Oversize gas port on 16" barrel?

[scottryan]

I was just reading a thread on another forum and this guy says that PSA is using oversize gas ports on their ARs and this is the first I have heard of this? Anybody else had such an experience.

I did have a AR with 16" barrel and don't know who made it but it definitely had a oversize port as the bolt was trying to open before bullet cleared the barrel and the extractor was trying to rip off a section of the case rim and it literally ruined every piece of brass it fired.

Another guy wanted it and I told him what was wrong with it and he did not care as he was not going to reload anyway so I let him have it.

To my thinking if PSA was doing this it would be ALL OVER but I have never heard of such except in that thread so was just wondering.

I do know when the M4s came out the first shipment had oversize gas ports and Rock Island checked and the same gas port as the 20" barrel had been put in the M4s so that got corrected quickly.

Almost every consumer/hobby grade manufacturer uses over sized gas ports.

[MontanaMarine]

My 14.7" mid-gas CHF FN barreled upper from PSA was rough on rims with a standard carbine buffer.

An H3 carbine buffer, or a rifle lower, settled it down.

[Sry0fcr]

Almost every consumer/hobby grade manufacturer uses over sized gas ports.

I would argue that they use proper porting for the ammunition that their customer base is likely to consume. People really need to consider ammunition and magazines as part of their AR system as a whole.

[MistWolf]

I would argue that they use proper porting for the ammunition that their customer base is likely to consume. People really need to consider ammunition and magazines as part of their AR system as a whole.

I'd like to counter by pointing out that I've never heard anyone complain about a Colt being ammo sensitive, yet they aren't over gassed.

[Clint]

Any idea on gas port size?

That's a good example of a heavier buffer reducing acceleration and extraction forces.

On the other hand, most properly ported barrels don't show extractor marks anywhere near that bad even with lighter buffers.

My 14.7" mid-gas CHF FN barreled upper from PSA was rough on rims with a standard carbine buffer.

An H3 carbine buffer, or a rifle lower, settled it down.

[MontanaMarine]

Any idea on gas port size?

I did pull the gas block and check it, but it was a couple years ago, and I didn't write it down. I cannot recall the numbers. Best I can recall from my online 'investigating' at the time, it was a bit generous.

[Sry0fcr]

I'd like to counter by pointing out that I've never heard anyone complain about a Colt being ammo sensitive, yet they aren't over gassed.

I'd counter your counter by pointing out that the folks buying LE Colts aren't usually the same guys that buy sub $500 PSA Freedom Rifles. Those guys are over on TOS talking about "breaking in" a Ruger BCG that won't come apart without tools...

[jsbhike]

I have an approximately 5 year old PSA FN CHF midlength barrel apart (trying the receiver facing/shimming/620) that the port size is between #49/0.0730" (eats this one) and #48/0.0760" (no go) drill bits. Would have narrowed it down, but the only supply store in town with numbered bits has very few metric and didn't feel like ordering those or pin gauges.

[Leonidas24]

I have an approximately 5 year old PSA FN CHF midlength barrel apart (trying the receiver facing/shimming/620) that the port size is between #49/0.0730" (eats this one) and #48/0.0760" (no go) drill bits. Would have narrowed it down, but the only supply store in town with numbered bits has very few metric and didn't feel like ordering those or pin gauges.

My old FNH made PSA CHF 14.7 mid-length barrel had a .076 port. Granted, that was back in 2011. I must have lucked out when I bought it because it had the lightened "Centurion" style profile and a true 5.56 NATO chamber. Before the ex got it in the divorce I had a little over 17k through it over 7 years without any major issues. With all of that said it was a sample of one and my last three barrels have been a BA Hanson 16", Sionics medium profile 16", and a Centurion Arms 12.5" carbine.

[jsbhike]

Checked an original M&P Sport barrel (bare upper and 1-8 twist Rock 5R rifling) and it would barely take a #52 (0.0635") drill bit.