I recently built a 458 ant took it out to test and every round I fired would hang in the extractor and stovepipe.  I could pull the BCG back and the case would just be hanging by the extractor.  I'm running a standard buffer with an adjustable gas block but haven't fiddled with it yet.  Brand new BCG as well with a single extractor.

If the bolt hold open isn't engaging, too heavy a buffer, too much spring, or weak loads.

Thanks for the reply.  The bolt hold works perfectly.  It just won't extract after firing.

Who made the bolt?  Is the ejector button moving freely?

the whole BCG is from Bear Creek Arsenal. I was going to build it as well but didn't for some reason.  The ejector seems to be free and has pretty strong tension.  the case actually hangs on the ejector hanging out the port at a 45 degree (approximately).

To me it looks like an excessive amount of brass shavings on the bolt face.

If it stove-pipes the empty case, it is extracting just fine.
You are having a failure to eject, after the case has been completely extracted from the chamber.

You either have an extractor hook rim-binding in the case head groove, or your upper receiver's ejection port does not have the rear half of the port raised...only the front half.  Or both.

As for excessive brass on the bolt face.  You have a 5.56 ejector installed instead of a 458 SOCOM ejector, and your bolt is probably incorrectly machined so there is a knife edge wall around the perimeter of the bolt pocket, between the locking lugs.

Tony Rumore
Tromix

ETA:  If your extractor will do this, it's bad, and will cause failures to eject.

Well, that says a lot.  I'd just send it back to them to deal with.

get a tromix bolt

Listen to this man, OP.

This is why friends don't let friends buy BCA .458 SOCOMs.  They don't have a clue on how to build them properly.

First off, listen to what Tony has said above.  He is the co-developer of the .458 SOCOM round and the man who made the AR platform work with the cartridge he and Marty designed.  Listen to him even if you don't listen to anyone else.

These are your choices for a properly made and functioning .458 SOCOM rifle:  
1.  Sell the POS you have or return it and buy a TROMIX, or at least a Rock River.  They are made properly also.  If you don't want to do this, then proceed to #2 below.
2.  Buy a complete TROMIX bolt and replace your BCA abortion.  The worst bolt I have ever had was when Tool Craft had a super sale on BCG in .458 SOCOM, and I needed a BC.  I already had the TROMIX bolt but I needed a BC, so since the thing came with a bolt, I tried the .458 SOCOM bolt that came with it.  It would not work at all.  Put in the TROMIX bolt and it ran like greased lightening.

3.  If you cannot do 1 or 2 above, at least consider the following:
A.  replace the extractor with a TROMIX extractor.  A crappy extractor is the most likely cause of your problem right now.
B.  replace the ejector with a TROMIX ejector.  If you do not see a bevel on your ejector from about 5:00 to 10:00, then they have not done their due diligence on making a proper functioning .458 SOCOM bolt.  The lack of a bevel on the ejector is a major cause of feeding problems which BCA has had a lot of issues with.
C.  buff the rim around the bolt face to remove the knife edge.  If you drag your finger nail across the rim around the bolt face and it shaves your nail, take some 600 grit wet/dry and buff the edge down until it is smooth and not dragging on your finger nail.  

Then, to check, remove your BCG from the rifle, take a fired case and insert in the bolt face, under the extractor and depress the ejector.  Let go.  Your case should be tossed easily from the bolt face.  If it hangs up, your bolt face may not be cut big enough and it is binding, that is if you have already replace the extractor and ejector.

That should cure your ejection problems.  IF not, do what Tony said and have your ejection port enlarged correctly.  I'd bet dollars to doughnuts it is only enlarged on the front half.  Paladin Machine Shop Service offers this but you will have to send him your your stripped upper, which means you have to tear it down before sending.  He will enlarge your ejection port properly and can even machine the front of your receiver square.

Last thought.  If the rifle is made correctly, you should be able to use a standard buffer and spring and there is no need for an adjustable gas block.  None of my 13 .458 SOCOMs from 6.75" to 28" have adjustable gas blocks on them and I shoot supers and subs, but no suppressor.
Also, there is no need for the o-ring around the extractor spring.  Too much tension on the extractor can cause problems.  The presence of an o-ring here is another clue that the maker is just phoning it in, not doing any real R&D testing on their own.

Then we can address feeding problems which often turn up with BCA uppers.

So stupid me. I was mixing apples with oranges and combining my 458 problems with my 308 problems. The real problem (Tony I’m listening) is that it’s not extracting the fired casing at all. It will cycle the bolt but the extractor never picks up the spent case from the breech. I will go online today and look for a complete Tromix BCG to replace the turd I have in it

If it is leaving the casing completely in the chamber, you most likely have a rough chamber and it needs to be polished.
It is also possible that the extractor has failed completely, but that is unlikely.  Usually, if the extractor is even half-ass holding on, the back pressure on the case will at least blow it clear of the chamber, if the chamber is in good condition.
You may also want to check the case rim, and see if the extractor is tearing a chunk off or has evidence of the extractor pulling past the rim as it's trying to extract the case from the rough chamber.

