How can you tell wether or not your bolt gun is running straight from one end of the pipe to the other. True'n or bkueprinting an action is something I've never heard of until recently. When I was taught to build guns it never was discussed but custom high end barrels were bought and fitted i.e. tailored the new receiver. That being said....
How can you tell if an action is true or not I'm on a store bought factory rifle?
It is not. Savages are no different than any other inexpensive rifles on the market. The more expensive model 12s in some cases may be. I don't have the experience that a gunsmith has but I have not seen one straight yet. The threads are usually slightly off axis and the face is not perpendicular and the lugs are not either. As for determining the trueness you need a lathe and a action fixture. You might also need a truing rod.
The Dunning-Kruger effect is alive and well.
When I swapped barrels I wanted to check if the action was square. I don't have a lathe but I do have a small surface plate so I stood my Mod 12 action on end. With machinist square it looked good. I know this is not super precise but I know its very close. At the same time checked for even contact of the bolt lugs with a depth mic.
I'm starting to believe that the best way to tell is to see how it shoots. If you're happy, it's straight enough. A person can spend a lot of time and money chasing 10ths.
This. Couldn't agree with you more. IF it shoot straight and you are happy, just enjoy.Originally Posted by gbflyer
Poor Mans Truing
Lay a piece of emery cloth on a glass plate or something similar, and lightly in a circular motion sand until edge of they action is uniform.
Dean
PS: This also applies for the Recoil Lug and Barrel Nut
RUMs are like woman in Stiletto heals, you know they are going to put you in the poor house, but that has never stopped anyone from pursuing them.
The floating bolt head is supposed to help negate action threads that are't square with the action face. I worry about the action being twisted when removing factory barrels. It is one of the reasons I use barrel blocks rather than an action wrench.
How would you check if the action rails were twisted or not? I remove the magazine box and try to lay the action rails flat on a surface plate, but I am not impressed with my findings.
Bill
I have always been curious as to how a floating bolt head substitutes for having a trued an action. True the savage design helps produce rifles that shoot small groups but there are other issues that can arise when your barrel is pointing different direction than what you scope is mounted to. Truing aligns everything so the center line of every bore is concentric. when assembling parts perpendicularity is a part of that function. Anything else is a compromise.A tool that slides in the bolt raceway down the flats works as a gauge. I will tell you when it binds that there is an issue. Rough dimensions might look like; .950 wide x .450 thick by 5 or 6 inches long. This tool is surface ground. Screwing two long 1/4-28 screws or studs and using line of site can tell you something as well. Bolt bind is another factor but not always true.If you grip the front of the action with an action wrench you do not have to be concerned about twisting your barrel.
The Dunning-Kruger effect is alive and well.
Robinhood, I am not sure I buy this.... but..... in theory....they say, if the threads in the action are not cut perpendicular to the face of the action, the floating bolt head is supposed to flex enough to make it perpendicular. Now.... what if the bolt recesses are not cut correctly????? Someplace in the archives I believe there is a post by Fred telling what he does in his T&T. He checks the action for twisting but doesn't touch the threads in the action. I may be wrong on that! He might true up the action face. He spends time on the cocking ramp...the bolt.
Is the tool you describe to check twisting available, or is it something you've made?
The action wrenches I have seen appear to clamp on the action rails, where do you get an action wrench the locks into the bolt recesses? That would be the best way.
Bill
Bill, I made mine to fix an action some terd sold me. Do you have a twisted action you are trying to straighten? I let you decide what is the correct way to true an action but I will say this. The floating bolt head addresses one problem but not one of the most important issues. Draw a thin rectangle on a piece of paper make one end out of square.obviously one of the long sides will be shorter. This will represent the Savage action with a face and threads that are out of alignment with the centerline of the action/bolt raceway. On the end that is out of square draw a straight line that is perpendicular to that line. this will represent the barrel bore. Now draw another line straight line down the center axis of the rectangle that represents the action. Now, contemplate what a bolthead does to correct this angular misalignment. Things to consider Your scope is going to mounted to the action. The optic does not bend light therefore you sight picture is a straight line. I am not condemning anyone elses philosophy. The windfall from doing it the way you describe is you don't have to have a custom barrel tenon for a modified action. The windfall for near perfect axial alignment is accurate windage calls at all ranges. An acceptable trade off most of the time. Post your thoughts.
