I am going to get my barrel turned down and it has a 3/4" barrel and I want it turned down to 5/16". My current front sight will be no good and I need one that will fit the 5/16" barrel. Does any one know where I can get one? I like the standard one too.
Why not just get it turned down between the FSB and the chamber area and keep your current FSB? Just a thought. Good luck!
-RD62
Exactly!
Contact Randall at AR15barrels.com and get some solid advice. Barrel turn downs are his specialty.
I emailed randall and he does not respond now to emails because of all the emails that he gets.
I have a colt that has the lightweight upper and the rifle balance nicely and that is the diameter of that front sight base.
I’ve only ever seen FSBs in .625"(5/8), .750"(3/4) and .9375"(15/16) I think Alexander Arms uses proprietary sized gas blocks on the Grendels .5625"(9/16).
You could have a custom one made but why? It’s much simpler to just leave the .750" area by the gas block ‘unturned’ down.
Our gas blocks for the chrome lined Grendel barrels are 0.750". The threads we use are 9/16-24 tpi due to the larger bore diameter.
As your front sight base has to locate against a shoulder to provide any durability in use, the best option would be a light profile using a 0.625" sight base. The shoulder can then sit at 0.725" but you can runthe barrel under this diameter under the handguards and between the gas block journals. I would suggest that you examine the proposed wall thicknesses carefully though before you proceed.
Bill Alexander
The colt that I have probably has the .625 front sight. I will probably just have the part under the hand guards turned down and to a government profile.
If I do this will there be any issues I should be aware of?