easy question?

[jamieorr]

I've been looking for muzzle velocities for various powder loads, and I've been finding quite a large variation between on-line tables. What's a good source for this information on-line? (Lyman gives a range from around 1300 to 1800 fps with FFFg.)

For reference, I'm shooting a 50 caliber rifle (Lyman) with 1:48 twist and a 28 inch barrel length, using FFg.

I'm posting this in "flintlock" because it the rifle is a flintlock and I don't know if there is a difference in velocities between cap and flint - it seems logical that some energy is lost through the vent/nipple.

This isn't essential information for my shooting but I want to use the ballistic calculator to figure the expected drop over different ranges.

Jamie

 

[Cowboy2]

My experience is that published load data velocities, be it with modern cartridges or blackpowder/substitutes, are often....lets call it "aspirational".

There are so many factors that go into velocity- barrel length, patch thickness and lubricant, roughness of the bore- that there really is no rule of thumb to go by. You can ask others what they are getting with X model rifle using Y powder and Z patch and ball combo, and that will be as close as you can get without running them over a chronograph. Personally, if its a real concern I'd buy a chronograph- they are pretty affordable and are handy little rascals to have around.

 

[Cowboy2]

For what its worth, at longer distances, I think you'll have to do a lot of trial and error regardless of what data you've got. A patched round ball has a ballistic coefficient only slightly better than that of a thrown cinder block. Once you get past 100-125yds, its bleeding velocity so fast that the importance of accurate range estimation rapidly overtakes velocity as the critical holdover factor.

 

[Grumpa]

I'd have to agree with Cowboy2. You can chronograph 2 "identical" guns from the same maker, same barrel length, same load - and get different results. They'll be close, but....

Using charts, magazine articles etc. will only give you a guesstimate of what your rifle is doing with your loads.

 

[ohio ramrod]

Charts are at best "better than a guess". If you want to get serious, you'll have to use a chronometer. But if you are only worried about drop at ranges a day of bench shooting at the desired ranges will do the job, and is a lot more fun than setting up a chronograph. :idunno: :idunno:

 

[jamieorr]

But if you are only worried about drop at ranges a day of bench shooting at the desired ranges will do the job, and is a lot more fun than setting up a chronograph. :idunno: :idunno:

True, but I'm stuck here at the computer today and got to poking around different sites, so....

 

[Zonie]

As the others have mentioned, there are so many variables, a velocity for any given powder/ball/patch/lube combinations could never be made.

Although it has a few questionable bits of data, for just generally approximating the expected velocity's of a powder/ball or bullet load, Lyman's BLACK POWDER HANDBOOK & LOADING MANUAL is (IMO) a good source of the information you want.

It doesn't cost much and sometimes it can be found at a used book store for even cheaper prices.

 

[Pete G]

You can get a pretty good chronograph for about $100 which will perform admirably until the first time you shoot it.

 

[Rifleman1776]

I want to use the ballistic calculator to figure the expected drop over different ranges.

There are too many variables for the charts to be anything but a very general guide.
The only way to determine the drop for your rifle and load is to shoot it from the bench. Put up a large target at 100 yards with a mark at the top. Sight on the mark and shoot. If the point of impact is six inches low, that's what your gun will do.

 

[George]

Although it has a few questionable bits of data, for just generally approximating the expected velocity's of a powder/ball or bullet load, Lyman's BLACK POWDER HANDBOOK & LOADING MANUAL is (IMO) a good source of the information you want.

I agree with Zonie on this. I've used the Lyman manual extensively for doing just what you want, calculating drop using ballistic calculators. I find that I get consistently reliable results feeding Lyman's velocities into them. I also use a chronograph, and have always found their published velocities a close approximation of my measured ones.

If you are interested in playing around with black powder ballistics, you won't go wrong with that manual.

Spence

 

[longcruise]

You can get a pretty good chronograph for about $100 which will perform admirably until the first time you shoot it.

Yes, and you don't have to actually shoot it! I hit the LCD screen on my Chroney with a patch and knocked it out. Manufacturer repaired it relatively inexpensively. The also informed me of the Plexiglas covers they make for both sensors.

 

[jamieorr]

Thanks everyone - A chronograph would be nice, and the Lyman book is on the wish list, but this new hobby (addiction?) has run me over $800 so far (who knew there were so many accessories!). I think I'll just have to pick the empirical option and go shooting. No more spending for now.

Still, a peep sight would be nice, and a mould would save money in the long run - and then there's the spotting scope....

Jamie

 

[azmntman]

Save all your coins (except pennies). Every day I empty pockets into the jar, never spend change just save it. Slow but works? I have over $200.00 in about 6 months....my gun fund. Think I'll get a .40 barrel now.

 

[longcruise]

Casting roughly 1300 balls instead of purchasing will pay for the casting equipment and the chronograph (give or take, it depends on caliber).