MY SFAR...RUGER SAYS (LONG......)

[sargeny11]

Hey All.. SFAR 16"...no lock back on empty mag..no matter what the gas reg setting...ejects but fails to feed next round in mag & bolt goes fully forward..fires a round and does not eject....so....i disassembled re the manual & found the gas block loose...the set screws were about to fall out...
cleaned rifle thoroughly including the set screws & loctited with Loctite 222...rifle functioned for approx.10 shots & starts its sidewalk act again...
no matter the gas reg setting...disassembled again & found the set screws slightly loose....
Called ruger yesterday & 'splained all above to them...also asked to send me the new "updated" gas regulator....was told that is "misinformation"....
there is no updated regulator and was told that the early production sfar's gas regulator setting #2 is UNDERSIZE...they are sending me a new current production gas regulator..acquired mine in OCT 2022...asked how to best address the loose set screws...put me on hold for 10min...said their techs said to use Loctite...!!!! I will try Loctite #242...am loathe to use #271 as it is "permanent"...As always YOU pay YOUR money & YOU take YOUR chances.....
Pete in central texas...

 

[NikA]

Piece of aluminum can as a shim on the non-port side? Sounds like the issue is overall tightness as well as screws coming loose.

 

[GasGuzzler]

Piece of aluminum can as a shim on the non-port side? Sounds like the issue is overall tightness as well as screws coming loose.

Or a piece of flattened out brass from a spent 22 LR (what I used as a trigger shim on my R92).

 

[Mobuck]

FIRST: make sure there isn't some sort of debris in the buffer tube preventing full travel. No kidding: I've seen this on AR's. Yes, you can manually retract the bolt by squishing the polymer bumper on the buffer but the operating system lacks the last bit of force to do so.
Another place to check is the gas port. "Stuff' occasionally happens: drilling chips are lodged in the hole, the hole didn't quite fully enter the bore, OR in one case I encountered, the broken off end of a drill bit was lodged in the gas port(I won't mention the brand).
The loose gas block seems to be the primary issue with the SFR. Once those set screws have 'chattered' a bit, it's going to be darned difficult to get them to hold position (or even get them back in the correct position). This is why I prefer 'clamp on' gas blocks. A little dab of lok-tite will hold them and still be easily removed by simply spreading the clamp a bit.
Obviously I don't work for RUGER and supposedly, their engineering dept has much smarter folks than myself so my suggestions aren't worth much.

 

[Mobuck]

Guys, the 'shim' would be so thin that positioning would be difficult and the set screws would simply mush or tear the shim when tightened. The set screws are supposed to tighten the inner top surface of the gas block against the upper port position of the barrel--that's how it's supposed to work. Shimming the underside would have no benefit.
I don't fully know the dynamics of SFAR gas port pressure, volume, dwell time, and such details but it's a very intricate balancing act getting this right within the confines of the AR 15 platform.

 

[duke3]

The stock buffer tube is too short--use a 7/8 position tube with factory spring or go to A5 system...I can't believe their lack of thinking on this...

 

[NikA]

@Mobuck is correct, for some reason I was thinking this was a clamp-on style block from the OP's description. Make sure the barrel is properly dimpled, consider using a softer metal spacer under the set screws (brass, I would think), and use plenty of Loctite. "Permanent" Loctite can be removed with just a bit of heat, should be fine in this application, though I'd guess the issue with the original application may come down to prep (have to clean and degrease for good Loctite bond).

 

[Hvymax]

Nothing is "permanent" a torch will loosen Red Locktite. I don't trust unpinned gas blocks. Just drill and pin it.

 

[Mobuck]

I had some 'issues' with a 6.5 Grendel that were finally solved by switching the upper to a 'rifle' stocked lower (vs the carbine stock/buffer).
Lots of options for spring rates and buffer weights.