We hear it all the time. Short actions are inherantly more accurate than a long action rifle. Which is generally true. BUT.............. it seems that the vast majority of the opinions on this is that the bolt being shorter and the receiver being shorter make them more stiff and this is conducive to better accuracy.

Now before I get started explaining my thoughts about this let me say that I do know why short actions of the same caliber are generally more accurate. I has everything to do with the shorter powder columns and the more moderate velocities generated.

When you look at a bolt action rifle the bolts lugs are on the front of the bolt. The lug seats are inside the front of the receiver. The recoil lug is in front of both of the other two. So being that the recoil is transfered to the stock before it ever gets past the recoil lug seats what differance could it possibly make how stiff and rigid the rear of the bolt and receiver are? They don't do anything but just sit there looking pretty until you cycle the action.

So why do the majority of folks always say that short actions are more accurate because they are more stiff?

Anyone else have an opinion on this?

The stiffest action I've seen is the Remington 788, it has a minimum of cuts of the smallest posseble size. A single column magazine, and just an opening for ejection, not the whole top of the action being cut away. It is made of heavy tubing, and the barrel seats a whole lot deeper than normal. It has the same internal barrel seat the Mauser 98 has, but with no extractor cut, and it is a short action. Additionally it has a very fast lock time. How come every precision shooter doesn't have one?

I like only ONE short action,and thats a .308,I only like long actions.

I am not going to say more accurate, but, but much easier for me to work up a load. I beleive its the powder ignition mostly. I am sure other factors go into play. I can almost watch a chrony and know which load is the best iwith a 308 or 7mm-08. Std dev go down down, then up, up as the load goes up. With my 300RUM or others like that, its hard telling.

I agree. I've never heard that short actions were more accurate, only faster due to the shorter bolt throw. And to be honest, it's hard to agree that a few milli-seconds is going to make a difference. Just my humble opinion.....

Short tube is going to be stiffer then a long tube..now whether 1/2" makes a difference that is hypothetical. It would also have faster locktime as some one else pointed out.

It’s rigid by the very shortness of the action itself. It’s similiar to bending arrows that are equal in every way except for length. For an example, one is 24” and the other is 30”. The 30” arrow will be easier to bend. Since the shorter action is stiffer it will provide a better support for the barrel that's screwed into it and the barrel will flex less. I know most benchrest guns have sleeves installed over their short actions, to make them even stiffer. So, it must improve accuracy. Finally, the unbelted case design means head spacing will be on the shoulder, which is more exact than head spacing on the belt of a belted cartridge. This also increases accuracy. However, the difference will not be seen in all rifles.

If we look at it from a pure machine design aspect this becomes a bit more clear for a couple of reasons.

If we study how loading occurs once the firing pin has fallen we see a couple of things. Begin by examining how the whole system is loaded once the ignition occurs... the inertia of the firing pin acting on the case for sake of argument is a negligable force.

Once the round "goes off" the you have a radial pressure resulting in a hoop stress of the barrel. at the same time you have a linear force pushing on the bullet, chamber (assumption bottle neck cartridge) and the bolt face (assumption that headspace is correct ). Assuming both the radial stress and the linear occur simultaneously we can deduce that the bolt face is acted upon and barrel channel under chamber first. The whole action flexes to some point due to barrel expansion and the bolt thrust tries to seperate the threads. The bolt thrust being the major line energy transmission thus transfers the "recoil" force to the barreled action and thus to the stock and finally shooter. The recoil is transmited through the bolt, to the bolt lugs which are an integral portion of the receiver. Since the stock is clamped (thru bolted) to the receiver the friction between the two sets off movement of the stock. This gives way to some minute amount of movement between the action screws and recoil lug then loaded against the stock.

Now considering this scenario lets look at some of the geometry within the system. Right off you have a moment in the system which flexes the action. Barrel lifts and naturally causes deflection of the stock downward. The action screws stretch to some extent and the tang is forced against the stock. Exaggerated the action would look like a U. Naturally a shorter moment arm (receiver) would be stiffer and deflect less. Next is the relationship of the bolt to the recoil lugs and bolt face to the actual case. If none of these are square you don't evenly transmit the energy down the C/L of the action. This also results in a bending moment on the receiver. IF both recoil lugs do not have contact (as say many remingtons don;t) and the bolt face is not square to the head of the case the bolt will be loaded in a moment. Now assume both recoil lugs are in contact but still a non square bolt face... the case will put pressure off center and still result in a bending moment , using the bolt as the lever arm.

One thing that a long action has going for it is the length of the bolt and distance between the raceways. For a given clearance a bolt will have a greater angular defection as the supports are moved closer together. Once the sear falls away and the firing pin falls there is nothing but the bolt face relationship to case head and bolt lug to receiver lug relationship holding the bolt in alignment.

In the case of attempting to stiffen a long action, or even a short a one piece scope base is beneficial if securely bedded to the receiver.

Reckon this was a quick and dirty synopsis and there are many more factors to take into account.. but the main point is that a short action will deflect less due to length and stiffness for a given load imposed in the system.

Jamie

Well all of that would be a great answer if the tang was actually taking any recoil. It's not. The recoil is transfered through the recoil lug to the stock which is in the front of the receiver. If the stock isn't fit properly and the tang does transfer any recoil to the stock you end up with a split stock right behind the tang.

Basically every part of the receiver and bolt behind the front ring just sits there during firing.

Don't assume. The chamber preessure has to build inside the case before the bullet starts to move. Only after the pressure has signifigantly risen is the bullet released fron the case mouth and begins moving to the lands of the barrel. And then only after the pressure has risen to 60,000 psi +- does the bullet continue down the barrel.

The radial forces in a chamber happen way before the linear forces do. As "way" as you can get in a milisecond.

The action screws do not play any part in the recoil of a gun. They are only there to keep the firearm inside the srock. There is signifigant clearance 360 degrees around them so that they do not contact any part of the stock.



A short action does not necessarily have a faster lock time. The firing pin is smaller and lighter yes but the spring is also smaller and weaker than a spring in a long action firearm. Thus canceling out the lighter firing pin. They both have to be cocked the same distance to get sufficient momentum to dent the primer.

I have also heard more accurate but at what range,between my 300 WSM and my 300 Ultra mags,the diffrence I could not tell under normal hunting conditions or off the bench shooting side by side out to 400 yds,when you have a miles of stubble feild behind your house I shot both to see how far they would go befor they hit dirt and tell you what,they went farther than I can kill anyting accurately.

As for short vs long,there is probaly some truth due to better groups to a more solid action and less metal to flex under presure.

BBJ