Aero/ ballistic advantage build

[gixxer822]

18in ballistic advantage barrel with nitrided bcg. I’m piercing primers on mild to low charges with h4895 and BLC
FIRING PIN HOLE -.078
Protrusion -.053
Ordered a JP high pressure enhanced bolt with FP. But thinking maybe I sell the ballistic shitvantage bcg complete and run a JP low mass. Anyone had issues with a low mass system. I already have the SCS and and adjustable gas block. Thx guys

 

[TonyTheTiger]

Anyone had issues with a low mass system.

Nope. I've got 8 low mass systems from various manufacturers in use right now. Stay away from aluminum carriers and you'll be fine.

 

[bfoosh006]

What brand primer ?

 

[MontanaMan]

Your only about .017" over max on your FP protrusion.............................just sayin"

MM

 

[Dildobaggins]

Aero and B.A are two different entities. Sorry to hear about your bcg. I have 2 aero BCGs for 223 and 6.5 Grendel and know a shit load of people running them with nothing but good feedback. I think they are pretty damn good BCGs. Ballistic advantage barrels are deff not my favorite, and I would agree with your sentiment of shitvantage.

 

[TonyTheTiger]

Aero and B.A are two different entities.

But not really.

 

[Dildobaggins]

But not really.

Correct. B.A is a majority owned subsidiary of Aero, but B.A manufactures barrels. I don't believe they take part as a company in the manufacturing of the BCGs lowers or uppers.

 

[msgriff]

Is this a large frame and what is it chambered in.

 

[rpoL98]

my Aero nitride 308 BCG's have FP holes of about .068" - .070", "HP". paired with the skinnier firing pin.

 

[Ravenworks]

FYI, Aero BCG use a small hole (HP) firing pin.
I ordered a standard JP titanium firing pin for BCG and it didn't fit.

 

[msgriff]

FYI, Aero BCG use a small hole (HP) firing pin.
I ordered a standard JP titanium firing pin for BCG and it didn't fit.

Which BCG? I have the nitride @ 0.070" aperture, but was told by a rep that the NiB uses a 0.059 FP. It would be great to get the aperture diameter of the NiB.

 

[Ravenworks]

All there large frame gassers use the small hole
They will NOT sell you parts, you have to RMA the whole BCG in.
You can however buy the JP pin that will work on their large bolt

 

[bfoosh006]

Your only about .017" over max on your FP protrusion.............................just sayin"

MM

Good catch MontanaMan

It does appear you have a "long" firing pin protrusion. ( Provided the measurement was done right , no offense )

How did you measure it ?

 

[gixxer822]

with a FPP gauge. i dont think that out of spec on 308ARs.
CCI primers
I see the JP HP enhanced bolt uses a .062 FP, should help significantly.
talking to Kyle Ware at Ballistic Advantage, he was less then helpful at diagnosing anything. they wont give specs. Send it in and wait is what was said.

 

[msgriff]

with a FPP gauge. i dont think that out of spec on 308ARs.
...snip

0.044" to 0.060" is generally considered spec, above 0.050 preferred.

 

[MontanaMan]

When I posted the FPP was out of spec, I assumed it was a 5.56.................your original post didn't say it was a .308.

MM

 

[r.tenorio671]

...what caliber is the barrel/BCG combo you purchased from BA? If it's a .223/556, most BCG's are using "MILSTD" bolts in them which do no have a "HP" configuration (which is the smaller hole diameter and firing pin tip diameter when claiming HP). Typically BCG's identified as "HP" means the bolts contained have been "HP tested", not that they have the smaller diameter hole/FP to mitigate high pressure primer flow. If you are getting primer piercing (commercial or handload?), you should check firing pin length, Brownell's sells a gauge for checking FP protrusion, note that it's specific to AR15's, not AR10's. The other possibility is hot loads, which can be caused by multiple conditions depending on commercial or handloads. Timing could also be an issue, early unlocking can also lead to pierced primers.

...if you are talking about the Aero BCG for .308, only the nitirided model is identified as being "HP", i.e., has the smaller diameter hole and FP tip. Although it's smaller in diameter than the phosphate and nickel models, it's actually a little larger than the JP offerings, basically right between the "standard" and JP offerings. Replacement/spare firing pins need to be checked for compatibility with the specific bolt being used. Too skinny of a FP for the bolts hole and you get primer flow causing the raised/pierced appearance on the fired primer or off-center strikes on primer. Too large of a firing pin diameter and you get light strikes or no strikes, depending on firing pin shape/contour.

 

[rpoL98]

Which BCG? I have the nitride @ 0.070" aperture, but was told by a rep that the NiB uses a 0.059 FP. It would be great to get the aperture diameter of the NiB.

my observation based on my own samples, Aero nitride, Brownells nitride, is that the HP aperture runs towards the high end of the "sixties", i.e. .067, .068, ... ,.070". and the FP is a few thou less than that, say, mid sixties. seriously, i haven't run across a Aero HP FP that was that small, 0.059". that's kind of a lot of clearance. Maybe things have changed, it's been over a year since I've purchased a 308 nitride HP BCG, maybe 2 yrs, pandemic shortage, etc.

JMHO.

 

[msgriff]

my observation based on my own samples, Aero nitride, Brownells nitride, is that the HP aperture runs towards the high end of the "sixties", i.e. .067, .068, ... ,.070". and the FP is a few thou less than that, say, mid sixties. seriously, i haven't run across a Aero HP FP that was that small, 0.059". that's kind of a lot of clearance. Maybe things have changed, it's been over a year since I've purchased a 308 nitride HP BCG, maybe 2 yrs, pandemic shortage, etc.

JMHO.

When the Aero rep told me about the Nickel Boron BCG firing pin tip diameter, I didn't think to ask about the aperture. Later on I wondered if the Aero NiB bolt has a 0.062" aperture. like the JP HP bolt (JPBC-EB308HP). I believe the JP standard 308 bolt (JPBC-EB308), which they also describe as high pressure, is a ~0.070" aperture. The basic DPMS standard was ~0.080" aperture w/ ~0.075" FP. and those were prone to pierced/cratered primers.