WTS: P556 Estes Adams 553 clone upper, SIG 556-to-551 barrel, Swiss 55X magazines, SE Vortex Ops Inc hider, C7/A1E2 upper, 552/3 HG
Estes Adams 553 clone upper built on US P556. Welded diopter sights, chopped/drilled 550 handguard with handguard cap, 3-prong hider, upswept cocking handle in US BCG, and unfluted flat wire recoil assembly. Some porosity in the welds that serve to delete the top rail bosses. Overall even finish wear from use. Gray/green finish and furniture scheme. Includes one 20rd Swiss mag. $900 shipped. $1000 shipped with three 20rd Swiss mags. Can include a gunfactory optic rail for another $100.
556-to-551 conversion barrel. Swiss 551 barrel with trunnion thread adapter to enable installation in a US 556 receiver. Will need completed by a gunsmith. Barrel comes with two-piece barrel extension as well, which enables a 16" length without any modification to the barrel itself. $250 shipped.
Used, "restricted" LE-marked, 20rd Swiss 55X mags. Three available. $95 shipped per mag, or $265 shipped for all three. All magazines will be inspected at known failure points before shipping.
Used, good condition. C7/A1E2 "A2 with field sights" upper. I've seen this configuration called a few things; I am not sure what is technically correct. It is not an actual Diemaco; it is marked with a D and a K. No M4 feed ramps. Fixed carry handle with A1 sight, forward assist, and brass deflector. $80 shipped.
Used Smith Enterprise Vortex flash hider 1/2x28 with external threads for Ops Inc Model 12 (AEM5/OCM5). $60 shipped.
Sig 552/553 Swiss SAN black plastic handguard. Used; like-new. $100 shipped.
Sig 55X upswept Swiss cocking handle. Used. Good condition. $75 shipped.
US Sig 556 "Patrol" recoil assembly. Brand new in the package PN: 1511879-R. This is the good, unfluted rod with flat wire spring. $150 shipped.
B&T Rotex flash hider for Sig 552/3. 14x1LH thread. $75 shipped.
Reproduction Sig 552 recoil springs. $40 each; shipped.
I also have some other unique and/or hard to find Sig 55X rifle parts. Let me know if there's something specific you're after.
Email for pictures or questions. Payment methods accepted are CC+4%, PPf+f, personal check, or USPS MO. Will not ship until a week after deposit of personal check. Additional shipping fees incurred for AK, HI, WA, CA, and OR.
Willing to cut a deal, for anyone buying multiple things.This message has been edited. Last edited by: KSGM,
September 09, 2022, 11:13 AM
KSGM
I have produced a small run of Sig SG551 silencer adapters. The adapters use a Halo-style collar and pocket attachment interface, and are compatible with silencers threaded in 1.375x24, otherwise known as “HUB”. The adapters are CNC machined from 17-4 stainless steel, and salt bath nitrided.
In the interest of transparency, I want to make potential purchasers aware of an idiosyncrasy:
The HUB threads on the adapters are on the small side; this means there is a bit of wiggle when you are screwing the adapter into the silencer; the play obviously disappears when the unit is completely tightened. This phenomenon is consistent across all units and all silencers I have threaded the adapters into, to varying degrees, depending on the silencer manufacturer's thread tolerances.
Q&A:
Q: Will the adapter work on a 550 or 551/3 LB?
A: No. Those weapons use one of two possible flash hiders of NATO dimensions. Depending on which flash hider your rifle has, there may already be silencer options available.
Q: Can you produce an adapter that will work on a 550 or 551/3 LB?
A: Yes. The same design can be modified slightly, and applied to a 550 silencer adapter. However, I don't intend to invest in a run of 550 adapters in the near future.
Q: Will this adapter work with my (insert make/model of silencer)?
A: Only if it is threaded 1.375x24 in the back. If the silencer manufacturer states their silencer is threaded “HUB”, 1.375x24, or 1 3/8 x 24, it will work.
Q: Will this adapter work on the 551 with the longer barrel without the grenade gasket?
A: No. This adapter is for a proper 551 only. Dimensions of the flash hider should be as follows: Diameter of flash hider not to exceed .845" Length of flash hider ~1.650" Length of flash hider including taper down to barrel diameter ~1.950" Barrel diameter behind flash hider not to exceed .570"
$140.00 shipped. Email for pictures or questions. Payment methods accepted are CC+4%, PPf+f, personal check, or USPS MO. Will not ship until a week after deposit of personal check. Additional shipping fees incurred for AK, HI, WA, CA, and OR.This message has been edited. Last edited by: KSGM,