JimGnitecki
Member
- Joined
- Mar 28, 2010
- Messages
- 1,258
I have been posting about my Pedersoli Sharps replica .45-70 rifle’s accuracy which has hit a wall, despite repeated improvement efforts with 500g class bullets when fired at my 150 meters = 164 yards testing distance.
The 150 meter testing range is NOT my ultimate planned target range. I want to be able to shoot at up to 600 meters = 656 yards. At that range, even my best 5-shot groups at 0.8 MOA (IF the 500g class bullets could maintain that accuracy at longer ranges) would create a 6” group. And unfortunately, the 500g powder coated bullets cannot seem to do the 0.8 MOA “best” groups consistently. Many fired groups reach as high as 1.6 MOA.
MY SDs with Accurate 5744 powder have been single digit, so I know the problem is neither the powder nor the low amount of powder within the large 45-70 case
Having done throat fit measurements using the Hornady OAL gage and BTO gage with .45” insert, I also now know I have loaded to the right range of BTOs, encompassing varied jump all the way to right into the rifling. I have also tested .460”, .459”. and .458” bullet sized diameters (after powder coating). So, I know that the fit in the throat and rifling is not the problem.
I also know my eyesight is not the problem, as I have had laser surgery and use a Leatherwood Hi-Lux semi-authentic Malcolm 6x full barrel length telescopic sight and see a perfect sight picture.
And I think my shooter skills are up to the task as I shoot my modern 6.5 Creedmoor sniper rifle with approximately 0.25 MOA accuracy at 300 yards.
I THINK the problems are bullet inconsistencies created by two sources:
I also wanted to try a lighter weight bullet that also is as aerodynamic as possible (understanding the inherent limitations of a plated versus jacketed bullet). The lighter weight, coupled with good ballistic coefficient, could flatten the trajectory a bit, and reduce the windage effects of wind on the bullet.
They would also enable practicing at decently long ranges (although not at 600 meters) using my Shotmarker target system, by keeping the bullets supersonic to longer distances. Using the Shotmarker system for practice and load development creates access to a rich variety of helpful data, including actual velocity at the target, actual bullet pitch, actual bullet yaw, precise group position / size / and MOA withOUT needing either a VERY good spotting scope or walking several minutes to the target and back every time I want to take a measurement or patch a physical paper target.
IF I could not find such a bullet, the next type of bullet I would explore would be jacketed.
So, I went looking for a 300g to 400g bullet that is .458” to .459” diameter, is aerodynamic, is cast, and is plated. And, I found a bullet that meets all of these wants, and is made by a Canadian manufacturer, so is available to me and at a reasonable cost that is higher than my home cast bullets but lower than jacketed bullets.
It’s the Campro 458 diameter 350g SPITZER Full Copper Plated (including the base).This is a SWAGED bullet, and the copper plating on it is .008” thick.
It was designed for 458 SOCOM use. For those, like me, unfamiliar with the 458 SOCOM, it is a cartridge designed to fit a .458 caliber barrel and bolt Upper that fits right onto a standard AR15 Lower. Its design purpose was to create a lower velocity large caliber round that could be fired with or without a suppressor, reliably penetrate body armour, and reliably stop an enemy combatant with one shot. Does this caliber sound like another caliber with which we are all familiar?
Put another way, its design purpose was to create a 45-70-like cartridge that would be short enough overall to fit inside a standard AR15 rifle. Because it was designed of course for smokeless powder, the cartridge case can be much shorter - about a half inch shorter - than the 45-70 case.
Load tables for 458 SOCOM show that a 350g bullet weight is one of its common bullet weights, and the velocity range for the 350g bullets is 1500 to 1800 fps - exactly the range I would like to have.
I’m sure You can see where I am headed here with my thinking. This Campro bullet was designed to work in 458 SOCOM, but when I asked Campro, they said it should work fine with the standard load data for any 45-70 load intended for a 350g bullet. And, it turns out it does.
And Accurate 5744, which I have been using, and have a good supply of, is one of the powders that is listed in Accurate load tables for use with 350g.
And that Spitzer ogive on the Campro bullet gives it an unusually high claimed BC of .342. Plus I have a 30” barrel, versus the much shorter barrels used on AR15s. high 45-70 velocities seem to be a potential possibility with this bullet, even in a rifle conservatively rated for only 28,000 psi peak pressures..
After buying a bag of of the Campro bullet, I did some statistical sampling of it. It has about the same weight consistency as my hand cast bullets: about 0.2g SD and about 1% ES. But its BTO measurement (on the bullet alone, not seated in a case) is much more consistent than my cat bullets. And after loading a sample batch, I found that the loaded BTO is FAR more consistent than my cast, powder coated bullets, with an ES of just .003”.
