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P14 Left Locking Lug
Hi,
New member here. I have two P14's, both Winchesters with one being a MKI and the other a MKI* and both are matching bolts/barrels. The left locking lug on MKI is .610" and .635" on MKI*. SN are 17## and 249##.
Having two like that allows me to directly compare things and I often wondered why the left locking lug was lengthened. Stratton wrote so as to strength it but I don't think that is the case. The metal is added past the point of the bolt face so how could this possibly contribute anything to the strength? I have always considered the dual locking lugs of P14 to be superior to other enfields with rear lugs so why would an additional 0.1" be necessary. especially considering this was wartime?
Anyway, I think I figured out why the left lug was lengthened. It helps during extraction. The brass is held during extraction process with extractor holding rim on left side with support on opposing side provided by the left lug. With the MKI ,the left lug actually sits below the height of the the brass rim so it isn't supported it very well.
If I place a cartridge on the MKI bolt, it takes very little to knock the brass loose while the MKI* takes quite a bit more before it slips off. The brass is removed from chamber reliably but once clear it can occasionally release from extractor prior to hitting ejector.
Stratton also indicated that MKI* left lugs are .725" longer but it seems like there are a lot of MKI* bolts that are smaller than .725" with mine being only one example I have seen or heard of so if you were adding metal to strength something you surely wouldn't want that to vary so drastically.
Anyway, that is my first post thoughts.
RJN
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04-16-2013 04:56 PM
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Good observations regarding the LH lug. I would agree that it was an operational reliability mod rather than a strength issue. The Japanese
type 38 has a similar lengthed LH lug, but it was there from the start. Pertinent because I've seen what happens when that lug heigth is reduced on rebarreled Arisakas. Not a happy situation!
Stratton and some of the other authors in that series of books don't seem to have had much of a manufacturing or engineering backgrounds. So don't be surprised to find more statements that just don't make sense. Still, the books have their uses.
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Originally Posted by
rjn
Hi,
New member here. I have two P14's, both Winchesters with one being a MKI and the other a MKI* and both are matching bolts/barrels. The left locking lug on MKI is .610" and .635" on MKI*. SN are 17## and 249##.
Having two like that allows me to directly compare things and I often wondered why the left locking lug was lengthened. Stratton wrote so as to strength it but I don't think that is the case. The metal is added past the point of the bolt face so how could this possibly contribute anything to the strength? I have always considered the dual locking lugs of P14 to be superior to other enfields with rear lugs so why would an additional 0.1" be necessary. especially considering this was wartime?
Anyway, I think I figured out why the left lug was lengthened. It helps during extraction. The brass is held during extraction process with extractor holding rim on left side with support on opposing side provided by the left lug. With the MKI ,the left lug actually sits below the height of the the brass rim so it isn't supported it very well.
If I place a cartridge on the MKI bolt, it takes very little to knock the brass loose while the MKI* takes quite a bit more before it slips off. The brass is removed from chamber reliably but once clear it can occasionally release from extractor prior to hitting ejector.
Stratton also indicated that MKI* left lugs are .725" longer but it seems like there are a lot of MKI* bolts that are smaller than .725" with mine being only one example I have seen or heard of so if you were adding metal to strength something you surely wouldn't want that to vary so drastically.
Anyway, that is my first post thoughts.
RJN
You hit upon the reasoning behind the change. In reality, most of the mark 1's that had the bolt face machined to proper spec worked just fine with the shorter left lug. Mine did.
In lengthening the lug on the 1* variation, they also machined a recess amounting to almost 3/4's of the barrels circumference on the back face of the barrel to accommodate the lugs extra length. This of course reduced the area that the cartridge rim bears against when a round is chambered. Definitely a tradeoff in Rim support for more positive extraction.
I believe the earlier mk1 to be better from a shooters standpoint, and theoretically more accurate due to the extra rim support.
My theory here is somewhat supported by the fact that all of the "Target" P14's I've seen have all been mk1's.
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