I have an older G3 build, on a Century stripped reciever, and it's too hard to pull the cocking handle back. The builder was okay with making FALS, but the G3 was outside his experience band. I finally have time to get it fixed.

After getting it properly headspaced with a new locking piece, it still is an absolute workout to get it uncocked and the bolt back.

I did the dime trick on the front of the carrier, and it is still in proper headspace and much easier to cock.

It shoots without any apparent issues with headspace, and the blueround training carrier worked fine with plastic rounds.

Here's my questions.

Is there a reliable way to add length to the front of the carrier? I'd rather not grind on the carrier or reciever.  

I have welder buddy that can weld anything anywhere, but I'm sure someone has experience with this problem.

If welding on the bolt is the best bet, any information on the right kind of material to use? Is it problematic to close up the end of the bolt carrier?

thanks!

The best fix would be to cut off the cocking tube assembly and relocate it closer to the receiver (into the correct position) and TIG weld it into place. This requires something like a copper rod (which also helps alignment) to be inserted into the cocking tube so you don't end up with weld and spatter inside there.

Then in the future it could still use any unmodified G3/HK91 bolt carrier. It should also make the handguard fit tighter (if you've got any issues with that now).

If you'd prefer to leave the tube where it's at, you could look into welding a flat disc into the front of it, where an insert already exists that the charging handle pivots against for leverage, but I've never done that and I'm not sure if you could get it adequately secured without burning through something.

You cannot close up the end of the bolt carrier because it moves backwards during cycling and the recoil spring's guide rod has to protrude through the front of it.

Just add a spacer (preferrably hardened) to the stop at the end of the c-tube. That will give you the extra leverage to unlock the bolt before pulling back on the handle.  If you want to test it out, place the dime in that spot and try it out.