I loaded only a small sampling of cartridges with this bullet, with 35, 36, and 37 grains of 5744 powder. The Accurate load table shows a minimum charge of 33,8g and a maximum of 37.5g, so I very roughly covered much of the range, just to get a very rough idea of how well this bullet might work for me. I favoured the higher end of the range a bit simply because this rifle has demonstrated a strong preference for stronger loads.
I got an average velocity of 1695 fps with an SD of 8 for the 35g load.
I got an average velocity of 1727 with an SD SD of 10.8 for the 36g load.
These both exceeded the 1676 fps velocity the load table claimed for a 37.5g maximum load. But the load table assumed a 24” barrel length. My Pedersoli barrel is 30” long.
I was unable to get an SD for the 37g load because the Labradar could only detect 2 of the 10 shots fired with the 37g load. On the drive home, I realized, too late, that this was because I had the Labradar set for “Handgun” velocities, because the normal velocities for 500g 45-70 bullets max out at about 1400 fps. Up until I loaded these 350g bullet loads, my highest muzzle velocity had been 1400 fps, so I had needed to use the handgun setting. So, after getting home from the range, I changed the Labradar setting to “rifle” versus handgun, so that next time I will be able to detect the velocity with the 37g load. The 2 shotswith the 37g load that WERE detected by the Labradar were at 1752 and 1757 fps. Just 5 fps apart.
The range testing went really well for a first, rough load range “ladder” test, with these big gaps between the 3 powder ranges, and only 10 rounds loaded with each of the 3 powder levels.
The very first 5-shot group fired, from a cold barrel, with that purely randomly selected 35g load, measured just a bit over 1 MOA, which I consider to be a VERY promising start.
The last group I fired was the 2nd 5-shot group I fired with the 37g load. It had ZERO horizontal dispersion - the bullet holes were in perfect vertical alignment! The vertical dispersion though was significant, at almost 2 inches, which at my test range of 164 yards is about 1.2 MOA.
I live in a Canadian location where winter temperatures require a LOT of home heating, and I HAD noticed during my loading session that for the first time this winter, I was getting some static electricity issues when pouring the 37g powder loads (the last loads i loaded in the session) through the funnel into the cases. I suspect that despite my best efforts to shake the powder down by tapping the funnel, some powder might have clung to the walls of the funnel’s lower TUBE where I could not see it. That MIGHT explain the vertical dispersion despite the zero horizontal dispersion.
These 2 best initial range test results are not as good YET as the 0.8 MOA best results fired with my cast powdercoated bullets. But, I had stalled out at those 0.8 MOA BEST groups with my cast bullets, with SOME groups still persistently going out to 1.6 MOA. Getting very first test attempts at under 1.2 MOA with the new bullet, with randomly selected powder loads, and no testing at ALL yet for optimal COAL, I view as a great start.
Primers for all 30 shots fired were perfect, which I expected, as the 37.5g maximum limit in the load table was based only on keeping peak pressure below the 28,000 psi for Pedersoli and other modern replicas of Sharps rifles.
The rifle barrel was VERY clean after the 30 shots - even cleaner than the barrel was after firing a like number of powdercoated cast bullets in previous range sessions. So, yes, the .008” copper plating works a LOT better at 1750 fps than any conventional bullet lubricant.
There’s more good news. The Labradar measures not only muzzle velocity, but also downrange velocity at intervals that you can specify. Normally, it can detect bullets out as far as 100 yards, but a Labradar technician told me that the huge size of the 45-70 bullets makes it possible for the Labradar to detect them quite a bit further out. I have in fact been able to detect 45-70 bullets out as far as 250 yards. With this range session, I did not get a usable set of measurements for the 37g load because of the handgun velocity setting, but I got solid results out to 250 yards for the 36g load:
Note that the chart has the correct typical “hockey stick shape”, where the BC gets better as the bullet slows down from its initially high muzzle velocity, and so the speed decay becomes slower versus distance. Based on what I see in this chart, the bullet MIGHT still be supersonic at somewhere between 375 and 450 yards, and so the Shotmarker MIGHT be able to detect it and give me that very rich data dump for each bulelt and each group fired. Remember, this chart is for the 36g load. The 37g load has the bullet going even faster,
Based on all the above, I think this bullet has earned further testing. It MIGHT be just what I have needed all along.
