Custom Actions - How Do They Enhance Accuracy?

[savagedasher]

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?

Smile So your telling me I can get a small bug hole with a junk barrel with a good action . Larry

 

[Toby Bradshaw]

Smile So your telling me I can get a small bug hole with a junk barrel with a good action . Larry

Didn't say anything of the kind. Everything has to work to shoot bugholes consistently. The action is part of the shooting system. Haven't read Vaughn, have you?

[And when you intend to contract "you are," the proper spelling is "you're." Your English teacher may have mentioned that the apostrophe represents missing letters. It's never too late to get an education.]

 

[savagedasher]

Didn't say anything of the kind. Everything has to work to shoot bugholes consistently. The action is part of the shooting system. Haven't read Vaughn, have you?

[And when you intend to contract "you are," the proper spelling is "you're." Your English teacher may have mentioned that the apostrophe represents missing letters. It's never too late to get an education.]

That I can agree with . But one think I do know a action won't make a bad barrel shoot . Larry

 

[Toby Bradshaw]

That I can agree with . But one think I do know a action won't make a bad barrel shoot . Larry

You mean "thing" and "an action," right?

A great barrel on a crooked action won't shoot, either. Read Vaughn.

 

[LHSmith]

There is empirical evidence that a good custom action will out perform a production action (even one that has been trued, blueprinted or otherwise enhanced) in the aggregate (i.e. over multiple match events). Not very long ago, custom actions were not permitted in IBS Hunter Class competition by rule. Around the year 2000, that was all changed and custom actions were permitted.Look at the match reports since that time. There is a overwhelming amount of data (from around +700 match aggregates contested) which will show the custom action rifles net better scores than non-customs. The fact is very few competitors campaign a non-custom ...and the reasons are obvious. Forum member, Eddie Harren, is one of the last hold-outs ....still shooting his Remington 721 which collected him lot of shooters points through the years.
I believe Tim Singleton summed it up the best.
Notice I prefaced with a "good" custom action....there are indeed lemons even in customs.

 

[dedogs]

My most accurate rifle is a Remington 700 that was cleaned up by a smith.

I believe the OP asked about custom vs. STOCK actions. If your Rem. 700 was "cleaned up" by your smith its no longer a "stock action" it's been made to "better than stock" specs and there-in lies what I believe to be the answer. As others have posted above, things are "straighter" and fit better on a custom action so they generally function smoother with less up-set in the bags when cycling the action. Most custom actions are stiffer than factory actions and therefore there is less movement in the action during firing. Harold Vaughn did some experiments on this subject and found that there was indeed a corollary between the two.
Having said all that I don't know for sure why some Savage rifles will beat the pants off of some customs-- perhaps it's the individual behind the trigger?
How many rifles does Rem. Win. Ruger etc. turn out in a day? How many a day for the custom action builder? dedogs

 

[geo.ulrich]

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

happens all the time in short range b.r. if its not working you either roll up your sleeves and fix it or out the door and get another

 

[savagedasher]

happens all the time in short range b.r. if its not working you either roll up your sleeves and fix it or out the door and get another

I know all about that . A friend who shot BR had 50 barrels chambered for two actions . Larry

 

[geo.ulrich]

I know all about that . A friend who shot BR had 50 barrels chambered for two actions . Larry

and the flip side I know one hof shooter that bought 75 actions in a year plus barrels and no he's not a gunsmith

 

[ireload2]

The large diameter receivers of the big custom single shot bolt guns have a larger section modulus.
Buy a copy of Machinery's Handbook and find the section on strength of materials.
It will discuss all the ways that the larger receiver is stiffer (more rigid) than the factory receiver.
It even has the formulae to permit you compare the two if you want to put the equations into Excel.
Stuart Otteson wrote a book called "The Bolt Action Rifle: A Design Analysis" which discusses the rigidity of most popular bolt actions.

