BCG staking

[jimbombo]

I have 2 carrier groups, both brand new, and one of them I am getting rid of.
Not too familiar with what is a "good" staking job.. the bcg on the right, one of the screw heads is dented ever so slightly during the staking. But the one on the left, the chrome lining does not appear to be as even, or "thick" as the bcg on the right.. so which one would you guys keep? They are the same exact specs on the bcg and bolt! If the gas key screw is slightly dented, does it make any difference, if not then I keep the bcg with the nicer, more even chrome.

Thanks all...

 

[hunttheevil]

It doesn't take that much staking to lock down a screw. I would keep the one on the right with the more even finish.

 

[Welding Rod]

Hard to tell in the pictures, but both of them look like they might be excessively staked. If one has fractures on the convex portion of the staked material, that is the one I would get rid of.

 

[taliv]

that staking looks good. why would you say it's excessive?

 

[jerkface11]

The staking gets into the screw head on both carriers. So either one.

 

[M1key]

I'll take either one off your hands...

M

 

[jimbombo]

taliv

If it looks ok, I am good with that! I am not too familiar with the parts and specs of the AR. So I thought I would ask...

Also the upper to lower fit, takedown pins are extremely tight. I can get both pins closed and there is absolutely no movement between upper and lower. Now I know that there can be variations in tolerances, down to .001 of an inch. And this can make the fit loose or not. But I have never put a build together where it was very hard to open and close the pins! After I open and close the pins a few times I am sure they will loosen a bit, but anyone see any reason to be concerned with this?? Everything lines up, its just that the holes are very tight!

 

[briansmithwins]

I'd keep the BCG with the more even finish. As far as the take down pin tightness goes, they will wear in looser with use.

BSW

 

[Bovice]

Someone's been reading too many elitist threads on ARFCOM. A screw is staked or it isn't.

 

[taliv]

like jerkface said, as long as it pushes metal into the screw, it's good. they may be got a little excited and pushed a little more metal in than they needed to, but i can't see how that would adversely affect it. i am not a metallurgical engineer though.

as for tight pins, i am NOT a fan. it probably would wear in and get a little looser. i'd try to do something to expedite that process.

 

[jimbombo]

Ok....but

I am satisfied with the staking! as long as the bolt and charging handle move freely, and work correcctly, any functional reason to worry about the tight pins? I gotta say I think they will loosen on there own, and there is no movement between upper and lower, which I like

 

[taliv]

no. i just don't want to need tools to open the gun up if for some reason i need in there (like say, i got a popped primer that landed under my trigger, or i just felt like taking it apart to show somebody how it is supposed to work, which seems to happen every time i go to a range.)

 

[jimbombo]

taliv

So then do you buy in to the train of thought that a tighter fit is better for accuracy? Just curious? And so mechanically it shouldn't make any difference whether fit is loose or tight.
Thanks for the advice... jim

 

[taliv]

seems like tighter would be more accurate but i have loose ARs that shoot great.

that said, it seems possible to have the best of both worlds. i can't imagine bedding the upper/lower but some folks do. just because they fit perfectly shouldn't mean you need a hammer to knock the pin out.

 

[MrCleanOK]

Jimbombo,

As others have said, the staking on either one of those BCGs is satisfactory. If they're a little "too" staked (if the deformed metal is rubbing the inside of the charging handle), you can just stone them down with a whet stone or a fine toothed file until they don't bind any more. The uniformity of the chrome finish inside wouldn't be much concern to me unless one is obviously defective. Most recreational shooters won't shoot enough rounds in thier lifetime to wear through the chrome in a bolt carrier. I've seen a few at work with some pitting, but that is most likely caused by over-zealous cleaning, not normal use.

Regarding receiver fit, I would not accept receivers that require a tool to move the take down pin. They just aren't supposed to be that tight. I don't mind a little wobble in the receivers, or light showing between the upper and lower. Most of the accuracy in an AR lives in the lock up between the receiver extension and bolt, and the optics and sights are all on the upper receiver. I can only see receiver wobble being a factor for someone like a serious bench shooter (who probably isn't using an AR-15 anyway).