Jim G
The 150 meter testing range is NOT my ultimate planned target range. I want to be able to shoot at up to 600 meters = 656 yards. At that range, even my best 5-shot groups at 0.8 MOA (IF the 500g class bullets could maintain that accuracy at longer ranges) would create a 6” group. And unfortunately, the 500g powder coated bullets cannot seem to do the 0.8 MOA “best” groups consistently. Many fired groups reach as high as 1.6 MOA.
MY SDs with Accurate 5744 powder have been single digit, so I know the problem is neither the powder nor the low amount of powder within the large 45-70 case
Having done throat fit measurements using the Hornady OAL gage and BTO gage with .45” insert, I also now know I have loaded to the right range of BTOs, encompassing varied jump all the way to right into the rifling. I have also tested .460”, .459”. and .458” bullet sized diameters (after powder coating). So, I know that the fit in the throat and rifling is not the problem.
I also know my eyesight is not the problem, as I have had laser surgery and use a Leatherwood Hi-Lux semi-authentic Malcolm 6x full barrel length telescopic sight and see a perfect sight picture.
And I think my shooter skills are up to the task as I shoot my modern 6.5 Creedmoor sniper rifle with approximately 0.25 MOA accuracy at 300 yards.
I THINK the problems are bullet inconsistencies created by two sources:
- my insufficient novice casting skills, coupled with
- slight variations in powder coat thickness that change the actual bullet ogive shape and size in non-controllable ways.
- I could need a LOT of elevation adjustment to reach 600 meters
- I could need a LOT of windage adjustment to handle even modest winds
- I cannot use my newly acquired Shotmarker electronic target system once the bullet velocity erodes with distance below 1120 fps (the local speed of sound at 3000 feet above sea level)
I also wanted to try a lighter weight bullet that also is as aerodynamic as possible (understanding the inherent limitations of a plated versus jacketed bullet). The lighter weight, coupled with good ballistic coefficient, could flatten the trajectory a bit, and reduce the windage effects of wind on the bullet.
They would also enable practicing at decently long ranges (although not at 600 meters) using my Shotmarker target system, by keeping the bullets supersonic to longer distances. Using the Shotmarker system for practice and load development creates access to a rich variety of helpful data, including actual velocity at the target, actual bullet pitch, actual bullet yaw, precise group position / size / and MOA withOUT needing either a VERY good spotting scope or walking several minutes to the target and back every time I want to take a measurement or patch a physical paper target.
IF I could not find such a bullet, the next type of bullet I would explore would be jacketed.
So, I went looking for a 300g to 400g bullet that is .458” to .459” diameter, is aerodynamic, is cast, and is plated. And, I found a bullet that meets all of these wants, and is made by a Canadian manufacturer, so is available to me and at a reasonable cost that is higher than my home cast bullets but lower than jacketed bullets.
It’s the Campro 458 diameter 350g SPITZER Full Copper Plated (including the base).This is a SWAGED bullet, and the copper plating on it is .008” thick.
It was designed for 458 SOCOM use. For those, like me, unfamiliar with the 458 SOCOM, it is a cartridge designed to fit a .458 caliber barrel and bolt Upper that fits right onto a standard AR15 Lower. Its design purpose was to create a lower velocity large caliber round that could be fired with or without a suppressor, reliably penetrate body armour, and reliably stop an enemy combatant with one shot. Does this caliber sound like another caliber with which we are all familiar?
Put another way, its design purpose was to create a 45-70-like cartridge that would be short enough overall to fit inside a standard AR15 rifle. Because it was designed of course for smokeless powder, the cartridge case can be much shorter - about a half inch shorter - than the 45-70 case.
Load tables for 458 SOCOM show that a 350g bullet weight is one of its common bullet weights, and the velocity range for the 350g bullets is 1500 to 1800 fps - exactly the range I would like to have.
I’m sure You can see where I am headed here with my thinking. This Campro bullet was designed to work in 458 SOCOM, but when I asked Campro, they said it should work fine with the standard load data for any 45-70 load intended for a 350g bullet. And, it turns out it does.
And Accurate 5744, which I have been using, and have a good supply of, is one of the powders that is listed in Accurate load tables for use with 350g.
And that Spitzer ogive on the Campro bullet gives it an unusually high claimed BC of .342. Plus I have a 30” barrel, versus the much shorter barrels used on AR15s. high 45-70 velocities seem to be a potential possibility with this bullet, even in a rifle conservatively rated for only 28,000 psi peak pressures..
