GB-tech SPR Mark 12 Mod 0 question

[HelloKitty]

I noticed that some retailer's pictures include three little silver rings and a black part, while others do not. What are they for?



vs.

[Primus]

Usually those silver rings are to shim the outer barrel/handguard and the little black thing is actually the charging handle oversized latch (and it is also in the second pic you posted).

[HelloKitty]

1) Oh I see, so the black thing is for the charging handle, but I probably don't need it since I'll be buying the G&P metal body accessories kit which comes with the charging handle and other little parts to furnish the bare bones G&P metal receivers.

2) For those silver shims, do they need to be GB-tech brand? I mean if I get it installed professionally at a store, would they have access to random shims lying around anyways? In other words, is it a big deal if my GB-tech kit does not come with those silver shims?

Thanks

[HelloKitty]

I looked more carefully inside the box, and I do see that it came with the special latch, but it only came with one metal shim.

Do you think that one shim will be sufficient for a tech to attach it to my G&P receiver?

Thanks

[Primus]

Umm, hard to tell, every installation is different. You may not need the shims or you may need 5 of them, you just never know. A good tech should have a few spares kicking around or at the very least he should be able to come up with something else to shim with.

[HelloKitty]

Ah I see, so it's not like it must be a GB_tech specified/proprietary part, since it could take more than what they normally include anyways (three of them) to get it to fit right.

[bruce]

Part of my review that I did on my GBTech kit.

what's in this conversion kit?
-#38 type SPR PEQ-2-MOD long rail
-Gen III type front guard
-OPS flash hider
-OPS suppressor
-Reinforced outter barrel
-M84 big latch
-flip up front sight

Kit comes assemble in the package.I had to disassemble everything to install on my Systema M16A3 metal body. Nothing too difficult but you have to be careful to aligne the barrel lock so that the front guard, which is connected to the lock with two pins, also lines up with the top rail of the receiver body.
After installing the front guard,barrel and the rest of the parts on the barrel, I connected the #38 rail to the body and front guard. Without the rail,the free floating front guard is strong enough for a solid feel. With the #38 rail installed, I have to say this is the most solid rail system I have.
The quality and finish of the kit is extremely high.The best I have seen is all I can say. There are steel helical inserts to better resist stripping the threads and the fit of the parts are perfect.
Instructions came in Chinese with B&W pictures.

If he needs more shims, he can get a thin brass sheet at a hobby shop and cut extra rings with it to help aligne the foregrip.

I think you might also need to increase the hole where the inner barrel goes through on the flash hider or trim down the diameter of a Prometheus inner barrel for it to fit.

[HelloKitty]

Thanks Bruce, at first I was thinking that missing shims in the package would be a major problem.

[ChiefInTrees]

Originally Posted by HelloKitty

1)

2) For those silver shims, do they need to be GB-tech brand?

I belive they are shims for where the front end meets the receiver.

[bruce]

IIRC, it's between the outer barrel and receiver.