DR marked .410 L.S.A. ShtLE MkIII from Century

Hi all, I have looked and couldn't find anything on this. I recently got a L.S.A. No. 1 Mk III in .410 and found the stock marked on one side DR and no other DR stamps on the metal. I have not been able to find any evidence that there were drill purpose rifles in a .410 configuration and I have looked everywhere. I would have discounted this as just the butt stock was swapped, but the firing pin was clipped.
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So the question I have been unable to figure out is, was this a Drill Purpose rifle with no visible modifications other than the clipped pin and paint on one side of the butt stock or were parts moved around (the bolt does not match - all other parts do).
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So I ask you knowledgeable people, what the heck happened here?

The rifle has been in use in India and was converted to .410 at their Ishapore factory hence the RFI (Rifle Factory Ishapore) on the left side of the butt socket. As far as I am aware India was the only country to convert to .410 it was a single shot, the magazine well being filled by a wooden block. It is probable that your rifle has been downgraded for training use as it seems to be a mix of parts.

Thank you for the reply, I was aware that RFI did the 410 single shot conversion and how a drill rifle should be not be fired, but couldn't find any other examples of a DP marked .410.
What I'm wondering is if they might have taken the much lower pressure 410 out of service at some time after conversion. Would the common view be if it has a painted butt stock and clipped pin that it was taken from service and shouldn't be shot?

The problem you have is that these Rifles had a multitude of Indian users, from various Policing related organisations, to the Army in Cashmere and other boarder Provences, were a 'larger' crowd stick was perhaps felt needed....

So probably downgraded to DP status via the Indian Police, purely for new recruit square bashing drill.

The miss matching could well be because it wasn't considered important on an Indian drill piece, or, perhaps more likely, thrown into a wire cage with a stack of bolts and sold to the trade, in 'as is' condition, as a job lot.