Welding bases on a receiver question.

[philip brousseau]

I have a remington 700
That the mount base holes are so far off that the rifle shoots 51 inches to the right at 100 yards with the scope mechanically centered. I want to have preferably two piece picatinny nightforce bases lazer welded on the receiver. If I have to I could live with a one piece rail. Is there any way to determine exactly where to place the base or bases? Thank you for any help with this.

 

[jds holler]

Lotsa room for advice on this one. Get ready. jd

 

[Hal]

PB
You might give Chad a call @ LRI and ask him his thoughts.
He can mount your action on a mandrel and machine everything true to the center line of the action.
While it’s still on the mandrel he can change the 6x48 scope base holes to 8x40. Hopefully correcting
your alignment problem.

OR sell that action and put that money and the cost of truing up your action money together and buy a custom action.
Buying custom is never a bad idea.


Hal

 

[Janeau]

In my book welding base to a receiver is not a fix for such a problem. Call Chad as suggested and let a pro fix it.
51 inches at 100 yards is HUGE. Must be something else crooked..might be the scope not centered with knobs..receiver not trued - flat..barrel tread not perfectly centered with the bore..this gun need professional help not a hacking job.

 

[hpshooter]

Personally, I would set the barrelled action up in a vertical mill, determine the true center-line of the barrel and drill /tap the holes in the proper location.

Without getting into the very real potential of possible distortion of the receiver and the need to refinish the receiver after welding a weld is like a tattoo basically very hard and expensive to undo .

 

[GenePoole]

Something like this: a Holland action v-block and a Manson action truing rod and bushings. Tram it or shim it to straight, then end-mill new holes for #8-40 screws (and hope the old one's aren't too far out to mostly clean up).

 

[Rewinder]

Had a Model 7 like that. Have you placed a 2' straight edge on both sides of the receiver to see how the barrel lines up. Mine hung the muzzle to the left an extra quarter inch.
Had the receiver trued up which included opening up the tenon threads .010 in the receiver and the barrel straightened right up after rebarreling and also the scope mount screw holes were straight without touching them.

 

[philip brousseau]

I bought the rifle new and never fired it. The rifling was the worst mess you could
Imagine. I thought no need to shoot it because it was bought as a doner receiver. Sent it to my smith and had receiver trued and bolt sleeved & krieger barrel.shot the rifle and saw it was 51 moa off. Took it to another local smith and they drilled holes off center in a 1 piece rail and that corrected it 25moa. I fixed the last 25 moa with burris signature rings but this makes the mating surfaces of receiver and rail not match properly. Sent it back to first smith and it could have been corrected by boring larger base holes but I guess the problem was overlooked and the out of alignment holes were opened to the larger diameter, 8x40s. Don't think holes can be fixed unless new holes are drilled in a base and the receiver. 338 rum. I'd like to have a good solid base. Rifle is extremely accurate. Lazer welding will not warp a receiver. You can visibility see that the receiver holes are out of alignment and with a steel straight edge against the foreword and rear base screws in the receiver shows about 1/4 inch off center at the muzzle.

 

[philip brousseau]

This rifle is said to be within 5/ 10,000 square and straight. I guess I will hear on this statement.

 

[Rewinder]

Did the Smiths true up the tenon threads with a Lathe or just chase it with a Tap.
did you have to increase the barrel tenon dia.

 

[philip brousseau]

I would like to get this done without removing the barrel but that may not be possible. I could line this thing up with a string better than it is.

 

[philip brousseau]

Tennon diameter had to be increased

 

[AlNyhus]

If the holes are try that far off, I'd TIG the holes up and start fresh. I can't imagine a scenario where welding bases would be beneficial.

There may be more to this, though...including where the muzzle is really pointing relative to the front of the receiver.

 

[philip brousseau]

Al , so tig welding won't warp the receiver?

 

[ShaunBrady]

It looks like smith #1 didn't check the external features against the internal ones. The bolt raceway is an extremely poor starting point for truing the rest of the receiver. Particularly on the horizontal axis because the raceways have removed all material you'd like to reference to. From time to time you read about truing train wrecks and it's usually the horizontal axis.

It also looks like smith #1 did a poor job of aligning the muzzle end downrange. This is the larger problem.

It sounds like smith #2 did their best by moving the scope mounting holes over as much as they could with a #6 to #8 conversion. I'm basing that on the 25 moa improvement downrange. The problem this created is the crown of the receiver and holes are no longer aligned. The fix to that is bedding the scope rail. Bedding may also take more of the remaining offset out.

The problem with welding the rail to the receiver is the fix to the current barrel problem will be baked into your receiver. The rifle has enough problems with things aligning, I suggest not compounding them by using a 2 piece scope base. It'll put stresses into the scope which has much less of a sense of humor about that than the receiver.

 

[paperpuncher]

Ill throw this out there FWIW. I had an M1 carbine that shot 4' to the right at 75 yards with as much correction as I could put on the sights. After carefully looking it over I found that it had been dropped and the muzzle was distorted at the crown I recrowned it and it shot as it should. Worth a look. If the scope holes are indeed off I agree with the above Line it up in the mill, buzz the holes with an appropriately sized end mill and retap to 8-40

 

[Sniperhandle]

If the holes are try that far off, I'd TIG the holes up and start fresh. I can't imagine a scenario where welding bases would be beneficial.

There may be more to this, though...including where the muzzle is really pointing relative to the front of the receiver.

I have heli-arced up scope mount holes on rec and redrilled and tapped them straight, This is also what I would do too.

Machine a close fitting alum barrel tenon plug to act as a heat sink and it will also keep the weld from going into the internal threads.

 

[NZ_Fclass]

When I get this guitar in tune, I'll weld it!

 

[STS]

When things get as far off as this rifle is, it’s almost 100% certainty that there is more than one thing at fault. I’d bet a crisp C note that if the action was dialed on center, the muzzle of the barrel would be wobbling around like a drunk sailor. The scope base holes may be (likely are) off center too. When you have more than one issue they can both be off in the same direction and you have a perfect storm thats 51 MOA off. It’s going to take some serious diagnosis efforts to identify the issues before corrective action is understood.

 

[Sniperhandle]

When things get as far off as this rifle is, it’s almost 100% certainty that there is more than one thing at fault. I’d bet a crisp C note that if the action was dialed on center, the muzzle of the barrel would be wobbling around like a drunk sailor. The scope base holes may be (likely are) off center too. When you have more than one issue they can both be off in the same direction and you have a perfect storm thats 51 MOA off. It’s going to take some serious diagnosis efforts to identify the issues before corrective action is understood.

I wouldn't trust the original barrel machining to be straight before I started going in all these other directions, I have seen some very crooked barrel tenon machining that never had a chance of being able to be on target, I would pull the barrel off and check that first.