new ar build issues

[jjracine]

i bought a new complete upper. but the forward assist will not engage the bcg. just slips right by it when you pull the bcg out while holding the FA inwards. i replaced it with my other bcg and it engages like it is suppose to. this video is another issue im having when shooting .223 55g. but when i shoot 5.56 nato i have no issues.. changed buffer spring no fix. this video is not mine but have the same problems..

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[MilitantBEEMER]

i bought a new complete upper. but the forward assist will not engage the bcg. just slips right by it when you pull the bcg out while holding the FA inwards. i replaced it with my other bcg and it engages like it is suppose to. this video is another issue im having when shooting .223 55g. but when i shoot 5.56 nato i have no issues.. changed buffer spring no fix.

this video is not mine but have the same problems..

Does the original BCG have the Forward Assist teeth?

 

[jjracine]

Does the original BCG have the Forward Assist teeth?

yes. but they seem small.. i even put it in my other ar and it does the same thing. my other one has no issues.

 

[MilitantBEEMER]

It may be that the test are just to small? What brand upper and BCG?
I recently saw a new Bushmaster that had a forward assist but the BCG had no teeth

 

[jjracine]

the top bolt is my old bolt. the bottom is the new one from palmetto state with the bcg included

PSA 16" Mid-length 5.56 NATO 1:7 Nitride Freedom Upper - with BCG and CH - 507281 different angle

 

[MilitantBEEMER]

Definitely a different cut on the PSA. I can imagine the FA would have hard time catching the slots..

 

[Stomper]

As for your cycling problem with .223 vs 5.56.... 5.56 tends to run a bit "hotter", so it sounds like the barrel's gas port underneath the gas block may need to be opened up a bit, or maybe the gas block is slightly misaligned and covering up part of the gas port.... which either is a distinct possibility given the apparent job done on the FA teeth on that BC.

Hope that helps.

 

[arakboss]

the top bolt is my old bolt. the bottom is the new one from palmetto state with the bcg included

View attachment 534474PSA 16" Mid-length 5.56 NATO 1:7 Nitride Freedom Upper - with BCG and CH - 507281

It's probably an illusion but it looks like the straight wall cut on the new bcg serrations (teeth) is angled in the depth of the cut vs the old carrier having a nice straight looking depth of cut on that portion of cut. Do you have a pic of both carriers side by side but oriented in the same direction?

 

[arakboss]

i bought a new complete upper. but the forward assist will not engage the bcg. just slips right by it when you pull the bcg out while holding the FA inwards. i replaced it with my other bcg and it engages like it is suppose to. this video is another issue im having when shooting .223 55g. but when i shoot 5.56 nato i have no issues.. changed buffer spring no fix. this video is not mine but have the same problems..

What was that little doodad thing that dropped down on table around the 50 second mark?

 

[notazombie]

Not sure, but I noticed it too.

To OP, I've had a few PSA BCGs and don't remember any having cuts that look like the bottom one. If the FA isn't engaging and you are able to replace it with another and it does, I'd call customer service and get it exchanged for a good one. They may have a bad batch on their hands.
By brother had a PSA upper that was ammo picky and wouldn't cycle reliably. We swapped lowers, no change. Swapped BCGs, no change. Tried different mags, no change. We lubed it really wet and ran through 2-3 mags, manually cycling when necessary, and it finally snapped out of it. We figured maybe it got a piece of debris in the gas system somewhere that finally worked it's way out.

 

[DirectDrive]

1) Your carrier's "scallops" are not cut to spec

2) As Stomper said, your upper is gassed for full power ammo.
XM193, M855 are examples of full power ammo.
Civilian .223 is not full power ammo.

It is also possible that your barrel's gas port is misaligned with the gas block.

1a) I wouldn't bother with the carrier, although I wouldn't be happy with it.
2a) You can fix the upper to run lower pressure ammo.
You have to decide if you want to do that or if you want to just send it back.
Once you monkey with it, you own it.

 

[jjracine]

It's probably an illusion but it looks like the straight wall cut on the new bcg serrations (teeth) is angled in the depth of the cut vs the old carrier having a nice straight looking depth of cut on that portion of cut. Do you have a pic of both carriers side by side but oriented in the same direction?

reposted a new pic

 

[arakboss]

reposted a new pic

sorry the cuts look more normal now. Couldn't tell ya why the FA would be skipping over the serrations.

 

[DirectDrive]

I just looked at that upper on PSA's website.
That is a waaay low cost upper and obviously they are sourcing low cost parts to put it together and make a profit.

After a quick Google this is about all I could find that was similar and you still have to add a BCG and charging handle...
Schuyler Arms | Aero Precision AR15 Complete Upper, 16" 5.56 Mid-Length Barrel w/ Pinned FSB, MOE SL Mid-Length
It would total about $300 with a good, basic BCG and charging handle.

 

[Tony617]

What weight buffer are you using? I am using carbine weight which I believe is a 3oz. I also have H1 and H2 buffers as well but the carbine one is what I am using and it work fine. I bought a Troy 16" fully assembled upper receiver for my first home build rifle. I mostly shoot XM193 55gr but I have also shot a few magazines 64gr Speer Gold Dot JSP rounds as well.

I did pop for a Nickle Boron BCG from PSA instead of using the default BCG included with the Troy upper. So far I have shot about 400 rounds with my home built rifle.

 

[jjracine]

i to changed to an old bcg with the parts. from my new bcg. it had no effect to my issue. changed to the old bolt from the old bcg and then changed my spring to a spring 1/2 coil shorter and used a steel mag. started to act better can get it to cycle. found out it does not like pmag it would not lock open on the last round but will with steel mags. it is working now just have a few bugs to tune in.. thanks for the replies and help from everyone..