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Product Image CNC Machined Precision Mag Shim For Tokyo Marui Pistols (Pack of 10)

CNC Machined Precision Mag Shim For Tokyo Marui Pistols (Pack of 10)


LPE CNC Machined precision magazine shims are one of the simplest and cheapest upgrades available for 'gas in mag' guns on the market today. Magazine shims are placed under the gas router on the top of GBB & NBB magazines to push the rubber seal up so it forms a better seal with the loading nozzle which can give some of the following improvements in performance*,

- Improved gas efficiency
- Improved shot-to-shot consistency
- Increased felt recoil
- A small increase in power/fps

Installation is very easy and completely reversible requiring no modifications to the gun or magazines, with the feedlips removed 1 – 3 shims are placed in the top of the magazine under the gas router and the feedlip reinstalled to get an optimal seal against the loading nozzle. Please note that more pressure on the feed lips will be required in some cases to reinstall retaining pins and care should be taken not to damage the pins or feed lips themselves.

Each shim is fully CNC machined in the United Kindom from 0.19mm thick plastic shim sheet.

Tested and confirmed to fit the following Tokyo Marui gas pistols :-

Detonics .45 Combat Master
Px4 Storm
Mk23 SOCOM Fixed Slide

Tested and confirmed to fit the following WE gas pistols :-

Px4 Storm

Tested and confirmed to fit the following KJ Works gas pistols :-


*Please note that improvements in performance will vary depending on the condition and/or fit between parts in the magazine and BBU assemblies, they are unlikely to improve a seal between the magazine gas router and loading nozzle that is already optimal.

UK Shipping Prices

Royal Mail First Class - £1.80, free for orders over £30.00
Royal Mail First Class Signed For - £2.70 flat rate

International Shipping Prices

Royal Mail Standard Airmail - £3.00
Royal Mail Standard Airmail – Free for orders over £30.00
Royal Mail Priority Tracked & Signed For Airmail – Starts at £9.00


Lees Precision Engineering does not ship to the following countries,
China, Indonesia, Peru

Dispatch & Delivery Times

Orders are normally dispatched within 3 working days of receiving payment.

Orders within the United Kingdom generally arrive within 1 – 2 working days of being dispatched however may take upto 10 working days, especially during peak times for Royal Mail.

International orders generally arrive within 3 – 10 working days of being dispatched but may take upto 15 working days.

International orders to Canada and South American countries often take slightly longer and may take upto 20 working days to arrive from the date of dispatch.