Chrony and Ballistics Tables save ammo

[petemi]

I know a lot of guys don't use either one.  I'd be lost without them.

I find a load I want to try and make up a batch.  I run three rounds through the chrony and average the three velocities.  These can be quite different from published data.  Next I go to the ballistics calculator and enter my information, BC, weight, velocity, temp., elevation, wind, etc.  I usually set my zero range at 100, 200 and 300 yards and the max range at 300.  I set the interval at 5 yards. 

The data comes up with the maximum point blank range and the sight in range for maximum point blank.  I then plug the max point blank sight in range into the formula and rerun it.

The table will show the bullet crossing line of sight or zero at two points, close and long range.  In a recent example, with a .243 it showed an inch high at 50 yards was on again at 291.  I sighted in at the one inch high at 50, and with only a few rounds was dead nuts on at 300.

This works for me.  If anyone has anything to add or modify, please do.

Pete

[mechanic]

Looks like you covered it Pete!  Now if all of us were steady enough for those 300 yd. shots, all would be great!
 
Ben

[petemi]

Ben, I let the bench bags do the work.  I nestle it down snug without wobble and all I gotta do is touch the trigger    I forgot to mention, with a new scope, I boresight, plunk a couple at 25-30 yards, adjust and then go to my close range zero.

Pete

[Blackhawker]

I use a bench bag with a "trench" down the middle and it holds VERY steadily.  However, I sometimes find that some break open single shots do NOT like this manner of shooting.  My T/C 30-30 and my W&H 38-55 are a little picky when it comes to being rested and I need to turn that bag 90 degrees and shoot across the trench and rest the rifle at a specific location to nail down any kind of accuracy. 

It's a little off subject but I thought I'd mention this in the case anyone tries a bag and gets poor results.  As most single shot users know, some single shots have to be rested in a specific area in order to get reproducible results.

[petemi]

I rest all my Handis on a V bench bag right up against the trigger guard and a second one under the butt stock.  They also all wear "O" rings.

Pete

[D Fischer]

I love my cronograph and the blastic table's I get from it. I think I was a better shooter when I wasn't being so finicky about velocity's and trajectories. I did more practice shooting, more range estimating and more getting closer.

[LaOtto222]

I do it slightly different. I guess it goes back to my reloading days before I could afford a chronograph. They were the price of a fine rifle or shotgun back then. Anyway, I look at the data and then decide on a load or three. When I find the load that shoots the best, I then run them over a chronograph and extrapolate the bullet drop tables.

Good Luck and Good Shooting

[Muddyboots]

I prefer shooting at least 10 rounds through my Prochrony, record the average and then also calculate the standard deviation of the 10 velocities. This tells you a little more on consistency of the load than just an average. Really not that difficult if you have Microsoft Excel, just use their template, drop in velocities and spits out SD.


Something I've been doing to test out a powder is to set the bullet jump  (usually I start at 0.020), select the powder, load five rounds for each 0.5 incremental charge up to max. In some cases, I may never reach max depending upon visual pressure signs, or just crummy down range results. I differentiate the 0.5 gr loads by color coding the primers which I also record on my datasheet. This also allows me to correlate case inspections to actually load data.


I use a target (100 yards typically)  I developed for recording results behind my load data sheet. Feel free to use and abuse.
Muddy

[Muddyboots]

Oh yeah, one more for the road. I use RCBS program which calculates about everything for any bullet out there. You can manually add bullets as well. One aspect which would be an improvement which I submitted was for a better LOS by actually showing the LOS on the trajectory graphs.  As stated the LOS is a neat ballistic calculation that shows you the first LOS which is a number you need to keep since this yardage can be used to sight in at the lesser distance which allows you to sight in at the first LOS and be certain to be dead on at the second LOS.
Muddy

[YRUpunting?]

Is there a particular website or program you use for the calculations?

[cwlongshot]

Just a quick comment because its a bit more of an issue with H&Rs because of the hammer.

A bullets trejectory based off velocity uses a theoreticle scope height of approx 1.5" over the bore. This is to the center of the reticule. NOT the top or bottom of the scope.  As many people simply mount in highest or "iron sighter" rings these numbers are useless to you.

Mount your scope as lo and centered over the note as possible.

If you can look at trejectories of open sights compaired to a scope you will see what I mean. The iron sights make a given bullet to appear flatter in trejectory. 

This lo scope mounting is a BIG thing if you expect long range accuracy. Have you ever seen high or shoot thru rings on a precision target rifle? NO and you will not either!

Great post Peter!!

CW

[Muddyboots]

I use RCBS load program:


https://shop.rcbs.com/WebConnect/MainServlet?storeId=webconnect&catalogId=webconnect&langId=en_US&action=ProductDisplay&screenlabel=index&productId=3672&route=SPECIALTY


One of the nice aspects of it is the continual updating that is available. Just like cwlongshot stated, you can adjust the scope height specifically for your firearm and scope ring height which translates to more accurate calculation.


Standard deviation is simple Excel calculation built into program.