Gunsmithing what would you do?

[_shawn_]

i'm expecting my new scope to show up tomorrow so i pulled the existing scope off the rifle today and noticed this

what would you do? the rifle is a springfield 1903a3 30-06. the current bases on it are weaver 11 in the back and weaver 25 in the front which according to weaver don't belong on this rifle.

i was thinking about getting a 20 moa 1 piece weaver or picanny base but nobody makes a base to fit this rifle and nobody makes a 1 piece base to fit the front receiver mounting holes.

until i can figure out a way to fix it correctly i thinking about bedding the rear mount to match the front then try and shim the base to line it up

oh and the gun smiths around here are a joke. of the few i've talked to i have more faith in myself with a cordless drill then the local guys. rumor has it there's a couple others close by who know what they're doing but i haven't been able to get any info for them yet

 

[zuke]

Re: what would you do?

If it worked with the old scope, why "fix" it?

 

[_shawn_]

Re: what would you do?

the old rings were kind of adjustable. set screws on both sides of the ring to mount connection and i'm pretty sure the new rings don't but they won't be here till tomorrow and i really don't want to screw up this brand new scope

 

[colchester]

Re: what would you do?

The rear base appears to be canted in relation to the front base. I dont think the rings are goin to be able to compensate for that. you will need to do some investigation to get to the root of the problem hard to tell from the pics

 

[_shawn_]

Re: what would you do?

yes the rear base is canted close to 2 degrees counter clockwise from the front. the rear of the receiver was drilled wrong. after thinking about it most of the day i'm going to try and find a 1 piece weaver style base tomorrow and redrill it to match the existing holes or match the front then fill and redrill the back holes just wanted to see what an actual gunsmith would do

 

[Dracozny]

Re: what would you do?

just my thought but filling the existing holes and redrilling seems like the correct way to do it. also to keep the holes lined up before you mark for drilling I would line up the front and back with a solid piece such as a rail riser (assuming there is enough space) to minimize the chance of movement

 

[_shawn_]

Re: what would you do?

aren't actions heat treated in some way? so if i filled in the holes and smoothed them out i'd need to have it re-heat treated? i can do the welding and drilling/taping but i really wish there was a decent gun smith close by

 

[Dracozny]

Re: what would you do?

if the holes do not line up at all then just fill with JB, if they must overlap the existing holes then you might have some heat treat issues but if you can keep the welds small enough and use some clay to protect the rest of the metal from heat I don't think it would make that dramatic of an effect.

 

[former naval person]

Re: what would you do?

If you move the screw holes, no need to re heat treat. Just make damn sure they are where you want them. Otherwise...you run out of options.

 

[_shawn_]

Re: what would you do?

guess i just need to find a base first and see what i come up with

 

[ddavis]

Re: what would you do?

There are a few "gunsmiths" around here that will install barrels, true actions, etc, but I'm not sure any of them could do what you need. I think those holes need to be TIG welded then re drilled and tapped. It could be interesting trying to drill the new holes when they are halfway on the old receiver steel and halfway on the new welds with different hardness. Best of luck to you sir.
-Dan

 

[_shawn_]

Re: what would you do?

what gun smiths are you refering to? i've talked to a couple shops down here when i was looking to get my barreled threaded for a brake and none of them instilled any confidence in me whatsoever

 

[LRI]

Re: what would you do?

If it were me:

First, ensure that the base was actually made correctly. There's no assurance that the holes in the bases are actually on location.

2nd, if you determine that its an issue with the receiver there's a couple ways to address it. If you have the resources you could machine a false barrel with no taper and screw it onto your action. Then you'd indicate the barrel blank straight. After this the base holes would be indicated in to see if they run on the same axis as the "barrel". You can do it off the raceway of the receiver, but then your making the (bold) assumption that the barrel is pointing in the same direction.

Often times it isn't-especially with "veteran" receivers like an 03 Spfld.

Assuming the holes are goofed up:

TIG welding the rear holes will cause no harm to the action if the torch monkey knows what he's doing. The business end of the receiver (lugs/ring) are far enough away that you don't need to be overly concerned with annealing those features.

Another option is to use a plug screw and some silver solder. Simply install the screw about half way, get everything warmed up with a torch, sweat some solder in there, and while keeping the coals poured to it, finish installing the screw until its just barely proud over the rear bridge. Allow it to cool, file/sand to flush, and relocate your holes.

The last and (hopefully) the best one is sending it to a shop (like mine) that has cnc assets. IF the holes in the action are out, but not far enough to exceed the inside diameter of a larger base screw (like going from a #6-48 to a #8-40 for instance) then its possible that the larger ID for the #8 will swallow up the alignment problem and make them straight again.

The trick becomes machining the new holes. Drills suck for this because they want to follow the existing holes. Especially with receivers that are hardened everywhere. The better option is to helically bore the new hole- using and endmill and spiralling into the material makes the hole on location and ignores things like tool deflection. (within reason, you can still goof it up if you go full throttle into the hole)

Then instead of tapping the hole, you thread mill it. I have thread mills for this stuff. Thread mills machine the thread instead of tapping it. Makes wonderful threads that are very accurate in terms of location.

The first two options are going to require refinishing of your action. The weld will likely cause some inclusions in the finish when you go to blue it. The different properties between filler rod and receiver will show up the moment they hit the salts. Silver soldering is going to leave a goldish ring where the screw is.

This makes a very good case for Ceracoat as it doesn't care about any of this.

Hope this helps and good luck with your fix.

Chad

 

[_shawn_]

Re: what would you do?

c. dixon you have a pm incoming

 

[tman300wm]

Re: what would you do?

I had a similar issue with my 03A3. However, in the case of my rifle the rear part of the receiver was considerably higher than the front, causing about a 30moa can't towards the muzzle. Not really a problem, but when you look through the scope you see the end of the barrel.

My smith used a Leupold one-piece base and built up the rear of the receiver with Devcon steel bed. It helped a bit, but the base still has a considerable amount of cant on it (about 20moa or so). I'm wondering if this is not endemic to 03A3s?

 

[_shawn_]

Re: what would you do?

i could be wrong but i don't think the 03a3 were ever built with scope mounts in mind and originally came with front and rear sights so they had to be drilled and tapped by somebody other then the manufacturer. i guess some were better then others at keeping everything straight

 

[_shawn_]

Re: what would you do?

well here's my temp fix

some jb weld and a couple aluminium shims later and they're on the same plane atleast. had to shim the front ring almost a 1/16" to the left to line the rings up but the scope just drops right in