Why does action trueness matter?

Just my opinion, but...

the reason that I think trueness of an action matters as follows:

The receiver face being square and true to the threads-- I think that this prevents the barrel from shifting in the receiver as it's fired and then pointing somewhere else as it comes to rest. If you've ever screwed a barrel into an action that isn't square, the barrel shoulder will hit the receiver shoulder or recoil lug and then keep on turning for a quite a ways (half a turn or more) after it hits the shoulder. On an action that the receiver face is square to the threads the barrel shoulder hits the receiver shoulder and then it's completely tight in just an 1/8 of a turn or so. The barrel fitted to a trued action locks up quick and solid. The barrel fitted to an out of square actions doesn't.

The receiver lugs being square to the receiver raceway and bolt lugs and face to the bolt body--- This is a function thing. When the bolt is closed if there is a cam lapped into the lugs, then the bolt will be harder to close as the bolt is closed on a tight fitting round. The bolt will try to move forward against the cartrige case as the bolt is closed getting harder to close the more the bolt is closed. If the action is true and square, then when the bolt is closed, the bolt body does not try to move forward against the cartridge case instead just rotates down on the locking lugs making it easier to close the bolt.

I doesn't have anything to do with black magic and don't know about harmonics, but its seems more a case of mechanical function to me.
 
Bnhpr said:
That's a little obtuse Stephen, I didn't deserve that. And let me be clear, that I am not a gunsmith, nor pretend to be one.

I am, However, a machinist/Chief Engineer, with 20 years experience in a manual shop, as well as 3 years teaching experience of machine tool operations, and 13 years of training of Marine Engineers. I've been involved with maching operations in the oil and gas industry, which you cannot imagine, or begin to comprehend.

And by the way, I do have a factory rifle that shoots a 1/2" group. It's a Remington XR-100.
Click to expand...

I refer you back to Butch Lambert's post (#19).

-Dave-:)
 
Ok, I'll definitely set up to check the action face. I appreciate the feedback from the experience here.

I have two ideas about how to true the action. I should get you guys feedback/technique.

1. Machine a male threaded piece (class2 fit?) that will screw into the action and allow me to put the action in a 4 jaw with brass shimstock to protect the action. I can dial the action to the threads (face and rim, face will be harder to dial)

or

2. Build a mandrel or use an expanding mandrel that goes through the action and dial the mandrel in a 4 jaw. (but the threads may be off to the bolt way)

or

3. Same as 2, except, use the threaded piece I described in #1, and dial off that. Again,

If the threads are off, angular to the boltway, would anyone consider oversizing the thread or going to a higher thread clearance for better barrel to action interface? What sort of safety factor is built into the action strength? I just don't know what the norm is here.

Thanks

Ben
 
The competition endofit

Speaking from the prespective of a competitior, a strong, stout action that is truely straight aids quite a bit in the extraction, re-loading, and overall life of cases. This produces a situation that allows the overall agging capability of the combination to perform at it's peak.
Or, at least it seems that way. I suppose unless someone like Gene Beggs went to the trouble to perform a series of double blind test in his tunnel to see how all of this plays out, we can't be absolutly sure.
An action that is not real straight, but has a killer barrel, will probably shoot circles around an action that is true to the Nth degree, but has a mediocre barrel hanging off. But what we are looking for is the action that IS trued to the Nth degree, AND has a killer barrel hanging off.........jackie
 
Fine mechanical devices of any kind are superior to "ho-hum" stuff because they are just that....."Fine"..... Everything is as parallel, perpendicular, co-axial, and well fit & finished as it can be. In a rifle, I think of it as promoting consistancy of operation from one round to the next to the next.

The concept of making a rifle competitive is kind of like rolling a bus over from the inside out...........the more people you can get in one row of seats, the more likely it is you'll be successful. With that said, keep in mind that obsessing over the unattainable, that is, getting everyone on the same side, is counterproductive. Don't wast time on the 90-pounders, but instead put your efforts into getting the biggest riders over there. If you are building a rifle on a production action, truing it properly is comparable to a 300-pound gorilla.

-Dave-:)
 
Trued action

Mike Bryants post #33 is dead on.One of my customers had a new m1a that would not shoot.
The cold bore shot would be an X and then the shots would string out towards 2 oclock,6" at 200.
Sent back to factory and then called them 2 weeks later to check satus.
spoke to the repair dept and was told that the receiver to sholder barrel fit was the problem,not square.They trued up everything and sent it back no futher problems.

