Bushmaster Acceptance Inspection (8/07)

[ST911]

Highlights from an initial acceptance inspection of an officer’s Bushmaster carbine. Photos included below are of anomalous items, or items of particular common interest. Photos copyright by me, all rights reserved.

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Manufacturer: Bushmaster
Type: Carbine
Model: Undetermined (Pending)
Serial Number: L452###




Lower Receiver:

L-prefix serial number. Standard single stage semi-auto fire control group. Note seam on hammer and possible mold mark on left side of hammer. Mil dim receiver, hammer, pivot, and takedown pins. Drain hole in magazine fence. Hex bolt in grip screw.








Buttstock Group:

Common Bushmaster type. Commercial dim receiver extension. Circumferentially larger and longer (3/4") than mil dim. 6-position. Hole spacing uneven. End of extension cut at angle. Buttstock plastic. Form of current mil type . Loose fit. Receiver extension (castle) nut unstaked. Nut could be unscrewed without tools after two attempts. Standard carbine buffer, correct weight.






Upper Receiver:

Flat top. Eotech 553 mounted. BUIS is flip-up, Bushmaster OEM, retained by allen screws. No addressing on rails. Extended feedramp machined pre-anodizing.






Bolt Carrier Group:

Bolt bears “CM” engraving. Extractor spring assembly 4-coil spring with blue insert. Carrier key bears small rectangular indents for staking with no material intrusion on carrier key screws. Bolt carrier includes shrouded firing pin and semi-auto rear tang.










Barrel Assembly:

16” barrel, marked “B MP 5.56 NATO 1/9”. Chrome lined chamber and bore. M4-type step on barrel. A2-type flash hider installed and timed correctly. Gas block shaved style with Bushmaster OEM flip-up front sight installed over the top of the gas block. Sight retained by allen screws. Gas block and pins installed prior to parkerizing. Sling swivel installed with rivet. Barrel extension cut for extended feedramps prior to parkerizing. Handguards M4-dim, lightweight plastic, single pair black heatshields.








Gauging:

Passes pertinent gauges.


Other:

Michiguns Ltd. 5.56mm NATO chamber applied to chamber. Small amount of material removed from chamber.


Function Testing / Live Fire:

Pending


Required corrections:

Stake carrier key screws. Stake receiver extension nut to receiver end-plate. Replace OEM extractor spring assembly with carbine extractor spring assembly. Replace grip screw with slotted screw. Apply thread locking compound to all sight components supporting optic. Corrections for Eotech optic as per standing order concerning same.


Recommendations:

Conditional approval. Return for inspection at every 500 round and 60 day interval(s).

*END*
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[rob_s]

Those kind of look like M4 feedramps in there.

[Robb Jensen]

Those kind of look like M4 feedramps in there.

You're right. The only Bushmaster upper receiver I've ever handled that had M4 feed ramps was a Bushmaster piston upper.

[AR15barrels]

You're right. The only Bushmaster upper receiver I've ever handled that had M4 feed ramps was a Bushmaster piston upper.

I have had one of the Texas DPS overrun uppers through my shop that had proper M4 feedramps as well.
Very uncommon though.

[KiloSierra]

I have had one of the Texas DPS overrun uppers through my shop that had proper M4 feedramps as well.
Very uncommon though.

My department bought 10 11.5" barreled Bushmaster's recently. Out of the three I've personally examined, one had M4 feed ramps, one had partially cut ramps and the other was a standard A2 spec upper. Two out of three had decents staking jobs and a black extractor insert and O-ring and one was staked and just had a blue insert like the one pictured . None of the three had a hammer like the one pictured.

[C4IGrant]

My department bought 10 11.5" barreled Bushmaster's recently. Out of the three I've personally examined, one had M4 feed ramps, one had partially cut ramps and the other was a standard A2 spec upper. Two out of three had decents staking jobs and a black extractor insert and O-ring and one was staked and just had a blue insert like the one pictured . None of the three had a hammer like the one pictured.

Good Lord! Is BM scrounging the country side for parts or what? Nothing seems to match from one AR to the next!



C4

[neodecker]

You're right. The only Bushmaster upper receiver I've ever handled that had M4 feed ramps was a Bushmaster piston upper.

I have feed ramps on my Bushmaster

[ST911]

I have feed ramps on my Bushmaster

Which model? How old?

How does yours compare to this one?

[ST911]

Regarding the hammer, is the general consensus that it does appear to be a casting?

[neodecker]

I think I got it late 2001 early 2002 its post-ban the s/n is L268### if that helps. Its a XM15-E2S if you want I can post some pics?