Justify short action accuracy over long

[MrClark]

I really want to see the actual evidence on the long action vs short argument in the accuracy department.

To me its a stupid argument,
Considering .308's and .300 WM's two differing action lengths but their both considered accurate enough for military use.
Long action vs short once the bolt closes on the chamber the cartridge is (in my opinion) more centred in a long action, theres less angle for play/mis alignment. I know short actions win more matches, but is that based on lessened recoil or actual action size?

[deye243]

yep it's all bs for me too.

unless we are talking bench rest type of accuracy ,

i have seen plenty of LA rifles shoot 1/2MOA or better .

[Tiiger]

In theory... Shorter action = less flex = less variation = more accurate.

If an engineer compared things in his CAD software I'm sure it stacks up.

Real world evidence though... Mix the theory in with the other 100 factors of shooting and accuracy and it's the lowest of priorities IMO. Possibly not measurable, and able to be 100% attributed to the action length in a shooting scenario instead of a computer one.

I've also never seen a clear real world demonstration showing shorter is measurably better.

[Chronos]

I really want to see the actual evidence on the long action vs short argument in the accuracy department.

To me its a stupid argument,
Considering .308's and .300 WM's two differing action lengths but their both considered accurate enough for military use.
Long action vs short once the bolt closes on the chamber the cartridge is (in my opinion) more centred in a long action, theres less angle for play/mis alignment. I know short actions win more matches, but is that based on lessened recoil or actual action size?

i don't think military use is any guide to a cartridge or actions accuracy, while a military sniper strives to hit a mans chest at 600y an F class or benchrest shooter is trying to put 5 shots into a couple of inches at the same ranges, infact to be competitive at an international level you'd probably have to have the skill and equipment to put 5 shots into 1" at 600y

I'm not sure action length has any measurable effect on accuracy but i'd be interested to see evidence either way but it would seem a shorter fatter case seems to be more accurate than a longer narrower case, take short range benchrest as an examoply. .222 used to rule at 200y with fast twist barrels and heavy bullets they were hard to beat .then along comes 22PPC then 6PPC. similar case capacity and similar weight bullets but they soon became the standard for accuracy at 100 and 200 yards and still are. Groups in the low teens and under are common, by low teens i mean in the order of .010" at 200y

at the middle ranges the BR variants seem to dominate, shorter than a .308 case but running at higher pressures they have been a top performer out to 600m or so. maybe a lot has to do with the lack of recoil and focus required to read the conditions at those ranges, who knows?

there seems to be a trend at the 1000y ranges toward shorter cases now, more and more WSM's are being built on high end single shot actions that may be replacing win mags in peoples safes



Chronos

[bobnob]

I think you refuted your own BS-call by acknowledging that short actions win more matches. What other evidence do you need?

Whether its stiffer rigidity, less recoil, shorter more efficient powder columns or other such guff, what matter do any of them mean if short actions win more matches?


I'm not trying to get a rise out of you by the way Clarkie. I agree there's a lot of silly argument over this stuff.


Good technique and precision assembly of firearm and ammunition are the biggest factors.

[Rakk]

Considering .308's and .300 WM's two differing action lengths but their both considered accurate enough for military use.

If you're hunting that's a reasonable argument. Hitting the vital zone is 'accurate enough'.

That's a whole different ball game to competitive shooting though.

[Deco]

.....acknowledging that short actions win more matches. What other evidence do you need?

Whether its stiffer rigidity, less recoil, shorter more efficient powder columns or other such guff, what matter do any of them mean if short actions win more matches?

Seems to me there would be an easy way to test.

There is no point comparing two different cartridges with different action lengths as you're introducing other factors.

But take a cartridge like the 6mm Dasher in a short action. If someone made the same rifle in a long action or in a magnum action chambered for 6mm Dasher as well you could see with difference the action length alone contributes. Shoot the two side by side and see what's what.

Guess it won't happen though. I don't think anyone would invest the time and money just for the sake of curiosity.

[bobnob]

Interesting point Deco.

