Quick detour.
For everybody here that has built an AR 10 and has a lot of experience with various receiver sets if you were doing a buy ones cry once and you don’t want to wait for a LMT MWS, upper
What receiver set and handguard would you go with?
Right now I’m probably going with a receiver, set from the same folks that make the ones for gray ghost precision, as well as a rail from Cross machine tool
That being said, because I can’t find the Seekins SP 10 builder set in stock. What would be your next best option? I asked that because I just got some word from Zev that they will be having the MML maten upper receivers back in stock within the next couple of months
The 3 main receiver sets I personally build off of for my own rifles are as follows..
Seekins SP10
Mega Maten
JP Enterprises
And if rebuilding/rebarreling used rifles, it's Larue with thier true free floating handguard design.
All three of the main ones listed above utilize the extended upper receiver with the internal barrel nut which increases the surface area and rigidity and prevents any direct pressure from the load/torque applied to the handguard transferring to the barrel essentially providing a free-floating barrel.
The only receiver sets that provide a "100% True" free floating barrel design is Larue, but!! You even have to do your due diligence with them because I've had several that required material relief from inside the handguard because the Barrel Nut was rubbing inside the handguard.
Every one of the above mentioned receiver sets has its own individual unique requirements to maximize thier performance. For instance if you go with JP Enterprises the upper receivers are machine to a tighter tolerance which makes them a mandatory Thermofit with most standard size Barrel extension.
Now when working on the Seekins or Mega receiver sets I make sure to measure the inner diameter of the upper receiver where the barrel extension slides into, so that way when I order my Custom barrels I make sure to order the appropriate oversized Barrel extension for each individual receiver set so that I get the same Thermo fit with the barrel to upper receiver as I do with my JP's ultimately increasing the barrel rigidity.
With the Seekins and Mega receiver sets I hand fit the Takedown pins on a Case by Case basis, some sets require it and some don't.
If you've got to have it now JP is the answer they keep a variety of receiver sets on hand with a very minimal delay in shipping time, you can choose from Side, Top or both charging Handles.. I use the LRI-20 with the Side Charger.
Hope this Helps...
And if you happen to already own a LaRue There's Hope for them as well...
Jake.