Chuck

P.S. AS a gunsmith of 45 years thumbs up on trued actions.
 
Jackie,

What I was actually referring to was your use of (probably) in paragraph two. :)


To those who don't already know it, Jackie is a topflight machinist and if memory serves, he entered the accuracy game AS a top machinist and a guy who'd been heavily involved in racing things with wheels. IMO Jackie applied this knowledge to his building/shooting right off the bat...........correct me if I'm wrong Jackie but I think I've heard you say "I've only got one other gun, a hunting rifle". I'll go out on a limb here and say that Jackie probably had a pretty solid understanding of "precision" and "alignment" and such from his prior working/competition days.


Is that fair to say Jackie? :)


Where I'm coming from is different. I spent 15yrs and beaucoup dollars, even went to Gunsmithing School, learning how to "accurize" rifles..........I thought I got perty good at it.


Here's my take on it, my :D OPINION :D , worth every dollar that you paid for it.


Get it done RIGHT the first time and save LOTS of time, money and aggravation. I myownself spent YEARS and DOLLARS cutting every corner that I could. I've got rifles built from factory actions modified to every stage from just screwing on a barrel to full-on Borden-Bumped and I can tell stories for hours.

The real nail in the coffin for me was Bill Calfee's articles. Bill refers to "flippers" a lot........and until you've fought a modified factory rifle that just HAS to shoot....a rifle that will put not three, not five, but maybe even 15 shots into the same hole and then FLIP one out..........you ain't SEEN aggravation!




FLIPPERS SUCK!!!!


:)



All I'm saying Jackie is that by your use of the word (probably) I'm assuming that you (probably) were wise enough to start off RIGHT!


Kudo's to you for that.



I on the other hand BELIEVE in custom actions or fully trued/blued and tattoo'd factory actions. And even the best of factory conversions give up quite a lot in handling to the customs, especially in LV configuration.


Regarding true "agg'ability", or the concept of shooting little ones consistently.............My own light came on when I ordered a Time Precision Bench Rest rifle. This wasn't by any means my first "custom rifle", it wasn't even my first rifle built by someone other than myself.............it was just my first BENCHREST rifle.


UN-freakin'-BELIEVABLE!!!! I could SHOOT! Just like ya' read about! And I could SEE THE WIND!!!


So Jackie, I'm not in any way arguing with your post. I'm just a firm believer in going straight to the top. In fact, I'll go so far as to say that buying one of the used rifles listed here on this site or one of Bob White's offerings with a pedigree is simply the biggest favor one could do for hisself in his search for accuracy. Take it from me, the learning/building/shooting curve is long and steep when undertaken from start to finish. I say just SKIP the know-how part for a while and check out the real deal............get something against which to baseline and compare the various "stages of build". My advice remains, buy a real gun with real brass and real dies and THEN try to match it.


I just wish that this board and the fine people here who're willing to share their experiences had existed when I first started shelling out shekels for shooting.........I'd have TWICE the rifles and HALF the equipment graveyard!






BossHoss............what's YOUR deal man??? I feel that threads like this are valuable.


But then I'm ALL ABOUT folks spending money and time on my favorite sport.................shooting.


May my CHILDREN's children have that right.............:cool:



I realize that I've digressed a liddle from the OP's question, I apologize Mr bnhpr. If you really want to know the "why" then take Boyd's advice and buy 'Rifle Accuracy Facts'. If nothing else it'll give you enough background that you can ask meaningful questions regarding the "why's" of real accuracy.



pass it on..............



al
 
I guess that it does not matter why.

It only matters that it does.

Why just helps me understand what parts of the process are the most important, and what I should spend the most time giving attention to detail.
 
Al ---- point is that this is probably one of the most rudimentary and simple things about our hobby and sport there is to understand. Well at least to me but then I have watched more actions being “printed” than I can recall but you are right --- it is about having fun and spending money on something you love to do!!!!:D:D


Spend the money and do it right then you only cry once!!!!!;)
 
Boss Hoss 540 said:
Al ---- point is that this is probably one of the most rudimentary and simple things about our hobby and sport there is to understand. Well at least to me but then I have watched more actions being “printed” than I can recall but you are right --- it is about having fun and spending money on something you love to do!!!!:D:D


Spend the money and do it right then you only cry once!!!!!;)
Click to expand...

