHT LINE PENETRATION counts with solids. If it veers off course, from the point it veers and turns, that is no longer VIABLE penetration....... You might as well MISS completely.
OMG This set Sam on Fire! Sam is extremely talented, has a Lathe and can do damn near anything. Sam was instrumental from this point on in our Solid Bullet Study, and our Endeavor to discover The Perfect Solid. In the end, We accomplished this, but it was many 1000s of rounds, 1000s of bullet fired and a tremendous effort that was put forth, and I am talking several sessions a week testing various designs.....
Barnes at the time was headed in the right direction with their Flat Nose Designs, as you see here, a hell of a big difference in Straight Line Penetration.......
After much work, much testing of various Factors involved with Terminal Penetration of Solids, which include the following........
Factors Involving Solid Straight Line Penetration & Depth of Penetration
#1 Meplat Percentage of Caliber
#2 Nose Profile
#3 Construction & Material
#4 Nose Projection
#5 Radius Edge of Meplat
Above Factors are in Bullet Design
#6 Velocity
#7 Barrel Twist Rate
#8 Sectional Density
The basic BBW #13 Solids were designed................
Other factors that we were working on, were Bearing Surface, this had a tremendous effect on Double Rifles in particular with "Barrel Strain"...... reducing bearing surface made these bullets perfectly safe to use in Double rifles, without having barrels separate. It also reduces pressures overall, allowing you to gain more with less pressure.
We worked with two bands, one top, one bottom, and this 3 band version two top and one bottom. In the end, we settled for 3 bands at the top, with one at the bottom. This allowed more versatility in seating the bullet in different cases at different depths. 4 Band pressure and barrel strain was no more than 2-3 bands. But if you went above 4 bands you started increasing both. No, accuracy with these bullets has no bearing. They are hole for hole if you do your part........
And here, you see a difference in penetration, this is mostly because of the Larger Size Meplat........
Sam was excited about his increased performance, and it was not long before he left for Africa with his 577 NE and some brand new bullets to test..... Sam was the first individual to use the New BBW#13 Solids on elephant and buffalo. When he left, I told him he was carrying the Most Effective 577 NE that had ever seen the African Continent. I was right....... He was extremely successful on both buffalo and elephant. The bullets had performed even better than we expected.
Now the Ultra Bores had proper bullets............. we are seeing success now with 600 NE, 577 NE and the various 600 OverKills that are out there.........
Below is a friend that used his 600 NE on elephant .................
Of course, with proper bullets.....
Sam still hunts with his 577 NE, but learning all we have from our test work, Sam took the weight down from 750 gr Solids and 700 gr Raptors, to 650 gr Solids and 600 Gr Raptors. Velocity can be increased, along with Terminal Performance with these in Double Rifles.
Sam has used this for many a buffalo and several elephants.........
Next up is the mighty 600 Overkill, here is a preview of this..............