Truing a target action

[alphapygmy]

I've never trued a Savage before but I'm wondering with how they're put together with a barrel nut if it's better to true them a little different. I figured to make a tight fitting threaded bar with a stub on the end to indicate off of and set it up off the action threads, not the centerline of the bolt bore. I also don't want to enlarge the factory threads so I can use pre-chambered barrels if needed. Thoughts?

[Robinhood]

dp.

[Robinhood]

If you do that you need to re drill and tap your scope base holes on centerline with your barrel. Think about it. Your scope is in one line or axis and your barrel(bullet path) is in another.

You need one axis for everything if you want best results.


When you chase threads you want to just take enough off to remove the run-out . Unless you want custom threads

[gbflyer]

Being an amateur, I've just machined a truing bar that threads into the receiver and fits very tightly in the bolt bore. I leave enough on each end to turn the bar between centers and true the action face.

Again, not a pro but I've been around one a bit. I don't recall ever messing with the scope mount holes.

[Robinhood]

Your way centers the rear bolt bolt raceway and the barrel threads. Much better method. You can tell if your method works by shooting targets at 50 100 and 200 yards out. if the point of aim keeps you centered on the target you're good to go. .002 off at the action face can mean as much as .040 off at the end of the barrel. Those numbers could get you 6" off at 100 yrds if your scope base is aligned with the centerline of the action. Have you ever heard about anyone being off target after they sight in at 25 or 50 yds then go to 100 or 200yds? Could be a bent barrel or it could be something wrong with the action face.

This is just my humble opinion. I don't machine actions for a living but I do run a HBM's, VTL's, Lathes, Mill's and Precision Grinders at least 250 days a year. Where tolerances are held to a minimum sometimes to .0001 on the grinders. Stacking tolerances are kept to a minimum.

[gbflyer]

Your way centers the rear bolt bolt raceway and the barrel threads. Much better method. You can tell if your method works by shooting targets at 50 100 and 200 yards out. if the point of aim keeps you centered on the target your good to go. .002 off at the action face can mean as much as .040 off at the end of the barrel. Those numbers could get you 6" off at 100 yrds if your scope base is aligned with the centerline of the action. Have you ever heard about anyone being off target after they sight in at 25 or 50 yds then go to 100 or 200yds? Could be a bent barrel or it could be something wrong with the action face.

This is just my humble opinion. I don't machine actions for a living but I do run a HBM's, VTL's, Lathes, Mill's and Precision Grinders at least 250 days a year. Where tolerances are held to a minimum sometimes to .0001 on the grinders. Stacking tolerances are kept to a minimum.

Hmmm....now you've given me something else to obsess about. Thanks a lot, pal. :-)[emoji1]

[Keith_A]

Boy, this topic really opens up Pandora's box...
Ok, it seems the goal is to perfectly align the Horizontal and Vertical axis of the scope and the H & V axis of the rifle bore, with a vertical displacement between horizontal axis the scope and bore. There are a lot of parts between the bore and the scope which could affect alignment - barrel nut, recoil lug, receiver, picatinny rail or scope mounts, scope rings. (Did I leave anything out guys???)

One factor that must be considered are all the mating surfaces flat? For example the recoil lug surfaces may be uneven around the alignment pin. That could change the angle between the barrel and the receiver There are a number of companies that make flat recoil lugs (at at premium price) to reduce this possible problem. Polishing the mating surfaces flat seems like a good starting point. That is, after test firing the rifle as detailed by Robinhood above...

[alphapygmy]

I'm not too worried about the scope right now. The rifle is used exclusively for 600 yard club shoots so if it has known repeatable adjustments at that range I'm fine. When I got the action it looked like one they started last minute on a Friday and finished with a hangover on Monday. All the threaded holes looked rough and there was flashing at almost every machined edge. I would guess that most aren't like this and I got one machined at the end of the toolings life. The year before I put together a long action from a plain hunting rifle and won my class averaging 198 of 200 and shooting several clean 200's. This year with the PTA I averaged closer to 195 and it shot less consistently. I keep pretty good records so I'm positive about something not working as well as the previous years. It could be a barrel that just doesn't shoot as well or the scope doesn't track as well but with how poor the action looked out of the box I think that's a fair place to start the investigation.

[Robinhood]

Kieth. Remember this is JMHO, If you are looking for precision you can't use one of the stamped factory recoil lugs unless you gring it. I can tell with no hesitation that most of those stamped units take over .010 to make flat(meaning just the ring of contact on the acton and the barrel nut) not including the stamped locating tab. speaking of the locating pin/screw/etc... It most definitely can be an issue with the recoil lug. Some of the manufacturers do not fit the groove in the action face so you must deburr and fit with a jewlers file or re mill the slot to the correct width and depth. It should fit freely and the recoil lug should set on the mating surface freely.

Why should you worry about scope alignment? Making correct wind calls at varying ranges is important. Also most scopes start to loose precise turret, read reticle movement, the further you adjust your reticle to one side or the other.

[alphapygmy]

Just for information I'm using a NSS recoil lug and nut. For rings I use the Burris Signature with the alignment inserts so I can keep the scope near the middle of its adjusment range.