As this was to be my first ever upgrade on an AEG, I wanted something that was going to be easy to perform.  Many of the usual suggestions for upgrades were made in the forums (spring / spring guide etc), however for my first attempt at an upgrade I did not fancy stripping down the gearbox.

One suggestion was to replace the stock 6.08mm inner barrel with 6.04mm tight bore inner barrel.  This upgrade interested me as it was relatively easy to do compared to replacing the spring.  It was also suggested that I could improve things further by increasing the length of the barrel, as the G36c only has a short 247mm barrel.

As a longer inner barrel would protrude out of the end of the G36c, and solution would be to "hide" this using either an extended outer barrel or a silencer.

Parts Required

Some further searching and reading led me to an interesting article on ArniesAirsoft, which lists the sizes of inner barrels for various AEG's.  Using this list of barrels, I eventually matched the barrel that I wished to use to a suitable silencer.

• G&P MK23 silencer - Measuring 195mm
• Systema 6.04mm barrel for HK51- Measuring 369mm

I also decided that replacement of the hop rubber and bucking should also be done, as replacing the barrel includes removing the hop rubber and bucking anyway.

Testing the AEG

Before doing the upgrades, I wanted to benchmark my AEG, the last thing I wanted to do was perform the upgrade and turn up at my next skirmish to find its performing worse than it did before.  So I decided that I should chrono the AEG before and after the upgrade, for this I borrowed a Combro CB-625 chronograph. Several test shots were done with this and gave me an average reading of 266 fps with hop up turned off.

Removing the G36c Inner barrel

Just before Christmas I purchased Airsoft Guide DVD – Volume 2, as this covers stripping and reassembling the G36, so armed with this I followed the barrel disassembly guide, removed the inner barrel, ready to remove the hop. At this point the DVD guide switched to removing the receiver. Fast forwarding confirmed to my horror that no guide on removing the hop up was found.

Not ready to admit defeat I turned to the internet, and found an amazing guide on www.airsoftforum.com written by KrYpTiK, this covers the removal of the barrel and hop up unit, along with the replacement of the hop rubber.   Following KrYpTiK’s guide I managed to remove the hop and rubber. At this point I noticed a slight permanent indent on the hop rubber were the hop buckling is positioned. This indicated the rubber did require replacement.

I could also at this point compare the size of the old and new barrels with the hop removed.

The new hop rubber was put in place and the hop up chamber was refitted again following KrYpTiK’s guide. I then followed the Airsoft DVD guide to refit the barrel. At this point the gun was reassembled with the new inner barrel protruding out of the outer barrel of the AEG.

Final Testing

I fitted the silencer and tested again using the chronograph, this time averaging 286 fps. Its unknown if this improvement is the result of the replacement barrel or the worn hop up rubber, however I am happy with these results.

Unfortunately as my back garden is not very big, range and accuracy tests could not be done.  So I’m looking forward to my next skirmish this weekend to see how the AEG now performs.  (edit: Keep us posted Mark as to the outcome...)

Conclusion

As this was my 1st time upgrading my gun I was nervous something would go wrong. However the upgrade was easy to perform, and hopefully quite beneficial. Well worth the money I spent on the parts.

My confidence has now grown, and I am already considering my next upgrade (spring and bushings).