.455 Webley loads

[pacman99]

Hello,

Im looking for some starting .455 webley loads that are pressure safe for mark 2 webleys or MAS 1873 conversions. Predominantly I am looking for bullseye or herco loads. I currently have a starting point of 3.2 grains for bullseye, but have found scant info on herco. Any help would be appreciated! Will be using both 200 grain and 270 grain soft lead cast bullets.

 

[Pelcat]

I shot 3.4 gr of Bullseye with 270gr hollow base MkII bullets. My chrono is in the moving truck so I can't give you the exact velocities but it was around 600 FPS with a pretty wide spread (going off memory so take with a grain of salt). My thoughts were that Bullseye is not the best powder for this cartridge, it's a bit loose and inconsistent in the big 455 casings but it is what I had on hand and it worked well enough for plinking.

Forgot to mention the firearm was a Webley MkII with 4 inch barrel.

 

[pacman99]

I shot 3.4 gr of Bullseye with 270gr hollow base MkII bullets. My chrono is in the moving truck so I can't give you the exact velocities but it was around 600 FPS with a pretty wide spread (going off memory so take with a grain of salt). My thoughts were that Bullseye is not the best powder for this cartridge, it's a bit loose and inconsistent in the big 455 casings but it is what I had on hand and it worked well enough for plinking.

Forgot to mention the firearm was a Webley MkII with 4 inch barrel.

Appreciate it, thank you. Is there a smokeless powder you would recommend over these two?

 

[bearhunter]

Herco and Unique are quite close when comparing their burn rates.

Unique loads will work well, because it's faster than Herco.

When I first started loading for my 455 chambered pistols, I had a lot of Herco on hand and wanted to utilize the powder.

I also liked it because it filled the case better, which, more than anything, was a "feel-good" thing for me.

My load with .870 length cases, was different from .760 length cases.

For .870 length cases:

4.7 grains of Herco, over CCI350 primers, under 250 grain HP bullets, soft cast 1/12 lead.

Because Herco is much slower than Bullseye, the cases need to be heavily crimped to get good velocity and provide enough pressure to obturate the bullet into the rifling, for good accuracy.

My load was safe in my MK1 Webley. You may want to start a bit lower.

For Short cases, I lowered the powder charge by .5 grain.

The Mas 1873 strength should be pretty close to my Mark 1 Webley.

I'm getting just under 500 fps with my loads of Herco, so pressures will likely be lower than the original Mas 11mm loads for the same weight bullets at 550 fps.

The original loads used black powder, and I believe the French loaded the cartridges with BP up to the mid 1890s.

They issued the pistols during WWI, I don't know if they used a smokeless powder. Likely they did.

 

[pacman99]

Herco and Unique are quite close when comparing their burn rates.

Unique loads will work well, because it's faster than Herco.

When I first started loading for my 455 chambered pistols, I had a lot of Herco on hand and wanted to utilize the powder.

I also liked it because it filled the case better, which, more than anything, was a "feel-good" thing for me.

My load with .870 length cases, was different from .760 length cases.

For .870 length cases:

4.7 grains of Herco, over CCI350 primers, under 250 grain HP bullets, soft cast 1/12 lead.

Because Herco is much slower than Bullseye, the cases need to be heavily crimped to get good velocity and provide enough pressure to obturate the bullet into the rifling, for good accuracy.

My load was safe in my MK1 Webley. You may want to start a bit lower.

For Short cases, I lowered the powder charge by .5 grain.

The Mas 1873 strength should be pretty close to my Mark 1 Webley.

I'm getting just under 500 fps with my loads of Herco, so pressures will likely be lower than the original Mas 11mm loads for the same weight bullets at 550 fps.

The original loads used black powder, and I believe the French loaded the cartridges with BP up to the mid 1890s.

They issued the pistols during WWI, I don't know if they used a smokeless powder. Likely they did.

That is very helpful, thank you.