What is small punch mark next to main screw under receiver

[TJCNz]

Hi
Just a question about a small punch mark next to the main screw under the receiver. Is this mark put there by the armoured? Is the slot in the screw thread supposed to line up with this punch hole?

Information

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[Surpmil]

Is that a Long Branch No4 you're looking at? If so, the indentation is made by a hardness testing machine.

[CanadianLanBoy]

Hi
Just a question about a small punch mark next to the main screw under the receiver. Is this mark put there by the armoured? Is the slot in the screw thread supposed to line up with this punch hole?

The slot in the screw should line up with the indentation, if all of the parts are matching of course.

[TJCNz]

Thanks
It is a no 4 Mk 1/2. It has been Fulton Regulated some years ago.

[breakeyp]

A punch mark aligned with a screw slot was done to prevent the screw from backing out.

[TJCNz]

Here is a picture of the punch mark.

https://hosting.photobucket.com/imag...=175&crop=fill
In
https://hosting.photobucket.com/imag...=175&crop=fill

[Eaglelord17]

Thats called 'staking'. Likely when it was regulated by Fulton they set it up and staked the screws in place so they didn't back off where they performed best when set up.

[TJCNz]

Thanks for that. So in theory the screw should be backed off a small amount so the slot in screw head aligns with the punch mark.
Thanks for all the input and sharing of experience.

[Surpmil]

Hi
Just a question about a small punch mark next to the main screw under the receiver. Is this mark put there by the armoured? Is the slot in the screw thread supposed to line up with this punch hole?

So you meant the punch mark was on the trigger guard, not the body? In that case your question has been answered by the other posters.

[Alan de Enfield]

Whilst the punch mark is 'staking' it should deform the metal so as to interfere with the slot in the screw head to stop it rotating - things do not align so it would suggest to me that the screw is possibly not original to the rifle or has been 'played with' for some reason.

The screw should not be 'backed out to align' with the staking the screw should be 'bottomed out' and tight into the socket, which, if it is tight in the socket, also suggests a replacement screw of fractionally different length or thread start position.

Notes from PL in 2008

Now it’s time to fit the trigger guard and Screw, rear, tie, fore-end if you have a Mk1/2 or 1/3. There’s a good chance that the rear of the trigger guard will foul due to the height of the new wood. If that’s the case, then simply scrape away the wood inside its seating to allow it to seat correctly all the way to the front. The trigger guard should not spring at the rear or front….., NO it shouldn’t! If it was meant to, it’d be made of spring steel! Now for a little tip. The COLLAR. You MUST have a collar and spring washer. This is what WE used to do. Put the front trigger guard screw into the trigger guard and body WITHOUT the washer or collar. Reverse it (that’s anti-clockwise …..) until you hear it click over the start thread and tighten it BUT COUNT THE TURNS UNTIL IT TIGHTENS AND LOCKS. Say, that it’s 7 ¼ turns to lock. Now do this with the collar fitted if it’s now, say 6 ½ turns, shorten the collar, a smidgin at a time, until the screw tightens up at exactly 7 ¼ turns. That way, you KNOW that the screw is tight, the fore-end is tight between the trigger guard and the screw and you are not crushing the living daylights out of the fore-end. And if it feels a little loose in a years time, then you can safely turn a few thou off the collar.

On properly staked screws you can see the slight deformation of the metal 'interfering' with the slot in the screw head.
If the staking doesn't line up with the slot, then its been removed and either replaced, or not correctly tightened.