ar308 80% help

[Victor Cachat]

PSA upper "PA10" I do not believe that it is compatible with LR308 lowers.

Yep!
I finished my Modulus lower and the PSA upper would allow the charging handle to come into contact with the lower where the buffer tube is attached.

If you leave the charging handle out, the lower will probably be 1-2mm taller than the shelf on the upper where the charging handle sits.

Get your upper from CDNN (on sale: http://www.cdnnsports.com/ar-308-str...l#.VLxx6UfF-9U) or get a PSA lower.

I have a series of pics, here are two that should help you see the problem:

The Bushmaster upper on the right is taller (PSA upper is on the left), so the charging handle sits higher, even though it is the same in relation to the BCG:


With the Charging handle installed, I cannot even install the upper because the rear pin will not fit:

[buellster]

OP,
I had the same problem with a PSA upper and cmmg lpk. The release tab is very thick on the bolt catch. I machined about half of it off the inside. I also had to take some off the portion that actually catches the bolt as it was too high. The same could be done with a dremel.

[kcstott]

Yep!
I finished my Modulus lower and the PSA upper would allow the charging handle to come into contact with the lower where the buffer tube is attached.

If you leave the charging handle out, the lower will probably be 1-2mm taller than the shelf on the upper where the charging handle sits.

Get your upper from CDNN (on sale: http://www.cdnnsports.com/ar-308-str...l#.VLxx6UfF-9U) or get a PSA lower.

I have a series of pics, here are two that should help you see the problem:

The Bushmaster upper on the right is taller (PSA upper is on the left), so the charging handle sits higher, even though it is the same in relation to the BCG:


With the Charging handle installed, I cannot even install the upper because the rear pin will not fit:

I'm having a hard time getting this, But with No milspec standard to follow i can see just how this can happen.

It is the one thing that sucks about a 308 AR be it a AR10, LR 308 or a SR25 pattern nothing matches up to any great deal if you wonder outside your platform


edit: I see it now the distance at the bottom of the BCG hole to the matting surface on the upper is thinner.