300 grain FPB's in a Black Mountain
09-27-2010, 02:32 PM
#1
Dominant Buck
Thread Starter
Join Date: Feb 2003
Location: Wisconsin
Posts: 21,193
300 grain FPB's in a Black Mountain
Today I hurried and got my work done so I could shoot before the rains came. I wanted to shoot the Hornady 300 grain FPB's that I had recently purchased. I was not sure which rifle I wanted to try them in and finally decided on the T/C Black Mountain Magnum .50 caliber.
Rifle: Thompson Center Black Mountain Magnum .50 caliber 1-28 twist with a 26 inch barrel.
Scope: Simmons Pro Diamond 4x32mm with Traditions QR rings
Projectile: Hornady FPB 300 grain conical bullets
Powder: Pyrodex RS 110 grains
Ignition: CCI musket caps
Distance: 25 yards for initial sight in, then back to 50 yards
Weather: cloudy, over cast, windy, 61 degrees, looks like rain.
I had remounted the scope into the rings a while back and was not sure where the rifle was going to hit. So I set the target at 25 yards. I wanted to shoot the Hornady FPB 300 grain conical bullets.
You can see the adjustments made. The puzzling part is after 1 & 2, I moved the scope to the left, but not up. Why this moved up I have no idea. Then I shot 3 & 4 and decided that was close enough to center of the bull so I moved the scope down and fired #5. I considered that pretty close to dead center bull.
Being worried #5 was a fluke, I shot two more.. 6 & 7 to make sure I was dead center, then made a slight adjustment to move off the bull one inch. I then fired #8. That looked good, so I took the target back to 50 yards.
Here it where things really got confusing for me. Or am I seeing this wrong...
Shots 9-11 I did not think should be that low. I made an adjustment of what I thought was about right and shot 12. Then I realized this scope moves 1/2 in at 100 yards instead of the 1/4 in like many other scopes. I wanted the scope to hit two inches high at this distance, and moved what I felt was the appropriate number of clicks. Shots 13-15 were at the right height, but why they moved off to the right, I have no idea. I also had ran out of bullets. Instead of getting another pack out, I decided to clean the rifle without removing the scope off the barrel, or the barrel out of the stock. Then I could retest it at a different time to see if the rifle needs further adjustment or what.
These show some definite trenching ability. I found where they were hitting back in the woods. They had blown a tree stump (small one) out of the ground there. I looked for any of the FPB's and could not find any of them.
Different forum members got my interest with their information on these conical bullets. I do believe they will be accurate to long range. Once I tame them to the scope and powder charge.
Some questions for those that shoot these... do they like a stiff powder charge or a lesser charge? I thought I remembered these being shot with a large charge which is why I went to 110 grains of Pyrodex. Also the card that came with them shows velocities for 100 grains and 150 grains. So the manufacturer must feel these handle still loads as well.
I also looked and the other packs I got were 350 grains FPB's. I for some reason took only one of the 300 grain. So now I have to play with a slightly larger conical. But they should not be that different you would think. I do believe they will make a good open field round in that rifle. Once I find the right powder charges. Any suggestions?
Rifle: Thompson Center Black Mountain Magnum .50 caliber 1-28 twist with a 26 inch barrel.
Scope: Simmons Pro Diamond 4x32mm with Traditions QR rings
Projectile: Hornady FPB 300 grain conical bullets
Powder: Pyrodex RS 110 grains
Ignition: CCI musket caps
Distance: 25 yards for initial sight in, then back to 50 yards
Weather: cloudy, over cast, windy, 61 degrees, looks like rain.
I had remounted the scope into the rings a while back and was not sure where the rifle was going to hit. So I set the target at 25 yards. I wanted to shoot the Hornady FPB 300 grain conical bullets.
You can see the adjustments made. The puzzling part is after 1 & 2, I moved the scope to the left, but not up. Why this moved up I have no idea. Then I shot 3 & 4 and decided that was close enough to center of the bull so I moved the scope down and fired #5. I considered that pretty close to dead center bull.
Being worried #5 was a fluke, I shot two more.. 6 & 7 to make sure I was dead center, then made a slight adjustment to move off the bull one inch. I then fired #8. That looked good, so I took the target back to 50 yards.
Here it where things really got confusing for me. Or am I seeing this wrong...
Shots 9-11 I did not think should be that low. I made an adjustment of what I thought was about right and shot 12. Then I realized this scope moves 1/2 in at 100 yards instead of the 1/4 in like many other scopes. I wanted the scope to hit two inches high at this distance, and moved what I felt was the appropriate number of clicks. Shots 13-15 were at the right height, but why they moved off to the right, I have no idea. I also had ran out of bullets. Instead of getting another pack out, I decided to clean the rifle without removing the scope off the barrel, or the barrel out of the stock. Then I could retest it at a different time to see if the rifle needs further adjustment or what.
These show some definite trenching ability. I found where they were hitting back in the woods. They had blown a tree stump (small one) out of the ground there. I looked for any of the FPB's and could not find any of them.
Different forum members got my interest with their information on these conical bullets. I do believe they will be accurate to long range. Once I tame them to the scope and powder charge.