Tony Rumore
Tromix

Tony,

It looks like the extractor is rubbing against the rim without actually catching on it. This is a home built 458 however I did buy the complete bcg from BCA. If this thing lets me post a picture I’ll take some of the used brass

If you have excessive head space or a shallow cut extractor hook, the extractor won't be able to clip over the rim when chambering, and you would be unable to extract a live round, by hand, from the chamber.
However, during firing, the empty case will back out of the chamber (if it's not rough) on it's own and clip itself under the extractor hook, and the case will be extracted normally as the carrier moves rearward.

Tony

Rim

https://hosting.photobucket.com/images/v314/OhmsLaw43/IMG_1334.jpeg

https://hosting.photobucket.com/images/v314/OhmsLaw43/IMG_1338.jpeg,https://hosting.photobucket.com/images/v314/OhmsLaw43/IMG_1339.jpeg

It doesn’t come out during firing. It also doesn’t come out by hand all the way. It will leave the breech but not the ejection port. It’s acting really weird to me

OP, did you enlarge your ejection port?  Do you have a Dremel?

I haven’t enlarged it yet but do have the tools to do so

Pffttttttt.....that bolt is junk.  

Whoever machined that, has no idea what they're doing.  They cut it exactly like a 5.56 bolt, but with a larger diameter pocket.  You can't do that.

Tony

Figures, given the vendor.  As I said prior, just send the POS back.

dremel go brrrr

Looks like I’ll be spending the $110 and picking up a Tromix!!!

IMO cut your losses and dump that thing and get a TROMIX.  The totally jacked up bolt may just be the tip of the junk pile.  Next will be a mucked up chamber, then a botch barrel extension, then God knows what.  
Send it back to BCA for rebuilding and if they can get it going, dump it.  Or ask for a refund from whoever you bought it from, if you can.  You’ll never be able to trust it knowing the lack of QC that went into building it.

I guess I missed that part in the original post.  
As backbencher pointed out, a .458 case won't fit through the ejection port of a mil-spec 5.56 upper receiver.

Tony

I did as well.  I guess we just assumed the upper was oversized, well, because that is a given.  Seems OP didn't dive deep enough.

Doesn’t matter as the extractor isn’t picking up the brass to eject it. I picked up an Anderson upper so I can play with the mil-spec 15 one enlarging the port

Do yourself a favor and send your upper to Paladin Machine Shop Service to have the ejection port enlarged. Your ejection port door will latch shut and it will be done right and not look like an botched up afterthought. He only charges $10 or $15 plus return shipping and while he has it he can square the front of your receiver.

Tp555(at)vfemail.net

Anderson also make an XL upper, which is already clearanced for the big bores

Anderson only raises the port at the front portion and leaves the center and rear portion (where the case actually ejects) in the same 5.56 position.
It sometimes works, and other times it causes random sporadic ejection failures. (stove pipes)  You can actually replicate the problem, hand cycling live ammo.

Tony

ETA:  There are plenty of guys out there, that own those receivers and they work perfectly, but there are others that have failures to eject and raising the port all the way to rear, fixes the problem.

I have well over a dozen SOCOMs in various calibers and several of them use Anderson big bore uppers.  Two or three, about half, worked fine as is, the other half did not and Paladin had to finish the job.  After Paladin worked on the Andersons, no more problems.  Now I buy one of Tony’s billet big bore uppers or send a standard upper to Paladin.  In fact, I sent the Andersons that did work to Paladin for enlargement, just to be sure.   I’ve done a couple myself over the years with a Dremel on standard uppers using a sanding drum and Pillar files but my time is worth more to me than what Paladin charges and his look much, much better.

Listen to Tony.  If he tells you that hog weighs 200 pounds, take that sucker to market.

Here is a diagram of the ejection port for clear passage for a DMPS LoPro upper, but that upper does not use an ejection port cover.  You remove almost .100 inch off the bottom and and about .015-.025 off the top, but I usually only remove about .010 off the top and maybe even a bit less at the port latch notch so it will firmly stay shut.  If you remove too much off the top, you cannot go back so tread carefully around the EP cover notch.  Or, send it to Paladin.

Attached File

Yeah, I know that the ports are still a little small. That’s why I’m ping to take the mil-spec upper on my end mill and get it right before I machine the Anderson.  Already ave the right indexed cutter for it

Does Aero do the same one theirs?

