7.62X51 bolt head ID

[Peter Laidler]

The problem with using s converted .303 extractor on a 7.62 rifle is one of geometry. There is a greater space between the bolt face of a .303 than the 7.62 and the start of primary extraction takes place later during the lifting of the bolt cycle. This is also a primary cause of hard extraction in civilian home conversions. That's why the extractors differ.

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[Frederick303]

The problem with using s converted .303 extractor on a 7.62 rifle is one of geometry. There is a greater space between the bolt face of a .303 than the 7.62 and the start of primary extraction takes place later during the lifting of the bolt cycle. This is also a primary cause of hard extraction in civilian home conversions. That's why the extractors differ.

No doubt about that, but on the 7.62 conversions, the modified 303 extractors seem to work. Now these rifles are being used slow fire, with generally a minute between rounds if one fires UK style and maybe 30 seconds if US style. Taking them apart it seems like the main modification is to thin the top of the extractor, so that the extractor pushed the case over enough to cause it to eject with the original ejector. Not all that reliable, but sufficient to tip up the case in all cases to make the case easy to remove when shooting a prone slow fire string.