FIRST thing you need to do before adding anything is make sure what you've got is right. I don't know how Spikes does things so I'm not picking on them.
-Remove the Bolt Carrier Group. Does it have a firing pin shroud? Does it have a full circle design at the back end? If the answer to either of these is NO, replace the carrier with one that has both
-Are the gas key bolts properly staked? If not, they need to be. It's best if you remove the bolts, clean the threads and clear away any burrs before doing so, and torquing them properly before re-staking. I don't know what the torque value is supposed to be
-Make sure the gas rings are in place and in good condition
-If it's a carbine length gas system, setting up the extractor correctly is essential. You must use the correct spring and the proper "O" ring is strongly reccomended
-Check to make sure the stock castle nut is properly staked. If not, it will eventually shoot loose
These things may not be a problem with a Spikes carbine but it doesn't hurt to check and it will doing them will teach you what to look for
Finally
-Lube the BCG thoroughly
Dear MistWolf here are my specs:
Spike's Tactical ST-15 M4 LE
M4 LE upper receiver group specifications
Spike's Tactical M4 flat top upper receiver specifications-
-CNC Machined from a 7075 T6 MIL-H-6088 Forging.
-Extended M4 feed ramps (done before plating).
-Mil-Spec 1913 picatinny rail.
-MIL-A-8625F Type III Class 2 Hardcoat anodized finish inside and out.
-Laser engraved T-markings.
-Laser engraved ST Spider logo.
-MIL-L-46010 Dryfilm lube on the interior.
-Mil-Spec ejection port door assembly with 5.3.1.2 MIL-STD-171 phosphate finish.
-Mil-Spec forward assist assembly with tool steel pawl and 5.3.1.2 MIL-STD-171 phosphate finish.
Barrel specifications-
-Barrel steel is Certified MIL-B-11595E Chromoly Vanadium Alloy.
-Raw barrel steel is Magnetic Particle Inspected prior to machining.
-Barrels are stress relieved.
-16" length.
-Mil-Spec M4 barrel extension with 5.3.1.2 MIL-STD-171 phosphate finish inside and out.
-1.2.2.2 MIL-STD-171 hard chrome chamber and bore.
-5.56mm Nato chamber.
-All chambers are Individually checked for head space twice (once before plating and once after plating).
-1:7 twist rate.
-All barrels are Individually High Pressure Tested (HPT) and then Individually Magnetic Particle Inspected (MPI).
-5.3.1.2 MIL-STD-171 phosphate finish on the barrel exterior.
-M4 Government profile.
-.750 diameter front sight base location.
-Carbine length DI gas system.
-1/2x28 thread pitch.
-Threads are concentric to the bore.
-Forged F-marked A2 front sight base with bayonet lug and 5.3.1.2 MIL-STD-171 phosphate finish.
-Barrel has 5.3.1.2 MIL-STD-171 phosphate finished under the F-marked A2 front sight base.
-The F-marked A2 front sight base is taper pinned to the barrel and perfectly straight.
-Rubber coated front sling loop attached with correct rivet.
Bolt carrier group specifications-
-Mil-Spec 8620 tool steel M16 bolt carrier w/shrouded firing pin.
-Carrier has 5.3.1.2 MIL-STD-171 phosphate finish inside and out with 1.2.2.2 MIL-STD-171 hard chrome bore.
-Laser engraved with ST Spider logo (visable through ejection port door opening).
-Mil-Spec tool steel carrier key.
-Carrier key has 5.3.1.2 MIL-STD-171 phosphate finish inside and out with 1.2.2.2 MIL-STD-171 hard chrome bore.
-Carrier key is attached with Grade 8 hardware and properly staked per the Mil-Spec.
-Bolts are CNC machined from Carpenter No. 158®.
-Bolts have 5.3.1.2 MIL-STD-171 phosphate finish inside and out.
-All bolts are shot peened per the current Mil-Spec.
-All bolts are Individually High Pressure Tested (HPT) and then Individually Magnetic Particle Inspected (MPI).
-Tool steel extractor, shot peened, 5.3.1.2 MIL-STD-171 phosphate finish, fitted with a Mil-Spec black extractor spring insert and Mil-Spec Viton o-ring.
-Mil-Spec firing pin with 1.2.2.2 MIL-STD-171 hard chrome finish.
-Mil-Spec cam pin with 5.3.1.2 MIL-STD-171 phosphate finish.
-Mil-Spec firing pin retaining pin with 5.3.1.2 MIL-STD-171 phosphate finish.
-Mil-Spec barrel nut with 5.3.1.2 MIL-STD-171 phosphate finish.
-Mil-Spec delta ring with MIL-A-8625F Type III Class 2 Hardcoat anodized finish.
-Forged Mil-Spec charging handle with MIL-A-8625F Type III Class 2 Hardcoat anodized finish.
-Mil-Spec 303 stainless steel carbine length gas tube.
-Double heat shield M4 hand guards.
-Round hand guard cap with 5.3.1.2 MIL-STD-171 phosphate finish.
-A2 Bird cage flash hider, 1/2x28 thread pitch with 5.3.1.2 MIL-STD-171 phosphate finish.
-Flash hider is properly timed with a crush washer.
-M4 LE lower receiver group specifications
-Spike's Tactical lower receiver specifications-
-CNC Machined from a 7075 T6 MIL-H-6088 Forging.
-Low shelf for RDIAS.
-Milled engraving.
-MIL-A-8625F Type III Class 2 Hardcoat anodized finish inside and out.
-Mil-Spec lower parts kit with rounded hammer.
-Trigger and hammer engagement surfaces have been jeweled/polished during the manufacturing process.
-.154 diameter stainless steel trigger pin with black oxide finish.
-.154 diameter stainless steel hammer pin with black oxide finish.
-7075 Mil-Spec receiver extension (buffer tube), 1.14" diameter, 6 position, MIL-A-8625F Type III Class 2 Hardcoat anodized finish inside and out with MIL-L-46010 Dryfilm lube inside and out.
-Mil-Spec castle nut and latch plate with 5.3.1.2 MIL-STD-171 phosphate finish.
-Castle nut is torqued to 38ft-lb. and held in place by a properly staked latch plate.
-ST-T2 Tungsten heavy buffer.
-Mil-Spec 17-4 stainless steel buffer spring.
-Spike's Tactical Mil-Spec M4 stock with sling loop, hardware has been properly heat treated and 5.3.1.2 MIL-STD-171 phosphate finished.