Some questions for those that shoot these... do they like a stiff powder charge or a lesser charge? I thought I remembered these being shot with a large charge which is why I went to 110 grains of Pyrodex. Also the card that came with them shows velocities for 100 grains and 150 grains. So the manufacturer must feel these handle still loads as well.
I also looked and the other packs I got were 350 grains FPB's. I for some reason took only one of the 300 grain. So now I have to play with a slightly larger conical. But they should not be that different you would think. I do believe they will make a good open field round in that rifle. Once I find the right powder charges. Any suggestions?
09-27-2010, 03:16 PM
#3
Boone & Crockett
Join Date: Apr 2007
Location: River Ridge, LA (Suburb of New Orleans)
Posts: 10,917
Those last three 50 yarders are pretty darn tight together Cayugad. It looks like the gun is going to like those bullets.
One of my five ProDiamonds tends to drift to the left when I adjust it "up", and to the right with a "down" adjustment. Other than that quirk it works fine. The other four do not do that.
One of my five ProDiamonds tends to drift to the left when I adjust it "up", and to the right with a "down" adjustment. Other than that quirk it works fine. The other four do not do that.
Last edited by Semisane; 09-27-2010 at 08:45 PM.
09-27-2010, 04:09 PM
#4
Dominant Buck
Thread Starter
Join Date: Feb 2003
Location: Wisconsin
Posts: 21,193
Well that's good to know. So I just need to move it over to where it should be and try again. Although it will be with some of the 350 grain.
Does that seem too low though for moving only twenty five yards. From dead center to almost two and a half inches low?
Does that seem too low though for moving only twenty five yards. From dead center to almost two and a half inches low?
09-27-2010, 04:52 PM
#5
Boone & Crockett
Join Date: Apr 2007
Location: River Ridge, LA (Suburb of New Orleans)
Posts: 10,917
Does that seem too low though for moving only twenty five yards. From dead center to almost two and a half inches low?
Let's assume your 110 grain load of RS is pushing that pointy 300 grain bullet at around 1450 fps at the muzzle. With the scope crosshairs 1.5" above the bore and sighted in for dead on at 25 yards, the ballistics should look something like this.
Range.....Velocity.....Impact.....Drop.....ToF.....Energy
........0......1450............1.5............0.........00........1401
......25......1397..............0........0.64......0.06........1300
......50......1349............0.39.....2.39......0.11........1212
......75......1304...........-0.43.....5.34......0.17........1133
....100......1261...........-2.53.....9.58......0.22........1059
It should actually be hitting almost a half inch higher at 50 yards.
EDIT: And that's with a 25 yard zero. I forgot that you adjusted it to be one-inch high at 25 (shot #8). With that, it should have been over two inches high at 50.
At least, that's my figuring. We need help from some of the true ballistic experts out there.
Last edited by Semisane; 09-27-2010 at 05:00 PM.
09-27-2010, 05:09 PM
#6
Dominant Buck
Thread Starter
Join Date: Feb 2003
Location: Wisconsin
Posts: 21,193
According to their ballistics chart... they talk Triple Seven 100 grains and talk velocity/energy. 1800/2158 muzzle. 1658/1830 50 yds. 1525/1549 100 yds. 1404/1313 150 yds. 1295/1117 200 yds. 1202/962 250 yds. Off their enclosed information card.
See I honestly expected for the bullet to hit about 2 inches high. Instead it shoots that low group. It just floored me.
See I honestly expected for the bullet to hit about 2 inches high. Instead it shoots that low group. It just floored me.
09-27-2010, 05:27 PM
#7
Boone & Crockett
Join Date: Apr 2007
Location: River Ridge, LA (Suburb of New Orleans)
Posts: 10,917
I based my 1450 fps velocity "guess" on chrono readings from shooting 300 grain Remington .458 semi-jacketed hollow point bullets from my Mustang using MMP orange sabots and 110 grains of RS. The next closest match I have is 300 grain Gold Dots in Harvester short black sabots over 105 grains T7 FFFG. My record shows a five shot average of 1637 fps.
Don't know if my chrono is accurate. But it gives me consistent readings from different range sessions with the same loads. My "base line" is the handloads from my 25-06 which read just at 3200 fps with every chrono I've ever shot them over, including mine.
Don't know if my chrono is accurate. But it gives me consistent readings from different range sessions with the same loads. My "base line" is the handloads from my 25-06 which read just at 3200 fps with every chrono I've ever shot them over, including mine.
Last edited by Semisane; 09-27-2010 at 05:32 PM.
09-27-2010, 05:35 PM
#8
Boone & Crockett
Join Date: Apr 2007
Location: River Ridge, LA (Suburb of New Orleans)
Posts: 10,917
See I honestly expected for the bullet to hit about 2 inches high. Instead it shoots that low group. It just floored me.
09-27-2010, 08:59 PM
#9
Fork Horn
Join Date: May 2003
Posts: 104
The most likely reason your scope isnt adjusting correctly is because its not square. It may look it but if its slightly canted then when you try to move it up, it will go up but also slightly left or right depending on which side it is canted to.
I didnt see what scope you were using buts most low end scopes do not track correctly even when new. Even some high end ones dont but its a rarity more than a common. Nice shooting tho
I didnt see what scope you were using buts most low end scopes do not track correctly even when new. Even some high end ones dont but its a rarity more than a common. Nice shooting tho