Chronograph MV results

ROE224

Well-Known Member
Gents,

On analysing the MV of a 20 shot string, how much deviation would you expect between shots.
What would be an acceptable tolerance of the batch before you would question your reloading technique.

Cheers Aye
 
Slngle figures is what your after for shooting longrange,20fps is more common, you have got to be real fussy to get single figures
 
Gents,

On analysing the MV of a 20 shot string, how much deviation would you expect between shots.
What would be an acceptable tolerance of the batch before you would question your reloading technique.

Cheers Aye

Almost impossible to say from this vantage point. I have seen good CF rifle loads in 308 with as little as 13 fps spread for 20 shots but this was ammo loaded to exceptional standards using new brass of the same LOT, sized and prepped identically. IT is noteworthy that the load with this brass was not the most accurate tested that day. A load with about 34 fps spread was.~Muir
 
If you want to be scientific about it then plot each batch on a graph. The spread on the vertical and the powder measure on the horizontal. If you record at sensible intervals you will get a sine wave with each 'sweet' spot visible.
 
I like to get a good load myself. (see 18" 308 loads thread) But to be honest if 3 or 5 bullets hit a group under a inch I'm happy. Nothing wrong with all this science etc and great if you enjoy it. I much rather go stalk a deer though. Even better if I manage to shoot one. Happy loading.
 
I like to get a good load myself. (see 18" 308 loads thread) But to be honest if 3 or 5 bullets hit a group under a inch I'm happy. Nothing wrong with all this science etc and great if you enjoy it. I much rather go stalk a deer though. Even better if I manage to shoot one. Happy loading.

My range is in a large wood and I often get a stalk on the way in or the way out!

It's never time wasted! But there again you need time in the first place. Personally if I couldn't do a proper job of it then I would just shoot factory ammo.
 
If you want to be scientific about it then plot each batch on a graph. The spread on the vertical and the powder measure on the horizontal. If you record at sensible intervals you will get a sine wave with each 'sweet' spot visible.
Hi Tackleberry,

Don't know much about the reloading game yet, your quote is interesting.
Does the sweet spot location on the sine wave vary from barrel to barrel and calibre?
 
Hi Tackleberry,

Don't know much about the reloading game yet, your quote is interesting.
Does the sweet spot location on the sine wave vary from barrel to barrel and calibre?

I'm no expert and I haven't done this with enough rifles/caliber to be able to answer from experience but theoretically it will be different for every rifle, calibre, bullet combination.
 
And where in the sine wave is the sweet spot, at the outermost parts of the wave or at the mid line? It might be worth looking up the dan Newberrys ocw method of load development to see how these correlate with these sweet spots
 
Gents,

On analysing the MV of a 20 shot string, how much deviation would you expect between shots.
What would be an acceptable tolerance of the batch before you would question your reloading technique.

Cheers Aye

I'm looking for a Standard Deviation of 10 fps or less. Sometimes I'm achieving this, but more often I'm not. I've observed that my clean cold bore shot is consistently slower than subsequent shots. This isn't an issue at stalking ranges, but is an issue on paper at longer ranges. You need to form a view on what your clean cold bore shot does.

This article is an interesting read - The Rifleman's Journal: Ballistics: Statistics for Rifle Shooters

A good chronograph is essential - March Scopes MagnetoSpeed Chronograph I wasted a lot of time last year before I got this gadget from Gary.

Regards

JCS
 
Last edited:
I'm looking for a Standard Deviation of 10 fps or less. Sometimes I'm achieving this, but more often I'm not. I've observed that my clean cold bore shot is consistently slower than subsequent shots. This isn't an issue at stalking ranges, but is an issue on paper at longer ranges. You need to form a view on what your clean cold bore shot does.

This article is an interesting read - The Rifleman's Journal: Ballistics: Statistics for Rifle Shooters

A good chronograph is essential - March Scopes MagnetoSpeed Chronograph I wasted a lot of time last year before I got this gadget from Gary.

Regards

JCS
Hi JCS

Your ballistic article will take a bit of digesting, watch this space!!!
Have I made an error on purchasing the super chronograph?
Cheers Aye
 
Back
Top