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Mounting a scope on a .303 – The Gun Rack Skip to main content

Mounting a scope on a .303

The old .303 has been a staple of the Kiwi bush for decades, and will most likely continue to be around for decades to come. Usually the pristine, fully wooded specimens are locked away in gunsafes and taken out for service rifle shoots, and even old sporters get treated with a degree of respect, reflecting their heritage from the culling days.

However, some sporters are the perfect base for a project that’s a little bit fun – a little bit different. So, looking out for the perfect beginning of a bush rifle project, an easy scope mounting scenario was high on the list for me.

Comparing two SMLEs, one with original fixed sights and one with a scope mounted and iron sights removed.
Comparing two SMLEs, one with original fixed sights and one with a scope mounted and iron sights removed.

Most of the older rifles with scope mounts have rails that bridge the gap between the front of the action and the stripper-clip/bolt guide. I think I’ve only seen one with weaver-style rings jimmied into place, and one with a scout-type mount that fit over the rear sight – similar to what you see on some Mosin Nagant scout projects.

Anyway, these older rails – they all tend to lack any Weaver or Picatinny type cross sections – the slots where the recoil stop sits. If you try and fit modern rings to one of these older rifles, you’ll find that after a few shots, the rings will start to slide back or loosen.

So, this means if you buy a rifle with one of these old rails you have a couple choices.

Find some old rings

You could try and find some old style rings that lack a cross-bar. These are similar to the dovetail rings you get for rimfire rifles and for modern Tika rifles. The difference is the width of the ring bases, so you may not be able to find a modern type that will fit your older rifle – especially if the angle of the lips doesn’t mate up with the angle of the rail.

With the ATI scope mount, a longer allen key will be very helpful for the rear grub screws.
With the ATI scope mount, a longer allen key will be very helpful for the rear grub screws.

So, you may have to try and find some old school rings. However there are two downfalls to this approach. Firstly, older rings were phased out for a reason. The cross bar on picatinny and Weaver style scope rings means the rings cannot slide back on the rail under recoil.

The second downfall is that you will be getting an unknown quantity. They will probably be for 1″ tubes only, and you won’t know whether they’re good quality, well-aligned, etc.

Remove the rail and replace

There are a few modern rail types that you can fit to your .303. There are ones that you drill and tap into the side of the action – I’m not a big fan, but others like them. They’re quite similar to the kind of aftermarket rails you’d use on an AK, Mosin or SKS – basically actions that aren’t designed for scope rails.

The grub screws in the rear of the ATI scope mount use tension to keep the rail in place.
The grub screws in the rear of the ATI scope mount use tension to keep the rail in place.

Because the rear ring of the action is quite different to modern actions, your standard MOA rails probably won’t be much help. However, ATI produces a mount that uses one screw into the front ring of the action and a couple grub screws against the rear ring of the action. While these two rear screws are not drilled and tapped into the action, the force they apply seems to be strong enough to keep the rail in place under recoil.

I’ve been using one on a project .303 for a while now, and have had no complaints.

With any aftermarket scope mounts on an SMLE, you’re going to have a pretty high scope. So, you’ll probably need to look at an aftermarket stock or some sort of cheek riser to allow easy and repeatable eye relief. More on that in another article soon, as this project continues to evolve.



Geoff is a shooting and reloading enthusiast who would rather be at the range, but is content to write about it. He is a member of Waiuku Pistol Club, and shoots rifle, pistol and shotgun in various disciplines, occasionally, managing to get out for a hunt.

7 thoughts to “Mounting a scope on a .303”

  1. Hi Geoff. I tried fitting one of these scope mounts to my .303 but after 20 rounds the whole set up just fell off. I see you have some loctite in the photo above. Did you use it? Where abouts did you apply it?

    1. Hi Russell,

      Loctite on the threads of the grub screws does help.

      I had a different problem, where someone had previously drilled and tapped the action, and doing the grub screws up too tightly was actually deforming the rear action ring, where there was not much meat between the hole and the edge.

      After I wrote this article, I ended up drilling and tapping some new holes in the action and drilling the scope mount to match.

      Solid as anything now!


        1. Hi Niao,

          No idea sorry. You see them on Trademe every now and then, or you might find some at a local militaria show (there are usually sellers who have odd bits and pieces, or who know where to get them).


    1. Hi Damon, sorry for the late reply – messages tend to get lost in between the spam every now and then.

      There are old Parker Hale side mounts I believe, but I’ve never seen one in person and couldn’t point you in the right direction (Ebay maybe??).

      Otherwise, aside from full on custom fitting something, you could look at a long eye relief scope that fits in a scout position. There is an example at the link below. I’ve never used it and can’t comment on it either way, but it is an option. Might even allow lower mounting than using the action.



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