I think that this is a good place to post this. It isn't about a completed GSG, it definitely isn't finished. It's more about about the effects of some modifications. I recently got my 9" barrel with trunnion. I'm still waiting on a flash hider, forearm and some other goodies to come. What I was most concerned about was how well my GSG would function after the changeover and also, would I lose accuracy with this barrel modification.
So, in spite of the fact the rifle is incomplete, here is what I found.
Rifle as it is at the moment. Waiting for more parts. Thorsbear? Thorsbear?
So, my first concern was function. Extraction can be an issue apparently. When I was assembling my barrel/trunnion it was suggested that you insert an empty cartridge in the chamber (prior to installing in the rifle), press the bolt over the trunnion, and then pull it off. If the case comes out with the bolt, the extractor is aligned with the extractor groove. If it doesn't, they recommended filing out the notch. Didn't really want to do that so was happy when the case came out when i pulled the bolt away from the chamber.
Completed the assembly of the rifle and headed off to the range. Loaded up a mag and pulled the trigger. Bang with positive extraction/ejection. Pulled the trigger again. Same result. Did the whole mag with no issues. During the shooting session this afternoon I only had 2 failures to feed out of about 150 rounds. Not one extraction issue. I think it was the ammo. Only happened with that brand.
Now came concern #2. Would it be as accurate as the original barrel? I have been quite pleased with the accuracy of the original barrel. Shoots very well with most ammo. So, here's the results with 3 different types of ammo and a new 9" barrel.
All groups were shot at 20 meters from a rest. I used a Holosun red dot. Not as precise as a scope but this is what I will be using so I went with that.
5 shots with Federal Match ammo.
CCI Standard Ammo
CCI Mini Mags
Rapid fire of Mini Mags (12 shots)
Based on these results, I am quite satisfied with the accuracy of this barrel. Mini Mags will be my cartridge of choice, hands down. I also set up a 6 inch gong at 25 yds. If you missed it was your fault. Double and triple taps were quite easy and a lot of fun.
So, I'm glad I made the change. Gun looks great with no loss of accuracy or function. Now, to finish it!! Thorsbear? Thorsbear?