Need help Id'ing a BCG

[DFSgunner]

First of all, thanks for any help in advance. It came out of an old Colt upper and had the lightning link cut on the bottom so I assumed it was an SP1 BCG, put it in a spare parts box years ago and forgot about it. I was doing some spring cleaning and decided to put up some stuff that I've collected over the years for sale, had a guy interested but said the tail was too long. I got out a few other BCGs to check and sure enough, it's too long to be an SP1 carrier. Any input on what it is? I tried my Google Fu and all I could come up with is there is an "enhanced carrier" that seems to be the same length but I couldn't find anything on an "enhanced carrier" with the lightning link cut. The BCG in question is in the middle of the 3 pictured. Top is a Toolcraft full, bottom is a semi out of an old Bushmaster. Thanks for any input 565415654256543

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[MegademiC]

Try taking a picture straight down, preferably with grid paper or a ruler/tape measure or some reference so we can tell the difference.

[DFSgunner]

Try taking a picture straight down, preferably with grid paper or a ruler/tape measure or some reference so we can tell the difference.Can do

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[DFSgunner]

Let me know if it needs to be any different. Thanks565485654956550

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[SmugPePe]

I think those picture aren't high quality or enough of them at detail points of mystery BCG to be help to us that doesnt immediately know who make those lightning cut tail BCG. I would suggest a close up HD picture of gas key staking, forward assit scalloping, bottom unshrounded firing pin, any marking on the bolt for a signtaure clue like rolled, engraved, dot matrix, laser etc. and close up picture of bolt lugs for machining signature clues. I would also like picture of extractor top side, claw and belly for casting mark clues. HD picture of bolt face and ejector.

I suspect it might be bushmaster, dpms, or RRA but Im leaning toward DPMS. It's old for sure due to unshrounded firing pin. I'm very good researcher my google fu is powerful after I get more HD pictures from you and researching I will likely ID it. But I warn you due us being in time now where many forum pictures and post lost due to failure to archive. There is some chance I will fail to ID it.

[jsbhike]

Might be of interest.

http://biggerhammer.net/ar15/barrelsbolts/boltgenesis.html

From what I can remember walking around Knob Creek prior to Colt using uncut bolt carriers, that cut at the rear was like snow flakes from vendor to vendor.