I’m looking to buy this BCG from a seller in my area. Its a Bushmaster BCG with RockRiver bolt.
I can see where the staking points are, but i’m not sure if it staked the screws properly. Hopefully you can see the pics ok. Thanks for the help!
A top down view would be more helpful.
IMHO from that angle they don’t even look like they’re touching the screws.
That is what I noticed, so I thought I’d get other opinions.
this is the only pic that the seller posted. I will have to ask him to post a pic of it looking straight down.
If not then just re-stake it.
Here is the full-size pic if it helps:
From what I have learned, the staking should also be visible/done on the screws themselves correct?
Those are not typical screws for Bushmaster (AFAIK). Are you buying this? Unless it is a screaming deal I wouldn’t. The carrier is fine, but the RR bolt is most certainly not up to spec.
So this BCG should be ok as long as I re-stake it properly?
The seller is asking $240 but I might be able to bargain a bit. He said the carrier has about 75rds throught it, and the bolt is brand new.
Nevermind. Bail on it.
How can we tell that the bolt is not up to spec?
I’m not buying it yet, but its the only BCG that is available locally to me. I did notice those screws are not the usual staking screws, which pointed me to the staking.
One last note, the seller mentioned was swapped out for a gas piston kit (if that makes a difference). Here’s the link to the actual ad:
I haven’t bought it yet, but now i’m having doubts. Unless someone can point me to a mil-spec BCG that I can buy in stock for around the same price or less.
Metallurgy, I doubt RRA even uses Carpenter 158 and Im positive they dont HP test or MP test.
I wouldnt pay 150$ for that carrier and bolt.
Ok, thanks for all the help. I guess i will pass on this one.
Because it’s made by RRA. I am fairly certain they do not HP/MPI test their bolts and there are no specs that I can find as to their bolts.
He probably had a carrier key for a piston on there, and then removed it, is my guess. Who knows.
My understanding all the CMMG gas piston kits (like the one I bought) have a one piece bolt carrier with the key machined into the carrier. In fact, on my CMMG gas piston bolt carrier the key is not removable. So I doubt the original owner modified the bolt carrier above.
I just built a nice little CMMG 11.5" gas piston SBR that doesn’t give me black face with my M4-2000 suppressor. I’m using a PSA bolt in mine, which is all I could find at the time. In the Palmetto State Armory (PSA) bolt I’m using a BCM firing pin, plus a BCM upper, barrel nut, and delta ring. But the barrel and gas piston kit is CMMG.
All topped off with AAC 18T Blackout flash hider for suppressor mount. I have a set of Magpul MBUS and a set of Troy flip up sights and can’t decide which to put on my new 16" ADCOR BEAR and which to put on the SBR. I’d prefer the Troy on the ADCOR, but worry the SBR gas block will be too hot for the Magpul.
I would pass. They don’t look properly staked and the bolts are not standard so who knows if they can handle the stress and heat vs. standard.
It looks fine. The bolts are Torx (vice 8-32 x 1/4) and the staking looks adequate.
Rock River’s bolt is a crap shoot. They don’t proof test nor Magnaflux.
Exactly.
I use grade 8 torx or torx+, and they work fine.
In todays hard to find environment, if that is the last thing you need to create a working rifle. Buy it and shoot it until it breaks. Hope that by the time that happens inventory will be back in everywhere.Depending on how much you shoot, even a non spec bolt may last a few years.
That’s a pretty HUGE undertaking! :eek:
:lol:
I’ve never seen SO MUCH emotional angst over a little metal bending. 
You forget port size measurements so quickly…
Port size is something these staker flakers should actually be looking at.
Maybe they can STAKE their gas Ports! 