The Dunning-Kruger effect is alive and well.
Robinhood, The floating bolthead; As I said in my post, THE THEORY IS and THEY SAY. I am not sure I agree. If the threads are cut crooked or off center in the action, you are screwed. If the threads are cut straight and the face of the action is not square with the threads, you can correct that. If the threads are cut crooked or off center on the barrel, you are screwed. If the threads are cut straight on the barrel and the face is not square you can correct that. Does that make any sense?????? Getting everything straight is why custom rifles are very expensive. You are 100% correct when you say it costs big buck chasing .10's. Probably the "floating bolt head" allows Savage to cut tolerances from.0005 to .001.
I do not have a twisted action, I just wondered if there was a "easy" way to check it. It would be easy to twist the action rails when removing a factory barrel. Especially if you were using an action wrench that clamped to the rails of the action. Do you have a action wrench that locks into the bolt recessed of the action? Don't think I have ever seen a commercial one, but it would not be hard to build one using a bolt head for a pattern. My machinist likes to see me with a new project. Says I am "jumping over dollar bills to save small change"!
Bill
Bill, I fully understand everything about the process and what a floating bolt head actually corrects. I have the good fortune in my opinion to make my living reverse engineering, modifying/machining and correcting worn, damaged and incorrectly machined parts. Not unlike what a Smith does when he blueprints an action. With regards to the action specifically, for me or any other bloke that can run a machine and has experience in close tolerance work, fixing the items you even describe as screwed is not an issue. --------------------------------------------------------------------------------------------------------------------------------------------- The ability to understand all of the things going on with an action takes a while if one does not have formal training, and how to correct them without having a negative impact comes with time and experience (and sometimes a 4 axis machining center). Books can be a big help here except for a savage. Correcting thread axis is curable but once that has been done your threads are now custom in most cases and over the counter prefits are no longer an option for that action. Unless you chose to take the thread to the large shank specs. The barrel can be another story. Repairing a bent tube would take some experience if you were wanting the id to be perfect. The OD R.O. is easy to fix. Repairing chamber that is not acceptable is conditional on the amount of room you have for a set back. This is not to say that a tremendous amount of experience and knowledge is not required to be good at chambering. There are many factors that can turn a chamber into junk if you do not have a great understanding of the process or the limitations of your machine. Centerlines being paramount. ----------------------------------------------------------------------------------------------------------- As for the Bolt raceway action wrench, They should be inserted until they come in close proximity to the barrel breech. This is true with the external clamp style action wrench as well. The weak link, and the place actions twist is in the port areas as there is less rigidity. If you try to control torque at the rear of the action it will twist. The barrel vise is the same. If you grab the barrel close to the muzzle and apply downward(rotational of course) force without support, the barrel will bend and a sporter profile may even twist. ----------------------------------------------------------------------------------------------- I have personaly never used the rear entry type of wrench because I use the barrel vise with a nut wrench for easy stuff and add a made by me action wrench. As for your machinist and his observations on money....this is what most serious hobbyist do.
The Dunning-Kruger effect is alive and well.
Robinhood,
Does your wrench clamp on the front of the action, that part containing the threads? How do you keep it from slipping? I always worry when I buy a takeoff barrel, hopefully they put the barrel blocks very close to the action. The first thing I do is clean it very well and check to make sure it seems straight.
You certainly have more expertise than I, but I think we are on the same page. The floating bolt head does make it easy to change to cartridges with different rim diameters.
Bill
Yes it does. I made a provision in one half of the wrench for the recoil lug. That required me to index it to one side or the other depending on if it was a removal or an install based on the shape I made the recoil lug cutout. When machining a part with a split line you can finish your dimension with a shim so It will get some compression. I machined min to 1.350 using a .010 shim.. Issues will make challenges for everyone now and then and I have had a couple but for the most part everything works fine. I do my best to keep angular forces to a minimum to avoid any possible distortion on either part. if possible I only have 6" or less between the action wrench and the barrel vice with both supported a little force on the nut wrench and its good to go.Yes it does.
The Dunning-Kruger effect is alive and well.