 

[savagedasher]

and the flip side I know one hof shooter that bought 75 actions in a year plus barrels and no he's not a gunsmith

Does he live in Florida ? Larry

 

[geo.ulrich]

Does he live in Florida ? Larry

nope

 

[savagedasher]

nope

Most are glued in actions so they must of had stock s also . He's the man .smile Larry

 

[Puzzaz01]

I'm grabbing some pop corn, this is getting good!

 

[geo.ulrich]

Most are glued in actions so they must of had stock s also . He's the man .smile Larry

 

[geo.ulrich]

yep funny part is bought all the same stocks I mean same color and configuration so his wife wouldn't notice a new gun spin up a barrel try it wasn't what expected and down the road

 

[dkhunt14]

Most are glued in actions so they must of had stock s also . He's the man .smile Larry

Don't you think they can unglue them? Matt

 

[savagedasher]

yep funny part is bought all the same stocks I mean same color and configuration so his wife wouldn't notice a new gun spin up a barrel try it wasn't what expected and down the road

Don't you think they can unglue them? Matt

Don't sound like it . Larry

 

[johnfred1965]

Phil3,
After weeding through the chaff of this thread, only Toby and Alex hit on what I think differentiates a custom from stock. Barrel whip/vibration/harmonics. While yes, a custom may be made from better or stiffer metal, smoother to operate, more consistent ingition, etc., the perfectly square and perpendicular faces of a custom action, when properly mated to a square and true barrel and chamber, will result in more consistent and repeatable harmonics when a 60000 psi explosion starts shaking things up. With everything as close to zero tolerance as possible, the barrel will be pointing in the same direction every time. If the face of the action is off one degree to the left, the top lug is off one degree, the bolt face is a degree off in another direction, the barrel harmonics will be different for every shot, with the muzzle whipping around in five different directions for a five shot group. The custom action controls these effects the best, allowing for the potential for the best accuracy, followed by a trued factory action, followed by a stock action. While a lot of stock actions will shoot well, the tolerance stack there does not lend itself to the greatest accuracy potential. More than my 2 cents, but I needed to vent

 

[Phil3]

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

I never bought into the "If I have to explain it you wouldn't understand". I interpret that statement as a way to save face when unable to come up with concrete evidence. I own a prestigous German sports car, and could say "If I have to explain it, you wouldn't understand". It performs no better than a Mitsubishi EVO I drove that cost half as much and performed just as well in every respect. But I own the German car because of build materials and quality. And I might want a Bat or Panda action, just so I can salivate over its workmanship, slickness, etc, but so far, I have not heard anything convincing that tells me the Bat or Panda will deliver superior performance (accuracy, the context of this conversation).

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

See my above response, but in this topic, we are talking about performance (accuracy). High build quality is nice, but does it deliver measurable superior on-target results?

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

Evidence to prove that?

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

Pretty much what I think.

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.

I want to know if the blueprinting, timed, deadnut centered action will deliver superior results on-target.

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.

Exactly.

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?

I would buy the book, but at $350+, a little pricey. I am trying to borrow a copy, but the person who has it is a bit of a drive, but I was told I could borrow.
The explanations here ARE an explanation of the benefits of a higher quality action, but still do not tell me what the on-target benefit actually is.
There is no way I am going to fire 50k rounds out of one action. Not at my age!
I am not trying to reinvent the wheel and I don't shoot "benchrest" rifles. This is my technical curiosity asking questions.
The rifles that rounds into one tiny hole are not rifles I care to shoot. My shooting skills measurement, while hardly ideal, are how well I improve with the same gun, and secondly, how well a good shooter (like a well experienced BR shooter) can shoot my gun.

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.

Understood, but as you said, it obviously seems to work, so maybe such perceived design faults are not as faulty as we think. I don't know, but surely wish there was some scientific testing done to test such things. The Vaughn book I believe will help...if I can get my hands on it.

Phil