Smokeless loads for .450 Adams/.450 Colt...?

MiltonBradly

MiltonBradly

CGN Regular
Rating - 100%
11   0   0
Location
Hamilton ON
Hey all,

I've been having a blast shooting my Belgian S&W top break copy lately and was wondering where one starts when considering developing a smokeless load for your antique revolver?

I have been shooting 200gr flat based lead RN bullets with a 10gr charge of fffg BP under a card wad and two layers of vegetable shortening loaded patch for ~550 FPS. I need to look into a hollow based bullet but for the time being I'm happy to have something to shoot out of it. I have read that The .450 Adams was a 225gr bullet propelled by 13gr of BP for 650FPS so I'm staying under that to go easy on old iron.

Reading through the "smokeless in antiques" sticky I understand that matching velocity is the goal with your chosen smokeless powder but how does one decide upon the appropriate starting load to work up from? I gather that the weight of charge with smokeless will likely be far smaller than the equivalent charge in BP but when your BP charge is only ~10gr the required smokeless charge will likely be tiny... an easy recipe for an overcharge I would think...

How does one determine the pressure limit to stay within, choose the appropriate powder and determine a reasonable starting point when considering developing a smokeless load?

Thanks
MB
 
If you search the black powder forum with just the word 'unique' you will come up with some posts on the subject, unique is a popular powder for these types of gun. Here are two recent threads that might give you some ideas, just take into account that a top break might not be as durable as a solid frame.

http://www.canadiangunnutz.com/forum/showthread.php?t=553091&highlight=unique
http://www.canadiangunnutz.com/forum/showthread.php?t=522479&highlight=unique


I used to have a solid frame belgian .450 cal revolver that took shortened .45 colt cases, I was trimming the cases to .890" or less and used 5.0gr unique with a 225gr bullet and 4.2gr with a 255gr bullet at 1.240" oal, it shot roughly to the point of aim with both of those loads. Since you have a chrony you could start below that and work up to a velocity you're happy with. You mentioned you're concerned about the possibility of an overcharge, the solution is to not overcharge, weigh each charge and look in the cases with a flash light to make sure theyre all the same.

As for pressure, from what I can tell most black powder pistol cartridges were under 12,000 psi / cup (psi and cup are not completely interchangeable but I never noticed a value much higher than that for either). The CIP max pressure for .450 ammo is 720 bar (10440psi).
 
I use 4.8grs of blue dot for 650fps with a 250gr bullet the 450 boxer was under 700 fps . start with 4.2 and work up from there would be my suggestion?
 
Read through more threads regarding smokeless in antiques. I currently use Unique but am rethinking it and will probably try Blue Dot (similar pressure curve to FFFg) and 2400 (similar to FFg). The thing about matching velocities is if your powder is a lot faster your pressure will be a lot higher.

Here is a table I saved from a thread on another forum I found in a google search:

34dml4p.jpg


It clearly shows that to match pressure (retain safe BP levels) for certain powders you need to have a lower velocity.
 
41 Colt said:
Read through more threads regarding smokeless in antiques. I currently use Unique but am rethinking it and will probably try Blue Dot (similar pressure curve to FFFg) and 2400 (similar to FFg). The thing about matching velocities is if your powder is a lot faster your pressure will be a lot higher.

Here is a table I saved from a thread on another forum I found in a google search:

34dml4p.jpg


It clearly shows that to match pressure (retain safe BP levels) for certain powders you need to have a lower velocity.
Click to expand...

There is a big difference between a 24" barrel and a 4" barrel.

Sorry, but this particular example doesn't work when you're comparing pistol loads. 14.5 gr of 2400 won't get you anywhere close to 1230 fps out of a 4" pistol barrel.
 
In the alliant manual it does show some loads with pistol length barrels where blue dot and 2400 generate more velocity than unique. Some are very close, I copy pasted some lower pressure loads that were similar in pressure below. 2400 doesn't show up much. I thought about trying blue dot or 2400 for .450/.455 but searching on google a lot of people were complaining about unburnt powder and erratic velocities when those two powders are used in non-magnum cartridges.

38 special 148 LWC 5.6" bbl 1.18" oal
3.3g unique=815fps@15.3ksi
5.3g blue dot=810fps@13.6ksi
-
38 special 158 LSWC 5.6" bbl 1.42"oal
4.3g unique=920fps@16.0ksi
6.1g blue dot=955fps@15.6ksi
-
380 auto
95 FMJ 0.975"oal 3.7" bbl
4.2g unique=910fps@14.6ksi
6.5g blue dot=910fps@14.2ksi
-
45 acp 230 FMC 1.19" oal 5" bbl
6.0g unique=895fps@16.0ksi
8.5g blue dot=900fps@16.2ksi
 
fiscus said:
In the alliant manual it does show some loads with pistol length barrels where blue dot and 2400 generate more velocity than unique. Some are very close, I copy pasted some lower pressure loads that were similar in pressure below. 2400 doesn't show up much. I thought about trying blue dot or 2400 for .450/.455 but searching on google a lot of people were complaining about unburnt powder and erratic velocities when those two powders are used in non-magnum cartridges.

