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Lm4 bolt catch (new version)


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#1 BoobieM4H

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Posted 13 July 2013 - 12:49 AM

https://www.youtube....be_gdata_player




#2 mr.ying

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Posted 13 July 2013 - 10:16 PM

View PostBoobieM4H, on 13 July 2013 - 12:49 AM, said:


YESSSSSSSSSSSS FINALLY!! thanks man!!!! :clap:  yah da best!

#3 Gascan_78

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Posted 18 February 2014 - 05:05 AM

Hello All,

I have a question about BoobieM4H youtube video's to modify the originale bolt catch so it goes higher and catch the bolt. The spring that comes out needs to placed back after I take some material off the bolt catch and bending the level-arm ?? For the KWA LM 4 PTR GBBR it is...
Thanks for your informations.

Edited by Gascan_78, 18 February 2014 - 08:29 AM.


#4 Chuck S

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Posted 18 February 2014 - 03:39 PM

Bolt stop plunger spring (#73).  It and it's corresponding plunger (#56) hold the bolt stop up or down by engaging a detent in the stop.  This function is eliminated with the modification and the spring gets re-used.  You'll find them when you -- carefully -- disassemble this part of the gun.  Easy job, even I could do it.  Take your time.

-- Chuck

#5 Gascan_78

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Posted 19 February 2014 - 02:09 AM

Thanks Chuck, for your information. I'll try to modify my LM4. One question remains about the spring (#73) where goes this after the modification? :drooling:

#6 gcw360

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Posted 19 February 2014 - 11:45 AM

View PostGascan_78, on 19 February 2014 - 02:09 AM, said:

Thanks Chuck, for your information. I'll try to modify my LM4. One question remains about the spring (#73) where goes this after the modification? :drooling:
One of two places:
  • It shoots across the room as you take out the block never to be seen again
  • It goes under the bolt release allowing it to remain disengaged until the mag engages it


#7 Gascan_78

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Posted 21 February 2014 - 05:54 AM

Hmmm, very funny :D, but I planned to disassemble in a transparant plastic bag so the spring wil not jump away! But I'm still wondering why this spring and plunger can't be used again on the orignal way?? What's de raison for that? :shocked: And if not, I have to drill a hole in the bolt catch and using the spring or a part of it? :blink: Do I understand it corretly in te video's?

Edited by Gascan_78, 21 February 2014 - 05:54 AM.


#8 akiraspeedstar

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Posted 21 February 2014 - 07:23 AM

It's not necessary as you can still use it in the original location, though you won't have the ability to release the bcg with the charging handle.

#9 BeachEMT

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Posted 21 February 2014 - 09:24 AM

Do you still need to trim the spring with the new bolt catches?

#10 Chuck S

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Posted 21 February 2014 - 04:12 PM

The whole purpose of the exercise (and the new bolt catch) is that the bolt goes forward when you pull the charging handle to the rear and release it.  So you don't need to press the bolt catch to release the bolt.  Just like the real M16-series.

You need a spring behind bolt catch so it's held OFF unless held by the bolt carrier and it releases when the charging handle retracts the bolt slightly.  If you put the spring and plunger back in their original positions the bolt won't go forward unless you press the bolt catch -- defeating the whole reason for this.

-- Chuck

#11 Gascan_78

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Posted 22 February 2014 - 03:55 AM

Hello Chuck,

Thank you for this information :drool:, I'm getting it now and understand it!! I shall do the Bolt catch modification for my LM4 soon!

#12 Chuck S

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Posted 22 February 2014 - 08:50 AM

Take your time and don't lose the small parts.  I modified my original bolt catch many months ago and it works like it should.

The metal in these airsoft guns is much softer than in the M16 rifle and closing the bolt by pressing (or "slapping" it like in the movies) will wear the bolt stop and face of the bolt carrier fairly quickly.  This modification makes operation of the gun more realistic and minimizes unnecessary wear.

-- Chuck




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