{"id":5683616,"date":"2023-01-31T13:17:09","date_gmt":"2023-01-31T12:17:09","guid":{"rendered":"https:\/\/www.optics-trade.eu\/blog\/?p=5683616"},"modified":"2026-10-02T11:53:57","modified_gmt":"2026-10-02T09:53:57","slug":"savage-rifle-screw-size-guide-how-to-identify-6-48-vs-8-40","status":"publish","type":"post","link":"https:\/\/www.optics-trade.eu\/blog\/savage-rifle-screw-size-guide-how-to-identify-6-48-vs-8-40\/","title":{"rendered":"Savage Rifle Screw Size Guide: How to Identify #6-48 vs #8-40"},"content":{"rendered":"\n

Recently, Savage made a change to the screw size used in some of their rifles. Starting sometime in 2020<\/strong>, instead of using the traditional #6-48 screws, they began using #8-40 screws in certain models<\/strong>. This change may cause confusion among users who may not be aware of the different screw sizes.<\/p>\n\n\n\n

It is important to note that the change in screw size is not a simple matter of replacing the screws<\/strong>. According to information from leading manufacturers of scope mounts for the Savage Model 110, it is necessary to purchase an appropriate scope mount for the specific screw size<\/strong>. Users must ensure that the scope mount they purchase is compatible with the screw size of their rifle to ensure proper fit and function.<\/p>\n\n\n\n

There are a couple of ways you can check the screw size on your rifle before purchasing a scope mount.<\/p>\n\n\n\n

\"Optics<\/figure>\n\n\n\n
<\/div>\n\n\n\n

Option 1: Do the Hex Key Fit Test<\/h2>\n\n\n\n

The first thing you could do to see if your Savage Model 110 came with #6-48 or #8-40 screws is to do a so-called \u201chex key fit test\u201d<\/strong>.<\/p>\n\n\n\n

Insert a 1\/8\u201d hex wrench into the screw holes on the receiver. If the hex key fits snugly into the holes, it indicates that the screw hole size is 8-40<\/strong>. If it does not fit at all, it means the screw hole size is 6-48.<\/p>\n\n\n

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\"A
A 1\/8″ Hex Key (Source: OTC Brand)<\/figcaption><\/figure>\n<\/div>\n\n\n

Option 2: Try Measuring the Screws<\/h2>\n\n\n\n

Another way is to measure the screws with a pair of calipers<\/strong>. This option comes in handy if you already have the screws that fit, but you aren\u2019t sure what size are they.<\/p>\n\n\n\n

To do this, you will need a pair of calipers. If the screws measure approximately 3.5 mm (0.138 inches), it indicates that the screw hole size is 6-48<\/strong>. If the screws measure approximately 4.17 mm (0.164 inches), it indicates that the screw hole size is 8-40<\/strong>.<\/p>\n\n\n\n

Keep in mind that these measurements are approximate, but you should be able to roughly determine the screw size.<\/p>\n\n\n

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\"Calipers
Calipers (Source: Wikipedia)<\/figcaption><\/figure>\n<\/div>\n\n\n

Option 3: Search for #8-40 Identifier<\/h2>\n\n\n\n

Savage centerfire rifles manufactured in 2021 or later that have receivers with #8-40 screw holes will have an identifier to help distinguish them from older models<\/strong>.<\/p>\n\n\n\n

Savage Model 110 Screw Size<\/h3>\n\n\n\n

Specifically, Model 110s with #8-40 screw holes will have an identifier on the bolt handle slot<\/strong>, as depicted in the image below.<\/p>\n\n\n\n

This identifier will be located on the top of the receiver and will be clearly visible when looking at the rifle from the side.<\/p>\n\n\n

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\"Savage
Savage Model 110 #8-40 Screw Size Identifier (Source: Savage Arms) <\/figcaption><\/figure>\n<\/div>\n\n\n

Savage Axis Screw Size<\/h3>\n\n\n\n

AXIS models, on the other hand, are a tad more complicated in this regard.<\/p>\n\n\n\n

Savage Axis models made before 2021 have flat cuts along the top of the receiver<\/strong>, as depicted in the image.<\/p>\n\n\n\n

Newer models with #8-40 screw holes, however, will not have these flat cuts.<\/strong><\/p>\n\n\n\n

Instead, the Axis receiver drilled for the #8-40 screws will appear completely round when viewed from the rear or back of the receiver.<\/p>\n\n\n

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\"6-48
Savage Axis #8-40 Screw Size Identifier (Source: Savage Arms)<\/figcaption><\/figure>\n<\/div>\n\n\n

Another thing that can help you identify a newer Axis model with 8-40 screws is the serial number. Savage Axis Rifles with serial numbers higher than N936371 are drilled and tapped for #8-40 screws<\/strong>.<\/p>\n\n\n\n

Option 4: List of Savage Models with #8-40 Screws<\/h2>\n\n\n\n

Savage provides a list of models that supposedly come drilled for 8-40 screws<\/strong>, but they go on and call this list \u201cnot all-inclusive<\/strong>\u201d. This is why we don\u2019t recommend you rely entirely on this list.<\/p>\n\n\n\n

Models with #8-40 screw holes on the Savage\u2019s list are:<\/p>\n\n\n\n