2nd Outing..what a difference!

[Sgt. PArnold]

This afternoon I was able to get to the range between storms. After my last visit, I was not sure what to expect.
Since my last visit (and thread), I installed a free float handguard and low profile gas block. While there, I checked and "repaired" what I perceived to be an issue. The existing gas port measured exactly .067 using pin gauges. After some research (including thread surfing ), I opened the port to .076. I secured the new gas block, rail, and re-installed my optic.
In a moment of optimism, I took seven different brands and types of ammo (see photos) with me along with four p-mags (20 rounders).
I began with zero testing with Federal Premium 168 BTHP Match. Got zeroed (see target) and no malfunction at all. Then I loaded the previously non-functioning S&B 147 grain FMJ, along with Winchester white box, 147 FMJ (listed as "7.62x51"), Remington 150 grain soft-point Core-Lokt (listed as ".308"), Hirtenberg .308 180 grain SPB, Monarch STEEL CASE 308 145 grain FMJ and finished with 7.62x51 "ball" with NATO mark (presumably 147 grain) FMJ of unknown origin.
Expecting the worst, I was very pleasantly surprised! It ALL functioned without problems. There were two fail to fire in the mystery 7.62x51 (visible impact on primer). Ran them through again and they fired. All the ammo "rang the bell" on a small steel silhouette target at about 75 yards.
After the gas port adjustment, this rifle is now "offically" acceptable as combat worthy!!

I still have to zero the iron sights and work up some distance dope, but that is the fun to come!!

Thanks to all of you that offered comments/suggestions on the first thread!

Questions??

 

[macliver]

Nice report Sergeant! Well done. I do have a couple of questions.

1. Can you expound upon your method of opening up the gas port? i.e.: what specific tools, lubrications (if any), etc.?

2. What kind of iron sights did you put on? Look like Troys!

I've had to put my rifle away for a bit as I am packed and moving to Texas on Sunday and once I'm settled I'll be seeking out a new range. I hear there is a 1,000yd range within 15 miles of me! Can't wait.

Again, great report.

Mac

 

[daddy2twins]

Nice report Sergeant! Well done. I do have a couple of questions.

1. Can you expound upon your method of opening up the gas port? i.e.: what specific tools, lubrications (if any), etc.?

2. What kind of iron sights did you put on? Look like Troys!

I've had to put my rifle away for a bit as I am packed and moving to Texas on Sunday and once I'm settled I'll be seeking out a new range. I hear there is a 1,000yd range within 15 miles of me! Can't wait.

Again, great report.

Mac

Glad you asked. I was wondering the same thing.

Sent from my SCH-I605 using Tapatalk

 

[copemech]

Good report PA! I just took my gas port to .073, we shall see?


Hey Mac, where are you moving? Texas is a big place!

 

[Sgt. PArnold]

Hi guys,
Good questions!!
first the easy stuff: MI handguard and gas block, Troy rear sight, YHM front sight.

After the research, I found that the standard gas port size was a MINIMUM of .080 for an 18" barrel. (Fulton, DPMS, AA and POF all sue that standard).
I used a pin gauge to check the original size. You can accomplish the same by using drill bits and a caliper. I found that the port was undersized, so I used a drill bit specifically for metal and honing oil as I cut. I would suggest using a drill press if available. I have done enough port work that I am ok using a hand drill. I would still prefer a press when available.
Use the existing hole as a guide. Go slow and pull back often. Once all the way through, make a couple more passes to "clean" the channel. Then clean barrel with bore brush and solvent.
That is how I opened the port, and the rifle runs as expected!