Hello. I am new to the AR15.com site, but very familiar with forum postings.

I am needing some help pertaining to the GSG "MP5" series rifles in .22 LR. I saw one on Budsgunshop.com and have been very interested in purchasing one ever since I saw how cheap they were. Since one of these can be had for the same price or cheaper then an AR15 .22LR upper, I am going to purchase one.

I have narrowed my search down to two different variants. I am not interested in the SD version. In MI, there is no such thing as a mag capacity, so I will be purchasing the 22 round mag version.

Links to which two I am interested in:

Rifle Stock-$209
Collapsible Stock-$267

My questions are:

1) Are these the plastic upper & lower versions?
2) If they are the plastic versions, where might I be able to find the metal versions?
3) There is a $58 difference between the two versions. What I was thinking of doing was purchasing the version with the complete stock for $58 cheaper, then if it came down to me not liking the stock, I would replace it for the collapsible stock, which in essence would provide me with two stocks rather than one. What do you think?
4) I am going to be getting the inner screw replacement set along with the H&K push pins. How many H&K push pins are needed?
5) I am also going to eventually upgrade to a rail system on the front of the rifle (hand guard). What rail system is recommended for a vertical grip and laser?
6) As far as the 110 round box mag goes, is that worth the money? I have seen there are issues with it. Would it be best to go with a box mag, or 2 extra 22 round magazines?
7) I found THIS (link) conversion kit for $20 and from what I can tell, its highly sought after. My question is, will it work with either of the two variants above and do I need it shipped to an FFL considering it is the "lower" of the rifle?
8) Last but not least, I am looking to mount a red dot optic on this rifle. I am looking for a sturdy mount to be able to put on the rifle to mount the optic on. What is a quality made mount?

If you have any tips, let me know!

All help is greatly appreciated!

-Thanks, Nathan

Nathan...I can help with some of the questions and my "opinions".

#1.  The link to Buds is for the LIGHT WEIGHT version, meaning it has a composite upper and well as the plastic lower.  From what I found recently buying a 522P model, the weight difference was less than 4 ounces.  IMO I'd stick with the metal-upper (zamak) version.  HERE  is a link to CDNNSports GSG offerings.  You can see where they clearly differentiate the LW from standard versions, and what the relative price differences are.  I got my 522P from them, excellent service, FAST shipping.

#2.  As noted above, CDNN Sports.

#3.  I think you're on the right track, get the fixed stock version, see if you like it, then maybe the collapsible later.  Some of them had complaints of being sloppy.   READ all of the background on the GSG5's on the  GSG Thread here...LOTS of good info.

#4.  I do not have the pushpins, but I've seen they come in sets of 4...3 "short", one ':long".  Caution, you MAY have to slightly enlarge the lower stock and receiver pin holes to accomodate them.  Personally, I don't understand their attraction...I've got a very early GSG5 that still works like a sewing machine and is very accurate, one of my favorites.  I'm not constantly removing the stock or the foregrip wherein the pins might be the only advantage.  JMHO.

#5.  Some have not given very kind reviews for the factory tri-rails.  RRages looks like a nice, strong construction and the guy has a good rep, but it's pricey...then again, you get what you pay for.

#6.  This is just personal preference...I think they're stupid, and problematic from what I've read.  The 22-rounders work great and they're cheap right now at CDNN.

#7.  Not sure, but I THINK I read where they don't fit the LW versions, but don't know why they would not.  As noted, I have an "original" (pre-lawsuit) GSG5 and just got a 522P for a project that I'll be posting pix of here eventually, the only thing I don't aesthetically carefor on the 522 is the dippled grip, which I'm going to cover with a rubber slip-on grip anyway.  Otherwise, I actually prefer the 522 version lower...again, just opinion.

#8.  The 522 has an integral rail on the top...my Eotech 511.A65 fits fine on it and is sturdy.

READ, READ, READ all of the GSG background here on ar15.com.  Also try hkpro.com, advanced search "gsg".    There's lots of vendors and prices on stuff can vary wildly...hotgunparts.com, hkspecialiststore.com, hkparts.net, RRages.com, as well as ebay and Amazon.  Have fun, proceed carefully.

s/fart

***EDIT addition***  Be aware that tinkering with your gun's internals may likely void your warranty!!!  Keeping that in mind, another important mod that I would do is the charging handle buffer, but it involves disassembly of the upper body to get to it from what I remember.

In regards to stocks, I'd definitely recommend the A2 fixed stock. Unless you need the compactness (in other words, you are going to SBR the gun), the collapsible stock is very uncomfortable to shoot. If you can find one locally to shoulder, I definitely would (cheek-weld sucks). Even still, the standard fixed stock that GSG includes is borderline garbage. Usually has some play in it. If it is important to you, I'd definitely would get a H&K A2 stock...

http://rrages.com/stocks/set.htm

I recommend RRages, being their stuff is ready to install. You will need to go with the H&K pushpins with that stock, and I do feel they are a good upgrade (will have to drill the handguard hole to fit, which isn't that hard).

http://rrages.com/pins/net.htm

I would say to go with the metal version, and if you want the MP5 look, get the GSG5 conversion kit.

In addition to the pushpins, I definitely recommend to upgrade the screws. The standard screws have a habit of loosening up, and will cause problems. If you go with the LightWeight model, you won't be able to do the screw upgrade.

http://rrages.com/screws/net.htm

Swap everything out and Loctite them in... and you are good to go. There is a YouTube video on how to do it, if you want to feel it out (very easy, but I also have some gunsmithing experience).

And if you are going to do the H&K charging handle slap, invest into one of these...

http://rrages.com/buffer/index2.htm

Will save the cocking handle from cracking if it is something you are going to do excessively.

No, I just ordered the retro kit from CDNN and had it shipped to my door. Also, on the buffer tube bushings, I found a cheaper alternative than the $15 delrin bushing here  There are a few in the package but one of them fits perfect like it was made for it.