If I order a DD barrel with a low profile gas block is the gas block pinned?

Are their stripped barrels cut out for pinned gas blocks or just dimpled?

If I take a dd barrel with a factory fsb and remove it will the pin whole line up with the riflespeed gas block so it can be be pinned without sending it off?
I got a riflespeed gb for my aero m5 that comes cut out for a pin and they provide a pin in the package. Here is a picture of that.

There’s a very good chance they won’t line up.

Even if they did line up, DD barrels are also drilled and reamed for a taper pin, whereas that looks like a simple coil pin.  I’d imagine a coil pin in a taper reamed pin cut probably wouldn’t provide the best mounting security, but someone can correct me if I’m wrong.

My guess is that RS block is pre drilled so it’s easier for the end user to drill and pin it to their undrilled barrel without the need for a drilling jig.

Stripped barrels will not be drilled for a pin at all. If you find one that it is, it means that barrel had a block or FSB on it and someone removed it.

The GB and barrel need match-drilled together as a mated pair for the pin to line up.  You generally cannot even swap previously pinned gas blocks or FSBs between other barrels that had already had another same device pinned to it. They are not interchangeable pieces because they are drilled as mated pairs.

Meaning it’s especially unlikely you’ll be able to drop a gas block onto a barrel that was previously drilled for an FSB.

A smith can fit one though. Or you can.  

For a virgin decice on a previously drilled barrel…Fixture up the barrel on the table so the existing pin hole(s) in the barrel indicates on center with the machine spindle with a dial test indicator.  The barrel holes may be partial, so you may need pins to hold in the hole as you indicate off of.  Put the gas block on and tighten the set screws to position the block where you want then clamp it in place firmly with an external clamp.  Then drill out your hole.  I’d recommend drilling a straight hole for heavy coil pin instead of a taper pin.  Easier install and equally effective.

If you’re device is drilled already, clamp the device on the barrel, line up the hole to the spindle bore and drill the hole.  The catch is you need to determine if the new hole is going to unfavorably interfere with the old barrel hole.  If it is, just skip the pin and  use quality set screws (ie: pay more than 98¢ at Lowes for them) with proper torque on a dimpled barrel and a drop of medium threadlocker.  That’ll handle anything.

Don’t get hung up on pinning… even actual combat issued MK18s don’t pin the gas blocks - dimples, set screws and loctite.
If the gas block is buried under a handguard and nothing can hit it, pinning is overkill.  If it’s an exposed FSB or gas block… pin it.

DD does offer stripped barrels w/GB. Some are pinned with a taper pin (generally not fully set in place) others with set screw GBs.


Do not expect your new GB pin holes to line up with an existing pinned GB. Components are match drilled in place and pretty much unique.

I’ve successfully pinned a LPGB on a previously FSB taper-pinned DD barrel using a large coil pin, so it is possible. I’d definitely try to get one without the block, though.