Chrono?

[Bookworm]

I've been reloading for a long time and I finally broke down and bought a chrono. Took it out for the first time today. The published speeds for the loads I was shooting were way off compared to what the chrono read except for my 257 weatherby. Is this pretty common? The loads were consistent from shell to shell, just that most of them were around 200fps slower than the book.

[dbllunger]

ABSOLUTELY....welcome to the world of truth versus fantasy!!!!!!!!!!!   You will find some that come close to the book depending on the book.  The closest I have found is the Hogden book because they use rifles instead of test barrels. 

[demontang]

 
When the 204 first came out my friend bought one and shot it though his crono. The factory loads claimed the 36gr bullet where going 4200 but where going 39XX. I shot my 22-250 though his crono and the 50gr nbt where going 390x man was my friend mad

[haugenna]

I've been reloading for a long time and I finally broke down and bought a chrono. Took it out for the first time today. The published speeds for the loads I was shooting were way off compared to what the chrono read except for my 257 weatherby. Is this pretty common? The loads were consistent from shell to shell, just that most of them were around 200fps slower than the book.

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The books are VERY optimistic on velocity and  VERY conservative on max loads.  Make sure you work up to max loads though.  Safety first. 

[Bigshooter]

I've been reloading for a long time and I finally broke down and bought a chrono. Took it out for the first time today. The published speeds for the loads I was shooting were way off compared to what the chrono read except for my 257 weatherby. Is this pretty common? The loads were consistent from shell to shell, just that most of them were around 200fps slower than the book.

.

The books are VERY optimistic on velocity and  VERY conservative on max loads.  Make sure you work up to max loads though.  Safety first. 

+1

[WA Redneck]

We call them high speed lie detectors.

[demontang]

  thats a good one.

[dbllunger]

We call them high speed lie detectors.

Could not be said any better.  The archery guys need these also as they have the same thing going on. 

[Bofire]

30 years ago I had a Rem 700 7mm mag. I swore that rifle was the killing, high velocity machine of the world. Shooting my max 160 grain load at 3150 the book said , shot it thru a chrono 2825.
my factory load 270 was faster at 2960/130 grain.
To this date I have not shot a load that was as fast as the book, reloader or factory, said. Some are/were close, some miles off.
Carl

[Huntbear]

Most load data for the books and ammo companies is shot through a 26" test barrel.  You have to figure you lose almost 200 fps for ever two inches of barrel lost.  Plus, a test barrel will shoot loads faster than a rifle will.  Soooooo long story short, you are gonna be disappointed with any results you get from a chrony.  I always work up my loads starting in the middle, and creep my way up.  I chronograph them all as I shoot.  If I get real close to published velocities and the accuracy is there, I am good to go.  If not, I will switch powders and start over, until I get the load I want.   

In the case of my 257A.I. I am actually getting 25/06 ballistics, but I also long throated the barrel, so I could seat the bullets out where they needed to be. 

Velocity is not everything though, I have some loads for my .308 that are well below published velocities, but three shots cut the same hole at 100 yards, and are about dime-sized at 200 yards. 

[Big10gauge]

I like mine to measure velocity and standard deviation, as the latter is really the most important of the measures IMO.

[Jamieb]

Like most guys, when I first got a crony I was shocked at how slow my loads were.
With all the load testing I do anymore I couldn't live without my crony. Probably one of the most valuable tools in my shooting gear.