I'm new to this forum and new to the Savage rifle, but not new to guns in general. I was also wondering how true the face of my receiver was. I am not a gunsmith or a machinist by any means, but I turned and threaded a mandrel on my lathe between centers. It is a nice tight fit in the bolt raceway and threads in the action and the shoulder of the mandrel bottoms out on the bolt face. I then chucked one end of the mandrel in a 4 jaw chuck and the other end went into a live center. I indicated the mandrel as close to 0 run out as possible. I then took a .0005" test indicator an indicated the face of the action and it showed that the face was out about .0025". I then took a total of .003" cut .001" at a time and now the face of the action shows no run out at all. I would say at the point, the face of the receiver is perpendicular to the threads, well as best as I can get it. Not sure how to post pics or if I even can since I'm so new, but I'll give it a try. Let me know if the pics worked.
Frank
I think that's a good way to do it if you don't want to mess with the action threads. In my mind, it gives you a pretty good average between the bolt raceway and threads, sort of like what your bolt is going to do? I don't know, I'm no smith or machinist either but in some cases I feel like it's helped. Only thing I do different is turn my centered mandrel with a dog cause it's easier than fooling with my 4 jaw.I'm new to this forum and new to the Savage rifle, but not new to guns in general. I was also wondering how true the face of my receiver was. I am not a gunsmith or a machinist by any means, but I turned and threaded a mandrel on my lathe between centers. It is a nice tight fit in the bolt raceway and threads in the action and the shoulder of the mandrel bottoms out on the bolt face. I then chucked one end of the mandrel in a 4 jaw chuck and the other end went into a live center. I indicated the mandrel as close to 0 run out as possible. I then took a .0005" test indicator an indicated the face of the action and it showed that the face was out about .0025". I then took a total of .003" cut .001" at a time and now the face of the action shows no run out at all. I would say at the point, the face of the receiver is perpendicular to the threads, well as best as I can get it. Not sure how to post pics or if I even can since I'm so new, but I'll give it a try. Let me know if the pics worked.
Frank
70oldsracer, Nice work! That is exactly how I did my first rig. I didn't chuck on the small end of the mandrell though. I did overkill and put a center in the chuck and drove the mandrell with a dog. Your method is absolutely the fastest way to get the action face perpendicular. Did you take the time to check RO on the outside of the action?
Savage rifles sure are a draw to you rocket boys
The Dunning-Kruger effect is alive and well.
I did make the mandrel between centers being driven by a dog leg I made, but once it's threaded into the action, I put it in a 4 jaw to indicate it for run out on the mandrel. Here are a few videos of indicating the mandrel and showing the run out on the face of the receiver. The last video shows next to no run out on the face of the receiver after the .003" cut.
https://youtu.be/W6AVbivbB28
https://youtu.be/PEV35HDWnAM
https://youtu.be/eHAzrL6bneM
https://youtu.be/VJgsSMYFMmI
There are a lot of guys who are going to learn something from your videos bud.
The Dunning-Kruger effect is alive and well.
Thanks. That's what it's all about, helping each other. I joined this forum to learn as well as help anyway I can. I always find that photos and videos explain everything such much better than I can, plus there fun to watch, at least I think they are lol!
Agree 100%. I was reading a thread on another forum recently where a fellow wanted to get some experience chambering a barrel. My goodness, some of the responses were amazing from the "pros". It was like they were being asked to cut off a limb. I wondered how it would be if no one ever gave them a chance. The shooting community spends a lot of time in neck deep water as it is. Makes no sense to throw one of our own an anvil.
Anyway, I digress. Thanks for the vids. Nice work!
Thanks.
you can do one more step, i am curious, take a depth mike and see what the difference is in the depth of each lug abutments,
Chet
Chet,
That was the next thing I wanted to do, but I'm not to sure how to change the rod on my depth mic. Right now the rod in there only reads from 0-1". I do have a digital depth gauge that I can try. I figure it shouldn't be anymore than .001 difference. Have you done this before? In hindsight, I really should have taken these measurements before to see how off it was from the factory. I made the same type of mandrel for my Mauser receiver and after the truing cuts on the face of the receiver, it was within .001" after measuring in 4 different places on the C ring.
Frank
For this reason I went to a conventional fixture for actions, it facilitated cutting the lug abutments (wait for it) and touching the threads at the same time.
For changing out the stems on the depth mic, twist on the thumb ratchet on the Starret and for Mitutoyo it is in the middle of the thimble i pretty sure.
The Dunning-Kruger effect is alive and well.
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