Big Bore 50-90 Sharps
After casting several different size bullets and trying multiple powder charges I have learned what I thought was the truth.
Largest bullet and maximum powder makes for a very accurate mix and plenty of energy for zero to two hundred yard kills on game as large as Elk. The first Elk I had taken with my sharps was 385 yards away and it dropped her where she was standing. A Painful kill as the bullet hit high and I am sure she suffered until I could get to her and finish the job.
If you are going to hunt with something that has the trajectory of a rainbow you need to learn to shoot it accurately or don’t hunt with it. Hard lesson learned.
Having developed the load I used a 600 grain cast bullet, 90 grains of Geox and a Magnum primer to create a great shooting cartridge with excellent accuracy. However it was an extremely nasty load to shoot multiple times.
During my work up of loads I began to study the effects of very slow burning modern powders. My choice was IMR 7828. Starting out with 45 grains and working my way up I found that 80 grains would push the 600 grain bullet about 100 fps faster than Geox and the accuracy was even better than the traditional load. The 80 grains of IMR 7828 showed no signs of excess pressure with respect to primer and case inspection.
Now keep in mind I am no Pressure Expert and in no way am I recommending any one trying this. These rifles are made for black powder only, with that said I tried my theory on one of the best built rifles’s like my Shiloh Sharps.
I really like the no mess of modern powder and the ease of loading and cleaning so I continued my experiment. After achieving what I thought was the perfect load I found my self looking for something different, and I think I have found it.
After sizing my barrel, which I did the first day I received my Sharps, I found it to be .510. Studying many different bullet types I found that Woodleigh made a soft nose 535 grain copper jacketed bullet in .510 diameter. So I ordered a few of those in.
Loaded with 80 grains of IMR 7828 I was curious to see how they would perform. But wait, there was trouble. The bullet seated to the crimp line would not chamber as it touched the lands and groove. Since I did not want to seat the bullet any deeper, as this would reduce powder capacity and eliminate the use of the crimp ring I thought long and hard on what to do.
I thought about shorter length trimming of the brass but this would result in less case capacity. With the aid of a bore camera scope I was able to see that the chamber end of the lands and grooves where sharp bull nose or 90 degrees from the chamber. Since I was only a few thousands from the new round chambering I begin to think, yeah I know.
Once I pondered on this for I while I weighed in on destroying my greatest treasure or just accept the fact there was nothing I could do.
Well the answer came to me, Marines don’t plan they improvise.
I figured that I could hone the lands to a slight taper to see if this would allow the new load to chamber, and it did. I got to tell you that it was scary having no idea what the results would be. You know lead versus copper jacket, pressure and who knows what else, I was a little nervous pulling the trigger on that first round. You know, I thought about life without a face or maybe only part of one, or being blinded by the unknown, still with all that said maybe my courage came from 35 years of reloading.
The Shiloh Sharps performed perfectly, a true hero when it comes to taking it.
The load produced velocities of 1536 fps average with excellent accuracy and no sign of excess pressure at the primer and or the shell casing.
My hopes where for bullet speed on 1600 fps + or -, however that did not happen. I did however have room left in the brass case for a little more powder if I dared and dared I did.
IMR 7828 is just an amazing powder for large caliber cases, I use it in 7 MM Magnum up to 338 Winchester Magnum and full case’s produce no sign of excess pressure. Now IMR has 7828 SSC or super short cuts which allows for a little more capacity and a nice free through from the powder measure versus the longer original 7828. Now if IMR would do the same for their 4350 powder all would be well.
So having case capacity left unused I proceeded in loading 87 grains of IMR 7828 which filled the case to the bottom of the Woodleigh bullet, tight but not compressed.
The result where as follows.
Velocity at 12 feet from the muzzle on 5/1/2008.
7 shoot averages was 1590 feet per second.
Low was 1584 fps, fastest was 1614 fps.
Bench rest shot spread result using veneer peep long range sites at 200 yards, keep in mind I am kind of Old where as follows.
200 yards gave me 2” group of 4 out of the 5 shots one shot was off the group by 2”, there is no way that could be the shooter.
So in review the 50-90 Sharps with my testing has created at 500 yards about 1507 lbs of energy.
True the 338 has about 300 lbs more energy from 200 to 400 yards but that is still very little difference, although one has to keep in mind the 50-90 sharps will have a bullet drop of over 100 inches versus the 338’s bullet drop of about 50 inches, hence the term rainbow trajectory.
What is left to do:
Since the IMR 7828 SSC allows for 4 % more capacity than the standard IMR 7828. That would equal about 90.48 grains to the bottom of the Woodleigh Bullet.
This may increase speed a few feet per second, not that it would matter much, but it would fill the case and I believe shoot extremely accurate with no danger to the shooter or the weapon.
Let’s see, 90 grains of powder, .50 caliber, yeap we have a 50-90 Sharps.
Next week will tale the tale.