A .22 Lee rifle, unsure of details.

[Alan de Enfield]

The majority of these that I’ve come across have mis-matched bolts.

Isn't that because of lack of knowledge of Lee Enfields by the US importers who, when they ship, them they have the bolts removed and shipped separately to the rifles, and then when they arrive the 'Saturday Boy' gets told 'take one of those bolts out of that box and put it in a rifle' without realising the importance of the correct bolt being fitted to the correct rifle..

Not as critical for a 22rf rifle, but potentially a serious issue in a 'full bore' 303.

[BVZ24]

The bolt looks too early for the rifle. If it was the right type of bolt for the original 303 rifle, wouldn't it have the cocking piece safety?
The bolt still has the fingers for the dust cover so it is for an early rifle that didn't have a charger bridge, which leads me to believe it's either modified, which looks possible, or an MLM I bolt, which would have been plentiful in spare parts bins pre WW2.

IMG-20230519-064018-HDR hosted at ImgBB — ImgBB

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[STG-98]

[Brian Dick]

I've had several through here over the years. About 50/50 with matched vs mismatch bolts if memory serves. Most had the rear handguard replaced with modified Mk.III type. My Dad bought one when I was a kid at a Big Oak Trading Post auction in Florida. I still have it! I also imported a couple of the Long Mk.II trainers for clients in years past. They are much more difficult to find.