1855 chiappa chronograph

[mitchz]

This is a new Chiappa 1855 .58 caliber rifled musket I bought through Cabelas. I shot it though a RCBS chrony at 18 feet instead of the 10 feet I normally shoot everything else through, I found that at 10 feet once you get 90 to 100 grain in a .58 the percushion blows over the chrony and if you anchor it it gets lots of powder burns. Any way this was done at about 8000 feet in the colorado mountians On a dry 80 degree day. All are loaded with Pyrodex RS. All were loaded with .10 lubed patch and I ran a patch dampend with borebutter after loaded. If you notice I maxed out at 125 grian thats all my shoulder could do.
Grain Feet Per Second
75 1555
85 1717
95 1746
105 1863
115 1904
125 1987
Hope this helps you guys. I also have numbers from 1858 stianless buffallo and 1847 walker if you are interested let me know and I will post.

 

[Dellbert]

Hay mitchz. Thinks for posting these numbers from your chrony. I'm a newbe to the .58 cal rifle and can use all the help and tips I can get. I have a Walker that I've only put 18 rds through so yes please do post the numbers you have gotten so I can try out some loads for this pistol. I'd like to find some good loads to work with .45 cal lead pistol bullets if you have the numbers for that in the Walker.

 

[arcticap]

Any way this was done at about 8000 feet in the colorado mountians

Holy cow, 8000 feet!
Where I live the altitude is only about 200 feet.
I suppose that the thinner air at the higher altitude really increases the velocity.
I wonder by how much?
That's all very interesting nonetheless.

 

[mitchz]

Arcticap: I'm in Colorado Springs It's listed at 6035ft but most of town is around 6500. The place I normally shoot is 30 miles north west at 8000ft and when it's hot I go 30miles striaght west and shoot between 9to 10000ft the top of that trial is at 12000 but not a good range on the top. As for the velosity it's very close. I reload .308 .357 and shotshell and I am always within 50 fps of what the charts say for sealevel.

 

[mykeal]

The place I normally shoot is ... at 8000ft and when it's hot I... shoot between 9to 10000ft ...I am always within 50 fps of what the charts say for sealevel.

That suggests to me that your chrono is in desperate need of calibration. At 8000 feet on a standard day (59 deg F at sea level) air density is 78% of that at sea level, which would be the calibration standard for your chrono. Velocity at altitude is inversely proportional to the square root of density, so your chrono appears to be in error by at least 12% (slow). I wouldn't trust it.

 

[Johnson1631]

According to information posted Mykeal is correct. Johnson.