Building a repo no.4 sniper, I have a problem!

[wazz]

I am building a reproduction sniper on a no.4 long branch rifle.
I followed Peter Laidlaws instructions to the letter and all was going swimmingly until I tried to mount the rear pad, I drilled the 4ba screw holes and threaded them encountering some case hardening on the inside of the action but not enough to prevent me from drilling through , threading and not bottoming out the screws.
The 1/4" bsf hole is another story all together, I can't get the hole any deeper than 2/3rds the way through and if I do I am concerned I won't be able to cut the thread.
Anyone have a suggestion where I go from here.
thanks warren

Information

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[CINDERS]

Apparently Cobalt drill bits are the go for hardened steel so you may be able to get a drill the correct size, though tapping it may be a different hurdle.

[tbonesmith]

I had this issue recently and used a 10mm and 8mm carbide end mill to create a stepped hole in the position, into which I (soft) soldered a mating plug of silver steel, which I then drilled and tapped as usual.

I know what you mean about hard, good luck getting through without carbide, and buckleys of tapping it if you do. I hope the attached photos help.

Be very mindful of where things are in relation to the locking lug recess when over-drilling this location.

Attachment 90661Attachment 90660Attachment 90659Attachment 90658

[wazz]

I had this issue recently and used a 10mm and 8mm carbide end mill to create a stepped hole in the position, into which I (soft) soldered a mating plug of silver steel, which I then drilled and tapped as usual.

I know what you mean about hard, good luck getting through without carbide, and buckleys of tapping it if you do. I hope the attached photos help.

Be very mindful of where things are in relation to the locking lug recess when over-drilling this location.

Attachment 90661Attachment 90660Attachment 90659Attachment 90658

Thanks Tbone that's very helpful I will give it a go.

[pisco]

get reloading wazz there is no excuses now