New member and build with initial issues. Advise and input welcome

[JT303]

19 hours ago, NF1E said:

Didn't pay much attention, or don't remember coils or buffer weight other that they were what was recommended. I do remember that I needed to close my agb half way because it was overgased and has run great with all ammos tried from 110gn to 175 without a hickup since.

I was running full open (SA ADJ GB) 18 clicks. I took video of my shots showing the bolt carrier barely ejecting spent single rounds and DF jammed every multiple loaded mags. Cyclic timing is definitely off. Gonna open Gas port .01mm or so and then reassemble and test fire next week. Right now im just using Fed GM 168 BTHP factory loads.

Overgassed should be throwing cases forward. Im getting 3 oclock little drop out of ejection port. But I will keep that in mind. 

Thanks !

 

[shooterrex]

I wouldn't worry about the buffer.

A little more gas and enough rounds to seal up everything should get it going.

If you are really worried about the recoil spring being to strong. Lock the bolt back and let it sit that way a few days. It will take a little of the spring tension out.

[NF1E]

Youse guys is da bestus!

 

 

 

[shooterrex]

4 hours ago, JT303 said:

 

Overgassed should be throwing cases forward. Im getting 3 oclock little drop out of ejection port. But I will keep that in mind. 

Thanks !

 

These guns are not like the small frame guns. Don't worry about where it throws the empties.

As long as it runs and locks back on an empty magazine it's all good.

[JT303]

1 hour ago, shooterrex said:

These guns are not like the small frame guns. Don't worry about where it throws the empties.

As long as it runs and locks back on an empty magazine it's all good.

Its currently not locking back on empty nor feeding after ejection. 

Hopefully the opened port will correct that issue. I got the adjustable GB because I may want to be able to bleed off if I go with a suppressor in the future.

Happy Easter !

[JT303]

4 hours ago, shooterrex said:

I wouldn't worry about the buffer.

A little more gas and enough rounds to seal up everything should get it going.

If you are really worried about the recoil spring being to strong. Lock the bolt back and let it sit that way a few days. It will take a little of the spring tension out.

Yep, exactly what I was thinking as well. 

Gonna set that up after my drilling time. 

[JT303]

1 hour ago, NF1E said:

Youse guys is da bestus!

 

 

 

Like the CMP shirt !! 

I went to the North store late last year for the end of year blow out. (I couldn't find a nice T-shirt while i was there) but......

Scored a nice SA

Happy Easter brother

[NF1E]

2 hours ago, JT303 said:

Like the CMP shirt !! 

I went to the North store late last year for the end of year blow out. (I couldn't find a nice T-shirt while i was there) but......

Scored a nice SA

Happy Easter brother

Well, that photo is 11 years old and I am sure the shirt is even older. Taken on Kauai while goofing off.

[JT303]

98. 

Drill worked super easy with 2.2mm bit. Its miked at 2.19mm(.086) now.

Little oil on the bit and I used an old cleaning rod with some double sided tape to catch any little filing that could fall. 

Worked like a charm. (Took longer to set up than drill). 

All back together and I will also put xtra oil when I go test hopefully later this week.

If I still experience a problem with undergassed, do you suggest opening the port any further or no more?

Thanks all  

[shooterrex]

You have an adjustable gas block. The port can be bigger and you can adjust it down w/the gas block.

[98Z5V]

9 hours ago, JT303 said:

If I still experience a problem with undergassed, do you suggest opening the port any further or no more?

I wouldn't even think twice about opening it up more, if it was my gun.  Bump it another step up, depending on what you see when you fire it.  I wouldn't even think twice, if it wasn't locking back on a single round in the mag, and ejecting the fired case.  Zero hesitation about punching it up again, done. Re-fire.  Take the tools with you to the range, and cut the research time, just because.   I've drilled a guy's barrel on a truck tailgate, in the middle of the night with a headlamp on, out here in the desert - to get the gun running.  You do what you have to. 

Run that Adj gas block wide open when you test it, or it's screwing up the work you did on the gas port - that's the only real way to know.  

Edited April 11, 2023 by 98Z5V

[JT303]

10 hours ago, 98Z5V said:

I wouldn't even think twice about opening it up more, if it was my gun.  Bump it another step up, depending on what you see when you fire it.  I wouldn't even think twice, if it wasn't locking back on a single round in the mag, and ejecting the fired case.  Zero hesitation about punching it up again, done. Re-fire.  Take the tools with you to the range, and cut the research time, just because.   I've drilled a guy's barrel on a truck tailgate, in the middle of the night with a headlamp on, out here in the desert - to get the gun running.  You do what you have to. 

Run that Adj gas block wide open when you test it, or it's screwing up the work you did on the gas port - that's the only real way to know.  

Perfect. Crossing my fingers that its opened up enough to lock bolt. If not, I will do just that.

Never had a problem with undergassed on a new gun ever before. Of course, most has been in 556 but I had the opportunity to use and carry the (under 60 serial numbered) KAC M110 when they were first deployed. The only issue with that was having 2 zeroes to deal with (1 with suppressor, 1 without). But thats a story for another post.

Will get back to you on progress and update the pics. 

Stay safe  

 

[JT303]

20 hours ago, shooterrex said:

You have an adjustable gas block. The port can be bigger and you can adjust it down w/the gas block.

Yes sir. Just wanted to make sure I dont exceed a max amount of Gas that could blow a tube/block or cause unnecessary damage to the bolt carrier/key. 

I believe that with my ultradyne muzzle break, its taking a lot of recoil out of the barrel vs a standard device. I should really get a chrono one of these days.

