It happens to everybody. You set the small parts on the bench, the phone rings, the dog comes through, and twenty minutes later you’re on your hands and knees with a flashlight looking for a screw the size of a grain of rice.
Or the mount’s been in a drawer for six years and the wrench is long gone. Or you bought the rifle used and whoever had it before you was one screw short of honest.
Weaver is here to help you find the right replacement for your ring, mount or base screw.
Find the Right Substitute
Scope base screws use 6-48 and 8-40 threads. Those are firearms-industry threads. They are not standard coarse or fine sizes, and a general hardware store almost certainly does not stock them.
What the hardware store does have is 6-32, and maybe 8-32 or 8-36. Those look identical to the naked eye. They’ll thread partway into your receiver, feel like they’re working, and cut across the threads your rifle actually has. An incorrectly threaded screw and firearm fit may actually cause damage to your receiver. Now you don’t need a screw — you need a gunsmith to plug and re-tap a hole in your receiver.
Another reason your local hardware store might not have what you need to fix your ring, mount or base is that length isn’t cosmetic. On a great many rifles, the mounting holes on top of the receiver are drilled all the way through into the channel the bolt rides in. A base screw that’s too long protrudes into that channel and stops your bolt — sometimes just stiff, sometimes solid. Rifles come into shops for exactly this. A screw that’s too short doesn’t grab enough thread to hold the base under recoil.
Head shape counts too. The counterbore in the base is cut for a specific head profile, and there’s more than one profile in common use on the same thread size. Wrong head, and the base won’t sit flush no matter how correct the threads are.
So: right thread, right length, right head — and a fastener actually hardened for the job. That’s several things to get simultaneously correct on a part.
How to Order a New Screw From Weaver
If you can’t find the appropriate replacement, our team at Weaver Mounts is here to help. The fastest way to get what you need from us is to fill out the contact form.
What to send us
The more of this you include the first time, the sooner your part ships. Missing pieces mean we have to write back and ask.
- Your full name
- Your email address
- A phone number we can reach you at
- A street shipping address — not a P.O. boxWe ship hardware by methods that can’t deliver to a P.O. box, so a box number means your part sits and waits while we contact you for a street address.
- The model or part number of your Weaver productCheck the part itself and the package it came in.
- A photo of that model numberSo we’re reading it rather than guessing at a typo.
- Photos of the productOverall shots, so we can see what you’ve got.
- A photo showing where the missing piece goesThis one does more work than any other item on the list — point the camera at the empty hole or the bare slot. We’ve been making these mounts since 1930 and there are a great many of them. A picture of the gap can help us get you the right part.
If you can’t find a model number anywhere — that happens, especially on older mounts and secondhand rifles — send the photos anyway and tell us what rifle it’s mounted on. Photos plus a rifle model will usually get us there. Our Weaver Base Chart and instruction manuals are also good places to confirm what you have before you write in.
Installing Your Replacement Screw
Check protrusion before you torque anything down. Install the base screws and look — they should all stand out from the bottom of the base by about the same amount, and none should reach through into the bolt channel. With the bases on and the screws snug, work the bolt through a full cycle. If it drags or stops, back out and sort the screw length before you go further.
Torque to spec, and use an inch-pound driver. Our published values for base screws are:
Ring values vary by family, so check your product on our Recommended Torque Specs chart rather than assuming. These are small numbers — much less than most people apply by feel — and over-tightening is the most common mistake in scope mounting.
If the replacement screw is going back into a mount you’re also re-seating, it’s worth running the whole job start to finish. Here’s the full process:
Weaver | How to Mount Your Scope