Mr. Boss,

Rudimentary is good for me, so, can you explain the whys, starting with the most important reasons? As an engineer, I could not work through it in my mind. Good advice, do it once, right. I just need to know what right is.



Jackie made a great point, I appreciate it. the case issue. The case will fire form to a crooked bolt, causing case damage. I can see an accuracy issue, there, just like fire forming. Cases will yield at an inconsistent point withing the pressure curve, causing inconsistent chamber pressures, shot to shot accuracy will then vary from the inconsistent pressures. Sounds logical. I'll buy that.

Mike Bryant makes a good point with the machine fit possibly changing shot to shot with apoorly attached barrel. Not sure, but it is possible, so must be considered. I would also buy that there is a frequency change in the barrel with a poor connection. Good point, but i'd like to quantify them. maybe vibration analysis? Vibration is a real thing, although sometimes called voodoo. Just change the the length of your boring bar, or cutting speed and see. (hear) I have done some vibration analysisof this with engines and turbines/machinery. maybe I'll talk with some people. As far as the bore/reciever connection changing. i'll have to come up with a may to measure/quantify that. Maybe a laser? Any ideas?

HalD, thanks for the link, that's exactly the information I need. I have a few books on rifle fitting, but they really seem to lack the real good tips that you guys are giving me/direct me to. I bough that chambering DVD from Grizzly for $59. I hope it will help.
 
Stress in the mess...

Hey Bnhpr,

Stephen Perry is a Civil Engineer. He means well and has contirbuted to BR shooting...its just a diff. style he has...hehe. Nothing wrong with different.

Anyways, I was thinking if you don't know about Varmint Al, his website maybe worth a visit. http://www.varmintal.com/abolt.htm
Rifle action stress...mmmm...good stuff.
Mr Al. used to be something else in a previous life...lol. See website for answer on that.

Also if you haven't already, there are some really mind numbing threads in the Centrefire forum. Ya just got to take what you can, then go shoot some, come back and read them again. Hehe.

Jackie and Alinwa are saying some interesting stuff...

Have fun!

:D
 
Bnhpr.... for "truing" the 700 action, you might also want to look at the tap / reamer set from Dave Manson. It's listed in .010" oversize, but i believe he also makes [at least i know he made it, since I have one] a standard size reamer / tap set for the 700. It's a bit pricey if you're only doing one, but I've found it works well, and have used it on several... maybe 10 or 12 so far. As an additional advantage, the tap also serves as a mandrel to set up and true the receiver face. http://www.mansonreamers.com/PriceList.htm

There has been discussion before regarding the fact that the tap won't / can't clean up and center the threads as accurately as single pointing them using the Gre Tan method... due to its natural tendency to follow the existing pattern. But this is more than offset by its simplicity, particularly if you're doing something other than a full- out BR job.. And the reamer does an excellent job of facing the locking lug surfaces in the receiver, which just about always need it. Like most others, I think you're better off with a custom action for BR.. You can work and work on a Remington 700 and you still have a 700, albeit a much nicer one than you started with..

Also, I'm in Maine, a "bit" north of you... but if you'd like to stop by my shop and see / discuss setups sometime, give me a PM. I always like talking to folks with similar interests... and I'd be picking your brain too... I like to learn something new every day.
 
It's difficult to visualize what a competitive, in tune, benchrest rifle will do, aggregate-wise, unless you have spent some time behind one.Aggregate is defined as (5)-(5) shot groups on (5) separate targets at differing times of the day as dictated by number of benches and shooter attendance. The .500 group that you used as a benchmark is a sure ticket to the bottom of the page. My humble suggestion to you is attend a sanctioned match and get an idea of the nature of the beast before you attempt to have an opinion of it. The major problem I see in your approach to determining what is required of a rifle, to be competitive, is your personal lack of understanding of the game and the equipment used therein. Your background as an engineer should establish that certain things related to engineering have been established through past practice. Competitive Benchrest is no different. The features that modern Benchrest rifles use have been established through trial and error work done by our predessors; it's truly a sport of evolution. The people that have bothered to respond to you have done so out of goodwill and a desire to further the game. Please understand this is very hard to do when the subject of the discussion is totally unknown to one party in the discussion. You asked and I responded to a question regarding bullet seating. Was your question on that subject answered to your satisfaction and understanding??

