Custom Actions - How Do They Enhance Accuracy?

[Phil3]

In the post http://forum.accurateshooter.com/threads/the-savage-barrel-system-costs.3907867/page-2, I wrote the following.

"...Please tell me, just what is it about a custom action that allows it to deliver superior accuracy vs a custom? What design attributes does the custom offer over a Savage that will allow the custom to print tighter groups? I am NOT talking about ease of operation. I concede the trigger is a plus for the custom. I am talking about both actions, cocked, loaded, locked down, same barrel (switched if possible), and fired. Is there something in the custom action that will steer that bullet to the target more accurately than a Savage? I really want to know...".

I did not get an answer on this, but still would like to know, regardless if the action is a stock Remington, Savage, Howa, Ruger, etc. I expect that in the area of barrel tenon threads, barrel shoulder face, bolt face, bolt lugs, etc., that the custom is superior in dimensions and tolerance. But just HOW does that translate into superior accuracy when a round is chambered in the barrel and then fired?

Phil

 

[dragman]

Better metal tighter tolerances. That is what it's about.
Look at a factory gun they might shoot a .1 group here and there but the custom will produce the groups on a more consistent basis.

 

[hogpatrol]

Action axes and surfaces precisely perpendicular to each other. That and accumulation of larger tolerances. Action built by X has to fit a barrel built by Y that has to fit a trigger built by Z. Then all that has to fit in a stock built by Billy Bob who's suffering from a hangover. That's your standard Remchesterage build and they all have to be able to function with every type of ammo known to mankind including the crap coming from foreign manufacturers.

 

[22BRGUY]

Maybe when a shooter is looking for the "why's" as to why the rifle will not group to his satisfaction, maybe it's peace of mind knowing the action is very or extremely unlikely to be the cause. With an action that may be out of square, have sloppy tolerances etc., the question in the shooters mind will always be there as to how much these things could be contributing to poor groups, and God knows there are countless things to consider already without the questionable action being thrown in. In a nutshell, peace of mind.
Also cases fired in an unsquared action can come out out of square and create reloading problems

 

[dcali]

They don't, really. My most accurate rifle is a Remington 700 that was cleaned up by a smith. Actions are more about gun handling, and general reliability/quality than inherent accuracy. Scope bases fit better, triggers are timed better, bolts are smoother, threads are cleaner. That sort of thing.

 

[HTSmith]

Tagging. This should be interesting.

 

[Tim Singleton]

Be happy with your savage and roll on. It maybe all your heart ever desires
For the ones looking for more than it can offer have to roll on themselves


What was the old saying ? If I have to explain it you wouldn't understand!

Seriously shoot your Savage for a while then build yourself a Bat or a Panda then you will know

 

[hogpatrol]

Tagging. This should be interesting.

Yes, I better break out the popcorn.

 

[savagedasher]

I never have seen someone change actions for accuracy. But I have seen a lot of barrels changed. Larry

 

[joshb]

While we're at it: Why is a Mercedes better than a Chrysler? Cause it's made better.

 

[Phil3]

Better metal tighter tolerances. That is what it's about.
Look at a factory gun they might shoot a .1 group here and there but the custom will produce the groups on a more consistent basis.

But HOW does a tighter tolerance in an action result in superior accuracy? For instance, if the action barrel threads are not directly in line with the bolt (let us say 1 degree), then the barrel will be slightly crooked on the action (1 degree). This means that the rear of the cartridge case is not sitting dead flat against the bolt face (cocked 1 degree). Fire the round, the case instantly swells to fill the chamber, sealing it, and the rear of the case will try to move rearward against the bolt face. Since in this example, the cartridge head is not dead flat against the bolt face, there will be a slight gap on one side of the case, between the case base and the bolt face. One might expect that loose side of the case to stretch a bit to meet the bolt face, thereby leaving the bottom of the case slightly cocked relative to the centerline of the case. Just HOW does this affect the accuracy of the bullet that left the case. Every cartridge will see exactly the same cocked barrel.

Action axes and surfaces precisely perpendicular to each other. That and accumulation of larger tolerances. Action built by X has to fit a barrel built by Y that has to fit a trigger built by Z. Then all that has to fit in a stock built by Billy Bob who's suffering from a hangover. That's your standard Remchesterage build and they all have to be able to function with every type of ammo known to mankind including the crap coming from foreign manufacturers.

As above, just HOW do axes and surfaces precisely perpendicular to one another (in the action) increase the accuracy of the bullet that is in the BARREL when it is fired?

Maybe when a shooter is looking for the "why's" as to why the rifle will not group to his satisfaction, maybe it's peace of mind knowing the action is very or extremely unlikely to be the cause. With an action that may be out of square, have sloppy tolerances etc., the question in the shooters mind will always be there as to how much these things could be contributing to poor groups, and God knows there are countless things to consider already without the questionable action being thrown in. In a nutshell, peace of mind.
Also cases fired in an unsquared action can come out out of square and create reloading problems

Interesting perspective, but I go about this in two stages. First, determine if a rifle component can possibly affect accuracy. The crown condition certainly can, and I know HOW it can. An out-of square action? Maybe it does affect accuracy, but I want to know HOW that machining inaccuracy actually affects accuracy. If that cannot be answered, then how can we be sure that machining inaccuracy really does affect accuracy? Just wondering.

