I was dead set on building a G36 clone, until I shot one...Personally, the platform isn't good enough for me to spend 2500.00+ on. Even after that expenditure, I would be left with a "cobbled up clone", not a real G36, so I would probably never trust it for HD use and its too much money/effort for a range toy/bullet hose. If you are an HK collector, by all means build one...if you are someone looking for one as a HD type weapon, I think you will be really disapointed.
IIRC, the G36 is now in A2 format. Im not sure what that gets you, but I doubt it addresses the most serious issues, as the only way to fix the G36 is to replace it IMO.
I found the stock to be weak and flexed noticibly during 2/3/20+ round bursts. The factory optics, while neat looking, SUCK. They are hard to use, uncomfortable and are notorious for fogging/losing zero. An Aimpoint/EoTech is mandatory for any serious use...Sustained automatic fire will melt the trunion and destroy the gun. This is kind of a "meh" issue for me...I won't ever own an automatic weapon, let alone a G36 and if I did, I would never do consecutive Cmag dumps with it. Don't kid yourself, sustained automatic fire will grenade an M4 too...probably just as fast/faster due to the increased heat associated with DI operation. A carbine isn't a SAW...the befuddling fact is that HK advertises a SAW type squad support variant of the G36. Wow...you would think they would no better, but the XM8 would prove otherwise. The magazines are fragile, and will easily break/ejacluate ammo when dropped. Also, they typically aren't compatible with STANAG type magazine pouches. Also, it is possible to bounce an empty case back into the chamber when shooting with the stock collapsed. Every gun has its nuances, but the G36 has some that are unforgivable IMO. Several LE Agencies returned/sold thier G36's because they were both unhappy with the guns quirks and couldn't get them to run right. IIRC, both DC Metro and a MI LE agency both had issues with thier fleet of G36's. The English and Spainish government have also had some issues. HK has it essentially on life support. Its the 416 that is being actively shopped to agencies.
A much better rifle IMO...
The AR15 has really spoiled us. It too is not without fault, but its an accurate/realible/ergonomic weapon which uses readily availible/inexpensive magazines/components. The HK G36 is a step down in performance IMO, especially a clone. At the end of the day, I couldn't justify that kind of money for a "toy", or atleast a rifle that wouldn't be functionally better than a 800.00 Bushmaster. If the G36 was made by HK and availible like the Sig 556, that would quell some of my concerns, but I still probably wouldn't own one. The Sig is a better rifle... If you are gonna spend 2000.00+ on a clone, it better offer 2k worth of performance, or atleast better than a 500.00 parts kit AR. That just isn't the case with a G36 clone...An Arsenal SLR106 is a much better piston 5.56 than the G36. If you are a collector/hobbyist, by all means... get one. They are cool looking and stuff, they just aren't the best fighting rifle availible, far from it IMO. Nowhere near the HK93 atleast...