So I’m at the stage in my build where I am assembling the upper -specifically the gas block.
One of my barrels is a LaRue* Stealth which has three dimples and I have the matching gas block. Beefy.
Should I get this pinned? Thoughts? *sidenote: I am having an multi-month ongoing CS issue with them right now.
Another of my barrels is a Ballistic Advantage Hanson. Comes with a pinned gas block, but no dimples. Should I send it off to have it dimpled?
Lastly, I have a GMR barrel with no dimples or pins. I originally wanted a FSB install, but I can’t find someone who will do it because the barrel is nitride’d. Should I dimple & pin? On this one I am using a nitride low-pro Brownell’s gas block. Weird set spacing at .415.
What’s the thoughts on dimpling? Pinning? Is it a must? - All of these rifles could potentially be duty use.
How can I make sure the gas block is properly aligned without the barrel being dimpled? Can I do any of this work myself -I haven’t found anyone in the mid-Michigan area I trust anymore.
Sorry if my thoughts are varied and scattered -ADHD like a mother.
While I’m not the definitive authority on gas blocks, I’ve not ever seen a properly installed gas block set-screwed under a hand guard come loose. In fact, it’s difficult to take off some factory installed gas blocks such as BCM.
I used to pin mine on no matter what; and while it’s the most bomb-proof way to install it, it’s overkill.
All exposed gas blocks or FSBs need pinned, no exception.
Could be your friend is thinking that the pressure from the set screws would pull the block tighter against the barrel contour thus providing a better seal. Don’t know if that is true or not, just an idea.
Reference your original post - if the gas block is pinned it does not need to be dimpled, so that BA Hanson barrel should be good to go.
Dimpling the barrel for a gas block is not that difficult. I’ve posted these instructions for installing a Geissele Super Gas Block several times in the past, they explain the process:
I believe ADCO will dimple opposite the gas port when installing the GB prior to drilling the pin.
It wasn’t long ago that this forum was adamant about pins, but that has softened probably based on BCM performance. I have had a few BCM uppers without pins and no issues.
For me, I had ADCO pin my set screw GB. Belts and suspenders!!!
If you own a drill and bits then just buy a jig and dimple your own barrel, they cost less than $40. I paid $35 for my SLR dimple jig, on one side it lines up on your gas port hole so on the other side the dimples are drilled in the perfect spot.
Furthermore, if I was to have the gas block pinned but then change the block to another in the future, would the pin hole size be applicable to other gas blocks?
Just my opinion but pinned is better, always. Screws come loose, Loctite makes it less likely but not impossible.
Not saying “if it can come loose it will”, but I will say “if it can come loose it might”.
The good thing about a lo-pro GB is that it doesn’t need to be so elaborate as two tapered pins-- because you don’t have a 2 1/2" steel lever (front sight base) to attach. There’s no big lever in place to get bumped. many lo-pro GB’s will be well protected under the hand guard.
For me the set screws are there to hold it in place while I cross-pin it. A 1/8 or 3/16 split pin is adequate.
I pin all mine. Just too easy to do. Granted I dont taper-pin them I just use a coiled stainless roll pin I pick up from BRDEngineering. My go to lo-pro block is the SLR GB7-PIN with a pinning flat already on the block ready to go.
Rainier Extended .750 on a Spikes Optimum Profile Barrel
So if I get a BRD for SLR jig, do I need a drill press or a vise + hand drill?
Also, I emailed Jake Carlson of BRD and asked if it matters which dimpling jig I get if I only intend to drill one dimple -making sure it’s the same profile width. He replied, “No sir, all of the jigs do one dimple under the gas port.”
Yes, I would use a vice. Lots of dimple jigs out there, I use the SRL because I already had an SRL gas block and my SRL jig does two dimples not just one. https://www.youtube.com/watch?v=m203m8jMYOk
Wasn’t there a thread here a while back where pinning, set screws, and clamp on blocks were compared? I want to say dimpling the barrel had some affect on the bore, where pinned had much less of an affect. I can’t remember if the difference was enough to even matter, but I decided to pin the Geissele gas block on my most recent SPR build anyway due in part to the info posted in that thread.
