[Texheim]

So I got my forend from hkpro member U.S. Praetorian, thanks buddy it got here no problem and looks good, and through no ones fault but CAI and myself for having bought one the forend does not fit properly because the craptastic weld job prevents the forend from sitting flush. I've looked online and haven't been able to ascertain whether or not I can SAFELY sand down the welds with a dremel or not. What say ya'll?

 

[hkshooterusp]

Smoothing out that FUBAR won't hurt anything. Grind away. Just don't remove so much metal that you compromise the weld completely.

 

[U.S. Praetorian]

T. your welcome! Sorry to see the fitment problem, I did not even think about the angry monkeys and their weld jobs. You can clean that up with a dremel. It won't hurt the gun as there is not supposed to be welding there to begin with. I would use a flat file to contour the weld as opposed to a dremel.

 

[Lohe]

I would take a flat piece of sheet metal and bend it to fit in the chanel around the barrel so you don't hit anything you don't
want to and maybe get a black touch up pen to refinish it?

 

[Texheim]

I would take a flat piece of sheet metal and bend it to fit in the chanel around the barrel so you don't hit anything you don't
want to and maybe get a black touch up pen to refinish it?

Keeping with the spirit of a CAI build, I LIKE IT!

 

[jdonovan]

. I've looked online and haven't been able to ascertain whether or not I can SAFELY sand down the welds with a dremel or not. What say ya'll?

I'd just wait for it to need a new barrel, and while its off getting the barrel fixed, have the smith clean up the weld job at the same time.

 

[Texheim]

I'd just wait for it to need a new barrel, and while its off getting the barrel fixed, have the smith clean up the weld job at the same time.

Excuse my ignorance, how many thousand of rounds are we talking here before a new barrel is warranted? I've slowed down in the past couple of weeks with only 700 rounds since mid January.

 

[jdonovan]

Most of the C93's have poor assembly problems leading to dramatic loss of bolt gap requiring a new barrel. It generally shows up in < 1000 rounds.

Have you checked your gap?

 

[hkshooterusp]

Why do these need a new barrel? Why not turn the barrel and repin it properly?

 

[jdonovan]

because the barrels diameter was reduced by the assembler, to make it easier to assemble, and there is no way to re-use the barrel.

 

[hkshooterusp]

Ah. Thanks.

 

[Texheim]

me .018 gap. why a new barrel and not simply + or - rollers to get you where you need to be?

 

[jdonovan]

me .018 gap. why a new barrel and not simply + or - rollers to get you where you need to be?

Sounds like yours was pressed properly.

the + rollers won't work because the barrel keeps sliding. The barrel is supposed to be a press fit with the trunion. When it was turned down by one of CAI's builders it had to use the pin to keep it from moving, and the pin can't support that kind of load.

 

[Chopstix Kid]

Before you start grinding down that weld, make sure the correct 6 welds are holding the trunion in. Whoever welded it may have omitted the correct welds in leiu of the one you want to grind down.

 

[JeepGuy79]

Man I would buy a new receiver and just redo it if it was me. It would eat me up knowing that was there.

 

[JTinIN]

Man I would buy a new receiver and just redo it if it was me. It would eat me up knowing that was there.

Just buy another one to keep in the safe and shoot the hell out of this one, then swap the receiver, barrel and internals if needed (i.e. change guns ;-).
Actually if the weld is ground down (and the correct welds are there ... but starting to sound like they are not ....) should be like new when the gun is painted again.

 

[6500rpm2]

Chops posted a valid question-can anyone confirm if the trunion was properly spot welded to the receiver on the C93's. kind of pisses me off at this point, I abrasive blasted the Century finish off a few weeks ago prior to spraying with MolyResin and it should have been easy to check if I'd looked. I do have what looks like witness marks from a belt sander around the diameter of the receiver at the front which would be consistant with sanding the welds flat, but no distinct weld marks.

 

[mt162]

No, they aren't. That's why that sloppy weld in the front was added.

 

[NE450No2]

Here is a random thought, have you tried one of the "fat" fore ends, ie the one that takes the bipod?

It might fit without any "grinding".
You can shoot with it till you see how the bolt gap is doing...

 

[a1fabweld]

If you're not worried about the finish, grind down the high spots first, then find someone with a TIG welder (unless you have access to one & have the know how to do it) & just pass over the existing weld in a side to side motion just using the arc from the torch. You souldn't have to use any filler rod. It will "blend" the existing weld & make it much more uniform & consistent looking. This is one way to cheat an ugly weld.