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12/5/2025 10:13:18 AM EDT
I understand that FSBs aren't perfectly interchangeable, they have to be drilled with the barrel for alignment or the FSB will be canted.

But say that I want to preserve the original FSB to potentially return to factory setup some day. Would a different take-off FSB be 'close enough' to use as a shaved down gas block under free float handguards?

The gas port hole in the FSB seems large enough to negate a small amount of misalignment. But I'm not sure if there would be excess misalignment of the gas tube and carrier key. Thoughts?
12/5/2025 10:37:20 AM EDT
[#1]
Why not just buy a standard lo-pro set screw gas block and have nothing to worry about?
12/5/2025 11:02:54 AM EDT
[#2]
It most likely will not be close enough. Just buy a used fsb and thread the holes for set screws.
12/5/2025 11:33:58 AM EDT
[#3]
Originally Posted By tyrian:

Would a different take-off FSB be 'close enough' to use as a shaved down gas block under free float handguards?
View Quote


Likely, negative.
"All welchers should be removed from the EE".-Aimless
12/5/2025 11:37:38 AM EDT
[#4]
Cut it down…
Attached File
You can't stop what's coming. It ain't all waiting on you. That's vanity.
12/5/2025 1:40:40 PM EDT
[#5]
Thank you for the feedback. I'd like a pinned option vs set screw for this particular project. I may have to reconsider cutting down the existing FSB or go set screw anyway.

For reference, it's a Diemaco RO933 (mg) parts kit from 2008.
12/5/2025 2:32:36 PM EDT
[Last Edit: Dex223][Edited] [#6]
Isn't a 0933 in 9mm.  If so, you don't have a gas port.  The FSB doesn't do anything other than support a front sight post, and maybe a hand guard cap.  If not for aesthetics, don't put anything on the barrel, especially if you're free-floating it.

Edit:  My mistake; I was thinking 0633.

Maybe, you could use a clamp-on FSB.
12/5/2025 6:00:37 PM EDT
[#7]
Use PRI flip up front sight.  Then you can pretend it is a Mk 12 SPR.  

It will never move.

Neither will the Yankee Hill clamp on front sights.
"Major, with the weapon shops out of the way we can introduce steadying laws that could not be flouted." -A.E. Van Vogt 1951

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