 

[Lapua40X]

I can't say that a "custom" action contributes to accuracy any more than a "tuned" factory action but I do believe that a "smooth as glass" action means less movement after each shot (stiff actions require a greater amount of body movement to work the follow-up round into the chamber) and that means less resetting the relationship between the body and the rifle for each shot. Putting two shots together on target (intentionally rather than out of happenstance) usually requires a consistent positioning of the body relative to the rifle. My own actions work well, but they're not as smooth and effortless to operate as some of the custom rifles my competitors own.

 

[dragman]

Because it just does. It's all about consistency. The metal is better (usually milled from one piece, usually stiffer and heavier)

 

[Steelnecktie]

The action has nothing to do with accuracy. Period.
A custom action CAN help you shoot more accurately by being smoother, timing, trigger, ect.....
All things being equal, barrel, headspace, ect, the action isn't doing anything special to help accuracy. Don't know if this is answer your looking for, just my thoughts.
Thanks

 

[rayjay]

If you don't use windflags then neither will have an advantage.

 

[R.Morehouse]

I know when i got my 2 port Borden with a blueprinted and timed Jewell and a 20min rail that i know is dead nut centered from the maker i felt i had a quality trouble free platform for my LA 1000yd BR build that would last a lifetime. At 58yrs old it is a buy once and enjoy for the duration.

 

[22BRGUY]

But HOW does a tighter tolerance in an action result in superior accuracy? For instance, if the action barrel threads are not directly in line with the bolt (let us say 1 degree), then the barrel will be slightly crooked on the action (1 degree). This means that the rear of the cartridge case is not sitting dead flat against the bolt face (cocked 1 degree). Fire the round, the case instantly swells to fill the chamber, sealing it, and the rear of the case will try to move rearward against the bolt face. Since in this example, the cartridge head is not dead flat against the bolt face, there will be a slight gap on one side of the case, between the case base and the bolt face. One might expect that loose side of the case to stretch a bit to meet the bolt face, thereby leaving the bottom of the case slightly cocked relative to the centerline of the case. Just HOW does this affect the accuracy of the bullet that left the case. Every cartridge will see exactly the same cocked barrel.



As above, just HOW do axes and surfaces precisely perpendicular to one another (in the action) increase the accuracy of the bullet that is in the BARREL when it is fired?



Interesting perspective, but I go about this in two stages. First, determine if a rifle component can possibly affect accuracy. The crown condition certainly can, and I know HOW it can. An out-of square action? Maybe it does affect accuracy, but I want to know HOW that machining inaccuracy actually affects accuracy. If that cannot be answered, then how can we be sure that machining inaccuracy really does affect accuracy? Just wondering.

What if, just saying, the tenon threading is not true to the center line of the bore? In other words the barrel is slightly cockeyed to the action? I wonder too.

 

[savagedasher]

What if, just saying, the tenon threading is not true to the center line of the bore? In other words the barrel is slightly cockeyed to the action? I wonder too.

Alex stated he just true the action to Remington threads . Larry

 

[Toby Bradshaw]

Read Harold Vaughn's "Rifle Accuracy Facts". In the OP's post above, the force (from combustion pressure) required to make the brass conform to the out-of-square action-barrel junction causes unwanted barrel whip/vibrations (not in line with the bore).

Sloppy bolt-to-raceway fit has a similar effect, with the trigger sear pushing up on the rear of the bolt, causing the upper lug to lose contact with the abutment, slamming the upper lug against the abutment under the pressure of firing. Hence Jim Borden's "Borden bumps" to reduce bolt-raceway clearance to near zero, even with brass that is a perfect fit for fast shooting (i.e., not jammed into the chamber at the shoulder).

I've seen Pandas, BATs, and Bordens that have had more than 50 barrels on each of them. Conservatively, for each action that's 50K rounds, or roughly $25K worth of components and another $25K in barrels. The price of a custom action is a very, very small fraction of the cost of ownership.

You'll never know how well you can shoot, or learn to shoot better, unless you have a rifle that can put them in one tiny hole, so that your mistakes become apparent. Might as well start with equipment that makes you the limiting factor. Why reinvent the wheel when everyone already knows how to produce a highly accurate benchrest rifle?

 

[Alex Wheeler]

The bolt face, lug surfaces and action face are most likely square to the centerline of the receiver. The threads are also most likely centered and parallel to the centerline. The biggest advantage is in the ignition system. Some customs are almost an exact copy of a Remington. Others have improved firing pin guidance and energy. An action has to provide a square face for the barrel to shoulder up to, and square lug surfaces to prevent binding or create unwanted harmonics. If threads are out, you have a situation where the shoulder is fighting the thread tenon. The thread joint can move shot to shot and a poor fit will not help that from happening. It must also provide a consistent ignition without bind or drag. And to a lesser extent a solid bedding surface. When a Remington is trued and the ignition system is optimized it will provide accuracy equal or better than any other. I do not like the Savage ignition system, and think the half pillar used in the rear is a poor design. The barrel nut is also a poor design in my opinion as it eliminates a solid shoulder on the barrel which is what aligns the barrel. With a nut your just relying on the threads natural tenancy to self center. It obviously seems to work, but I dont care for it.