Jump to content

Bolt and/or bolt carrier cam issue

Recommended Posts

This is a brand new bolt and carrier. The bolt carrier will not fully close up with the bolt installed. With the bolt out, the bolt carrier will fully cycle. This tells me that the bolt and bolt carrier have an issue.


And I think I identified it.





It appears and feels like either the cam way on the carrier wasn't cut properly or the cam surface on the bolt is incorrect. Or some combination of the two.


I just have no idea how to fix it.


This is the replacement for the bolt and bolt carrier that tore themselves up in very few rounds. Same issue I suspect, tho at least it fired...


Anyone have any idea how to fix it?

Edited by 1Andy2
Link to post
Share on other sites

You could also ask around, see if anyone else in your area has a S12, and try swapping out both parts one at a time. That could help you isolate which is defective and give you a cost base for when it's cheaper to smith or replace.


If you go with that route, I'd also bring along a snap-cap/dummy round to see if it's feeding and locking.

Link to post
Share on other sites

Several of our business members have a lot of experience with the S12 bolts.(ie. Cobra,Pauly,CS)

These pieces are all custom fit to the guns.

Looks like your barrel hood is attempting to initiate rotation without the locking lugs being lined up with their embutments.


Long ago I found that I could test FCG's function to carriers, but MANY of the bolts I came across would not function well in my test gun.

I don't even try to install different bolts in my test gun any longer.

Just carriers to test FCG function.


Often times extractors don't even line up with extractor slots in the barrels, not to mention lugs & embutments not being synchronized gun to gun.


Heck, there's guns with their own factory bolts that I've run across where the extractor doesn't even line up with the extractor slot in the barrel correctly, or the hood trys to initiate rotation early or late jamming up on the embutments.


This all needs to be fit to the particular gun if malfunctioning.


I'm not taking full guns at this time.

My call is to send it to Jack being as this is a continuing issue for the OP.

Link to post
Share on other sites

In looking at the pictures you posted, it almost looks to me like there are new rub marks on the side of the bolt head, like it's picking up paint off the barrel hood. There appear to be black 'smudge marks' on it, just left of the extractor. If your particular gun is not lined up correctly with the correct path of the rotating bolt, then it could be causing wear on it like what I saw on your original bolt, and what already appears to be happening on the new one.

See that little dent right before the first shoulder on the inside of the cam channel in the bolt carrier? That doesn't look like it was there, before putting in your gun and trying to force it to close all the way. It looks to me like the bolt is coming in contact with the barrel hood, and possibly the ejector block, causing extreme pressure and friction on the bolt while it's trying to close.

A little background here...

The bolt the OP sent me to polish, was having "issues". I noticed some very abnormal wear on the bolt cam, and in the channel it rides in the bolt carrier... I immediately contacted Tom Cole about it, and asked if there was a way to get him a new bolt & carrier, because I believed this one to be defective. The original bolt & carrier were literally destroying each other. The leading edge of the cam, as it starts to go backwards and begins to turn and unlock from the trunnion, had worn a new facet (at first I thought maybe it had been cut wrong at the factory)... causing it to start turning prematurely, and was wearing the first corner completely off the channel in the carrier. It had gotten so bad, it was trying to ride up and out of the channel. Both parts were causing increasingly destructive wear on each other.


So when Tom told me he didn't know what to do about it but try a replacement set, I called Clyde and sent him these photos of the parts.

Notice the similar 'dent' where the bolt is contacting the carrier first....



The bolt cam...



In this photo, the defective or damaged bolt is on the left. You can see the extra facet I'm referring to where it's bashing into the channel and wearing the corner off.



Clyde contacted me immediately, and said to ship them to him, and he would check them out first hand. After looking at them, he said it could be an alignment issue with the gun itself, to cause that kind of damage to the B & BC. He said he would work on getting me a replacement set to try, and see if it worked. I then polished the new parts free of charge, and shipped them back to the OP. We wanted to see if this set would cycle smoothly (by hand) in the weapon, and if it did then the original bolt and carrier milling would have definitely been the problem.

Now it's obvious that it was indeed the gun causing problems for the moving parts, not the other way around.


As for what needs to be done next, I have been on the phone this morning with RAAC about this, and they said to simply ship the whole gun directly to them, so they can assess the situation first hand, and it would either be fixed, or the entire gun replaced. There's no need to go sending it to any gunsmiths, or asking for advice on how to fix it. This is, and has always been a warranty issue, and RAAC stands behind every weapon they sell. That's why I would only purchase a new S-12, if it was imported by them.


It's very rare with the loose tolerances in these guns, for one bolt & carrier to not be interchangeable with another, like the rest of the parts. In five years they have only seen very few guns to have an issue like this. It's not common at all.


PM sent to the OP with details on shipping the gun in for warranty service...



Link to post
Share on other sites

Yeah I guess you should. Maybe you should pick up the phone and speak to some people who have had thousands of these firearms go through their hands, and through their shops. You don't have to believe what the actual importer says, the ones who KNOW how many of these type of problems occur... but I do.

Link to post
Share on other sites

I am pleased with the work shannon did and am 100% sure this was an issue unrelated to anything he did. He definitely went the extra mile with my parts even doing the replacements free of charge.


Original bolt and bolt carrier ate eachother up after only a couple of hundred rounds of light bird loads.


Work sucked today, so I'll call RAAC tomorrow when I'm in a better mood. But I suspect some of ya'll may be right with it being a barrel/bolt headspace issue.

Edited by 1Andy2
Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Chatbox

    Load More
    You don't have permission to chat.
  • Create New...