After buying a bag of of the Campro bullet, I did some statistical sampling of it. It has about the same weight consistency as my hand cast bullets: about 0.2g SD and about 1% ES. But its BTO measurement (on the bullet alone, not seated in a case) is much more consistent than my cat bullets. And after loading a sample batch, I found that the loaded BTO is FAR more consistent than my cast, powder coated bullets, with an ES of just .003”.
I loaded only a small sampling of cartridges with this bullet, with 35, 36, and 37 grains of 5744 powder. The Accurate load table shows a minimum charge of 33,8g and a maximum of 37.5g, so I very roughly covered much of the range, just to get a very rough idea of how well this bullet might work for me. I favoured the higher end of the range a bit simply because this rifle has demonstrated a strong preference for stronger loads.
I got an average velocity of 1695 fps with an SD of 8 for the 35g load.
I got an average velocity of 1727 with an SD SD of 10.8 for the 36g load.
These both exceeded the 1676 fps velocity the load table claimed for a 37.5g maximum load. But the load table assumed a 24” barrel length. My Pedersoli barrel is 30” long.
I was unable to get an SD for the 37g load because the Labradar could only detect 2 of the 10 shots fired with the 37g load. On the drive home, I realized, too late, that this was because I had the Labradar set for “Handgun” velocities, because the normal velocities for 500g 45-70 bullets max out at about 1400 fps. Up until I loaded these 350g bullet loads, my highest muzzle velocity had been 1400 fps, so I had needed to use the handgun setting. So, after getting home from the range, I changed the Labradar setting to “rifle” versus handgun, so that next time I will be able to detect the velocity with the 37g load. The 2 shotswith the 37g load that WERE detected by the Labradar were at 1752 and 1757 fps. Just 5 fps apart.
The range testing went really well for a first, rough load range “ladder” test, with these big gaps between the 3 powder ranges, and only 10 rounds loaded with each of the 3 powder levels.
The very first 5-shot group fired, from a cold barrel, with that purely randomly selected 35g load, measured just a bit over 1 MOA, which I consider to be a VERY promising start.
The last group I fired was the 2nd 5-shot group I fired with the 37g load. It had ZERO horizontal dispersion - the bullet holes were in perfect vertical alignment! The vertical dispersion though was significant, at almost 2 inches, which at my test range of 164 yards is about 1.2 MOA.
I live in a Canadian location where winter temperatures require a LOT of home heating, and I HAD noticed during my loading session that for the first time this winter, I was getting some static electricity issues when pouring the 37g powder loads (the last loads i loaded in the session) through the funnel into the cases. I suspect that despite my best efforts to shake the powder down by tapping the funnel, some powder might have clung to the walls of the funnel’s lower TUBE where I could not see it. That MIGHT explain the vertical dispersion despite the zero horizontal dispersion.
These 2 best initial range test results are not as good YET as the 0.8 MOA best results fired with my cast powdercoated bullets. But, I had stalled out at those 0.8 MOA BEST groups with my cast bullets, with SOME groups still persistently going out to 1.6 MOA. Getting very first test attempts at under 1.2 MOA with the new bullet, with randomly selected powder loads, and no testing at ALL yet for optimal COAL, I view as a great start.
Primers for all 30 shots fired were perfect, which I expected, as the 37.5g maximum limit in the load table was based only on keeping peak pressure below the 28,000 psi for Pedersoli and other modern replicas of Sharps rifles.
The rifle barrel was VERY clean after the 30 shots - even cleaner than the barrel was after firing a like number of powdercoated cast bullets in previous range sessions. So, yes, the .008” copper plating works a LOT better at 1750 fps than any conventional bullet lubricant.
There’s more good news. The Labradar measures not only muzzle velocity, but also downrange velocity at intervals that you can specify. Normally, it can detect bullets out as far as 100 yards, but a Labradar technician told me that the huge size of the 45-70 bullets makes it possible for the Labradar to detect them quite a bit further out. I have in fact been able to detect 45-70 bullets out as far as 250 yards. With this range session, I did not get a usable set of measurements for the 37g load because of the handgun velocity setting, but I got solid results out to 250 yards for the 36g load:
Note that the chart has the correct typical “hockey stick shape”, where the BC gets better as the bullet slows down from its initially high muzzle velocity, and so the speed decay becomes slower versus distance. Based on what I see in this chart, the bullet MIGHT still be supersonic at somewhere between 375 and 450 yards, and so the Shotmarker MIGHT be able to detect it and give me that very rich data dump for each bulelt and each group fired. Remember, this chart is for the 36g load. The 37g load has the bullet going even faster,
Based on all the above, I think this bullet has earned further testing. It MIGHT be just what I have needed all along.
Jim G
