I'm tinkering with the idea of converting a sporter lee enfield into a pistol or intermediate calibre.
The rifle is intended to be used for 3 gun matches for manual/single shot division. I'm well aware there are other options costing similar if not less than converting an LE. But I wanted to try something different and fun. To my understanding the key to a competitive rifle in this division is to have 1. fast cycling action, 2. have at least 10 round capacity and ability to quickly reload it, and 3. a light recoil calibre that's not expensive to shoot. SMLE checks the first 2, but 303 brit is both too expensive and powerful for most 3 gun matches. Hence the idea came forth.
Since the rifle is originally designed for a rimmed cartridge, 38/357 might make the conversion easier? The challenges I see are mainly:
1. Extraction - 303 brit has .540 rim diameter while 38/357 has .440 rim diameter. For extractor to properly grab the case, the bolt head would need to be modified to deepen the cut on the extractor slot further toward the centre of the bolt?
2. Ejection - Empty case ejection on LE is done via friction against left side of the receiver wall, but this is a no go for the much smaller base diameter on 38/357. But there's another ejector screw further back for kicking out live rounds. Can that be used to eject the 38/357 case out? Alternatively one can drill and tap the left side wall to install an additional sidewall block to match the rim profile of the new cartridge?
3. Feeding - From what I gather the control feed is done via the extractor and the side wall? So in order to feed the cartridge straight into the chamber, the additional the left side wall profile still needs to be addressed?
4. Magazine - No idea if 38/357 will fit into the original SMLE mag, potentially with a block + feed ramp installed at the front to take up the difference in COAL?
I know AIA has a Lee Enfield action in 7.62x39. Given 7.62x39 has similar rim diameter as the 38/357, how do they solve these problems?
The rifle is intended to be used for 3 gun matches for manual/single shot division. I'm well aware there are other options costing similar if not less than converting an LE. But I wanted to try something different and fun. To my understanding the key to a competitive rifle in this division is to have 1. fast cycling action, 2. have at least 10 round capacity and ability to quickly reload it, and 3. a light recoil calibre that's not expensive to shoot. SMLE checks the first 2, but 303 brit is both too expensive and powerful for most 3 gun matches. Hence the idea came forth.
Since the rifle is originally designed for a rimmed cartridge, 38/357 might make the conversion easier? The challenges I see are mainly:
1. Extraction - 303 brit has .540 rim diameter while 38/357 has .440 rim diameter. For extractor to properly grab the case, the bolt head would need to be modified to deepen the cut on the extractor slot further toward the centre of the bolt?
2. Ejection - Empty case ejection on LE is done via friction against left side of the receiver wall, but this is a no go for the much smaller base diameter on 38/357. But there's another ejector screw further back for kicking out live rounds. Can that be used to eject the 38/357 case out? Alternatively one can drill and tap the left side wall to install an additional sidewall block to match the rim profile of the new cartridge?
3. Feeding - From what I gather the control feed is done via the extractor and the side wall? So in order to feed the cartridge straight into the chamber, the additional the left side wall profile still needs to be addressed?
4. Magazine - No idea if 38/357 will fit into the original SMLE mag, potentially with a block + feed ramp installed at the front to take up the difference in COAL?
I know AIA has a Lee Enfield action in 7.62x39. Given 7.62x39 has similar rim diameter as the 38/357, how do they solve these problems?
and a few enfield sporters kicking around. 