Yes, the Aero XL receiver is machined the same.  See pic in link.
I found it interesting that this "idea" to only machine the front of the port, may have started with the Lietner-Wise 499.  See link on that as well.

https://www.aeroprecisionusa.com/ar15-xl-stripped-upper-receiver-anodized-black

https://www.youtube.com/watch?v=XNDJOghZUH8

Tony

Go to 6:45 in the 499 Leitner Wise video to see the reference to raising the ejection port, only in the front......"to accept the 50 caliber cartridge".   Which ejects at the rear of the port.

Tony

I think the idea is to get the mouth of the case started in the opened up area forward of the catch, and the case riding the rest of the way out.  There is some material that can be removed from the bottom of the port to give some more room, but I don't know if removing material from behind the catch is going to do much because the case has to get by that point regardless and you can't remove it if you want to be able to close the door.  My 450 BM is only opened up in front of the catch and it works fine, but I realize there are larger cases.  I just haven't worked with them.

So, installed the Tromix bolt and after gently massaging the ejection port on the Anderson upper, my 458 cycles flawlessly.  Only sent 40 rounds downrange as they are expensive rounds. Thanks everyone for all the info and especially Tony for making such a great product. Amazing what spending a little money can do

This is why I went with a tromix upper after my horrible experience with a radical upper.

FYI, one can take a little off the EP locking nub, but not much. That’s why I let Paladin do it on my uppers or buy a TROMIX upper.

So, new issue. With the tromix bolt it ejects like a big dog. That said, now it won’t pick up a round from the mag (FtF). I’m running a SS Duramag with the 458 SOCOM follower. Would the mag be causing this or is the bolt not moving far enough back to pick up the next round?  I see no dents on the casings and am running an adjustable gas block. Maybe not enough gas?

Pre - Edit: You successfully ran 40 rounds through it a few weeks ago, what have you changed between then and now because that's where I would look.

You mentioned two different scenarios so i'm going to assume you mean won't pick up a round from the mag and not a failure to feed.. That would mean it's attempting to chamber a round but not able to do so succesfully..
So i'm guessing with the bolt closed you insert a loaded mag and pull the charging handle; Or the bolt is locked open you insert a loaded mag and hit bolt release - either scenario successfully loads a round? After that round fires you attempt to fire again and get a click only to find out the next round is still in the magazine? If so then the bolt and mag combination are able to successfully strip rounds from the magazine into the chamber and not the issue. Easy test is to load a round in the chamber with an empty mag inserted and see if the bolt locks open after firing, if it does not then you have a short cycling issue.

Any chance it's a superlative arms bleed off block? They work great however some people had difficulty with the instructions and did not have them adjusted properly.

The 40 rounds were a little misleading. I let a friend take it out to test as I was with my wife for an appointment. He said if fired 40 but had to manually rack a round each time. Yeah, it’s not stripping a round from the magazine. I always load a new magazine with the bolt open. Old habits die hard. Once I receive more ammo Monday I’ll try the single round in the mag.  I also used a Davidson Defense adjustable gas block on it

If he was able to rack a new round in by cycling the charging handle each time then yes it's a cycling issue most likely not enough gas. I have no experience with Davidson adjustable blocks.

While we're on the subject of chambering socom rounds, since you're somewhat in a situation where you may inadvertently do this.

Don't load a round in the chamber manually and drop a locked back bolt on it until you're certain you don't have excessive firing pin protrusion. Not sure if your friend brought your brass back to you, but this normally shows up in the form of pierced primers. If you see pierced primers in those 40 pieces of brass then you'll want to do a search for 458 socom firing pin protrusion, you'll find more knowledge that Big-Bore has preached many times before.

Yeah checked that as I reload everything I shoot. Primer strikes look normal so I think firing pin protrusion is right. I diddled with the gas block prior to installing it on the barrel so I probably turned it down too much. Might just order a new non-adjustable gas block and try that as well

First, try a standard 5.56 mag.  You don’t need a special follower for the .458 S.

I have .458 S from 6.75” to 28” and shoot supers and subs through all of them and have never needed an adjustable gas block.  I don’t shoot suppressed though.  If you’re not using a can, there is no reason for an adjustable gas block if the barrel is ported correctly.  
Make sure you are using a standard buffer and spring, open your gas block all the way open, make sure your gas port in the barrel and gas block are aligned properly (measure, don’t just blow through it) and if it still won’t lock back when shot with only one round in the mag, check your bolt carrier gas key screws.  If they are OK, get the barrel’s gas port size and get with Tony.  He’ll tell you what size it should be and if too small, you’ll have to drill it out slightly.

This is why I get so down on BCA .458 S barrels.  Too many people just chase their tails trying to get them to work and end up wasting money fixing one thing then another.