Unusual wear on firing pin and FP retaining pin (update pg 2 pic of sear block)

[DaBears_85]

I was unaware BCM was cheap chi-com stuff. I better get rid of my 16" middy.

[SoCalTrojanSoldier]

@andy_t

You should use the same bolt. I view my bolts as being “married till death do you part” to a barrel since they wear together. And while it’s not critical, I prefer it that way.
Carrier can be mixed and matched with no issues.
I had the same issue on an all Colt pre ban lower with Colt semi circle carrier. I fixed by going to a semi auto carrier.
Before going with a full auto carrier, make sure your lower doesn’t have a sear block sticking up a little out of the lower that prevents the use of full auto carriers. If the carrier is shrouded, the same firing pin will work fine.

It does have a sear block but doesn’t stick out. Will any carrier work with this sear block?:

[Blankwaffe]

Yeap,you should be good to go.
By the way the casting seam in the center of the hammer face notch looks to have a bit of an edge to it.I’d suspect that is what is causing the wear you note.I’d dress/radius that shiny spot a bit just for good measure.All of my notched hammers were that way too.

[SoCalTrojanSoldier]

@Blankwaffe

Yeap,you should be good to go.
By the way the casting seam in the center of the hammer face notch looks to have a bit of an edge to it.I’d suspect that is what is causing the wear you note.I’d dress/radius that shiny spot a bit just for good measure.All of my notched hammers were that way too.

Thank you. I noticed the edge too and smoothed that down a little already but it looks like it needs some more work. It’s funny how things tend to show up in the pics that I never really noticed when looking at it in “real life” (eg the “rust” or extra oil on the selector and the hammer and trigger pins).

[ForTehNguyen]

so the concensus is that its an unshrouded firing pin causing the wear?

[ST911]

@ForTehNguyen

so the concensus is that its an unshrouded firing pin causing the wear?

Yup. Hammer drag. Not a critical problem, as long as the parts remain quality and are replaced at intervals. Easy correction is to get an M16, or at least shrouded, BC.

[hellbound]

@SoCalTrojanSoldier

It does have a sear block but doesn’t stick out. Will any carrier work with this sear block?:

that’s not a sear block.
a sear block was a piece of aluminum blind pinned into the receiver where an auto sear would go. the pin holes were bigger than sear pin holes but in the same location, so even if you removed the block you couldn’t install a sear.

any carrier will work with your setup. I’ve used an LMT and BCM (apparently chicom crap…) carriers with my colt lower. my factory MT6400C started to exhibit excessive wear on the firing pin and the hammer face not nearly as bad as yours though.

i have a transitional Colt carrier I acquired somewhere that has a shrouded firing pin, but is only half circle at the rear. IIRC, one of the colt experts told me it was used on the LE guns before they started shipping all of their rifles with FA carriers…

[BWT]

@MK18Pilot

Colt firing pins are chromed and this one is clearly stainless. That firing pin is a Chi Com part from BCM, DPMS, Spikes or one of the many less than legit clone companies.

Wasn’t aware that BCM was Chi Com… I mean they do build everything in country.

I usually refrain from things I’m not familiar with.

But do you have anything to substantiate that statement, at all?

I mean one example, period. To give that any substance?

[Byron]

Don’t ask him for substance: he’s got an agenda to serve.

He popped in to defame a company he doesn’t like with libelous statements while simultaneously alluding to the infallibility of Colt. Even after numerous Colt owners said that they had seen this type of wear with their Colts and the OP said his was a Colt*, MK18 will not be back to offer an apology or retraction, nor will he probably come down off his high horse (or pony, as the case may be).

*Not that I am saying anything bad about Colts. Unlike MK18, I have no brand agenda here. I just take offense (as a number of you clearly do) with this forum being used for baseless slander. I do appreciate the irony of how it all unraveled though.

[Ridge_Runner_5]

@MK18Pilot

Colt firing pins are chromed and this one is clearly stainless. That firing pin is a Chi Com part from BCM, DPMS, Spikes or one of the many less than legit clone companies.

All that hates gonna burn you up, kid.

[ST911]

Took these an hour or two ago.

Left side: Colt LE6920, ~2004 production or so, half-circle unshrouded carrier, identical to the OP’s gun.

Right side: Spare Colt FP and FPRP.

[Eric]

@hellbound

that’s not a sear block.
a sear block was a piece of aluminum blind pinned into the receiver where an auto sear would go.

You get partial credit.
Colt uses a steel block.

[hellbound]

@Eric

You get partial credit.
Colt uses a steel block.

will there be extra credit?

[Belmont31R]

@hellbound

that’s not a sear block.
a sear block was a piece of aluminum blind pinned into the receiver where an auto sear would go. the pin holes were bigger than sear pin holes but in the same location, so even if you removed the block you couldn’t install a sear.

any carrier will work with your setup. I’ve used an LMT and BCM (apparently chicom crap…) carriers with my colt lower. my factory MT6400C started to exhibit excessive wear on the firing pin and the hammer face not nearly as bad as yours though.

i have a transitional Colt carrier I acquired somewhere that has a shrouded firing pin, but is only half circle at the rear. IIRC, one of the colt experts told me it was used on the LE guns before they started shipping all of their rifles with FA carriers…

That is a sear block just not the old style pictured above. Its the newer style and has been around for years now.

I guess they found it was just easier to mill a web into the receiver than put a huge block and hole in the side but the web block is designed to keep someone from installing a sear.

[Pappabear]

My Colts have no Sear block at all. I drove to Timney Trigger in Phx to buy a trigger last year, they said " you cant, must do a sear job". FK That! So I did not buy the Trigger. Later find out, my 6940 did not have the sear Block. Thats my story and heres my question?

Whats the story on the Shrouded vs unshrouded? Shrouded better? Is there unshrouded Carriers? Any pics comparing? Just trying to learn something as usual.

pb

[whiterabbit05]

Top: M16 BCG
Middle: Shrouded AR15 BCG
Bottom: Un-shrouded AR15 BCG

[Darkop]

@Skintop911

Took these an hour or two ago.

Left side: Colt LE6920, ~2004 production or so, half-circle unshrouded carrier, identical to the OP’s gun.

Right side: Spare Colt FP and FPRP.

I have seen a lot of battered FP in the older unshrouded BCG’s and have a couple myself. I just chuck them up in a drill and stone the collar to a round configuration. Also round off the hammer notch a little. Have thousands of rounds through an old 6920 with an unshrouded BCG. No biggie!

Until that day,
Darkop

[Pappabear]

Whiterabbitt, thanks for the pics