MP40's Modelguns Forum

International Forum for Modelgun enthusiasts
 
HomeFAQRegisterLog in

Share | 
 

 Marushin MP40 Basic Troubleshooting Guide

View previous topic View next topic Go down 
AuthorMessage
Cerwyn
Cerwyn (Site Admin)
Cerwyn (Site Admin)
avatar

Number of posts : 10709
Age : 58
Location / Country : North Wales
Registration date : 2008-07-20

PostSubject: Marushin MP40 Basic Troubleshooting Guide   Fri Sep 26, 2008 6:32 pm

Marushin’s MP40 (abs)…Troubleshooting


 "

Field Stripping, Cleaning, Inspection and Re-assembly have already been covered in previous Step by Step Guides so this guide aims to pinpoint causes of problems when your MP40 refuses to operate correctly.

Marushin’s MP40 is one of the most reliable and consistent firing pfc model guns available. Failures are generally rare given normal hobby use but nevertheless, problems can crop up from time to time.
The ones that do tend to be caused by Maintenance problems or general wear and tear. It is an easy model gun to strip, check and restore to good firing order.


1. Rounds failing to ignite.

Have the cartridges been prepared and loaded correctly?
Are the caps used the correct type and in good condition?

Ref:
Beginner’s Guide… Loading Marushin 9mm Cartridges
http://mp40modelguns.forumotion.net/t922-loading-marushin-9mm-mp40-uzi-cartridges

Check condition of Detonator Pin


Ensure the Pin is clean and not bent

2. Rounds fire but will not extract from Chamber.

Check that the Detonator Pin and Chamber are clean and not clogged up with Dirt and deposits left from previous firing sessions.
Clogged up Chambers will grab cartridges and stop them being withdrawn by the extractor.







Ref:
Marushin MP40 (ABS) Cleaning and Lubrication…Step 1

Check the Extractor is working correctly.

Load a round with a “Dead” cap and insert it into the magazine.
Fit the mag’ into the gun, cock it and pull the trigger.
The bolt should strip the round from the mag’ and feed it into the Chamber. It will not fire as the dead cap has no charge so the gun now has the Bolt fully forwards and closed.
As shown here…




Hold the gun level and keeping an eye on the ejection port, slowly pull the bolt back manually by the cocking handle.
The round should be seen to be pulled back out of the chamber as it’s gripped to the bolt face by the Extractor claw.
As shown here…







Ease the bolt back until the round is almost at the Ejector.
Look closely to confirm the Extractor’s Claw is hooked onto the cartridge’s rim, like this





If the round fails to withdraw at all, it may be stuck in the chamber in clogged up dirt.
If the round starts to withdraw, but drops off the bolt face before reaching the Ejector, then there may be a problem with worn out or broken Extractor Claw, Claw Spring, or Bolt Face


Ref: Marushin MP40 (ABS) Inspection Guide… Step 2

3.Rounds Fire but fail to Blow Back.

Check that Detonator Pin and Chamber are clean… see above
Ensure that cartridges are prepared, lubricated and loaded correctly … see above

4.Rounds extract but will not eject from the gun.

Check that the ejector has not broken.





Check bolt face, check condition of feed rails


Being ABS, the Feed Rails will eventually wear out causing cartridges to drop from the bolt face' grip


  New bolt on Right, Old bolt on Left.
Notice how both Feed Rails are flattened on the old bolt


Feed Rails not only push cartridges from the magazine into the chamber. They also assist the Extractor claw to hold the cartridge securely during extraction.


These photos show how the cartridge is held correctly in a serviceable bolt:


 



Check that the Magazine spring has enough tension to bring the next round up into the gun thereby pushing the fired round out.
Magazine not Feeding rounds up under tension.





Push the carrier down into the magazine body to check for spring pressure(see above photo).

If it feels sloppy or sticks, then dismantle the magazine and check the spring for breakage, rust and the carrier for burrs that may cause friction in the magazine.

5.Bolt not stripping rounds from the Magazine.

Magazine spring too strong… unlikely if it is a Marushin mag’ but possible if using real magazines.
Magazine Feed Lips bent, burred or damaged
Bolt feed rails broken, chipped or missing (see above)

Ref:
Marushin MP40 (ABS) Inspection of components…Step2


Recoil Spring worn out and too weak.


One quick check in to hold the gun vertically, muzzle upwards. Lift the gun upwards sharply and pull it back down again sharply in a swift movement. If the bolt can be seen to bounce easily and without much effort, the recoil spring could be worn and in need of replacement.

6. Trigger and Sear.




Problems here may lead to the gun firing accidentally and uncontrollably or the bolt refusing to move forward when the trigger is pulled.
The Sear moves down into the Lower Receiver when the trigger is squeezed. Ensure it drops into its recess cleanly and that it returns smoothly when the trigger is released.


Cerwyn

_________________
Cerwyn

Hobby collector of Replica model guns and Militaria.
also member of Living History Reenactment Groups.


Last edited by Cerwyn on Tue Nov 14, 2017 11:27 am; edited 6 times in total (Reason for editing : images converted to servimg. New photos and text added)
Back to top Go down
View user profile http://mp40modelguns.forumotion.net
Cerwyn
Cerwyn (Site Admin)
Cerwyn (Site Admin)
avatar

Number of posts : 10709
Age : 58
Location / Country : North Wales
Registration date : 2008-07-20

PostSubject: Re: Marushin MP40 Basic Troubleshooting Guide   Wed Nov 08, 2017 11:47 am

New photos and text added

_________________
Cerwyn

Hobby collector of Replica model guns and Militaria.
also member of Living History Reenactment Groups.
Back to top Go down
View user profile http://mp40modelguns.forumotion.net
 
Marushin MP40 Basic Troubleshooting Guide
View previous topic View next topic Back to top 
Page 1 of 1
 Similar topics
-
» Raybestos Chassis Professional Grade Steering & Suspension Parts 1977-1996 B-Body
» Infrared Thermometer - neat troubleshooting gadget!
» Guide 147 Canadian Canoe for sale
» A guide to the Scrum and Lineout
» Irish River Guide

Permissions in this forum:You cannot reply to topics in this forum
MP40's Modelguns Forum :: Marushin Modelguns :: Marushin MP40-
Jump to: