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Deep in the Cumberland Plateau we have been covertly reinventing the Kentucky rifle...

Extractor Spring Conversion for the Enfield S.M.L.E No.1 mk. III Rifles


Thank you for visiting our website for the Lee-Enfield S.M.L.E (Short Magazine Lee Enfield)  No. 1 mk. 3 extractor spring upgrade kit and modification service for your S.M.L.E bolt head and helical twisted- wire extractor spring and retention pin installation. 

We love our S.M.L.E. rifles of original British and Ishapore manufacture.   However, the extractor spring is a true weak point (if the only weak point) of the rifle’s design.  Some may criticize the rear locking feature of the S.M.L.E. bolt and receiver, but this is actually a safety feature as there is more material available for stretching of the receiver and compression of the bolt to relieve cartridge pressure during an over-pressure event.   In addition, the smaller diameter of the bolt head of the S.M.L.E. provides less surface area of cartridge pressure to act on, leading to less force acting on the locking lugs.  Other than the original extractor spring, the S.M.L.E. is one of the best and strongest designed bolt action rifle from the turn of the century. 

This kit requires drilling (micro-boring) of the existing spring location hole in the side of the bolt head of the S.M.L.E. for No. 1 mk. 3 with a #43 drill (.0890 inch diameter).  A small end mill or file is used to create a spring retention groove  (0.140" wide x 0.050 deep) across the back of the original extractor for the location of the new helical extractor spring  (see pictures).  The notch in the back of the extractor is located by drilling out the extractor spring retention hole and marking with the same drill tip for the center location of the notch.  The depth of this notch or stress concentrations caused by this modification does not appreciably reduce the strength of the extractor.

Modification of the bolt head for installation of the helical extractor spring is a relatively simple job with the right fixturing, tooling, machinery, and skill.  We can also perform this modification as a service for your S.M.L.E with all parts installed. If you send us your bolt head (easily un-screws from your SMLE bolt) we can drill out the spring retention hole, notch the back of the extractor and install our helical twisted-wire spring and spring retention pin and return your improved bolt head to you.


  1. We cannot guarantee that your original extractor spring will be undamaged during the process of removal.  This is a fault of the SMLE design.
  2. Do not send us the entire bolt or a complete rifle.  This avoids FFL issues and streamlines turnaround. 
  3. We cannot sell these parts to or perform this service to customers outside the United States.

We do guarantee however, that out helical extractor spring replacement will provide a lifetime of use. The helical spring will never have to be replaced again.  Unfortunately for the SMLE, either your original V-flat extractor spring is already broken, or it will break sometime in the future with use or during removal / re-installation for weapon cleaning.

Our twisted-wire helical spring is of the highest quality music wire and the spring retaining pin is manufactured by us from 4140 Chro-Moly steel for the best quality possible.  Removal and installation of the helical spring and spring retaining pin is far easier than the removal of the original V-flat spring for rifle cleaning and maintenance and can be removed and reinstalled repeatably without damage.

We are offering these parts and service through EBay.

Our shipping address is:

Arend Engineering

138 Twin Ponds Lane

London, KY 40741  USA