So whats wrong with a railed gas block?

[dialM4murder]

I hear the argument it's not as "strong" as a standard FSB. Ill probably end up with the LMT 16" upper with the standard FSB. I initially was interested in the Stag 16" upper with the railed gas block. My main reason for wanting a railed gas block is that I hate having a cluttered sight picture, ie co-witness. With the railed block I could go with a flip up front sight, therefore giving me a clean sight picture. Explain to me why a railed block isn't a good option.


Thanks.

[Slinger]

I'm with you on this. I don't like the clutter either. If the railed gas block is pinned, I'm told it'll be fine. Just set screws and it might work loose.

[rob_s]

Slinger has it, pin it on and it should be fine. Set-screws and clamping are not the best ways of attaching an item critical to the continued function of your rifle.

[dialM4murder]

Ahh ok. Yes it appears the Stag set up uses set screws. I guess I can just use a riser on the LMT upper to free up some real estate in the Eotech sight picture.

What other options do I have? How are the low profile Vltor blocks? If I go that route it appears ill have to the free float the bbl with a rail set up, then use the appropriate height flip up front sight.

[rob_s]

My personal favorite option is to shave the stock FSB down and install a longer rail over top of it, then mount the flipup fron BUIS on the rail.

http://i134.photobucket.com/albums/q111/rob_s/gun%20stuff/DSC_1762-Small.jpg

[rathos]

I have seen a lot of armalites with a railed gas block. Actually all of the ones we sell at the gunstore I work at have them. They never have issues coming lose. A friend of mine bought an ar-10 from armalite with a railed gas block and it hasn't come lose after over a 1,000 rounds of .308. I would say for for it.

[RyanB]

My problems with them are mostly related to them being heavy and ugly. I would rather have a PRI flip, or just use a longer rail over a VLTOR block and put a Troy flip sight on it.

[BushmasterFanBoy]

My personal favorite option is to shave the stock FSB down and install a longer rail over top of it, then mount the flipup fron BUIS on the rail.

http://i134.photobucket.com/albums/q111/rob_s/gun%20stuff/DSC_1762-Small.jpg

I strongly prefer this option as well. I see no need for a railed gasblock when a longer set of railed handguards will do the job better.

[Stephen_H]

The gas block is a major conduit for heat and can get over 500 degrees during sustained fire. I wouldn't mount anything on one, especially a light or electronic/battery powered aiming device. A longer set of handguards covering a low profile gas block is a much better option.

Stephen

[dialM4murder]

Hmmmm. I think ill just use a riser on my flat top and use a lower 1/3 co-witness.

[dialM4murder]

I wonder if Grant could shave the factory block for me? Listening Grant? :)

[KevinB]

The gas block is a major conduit for heat and can get over 500 degrees during sustained fire. I wouldn't mount anything on one, especially a light or electronic/battery powered aiming device. A longer set of handguards covering a low profile gas block is a much better option.

Stephen


100%

I've seen may AR10 blocks shift ove rthe course of time -- and many PRI front flip sight gasblock combo's -- I wont use a non pinned block

cover it with a longer rail and use a flip sight if that is the function you desire

[dialM4murder]

My personal favorite option is to shave the stock FSB down and install a longer rail over top of it, then mount the flipup fron BUIS on the rail.

http://i134.photobucket.com/albums/q111/rob_s/gun%20stuff/DSC_1762-Small.jpg

Hey Rob, what rail is that on the FDE colored AR(bottom)?

[dhrith]

I myself am fond of railed blocks from a real estate view point but have always been cognizant of the reports of loosening. I've pondered this a bit and contemplated if perhaps the issue is partially due to the railed blocks being made from Aluminum and having a coefficient of thermal expansion somewhere between 2 and 4 times greater than steel and this being where a significant portion of the issue arises (sorry my memory is foggy on steel). 1) If your not doing heavy or sustained firing your not going to generate the temperatures causing the issue, generating lots of confusing and contradicting reports on the net. And 2) Can anyone with decent varied product experience comment on typical materials for railed FSB's being generally Steel or Aluminum? If we use the previous gentlemens comment as the FSB being able to reach 500F than the growth per inch diameter will be either .0015 or .003 in steel, again sorry for the foggy memory, in Aluminum it will be somewhere close to .00685 LARGER. Hence, slip fit. Could this be mechanically designed out? Yes, i think so. But again it reminds me of the full length guide rod solution. The one to the problem that didn't exist in the first place....;p. Just use a pinned block. ;p I would think that a simple material change though would eliminate it also with a minimal of muss and fuss. If someone or someone's can chime in on what they've seen these in the majority made from i'll assume my theory as valid and just machine my own from steel and try it out. The hardest use my gun will likely ever see is a three gun match or maybe a class somewhere. If I had a reasonable belief I'd need this particular gun for defending my life I'd probably cut the variables out and just go with an old fashioned tried and true FSB or Rob_s solution.

[hellbound]

Hey Rob, what rail is that on the FDE colored AR(bottom)?

Looks like a DD M4 Rail 10.0

Using a shaved gas block is a better solution as far as using the existing taper pins and looks cleaner than the railed gas block IMO

[KevinB]

My biggest issue with railed gasblocks is WHY?

If you want a flight front sight gasblock - get one - KAC, VLTOR, and GG&G make them that you can get pinned on.

Adding flighlights, grips etc whatever to a railed gasblock is a bad idea -- and increases the chance it will get bumped out of alignment.

Go with the longer rail and the shaved pinned block if possible