Best regards;

Mike Swartz
 
Crow99 said:
Bnhpr.... for "truing" the 700 action, you might also want to look at the tap / reamer set from Dave Manson. It's listed in .010" oversize, but i believe he also makes [at least i know he made it, since I have one] a standard size reamer / tap set for the 700. It's a bit pricey if you're only doing one, but I've found it works well, and have used it on several... maybe 10 or 12 so far. As an additional advantage, the tap also serves as a mandrel to set up and true the receiver face. http://www.mansonreamers.com/PriceList.htm

There has been discussion before regarding the fact that the tap won't / can't clean up and center the threads as accurately as single pointing them using the Gre Tan method... due to its natural tendency to follow the existing pattern. But this is more than offset by its simplicity, particularly if you're doing something other than a full- out BR job.. And the reamer does an excellent job of facing the locking lug surfaces in the receiver, which just about always need it. Like most others, I think you're better off with a custom action for BR.. You can work and work on a Remington 700 and you still have a 700, albeit a much nicer one than you started with..

Also, I'm in Maine, a "bit" north of you... but if you'd like to stop by my shop and see / discuss setups sometime, give me a PM. I always like talking to folks with similar interests... and I'd be picking your brain too... I like to learn something new every day.
Click to expand...

I did see the tap, and asked in a previous post, (maybe different thread), what the oversize tolerance was, from a strength perspective. The fact that they sell a +.010 tap tells me that the connection has some excess strength.

Chasing a thread in a lathe, especiall internal is an advanced technique. I have no problem with that. When you do it in an action jig, it goes from advanced to risky to me. there is a lot that can happen with the tool. Especially, with an eccentric thread your chasing. I've broken tools before chasing internal acme threads in a lathe.

It sounds like a good technique, but does not cover some of the bases, aforementioned, so expect to get hammered!

This can be a tough crowd......but I like that!
 
Mike Swartz said:
It's difficult to visualize what a competitive, in tune, benchrest rifle will do, aggregate-wise, unless you have spent some time behind one.Aggregate is defined as (5)-(5) shot groups on (5) separate targets at differing times of the day as dictated by number of benches and shooter attendance. The .500 group that you used as a benchmark is a sure ticket to the bottom of the page. My humble suggestion to you is attend a sanctioned match and get an idea of the nature of the beast before you attempt to have an opinion of it. The major problem I see in your approach to determining what is required of a rifle, to be competitive, is your personal lack of understanding of the game and the equipment used therein. Your background as an engineer should establish that certain things related to engineering have been established through past practice. Competitive Benchrest is no different. The features that modern Benchrest rifles use have been established through trial and error work done by our predessors; it's truly a sport of evolution. The people that have bothered to respond to you have done so out of goodwill and a desire to further the game. Please understand this is very hard to do when the subject of the discussion is totally unknown to one party in the discussion. You asked and I responded to a question regarding bullet seating. Was your question on that subject answered to your satisfaction and understanding??

Best regards;

Mike Swartz
Click to expand...

I do not really have an opinion on benchrest shooting. To me, benchrest shooting is from my picnic table, on my back deck, 225 yards to the dirt pile. I wish there were competetive matches in my area, I'd love to go watch and meet the people and see the futuristic looking rifles.

The only competetive shooting I've done is collegiate small bore, 3 position (prone, standing, kneeling),with my old Anshutz 54, where the standing position always determined the winner, because anyone in the match can hit 10 targets the size of a pencil lead at 50 feet, prone and kneeling? Right?

Are benchrest matches seem to be won at the lathe?

I'm too old and fat to shoot well standing anymore, so I just stick to the lathe.
 
Orrington Maine benchrest matches

The Orrington Maine Rod and Gun club runs registered benchrest matches and according to my maps the club is 28 miles from downtown Monroe Maine--so there might be a place for you to particpiate in Benchrest.

Jim Borden
 
Jim Borden said:
The Orrington Maine Rod and Gun club runs registered benchrest matches and according to my maps the club is 28 miles from downtown Monroe Maine--so there might be a place for you to particpiate in Benchrest.

Jim Borden
Click to expand...

Thanks Jim, can you email me the list of Maine clubs?
 
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