Tried out my new chronograph yesterday!

[oldracer]

I got one of the RCBS chronographs last weekend at the gunshow in Delmar CA and gave it a testing yesterday. Works really well and I found my 357 cased wadcutters were within 10 to 12 fps of each other. I had loaded these on the new Lee Loadmaster I bought a short while ago. The spread in some older 38 spcl wadcutters that I loaded 9 months ago with the single stage press was higher, some were 30 to 40 fps off. I also tried some 40 S&W loads I did and they were nearly all exactly the same and were within 10 fps of a box of factory ammo I had.

For fun I also tried some bulk Federal 22LR rounds in a Ruger Single Six and they were all within 10 fps and slightly higher that the same ammo in the Sig 226 with the 22LR top on it.

Anyways, it is a really cool toy and it gives me an excuse to do even more shooting!

 

[Erich]

Oldracer, I'm glad to hear that you're finding it a helpful and interesting tool. I love the feedback that a chronograph provides . . . trying to handload without one is like homebrewing without a hydrometer - one can certainly do it, but that would be missing out on essential and useful information.

(By the way, I'm aware that this post underscores how I'm a giant nerd in two hobbies. )

 

[PDL]

Ok, so I've got to ask since I don't have a crono yet, how many different distances are you measuring at. Or do you just set it up at one and call it good? When I'm doing some external balistics calculating or balistics coefficient, forget which, the software wants several velocity readings from different distances.
Thanks.

 

[Erich]

I only measure at one distance: about ten feet out from the muzzle.

 

[oldracer]

The RCBS instructions said about 10 feet from the muzzle unless you are shooting big bores like a 500 S&W or Desert Eagle or similar and then go to 20 feet to clear the muzzle blast.

 

[ajpelz]

Oldracer, I'm glad to hear that you're finding it a helpful and interesting tool. I love the feedback that a chronograph provides . . . trying to handload without one is like homebrewing without a hydrometer - one can certainly do it, but that would be missing out on essential and useful information.

(By the way, I'm aware that this post underscores how I'm a giant nerd in two hobbies. )

I can't think of two better hobbies! Nothing better than going to the range in the AM, and boiling up some wort in the PM.

 

[Erich]

Thanks, ajpelz. We ought to form a Desert SW BrewLoaders Club or something. I can't tell you how much bottlecapping reminds me of seating/crimping.

 

[PDL]

Thanks guys, I didn't want to hijack the thread and i've got 3 pistol permits in the works. So the chrono's on the list for later, but it seemed like a reasonble question

 

[oldracer]

The question about where to set the chrono is interesting and at 10 feet it gets the velocity leaving the gun. But what is the velocity where the target gets hit which when calculated with the bullet weight will give you the force on impact. I imagine the setup could be stationed about a foot from the target and get some interesting readings BUT a low shot would destroy the case which is also used to store all the pieces, etc and it is just plastic.

 

[Acorn1754]

Oldracer, once you know the muzzle velocity, obviously you know what bullet you are loading, therefore the drag coefficient is known (or can at least be easily found) and you can calculate what the velocity drop is at different distances based off of the muzzle velocity as several charts and tables exist for just that.

 

[oldracer]

The info about calculating velocity drop is right on the money. I am always curious if the numbers are always correct and I guess it is my nature to test things a bit more. I'll probably not do that as I am afraid I'd shoot the nice plastic case and also the cables are way too short.

 

[FrankD45]

If you are into ballistic calculation, go here Remington Shoot Ballistics Software and download the Remington Shoot software. I use it to calculate true muzzle velocity from a 10 foot reading but you can also calculate down range velocity.

I hope that helps,

Frank