Chronographing loads

[Col. Batguano]

I want to chronograph some of my loads to find out exactly what sort of velocities I'm getting. I've never chrono'd anything other than modern guns and arrows before, and those obviously do not have patches around the projectiles. Questions;
Is there a risk that the readings will be off the patch instead of the ball?
At what range (from the muzzle) is it best to set it up?

 

[roundball]

Questions;
Is there a risk that the readings will be off the patch instead of the ball?
At what range (from the muzzle) is it best to set it up?

Mine came with 15' cables and recommended to set it up at the 15' length; Chronographed loads out of .45/.50/.54/.58cals and never had any unexplained readings or indications that patches caused any issues.
PS:
One thing I did at the beginning was to cover each sensor with a strip of 2" wide clear Scotch Packing Tape to prevent any possible effects of burning particles from landing on the sensors...folded the tapes ends over as tabs to grab and peel off to replace each year, etc. Just something I did, don't know if its 'required'.

 

[George]

My experience is like Roundballs, I set my screens 12'-15' from the muzzle and have had good results. Patches and smoke have never been an issue, to my knowledge. My chronograph is the CEDMillennium from Competitive Edge Dynamics, and the screens are down in a housing so that they cannot be contaminated by fouling, damaged by a patch or anything short of an actual bullet.

Spence

 

[Loyalist Dave]

I also put up a cardboard piece between the "screens" and the muzzle...well first I put up the cardboard, and shot a hole in it then used a piece of twine to mark the bullet path...then I put up the chronograph

Did this after a buddy damaged the top of his forward screen with a piece of patch...leather not cloth...and he and I both expected the patch to fly clear :shocked2: but it caught the edge and was moving fast enough to mess it up. We now use the side of a cardboard box and cut a little access space to be able to read the chrono... and the idea of the clear packing tape is a very smart one


LD

 

[roundball]

This is the PACT Pro set up at a little informal range I use...the sensors are in their housings at each end of the screen bar, but I still wanted the added measure of protection for their little glass or plastic covers, so added the clear tape.

 

[FishDFly]

PC/HC: brass balls, marbles, Chrony, bring on the sabots and brass hollow points.

Did they have Chronys is 1865????

 

[longcruise]

I ditto the distance between muzzle and chrono. With modern stuff, eight to ten feet is plenty, but with Bp it sits at 15. Your velocities are going to be slightly reduced, but some ballistic programs can correct for the distance. In any case, it's not much of a diff.

My chronograph is the Chrony and it has it's LED screen on the face of the actual device. If yours has that type of display, then patches can damage the LED screen. Had it happen to mine! And, if you do use a chrony, they make Plexiglas screen covers for it and you NEED those covers.

The patches don't affect your readings. By the time the patch gets to the chrono, the ball has long since passed through it.

Of course, chronographing your ML is strictly for those with enquiring minds and a healthy curiosity. Avoid using your device around backward thinkers, as you might find yourself tied to a pole surrounded by dry fuel.

 

[ohio ramrod]

%They did not have chrony's but they did have balastic pendulums. It was a known weight of wood that was hung beside of a calibrated chart so they could measure how far it would swing when shot into. It took some calculating but it was reasonably accurate for the time. :idunno: :idunno:

 

[George]

PC/HC: brass balls, marbles, Chrony, bring on the sabots and brass hollow points.

Did they have Chronys is 1865????

You might enjoy reading this about the work of Benjamin Robins in early 18th century.

http://arc.id.au/RobinsOnBallistics.html

Or maybe not.

Spence

 

[roundball]

Good one as usual Spence.
:thumbsup:

 

[19 16 6]

I got a reading of 670 fps once & it turned out to be the patch speed. I then put the crony further away.
O.

 

[FishDFly]

Both interesting, wonder if they were powered by 9 Volt or 2A batteries as in today?

 

[Loyalist Dave]

I don't understand what seems to be the implied criticism of wondering about muzzle velocity from a given load from a person's rifle or gun. I doubt most folks back two centuries ago, let alone in the CW, didn't know the formula for gunpowder, nor the ingredients, nor how to obtain them, let alone how to fabricate our own gunpowder...while many of us today have no problem with that information.

:idunno:

LD

 

[roundball]

I don't understand what seems to be the implied criticism

When you're right, you're right!
:thumbsup:

Unfortunately, a bane of public forums are the trolls, holier-than-thou attitudes, disruptive personality types, etc...systematically going up and down forum categories looking for threads to post negative disruptive comments in, no positive contribution made.

 

[azmntman]

I don't understand what seems to be the implied criticism

When you're right, you're right!
:thumbsup:

Unfortunately, a bane of public forums are the trolls, holier-than-thou attitudes, disruptive personality types, etc...systematically going up and down forum categories looking for threads to post negative disruptive comments in, no positive contribution made.

Im glad that doesn't happen HERE! :rotf:

 

[Billnpatti]

Like marmotslayer, I have an Alpha Chrony. I didn't know the exact reason why it seemed to work better when I placed it at about 15 yards from the muzzle of my gun. I found that I had fewer bad readings with it that far out. I have a computer program that adjusts for the distance from the muzzle of the gun to the chronograph to give accurate muzzle velocities. I made a plexiglass cover to protect the sensors from burnt powder and now, everything works fine. My next move is to have it upgraded to one with a cable so I can place the chronograph at the chosen distance and get my readings at my bench. The upgraded chronograph will have a 15 foot cable but I am going to order an extra length of cable so I can set it further away than the 15 feet that the single length of cable will allow.

Why chronograph a muzzleloader when neither Ol' Davy nor Great grandpappy used a chronograph and they killed plenty of "bufflers" and "Injuns" without one? Inquiring minds just want to know. :haha: :hatsoff: Ignorance is bliss but knowledge is power. :v

 

[Maven]

Solar powered (wind would distort the readings).

 

[Jim C]

"Im glad that doesn't happen HERE! :rotf:

:rotf: :rotf: :rotf:

 

[George]

I don't understand what seems to be the implied criticism of wondering about muzzle velocity from a given load from a person's rifle or gun.

It seems inevitable that someone will object to the use of modern gear to investigate how our guns work. There can be many reasons for that, but one which seems common to me is a lack of understanding of the history involved. A very large percentage of shooters believe the old boys all, to a man, lived in a very primitive time, that they whittled all their gear out with a jackknife, wore nothing but animal skins and knew very little about the guns beyond how to load and shoot them. The fact that Isaac Newton had written THE book of the physics involved in the flight of bullets and anything else in 1687, and that Benjamin Robins had investigated the same in detail in the early 18th century is just not in their idea of the world at that time.

I understand where they are coming from, I understand the appeal of that way of looking at the old times, and I can't fault them for it, it's their choice. We all get to choose our own level of understanding. Too bad they never seem to extend the same courtesy to those of us with a different outlook.

Spence

 

[robinghewitt]

So it would be a pretty stupid idea for a body to mention it on here that he made chronographs professionally, I suppose? :idunno:

Just wondering, hypothetically, y'know :yakyak: