Firing pin and block are VERY stuck

[Raptorjamboree]

I just bought a semi auto bren MKI conversion by Stemple, and everything seems to be in order except for the firing pin and bolt block. The pin is completely immobile, and no amount of oil or hopps solvent seems to loosen it. Based on how sticky the retaining pin in the block was, I assume grease and grime has completely stuck the pin and spring in it's captive spot. I am taking it to a gunsmith on Monday to see if it can be removed and still used, but if it can't, where can I buy replacement semi auto parts? I've looked at firingpins.com, wiselite, sarco, and pretty much everywhere else I know of that used to have such items, but nothing is available.

Information

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[SNAFU22]

Hi Raptor, if you're not already, register on Weapons Guild. There is a ton of information over there for building semi conversions and parts. Good luck with your Bren. I am not implying that this is not a great forum also and if this offends anyone, please have a moderator delete the post.

[browningautorifle]

I am not implying that this is not a great forum

But still you send him away right away...

Its hard to say just from those pics why it's stuck solid, but hang on a minute...

[SNAFU22]

Hi Raptor, there were two common styles of firing pins. One milled a slot through the post and the other uses a box (rectangle) around it. It looks like you have the slotted post. More pics would help. Unfortunately the people that designed those are on other forums. The pic I attached is one style of one design. It may match yours or not. If you could contact people that are familiar with your Bren builder I am sure they could help. You or your smith should be able to make a new pin if one is not available. I use O1 drill rod for firing pins. There is an older post here "Bren semi build USA" I don't know how to link it so you will just have to search for it. It looks like the same setup as yours. Also the face of the bolt should be smooth. Good luck

[Raptorjamboree]

So I have no opportunity or desire to learn how to modify these parts myself, but I do know a few gunsmith's who might. I don't think that's the style of my firing pin. I can't see more than half of it of course, but it looks a little more rounded on the back half. I'm pretty sure it has the slot, though that's just a guess unless I can get it out. Are there any specifications for modifying the block? I know you have to shave away two ridges at the firing end, and I think all the ones I've seen for sale are unmodified.

I am including a couple more pictures. Let me know if you want a specific angle.

[browningautorifle]

Here's a drawing in post one of this thread showing measurements and they may shed some light. https://www.milsurps.com/showthread.php?t=62508

The described thread had no info about this problem.

From your top pic showing the firing pin from the back there looks to be something in the channel on both sides of the firing pin.

[Raptorjamboree]

I'm not sure what you mean by something in the channel blocking both sides of the firing pin? There's the captive holding pin in the side, but that's the only thing I'm aware of.

[browningautorifle]

The hole in the bolt that the firing pin goes through, look at the picture you posted. At the back you can see something inside the firing pin channel. Nothing to do with the transverse pin sticking out.

At the ten and two position of the firing pin channel... Like there's something else in there.

[Raptorjamboree]

Oh, yeah, I noticed that too. I couldn't tell if it was globs of the oil that I tried to inject reflecting light, or metal. Surely it's not been welded in there? I don't know why that would be done, but it's a serious case of false advertising if it is. In either case there is no external indication of what that is, or how to remove it if it's another captive pin.

[browningautorifle]

Surely it's not been welded in there?

Just looks deformed and perhaps those are misshaped enough to jam it.