Converting a 4.5mm bb GBB pistol to a 6mm airsoft

Discussion in 'Gun Building, Modifications & Repairs' started by mihajlo525, Aug 27, 2015.

  1. mihajlo525

    mihajlo525 New Member

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    Hey, I have been playing paintball for quite some time now because there was never an airsoft field anywhere near me. Recently one opened up and one of the refs there said they would like to see me play there (used to be a paintball ref). The only gun I had was some cheap crosman AEGs from my childhood, BUT I do have a GBB 4.5mm METAL bb pistol. (search up gsg 92) It's just as realistic as can get and as good quality as the high end GBB airsoft pistols, even modded it to go full auto (which was disabled). Anyways since it can field strip (like the real thing) You can replace the barrel. So all I'd have to do is replace the barrel and magazine and it can shoot 6mm bbs! The only problem is I can't really find either of those Can anyone recommend a barrel or Mag that can work with my gun????[​IMG][​IMG]
    Here's some stock photos of the gun.
     
    Last edited: Aug 27, 2015
  2. Rushin

    Rushin Well-Known Member

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    I don't think you'll be able to, sadly, but those guns tend to have a crazy high FPS, so you wouldn't be able to play with it without hurting people. :/
     

  3. mihajlo525

    mihajlo525 New Member

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    Windsor
    Gun only averages out around 310 fps new and it's 2 years old, it wouldn't go any higher than 380...
     
  4. kazuma5201

    kazuma5201 New Member

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    Raleigh
    Even if you're able to, it wouldn't be worth the hassle. There are FPS limits on Airsoft fields/grounds too... and I'm not sure how that'd convert for your current item. Assuming you changed the air nozzle, and barrel... maybe it'd essentially tone down the FPS since it wouldnt be so concentrated on a 4.5mm barrel?

    You'd have to replace the air nozzle, magazine, and probably remove the inner barrel if there even is one(it's hard to tell from the picture, but probably safe to assume there would be). If the 4.5mm barrel fits snug in that outter barrel, you'd have no way to incorporate a 6mm barrel in there. The diameter would be too small. If you replaced the outter barrel and inner barrel, it could work, Then you'd have to check to make sure the metal slide would actually hold it though. If it doesn't, you'd have to replace the whole slide.

    There are a lot of compatibility issues here.

    Overall, just get an M9-fashioned gun from TM. You'll probably spend less on that, then you would on converting your current one. Less headache too.

    I don't mean to be negative or oppressive, but I just don't see this as efficient; though plausible.
     
  5. mihajlo525

    mihajlo525 New Member

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    Windsor
    It does have an inner barrel, And yes I know I'd have to replace the whole barrel I'd just need to find a m9 barrel that could fit that's the only trouble I'm having. My local field is an outdoor field, last time I chronoed the gun it shot up to 300 fps only, it would be shooting AIRSOFT bbs only at around 380 max which really isn't too hot if not just a little above average for a pistol. The only thing I need is a compatible m9 barrel.
     
  6. kazuma5201

    kazuma5201 New Member

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    Raleigh
    The way this gun looks... the M92 is your only compatible one I believe. The spring guide sits directly into the HopUp area... which is just like my M92(Samurai Edge, RE2 Replica).

    Grab the "new" NG3 Hop Up Assembly from Evike or someone. Make sure it's for an M92.

    http://www.evike.com/products/51134/

    My only concern is if that hopup is too long compared to your current one, and how that'd effect it.

    If you're at 300 with 4.5mm bbs... it'd probably be close to the same or a little stronger with 6mm once you convert it and have the bigger inner barrel. Those brass bbs are much heavier than the plastic 6mm bbs.

    Good luck!
     
  7. mihajlo525

    mihajlo525 New Member

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    Windsor
    Thanks so Much!!!!!!!:)
     
  8. Rushin

    Rushin Well-Known Member

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    Depending on what type of BB you're using, it will be much, much heavier than a 6mm BB. Brass and copper ones at the 6mm size weigh a little under .98 grams. So you're probably looking at .35 grams... Which is a whole hell of a lot heavier than a .2. You're probably going to be clocking 400, after you factor in the larger barrel.

    Source:
    http://www.airsoftforum.com/board/topic/258892-harder-impact-energy-45mm-bb-or-6mm-20-g-bb/

    So yeah.
     
  9. mihajlo525

    mihajlo525 New Member

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    Windsor
    How does something only .15 grams lighter immediately clock it at 100 fps higher???? That doesn't really make sense.
     
  10. kazuma5201

    kazuma5201 New Member

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    Raleigh
    Well, if it's anything like going from a .2 at 600FPS and then switching to a .41 at 420FPS... I'd say it's plausible to change around 90FPS +/-15 or so. I know this from after I converted my G36 from the .2 poopoo to the .4x DMR it is now.
     
  11. mikejosephman

    mikejosephman Moderator Alligator Staff Member Moderator

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    Just buy a 6mm M9, tired of seeing these threads pop up. It's not worth the time, and you will break it.
     
  12. Rushin

    Rushin Well-Known Member

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    This.

    And, it does make a lot of sense. It's usually +40 FPS for every .05 you take off of the BB weight, more or less.

    Plus, why argue with me? I know what I'm talking about. Conversions never end well or pan out. If you do get it to work (act of God.) you'll find the performance is equal to that of a $5 springer.
     
  13. Grudge

    Grudge New Member

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    Winnipeg
    Crossman copper coated bbs (4.5mm) weigh in at 5.28 grains (according to Amazon who was selling themhttp://www.amazon.ca/Crosman-Copperhead-Copper-Coated-Bottle/dp/B000HKKY7M). This converts to .34 g.

    using : http://www.coderedairsoftpark.com/pages/park-rules-and-hours/fps-calculator.php

    .34g at 300 FPS = 1.41 j of energy.

    Converting 1.41j with a .2 bb gives 389.48 FPS

    Using 4.5mm pellets they come out at .45g at 300FPS = 1.87j

    Converting 1.87j with a .2 bb gives 448.53 FPS

    The math pans out, but is it worth the effort. Maybe.
     
  14. mikejosephman

    mikejosephman Moderator Alligator Staff Member Moderator

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    No it's not, or else there would be plenty tutorials on the subject. Want airsoft gun? Buy airsoft gun. Stop trying to reinvent the wheel.
     
  15. cascade

    cascade Member

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    3
    Buy an airsoft version M9 and compare the slide to see what kind of machining would need to be done to fit the airsoft internals. Then compare mags to see what it will take to make the airsoft mag fit. Then realize how much work it is and dont bother, because you just bought an airsoft M9 that was built around 6mm.