[deye243]

Seems to me there would be an easy way to test.

There is no point comparing two different cartridges with different action lengths as you're introducing other factors.

But take a cartridge like the 6mm Dasher in a short action. If someone made the same rifle in a long action or in a magnum action chambered for 6mm Dasher as well you could see with difference the action length alone contributes. Shoot the two side by side and see what's what.

Guess it won't happen though. I don't think anyone would invest the time and money just for the sake of curiosity.

i'm part way through this kind of thing.

building a short cartridge on a long action will let you know how it go's .

[brett1868]

Deco is on the right track and that's probably the only true test in this case. Action length vs. accuracy I don't think is a relevant comparison though case length would probably be more a factor. Longer case, more "slop" in the chamber and higher variation of projectile to bore alignment. Just my thoughts, no hard science or knowledge on my part, I have small to XXL action riles and can't pick any real difference in accuracy. The .204 has shot .3 MOA as has the .300 Weatherby Mag, I've even managed .5 MOA from the 50's and .416.

[1290]

There are far too many variables to unequivocally answer the question of what or which is best for this that or the other.

Comparing one shooter with a particular setup to another, the same, is futile or at least difficult unless both tested on a machine rest, indoors, where all or most external factor are eliminated.

Are the short and long actions chambered in the same round? Normally a short round/short action, long to long....

Chamberings themselves have many variable, before you ream it into a barrel.. freebore, no freebore length of freebore, diameter of freebore, is it oversized to proj? undersized, length of proj to freebore, to bore.... will a relatively short proj cant while engaging rifling?...does it engage the rifling sufficiently before leaving the case?

rifling Leade angle, sharp or loooooong take up of rifling...

....and you havent left the neck of the case yet!!

Will a short case give a more consistent burn? But will a strong primer engulf the whole powder column and counter the consistency issue?

Are the accuracy advantages in the short target rounds mostly on account of the higher quality actions, barrel, reloading processes, projectiles and more consistent loadings?

On account of the action length,
A longer action compared to the same make in a short, will may less inherent stiffness (that you would probably never perceive with the naked eye when firing), Does the action have a small port or all of the top steel missing?? and the combination of the action and stock? more variables...

Does the action use a fixed bolt head or floating? -

Common Rem type fixed:
If the luggs are not perfectly aligned, bolt to action, concentrically along the centreline of the action, then there WILL be a moment generated with the impulse of the fired round. That means a rotating force transmitted BY the bolt resulting in a sideways force at the back end of the bolt where it contacts the action. This force may be unpredictable in resulting action flex, stock flex barrel movement....

So what... you say?
a Longer action will result in a reduced 'sideways' force compared to the shorter action.

If all absolutely aligned there is no twisting of the bolt shaft...

Or if the bolt face is isolated from the bolt shaft, enter Savage. Within a tolerance of out-of-alignment; there will no twisting/rotating forces transmitted through the bolt to the action...

Then theres another big one; the taper of the case and its adhesion to the chamber wall upon firing.... this directly relates to the thrust and resulting actions through back through the bolt and action....

There is the barrel. Is it cut, buttoned or hammered, has it been fully stress relieved....
Has the chamber been cut to spec, bit tight bit loose...

So.....its difficult to answer which long or short is best....but once you've chosen your round, use an action length to suit, and no longer than necessary

[Deco]

building a short cartridge on a long action will let you know how it go's .

Well there you go, someone can be bothered

[Khan]

Just my 2 cents but pick the cartridge you want, not an action length, and get shooting with it.

[deye243]

building a short cartridge on a long action will let you know how it go's .

Well there you go, someone can be bothered

long pills and short actions don't get on too well in the mag department .

[Sender]

So.....its difficult to answer which long or short is best....but once you've chosen your round, use an action length to suit, and no longer than necessary

Easy to answer!

Answer = Who cares? Buy rifle. Shoot!

[1290]

Easy to answer!

Answer = Who cares? Buy rifle. Shoot!

You mean..... ALL OF THEM!

[Sender]

I'd be happy with that