38 special 148 LWC 5.6" bbl 1.18" oal
3.3g unique=815fps@15.3ksi
5.3g blue dot=810fps@13.6ksi
-
38 special 158 LSWC 5.6" bbl 1.42"oal
4.3g unique=920fps@16.0ksi
6.1g blue dot=955fps@15.6ksi
-
380 auto
95 FMJ 0.975"oal 3.7" bbl
4.2g unique=910fps@14.6ksi
6.5g blue dot=910fps@14.2ksi
-
45 acp 230 FMC 1.19" oal 5" bbl
6.0g unique=895fps@16.0ksi
8.5g blue dot=900fps@16.2ksi
Click to expand...

Blue dot is a useful powder in smaller capacity low pressure cartridges in short barrels. IMO 2400 is not so much.

I'm not at home right now so i can't run the numbers through Quickload, but IIRC using 2400 in .450 adams and .455 mkII webley, less than 1/2 the powder burns in a 4" barrel and ballistic efficiency is absolutely terrible, which accounts for the erratic results some people report. It would be great for starting brush fires, though!

Based on some of the stuff i read here, I tried sme 2400 in my .455. It really sucked, velocity-wise. Couldn't get enough powder in the case to break 500 fps with a 265 gr bullet. Fantastic muzzle flash, though. When i plugged the numbers into Quickload it came up with the same results.
 
This may be anathema to some guys, but I have been using Bullseye in my .38/200 Webley Mark IV and in a slew of Enfields. Two-point-one grains of the stuff with a 158 SWC bullet seated to OAL of a military load shoots pretty much to point of aim at combat distances in all of these guns and runs very close to the 630 ft/sec ideal. NO unburnt powder. These guns all are proofed for 3-1/2 tons (long) /sq. in. service loads. I have had no problems and a lot of good shooting.

I think you need a fast powder with a revolver because of the substantial pressure loss at the cylinder gap. Take a picture at night and youll see the extent of it.

But then, what do I know, anyway?
.
 
jethunter said:
There is a big difference between a 24" barrel and a 4" barrel.

Sorry, but this particular example doesn't work when you're comparing pistol loads. 14.5 gr of 2400 won't get you anywhere close to 1230 fps out of a 4" pistol barrel.
Click to expand...

It is still a good example of how using a faster powder you need to reduce your velocity to stay at safe pressure levels.

These threads from another forum contain a lot of info, some from our own Win 38-55.

http://levergunscommunity.org/viewtopic.php?f=1&t=7793

http://www.levergunscommunity.com/viewtopic.php?f=1&t=27410

This might be useful too.

http://www.chuckhawks.com/powder_burning_speed.htm
 
I use blue dot in all my antique pistols I just keep velocity slightly bellow original it works great with heavy bullets a good crimp is also needed its not a good choice for 8mm revolver etc I use 6grs in the 44russian, the 450 boxer is Ideal it burns great smaller case capacity and a heavy bullet it burns up most of the powder. I use the short MKII cases in my 455 and 5-5.5grs give me good moderate power.
 
Take a picture at night and youll see the extent of it.
Click to expand...

is'nt discharging a fire arm at night illegal in Manitoba? Or are you doing it in a black tent in the day time to 'skirt' the law? LOL

Sorry smellie could not resist.
Cheers
 
41 Colt said:
It is still a good example of how using a faster powder you need to reduce your velocity to stay at safe pressure levels.

These threads from another forum contain a lot of info, some from our own Win 38-55.

http://levergunscommunity.org/viewtopic.php?f=1&t=7793

http://www.levergunscommunity.com/viewtopic.php?f=1&t=27410

This might be useful too.

http://www.chuckhawks.com/powder_burning_speed.htm
Click to expand...

The data I was commenting on from your previous post is good data, as long as the person reading it realizes that it's only relevant for rifle length barrels and does not directly corelate to shorter barrel lengths and small capacity cartridges that were the subject topic.
 
jethunter said:
The data I was commenting on from your previous post is good data, as long as the person reading it realizes that it's only relevant for rifle length barrels and does not directly corelate to shorter barrel lengths and small capacity cartridges that were the subject topic.
Click to expand...

Obviously velocity will be slower out of a pistol but according to my manual, as an example, 44-40 loads for various powders of the same grain give the same pressure whether it's shot from a pistol or rifle. Velocity is the only thing that changed.
 
41 Colt said:
Obviously velocity will be slower out of a pistol but according to my manual, as an example, 44-40 loads for various powders of the same grain give the same pressure whether it's shot from a pistol or rifle. Velocity is the only thing that changed.
Click to expand...
Exactly - velocity changes in a shorter barrel and that is my point - 2400 is a poor choice for .450 adams cartridge and will NOT match Unique for velocity in a 4" pistol barrel. Been there and proved it in the .450 and the .455 cartridges. You can't cram enough 2400 into a .450 adams case to get reasonable velocity in these cartridges - it's just too slow.
 
You must log in or register to reply here.
Back
Top Bottom