The Accurate Reloading Forums
How much difference would you expect?

This topic can be found at:
https://forums.accuratereloading.com/eve/forums/a/tpc/f/6711043/m/6641023091

26 June 2013, 22:34
308Sako
How much difference would you expect?
If shooting the same bullet, let's say a 70 grain Nosler Ballistic tip in a .243 Ackley vs a 6 XC. What sort of gain or loss would you expect from top end equal pressure loads






Member NRA, SCI- Life #358 28+ years now!
DRSS, double owner-shooter since 1983, O/U .30-06 Browning Continental set.
27 June 2013, 09:18
Luckyducker
I don't know about a 70 grain bullet, but according to a resource I found a 107 grain will run +/- 95 ft/sec faster from the 243AI. That is measured from two rifles only and therefore is not a very broad spectrum to draw solid facts from, and they were loaded by two different hand loaders. Also two different barrels may not shoot equal velocity even when loaded identically.


Dennis
Life member NRA
27 June 2013, 15:59
TX Nimrod
The 6 XC factory load will send a 100 grain bullet out the muzzle around 2950 fps. The AI will beat that, by how much depends on the chamber pressure.

http://www.norma.cc/sv/Produkter/Jakt/6XC/Oryx/
.
29 June 2013, 16:02
Bushchook
Usual to expect 1% velocity increase for every 4% increase in case capacity with all else being equal. Found this to be a good rule of thumb when comparing loads in my 2 x .243AI's to the standard .243.


The hunting imperative was part of every man's soul; some denied or suppressed it, others diverted it into less blatantly violent avenues of expression, wielding clubs on the golf course or racquets on the court, substituting a little white ball for the prey of flesh and blood.
Wilbur Smith
29 June 2013, 20:40
308Sako
quote:
Originally posted by Bushchook:
Usual to expect 1% velocity increase for every 4% increase in case capacity with all else being equal. Found this to be a good rule of thumb when comparing loads in my 2 x .243AI's to the standard .243.


Interesting rule of thumb there, thanks...

I'm experiencing a bit the opposite, however the sample of 2 is way to small to mean a thing.






Member NRA, SCI- Life #358 28+ years now!
DRSS, double owner-shooter since 1983, O/U .30-06 Browning Continental set.
30 June 2013, 19:13
Bushchook
quote:
Originally posted by 308Sako:
quote:
Originally posted by Bushchook:
Usual to expect 1% velocity increase for every 4% increase in case capacity with all else being equal. Found this to be a good rule of thumb when comparing loads in my 2 x .243AI's to the standard .243.


Interesting rule of thumb there, thanks...

I'm experiencing a bit the opposite, however the sample of 2 is way to small to mean a thing.


That isn't a rule of thumb that I invented. It can be applied to cartridges of all calibres, so if you're experiencing the opposite then there are likely to be other factors at play.


The hunting imperative was part of every man's soul; some denied or suppressed it, others diverted it into less blatantly violent avenues of expression, wielding clubs on the golf course or racquets on the court, substituting a little white ball for the prey of flesh and blood.
Wilbur Smith
23 July 2013, 11:11
Saeed
quote:
Originally posted by Bushchook:
quote:
Originally posted by 308Sako:
quote:
Originally posted by Bushchook:
Usual to expect 1% velocity increase for every 4% increase in case capacity with all else being equal. Found this to be a good rule of thumb when comparing loads in my 2 x .243AI's to the standard .243.


Interesting rule of thumb there, thanks...

I'm experiencing a bit the opposite, however the sample of 2 is way to small to mean a thing.


That isn't a rule of thumb that I invented. It can be applied to cartridges of all calibres, so if you're experiencing the opposite then there are likely to be other factors at play.



And like all rule of thumps, you will get occasions where it does not work.

I am not sure why, but have an idea that it might be due to the differences in barrels.

I had 5 identical Mannlicher Luxus rifles, all in 270 Winchester, and Norma 150 grain SP ammo.

We got about 150 fps difference in velocities between the fastest and slowest barrels!!??

Also, had a number smaller case cartridges - 300 RUM against the 30-378 Weatherby - that gave faster velocities.

Actions are just as individual too.

We have had some rifles that showed signs of high pressure with starting loads.

Other rifles would take several grains more powder over book maximum.


www.accuratereloading.com
Instagram : ganyana2000
23 July 2013, 22:14
wasbeeman
My best rule of thumb comes from the Hornady load book: each rifle is unique and generalizations should be made with circumspection. Smiler


Aim for the exit hole
24 July 2013, 08:22
Atkinson
Maybe some humans can tell the difference but I doubt that any animal could. As to trajectory it would be miniscule in the field...Usually the case in most of these discussions.


Ray Atkinson
Atkinson Hunting Adventures
10 Ward Lane,
Filer, Idaho, 83328
208-731-4120

rayatkinsonhunting@gmail.com
03 September 2013, 01:18
DM
And then, some bbls are just plain "faster" or SLOWER than others, usually for some unkwown reason...

DM
06 September 2013, 02:24
jørgen
So mutch guessing and spekulations.
There is no magig in why some barrels are faster or slower than others.
It all comes Down to internal dimentions, (boring dimentions, rifeling dimmention, length and angel of throat, eventual freebore, and chamberdimentions. Surfacequality also influence.
Often a pretty rough lapped barrels (gritt 180)(if the lappingroughness follows the rifeling) produces higher vel. than a highly polished barrel.
A large number of 6.5x55 barrels tested by Norma shoved thar systematically lapped barrels produced 40-140f/sek, higher vel. than in other wise identical hammerforged barrels. The higher vel. was acheved without increase in presure.
13 October 2013, 16:57
mmassey338
Just an interesting fyi:
The 'rule of thumb' has been said to derive from the belief that English law allowed a man to beat his wife with a stick so long as it is was no thicker than his thumb. In 1782, Judge Sir Francis Buller is reported as having made this legal ruling and in the following year James Gillray published a satirical cartoon attacking Buller and caricaturing him as 'Judge Thumb'. The cartoon shows a man beating a fleeing woman and Buller carrying two bundles of sticks. The caption reads "thumbsticks - for family correction: warranted lawful!"