Gonna give it a test run with it opened up a little. 

[shooterrex]

The gas tube is the limiting factor there. It is only so big. The gas port can be larger than the gas tube but there can only be so much gas going down the tube. The upper limit is the ID of the gas tube.

[98Z5V]

9 hours ago, shooterrex said:

The gas tube is the limiting factor there. It is only so big. The gas port can be larger than the gas tube but there can only be so much gas going down the tube. The upper limit is the ID of the gas tube.

^^^   Truth, right there.  Max ID on a gas tube is 0.125".  That's all that gas ports can go up to, because, just as you stated Rex - anything larger doesn't matter.

There are ways around that, when you get close to 0.125" port diameter on a gun.  You change the barrel profile to a larger diameter gas block journal.  Very, very few manufacturers have this figured out - but Fulton Armory does.  FA doesn't build their own barrels - they just have great barrel companies make the profile that they directly  specify.

I could go hours on this one, but I'll stop myself here.  

[JT303]

10 hours ago, 98Z5V said:

^^^   Truth, right there.  Max ID on a gas tube is 0.125".  That's all that gas ports can go up to, because, just as you stated Rex - anything larger doesn't matter.

There are ways around that, when you get close to 0.125" port diameter on a gun.  You change the barrel profile to a larger diameter gas block journal.  Very, very few manufacturers have this figured out - but Fulton Armory does.  FA doesn't build their own barrels - they just have great barrel companies make the profile that they directly  specify.

I could go hours on this one, but I'll stop myself here.  

Wow. Another great piece of knowledge right there by 98. Seems pretty simple in the eyes of an engineer ! Make a bigger GB to compensate for higher pressures. 

I believe in the heavy contours and full barrel sizes for harmonics. Which is key to your accuracy. I often wondered if handguard manufactures ever figured out that you will need bigger handguards to compensate for the bigger diameter barrel and GB's. 

Hey, lets start up our own XL handguard Co. and retire.......lol  🙂

[98Z5V]

12 hours ago, JT303 said:

Seems pretty simple in the eyes of an engineer !

Eh, I'm no engineer, but I've built alot of engines and pissed around with turbocharging and fuel injection, nitrous, and methanol for a main fuel, for a long time. 

Math matters, or your engine scatters...  

These things are no different. 

Here's a Fulton Armory barrel-profile example:  For years, they had Criterion making a stainless steel .308 Win chambered barrel, 16" length, rifle gas.  Dwell time on a 16" rifle gas barrel is very short (2.875" on a properly build barrel).  To make this barrel functional, it had a 0.936 gas block journal diameter, and ran a 0.105" gas port diameter.  It had to be that way.  Bring that journal diameter down to 0.750" like a standard barrel, and it's danger close to being 0.125" - which is no bueno. 

[JT303]

12 hours ago, 98Z5V said:

Eh, I'm no engineer, but I've built alot of engines and pissed around with turbocharging and fuel injection, nitrous, and methanol for a main fuel, for a long time. 

Math matters, or your engine scatters...  

These things are no different. 

Here's a Fulton Armory barrel-profile example:  For years, they had Criterion making a stainless steel .308 Win chambered barrel, 16" length, rifle gas.  Dwell time on a 16" rifle gas barrel is very short (2.875" on a properly build barrel).  To make this barrel functional, it had a 0.936 gas block journal diameter, and ran a 0.105" gas port diameter.  It had to be that way.  Bring that journal diameter down to 0.750" like a standard barrel, and it's danger close to being 0.125" - which is no bueno. 

100 % Math matters. 

I was saving my next upper Ar build to swap out on my lower to be a Criterion (Maybe 24") heavy barrel. I may be switching gears to building a semi-race bolt gun instead in 6.5 caliber. I am way behind on the times when it comes to the 6.5CM, as I know its the best flat shooting plane trajectory round (over 308) but I'm old school M24. My initial goal was to build a solid sub-moa AR308 first to work the bugs out of the system and rate the performance vs a bolt gun. I have always been a bolt guy in HP and AR guy in (well, I just dont call 556 HP). 

You will have to school me on the dwell times, or if you have a blog/post on that already? Im convinced the muzzle device plays a part too.   

When I was young I had a 91 Mustang with DIY RAM air with juice (nitro) and some upgrades. Wish I still had it today. 😍

   

[JT303]

FINALLLY.>>>>>>>>

I finally got myself to the range to test out the re-drilled gas port and compressed buffer spring. 

All set up and test fired. No lock back !! Dang it. I opened her up just a bit so I probably have a little more room to go bigger. 

I must say that in advance, I pre-purchased the JP SCS and a odin works/carbine set up to have 2 contingency plans. 

I tested the JP Enterprise SCS bufer with the lightest spring and all steel buffers. BINGO !!

Lock back no issues and nearly perfect 3-4 o'clock ejection. Decent distance as well. 

It should be noted that i oiled her bolt/carrier/CH more than most strip joint gals. (LOL) 🙂

I then test fired a string of 5. Dang, I was on. She printed nicely and the recoil with the Ultradyne beffer/JP combo felt like effortless. 

Going to say that it was flawless. No malfunctions. All on where it should be and the ejection pattern was all 3-4 oclock with a distance of from 4-7 feet. 

I took some videos and pics too. 

[JT303]

Not too bad. BA barrel Vortex 25x combo. Fed 168 BTHP. 

Will work on some home made stuff in the future. 

Then I may be ready for 98's camp. 

looking forward to some fun and challenges soon !