I’ve heard a gunsmith say that gas blocks wont get as much gas if they are installed without a handguard cap. Presumably because the port in the barrel and the port in the block will be slightly askew. He said to you should “set it back” to compensate. Using a shim or something?
Have you ever noticed failures or reduce function because of this? Interesting idea, but seems like it’s too minor to make a difference.
Depends on the gas block. My SLR Rifleworks Sentry 6 & 7 blocks were designed to be placed directly against the shoulder of the gas block journal. They accounted for the small space where there handguard cap would have been.
The key is knowing your parts and assembling them correctly. Some gas blocks can go directly against the shoulder (as noted above) and others can not.
The proper way to do a lo pro gas black is to make an indexing dimple opposite the gas port for the rear set screw. That way it will line up perfectly unless the gas block or barrel shoulder is out of spec. The port opening should always be directly above the rear set screw. Don’t worry about dimpling the front screw as gas blocks have different distance to centers.
http://slrrifleworks.com/index.php?route=product/product&path=57_129&product_id=579
Or
I installed an MI low profile that uses 3 set screws.
Inverted gas block on barrel and lined up gas hole.
Used a feeler gauge between block and barrel.
Used feeler gauge to space it off and installed.
Clarence
Now that’s a good tip!
The gas block shoulder’s purpose is to hold the hand guard cap, not seal in gasses.
Its optional and not required with low profile blocks used under rails.
The gas block should always be centered over the gas port, regardless of what else is going on.
If I needed some AR work done, I’d find an armorer and forget this “gunsmith”.
Only if installed improperly.
If they are pinned or have a set screw a dimple it can’t be in the wrong place.
Yeah, what others have said, just leave a .025 gap and you are set.
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