DPMS gas block issue...

[Ruffnek]

Wanted a standard FSB rather than the low profile one that came on my Recon 556 so I bought one from a friend.The barrel has two spaces for set screws from the original gas block but the FSB has two pins to be driven in which won't fit due to the round shape of the barrel inside the sight base.What should I do?

 

[churchmouse]

It sounds like you will have to make some channels for those pins. I would stay with the original Gas block.
You can make the pinned piece work but if you lack the skills/tools to do so it will be a gunsmith process.

 

[shooter521]

What should I do?

By a clamp-on A2 front sight base. Don't try to drill the barrel.

 

[rvb]

std gas blocks / sight towers are installed with taper pins. the holes in the sight and the barrel are usually drilled and taper reamed AT THE SAME TIME. Starting with a sight that has already been installed will be tricky at best, but there are places (adco?) that can attempt to drill the barrel to align with the existing sight holes. Sometimes this requires larger than std taper pins if they have to slightly re-ream the sight to get everything to align perfectly. The dimples in your barrel for the set screws are not used for a std sight tower.

your options are
1) a clamp-on sight tower as recommended above. This would be my least favorite approach. With a tall sight tower that is just clamped to the round barrel, it's easy to put a lot of torque on the sight if you bump it and knock everything out of alignment. OK if you are just shooting high-power or something and largely babying your gun, not so good if you are using it for 3-gun or defensive use.
2)see about a smith with the right tooling to drill/ream the sight/barrel and install the taper pins.
3)replace the barrel.

-rvb

 

[churchmouse]

By a clamp-on A2 front sight base. Don't try to drill the barrel.

This is the best way^^^^^^^^^^^^^^^^^^

 

[mvician]

https://www.adcofirearms.com/shopservices/shop_qnew.cfm?code=FSB Install

 

[Squirt239]

I have drilled a barrel before for the taper pins for a FSB. It's not difficult. Just takes time and the proper tools. I'd be happy to help you out if you are wanting to drill it. Thanks.

 

[Ruffnek]

Thanks for the offer but I think I'm just gonna save up and use this as an excuse to get a Spikes barrel.The AR is down right now anyway because stupid me lost the gas tube roll pin.

 

[sloughfoot]

While it may be true that rifles used in High power competition are babied, that doesn't mean that they are not strongly built and durable. No matter the purpose an AR is being used, dropping it on its sights is never a good thing. I have been informed by USAMU members that they would gladly use their custom M16 High power rifles in combat.

The tapered pins manage a manufacturing problem, they don't contribute strength to the FSB mounting. Study it and realize the simple fact that they do not provide rotational stability. They only provide longitudinal stability.

I have used 2 set screws on each side of a FSB and one underneath for mounting and securing the std FSB. I prefer this method over the taper pins. Some machine flats. I don't. Just my