new rifle - ladder rounds

[outrider58]

I bore sighted it as shown in post #9. Then I sited it like it was a bolt action. I checked it again this morning and the barrel look remarkably clean for being fired 30 - 40 times. I have not ever adjusted a gas blocks or if they need adjusting. There has never has been any factory ammo through this upper unless PSA used some to test it before shipping, as I think they do.

I watched a video about one round in a mag and opening it up one turn until it locks back each time. Then another turn for colder weather. This is the problem I am having. The highest load I had rarely ejected shells and did not lock back or chamber a new round. They would reset the hammer and push the spent casing back into the chamber as they did not travel far enough backwards.

Opinions and guidance? I'll probably bring Byron up on Saturday or Sunday and make him a deer steak and have him help/show me. The Gas block has two screws on the side, one block by the hand guard. One looking to be facing the muzzle. Scope front mount is on the hand guard. So I am assuming all this needs to come off to adjust it.

What kind(brand and type) of gas block do you have on the gun Rob? What kind of buffer spring and weight of buffer is in the gun?

Did this gun start out with a different upper on it? If yes, what barrel length, gas length, and caliber?

 

[King Chicken]

That build was as much a learning experience for me as it was for you. My first short barreled middy. My thinking is, the gun with an H1 buffer is behaving as it should. The GB is wide open and the gun is soft(to me) to shoot as is. If and when you decide to add a suppressor, you will be able to dial down the gas into bleed-off mode to offset some of the gas-face and added back pressure.

There are things we could do, but to me, seems like nothing more than a trade-off for the same effect.

a) We could put an H buffer in it which will allow you to dial in a bit of bleed-off while shooting unsuppressed.

b) We could keep the H1 in there and switch to a yellow spring, which might allow dialing the GB into bleed-off mode.

c) Or, we could the H1 or H buffer, the white spring, and open up the gas port in the barrel.

At this point, I recommended keep the gun where it is(H1 buffer with white Sprinco spring) and break the gun in with a few hundred rounds. That will not only clean out the over spray in the upper receiver, but also foul and seal the gas block properly, then go from there.

I have a few ARs, all of which are set up to shoot suppressed. All of which I built myself. They all have adjustable gas. None of them has or needs an H2 buffer, and all handle light to subsonic(300 Blk) loads and will handle full power NATO loads as well.

The AR 15s of old could be considered Legos. The modern ARs, no so much, given the myriad setups available to the modern builder.

Suggestions are always appreciated.

ETA: The gun, as is, is not under gassed. Ejection pattern is 4:00 to 4:30 with the gas all the way open. It has been my impression, that's how middies are supposed to run, the whole point of the extended gas length.

I should apparently be in an H with 14.5 mid length. I got greedy and bought the wrong item i guess...although others on many forums are able to run that.
As someone from another forum commented on someone in my situation.
"h buffer and call it a day" and then switch back to h1 if possible.
DD uses an H on their 14.5 middie, as does BCM apparently.

 

[trickg]

"cold bore" is a myth. I have proved that many times while teaching precision rifle and shooting long range comps.
https://www.mdshooters.com/threads/...rofile-effects-questions.274040/#post-7027086

My last step of cleaning is typically a dry patch - dunno if that's what I'm supposed to do, but it's what I do.

I've gotten more than one dead-on bullseye at 100 with my 223 precision build on a clean, cold bore, and always thought it was a fluke.

 

[Archeryrob]

What kind(brand and type) of gas block do you have on the gun Rob? What kind of buffer spring and weight of buffer is in the gun?

Did this gun start out with a different upper on it? If yes, what barrel length, gas length, and caliber?

I bought the PSA blackhawk lower parts kit as part of a package back in 2013. It does not state about the spring.

https://palmettostatearmory.com/psa-classic-blackhawk-lower-build-kit-black-5165447982.html

I bought the upper separate for the same lower. All it says is .750 and low profile. It came with a card talking about 3 and 5 position adjustable gas blocks, but I have no idea what is in it. Says they shot it with 115 grain bullets and mine are heavier.

https://palmettostatearmory.com/psa-18-mid-length-6-8-spc-ii-1-11-stainless-steel-15-lightweight-m-lok-upper-with-bcg-ch.html

 

[Archeryrob]

This gas block is driving me nuts. Could 4227 or cast bullets cause a problem and clog it or not be enough?

I close the gas block and they listed it from PSA at being at 7 clicks. I opened it to 8.

Started with a 2102 fps round and no ejection,

then to 10 no ejected shell

12 clicks and shell ejected but not locked back.

13 click no ejection,

15 clicks it ejected and locked back.

Then I tried the lowest in the ladder at 1955 fps and no ejection.

Opened to 17 clicks and wide open and 1955 fps no cycle or ejection.

Try another 2102 fps round that worked at 15 clicks and 2 round and no ejection. WIDE OPEN!!

 

[Russ D]

Have you tried factory ammo?

 

[Archeryrob]

No and not sure if I can find 6.8 around here.

 

[outrider58]

I have my top man working on it right now... top man!

 

[Archeryrob]

Had a couple of beers, to ease the frustration. So maybe ride up there and drop the rifle off tomorrow.

 

[outrider58]

Had a couple of beers, to ease the frustration. So maybe ride up there and drop the rifle off tomorrow.

Sounds like a solid plan.

 

[gungate]

No and not sure if I can find 6.8 around here.

One way I found my reloads were not working is I removed the upper from the lower, put the upper in a stand (upside down), and manually fed the rounds. I found many of them would not seat all the way and were getting stuck in the bore. Have you tried putting your empties back in the bore and seeing if they get stuck?

 

[Archeryrob]

My reloads are shooting and sized to the chamber/bore. I chambered dummy cartridges before loading some to check OAL and fit to the chamber.

Nothing sticks but the bolt is not traveling far enough back, with enough force to operate the gun. I am not getting gas to cycle the bolt. I am taking it to Byron's (outriders) expert tonight. I am not ruling out it is something I did, but the gas system hardly changed with me moving it from 8 clicks to 17. I was expecting the bolt to be banging back hard enough to wear out parts.

Many times it reseats the fired case in the chamber and the hammer can drop on it again.

 

[trickg]

Color me stupid, but could it be that there's a misalignment with the gas block?

 

[E.Shell]

Color me stupid, but could it be that there's a misalignment with the gas block?

I had the same thought. A few factory loads would rule out potential ammo issues, especially malfs with "starting" loads.

 

[Archeryrob]

Possible, but my ignorance of gas block overrides my ability to know. That is why I am dropping it off to Byron's expert. I have done about all I am capable of. PSA test fired it and supposedly work for them. First shot for me failed to eject.

 

[Mike3888]

This gas block is driving me nuts. Could 4227 or cast bullets cause a problem and clog it or not be enough?

I close the gas block and they listed it from PSA at being at 7 clicks. I opened it to 8.

Started with a 2102 fps round and no ejection,

then to 10 no ejected shell

12 clicks and shell ejected but not locked back.

13 click no ejection,

15 clicks it ejected and locked back.

Then I tried the lowest in the ladder at 1955 fps and no ejection.

Opened to 17 clicks and wide open and 1955 fps no cycle or ejection.

Try another 2102 fps round that worked at 15 clicks and 2 round and no ejection. WIDE OPEN!!

I’m thinking 4227 is too fast for heavies in 6.8.

 

[outrider58]

Color me stupid, but could it be that there's a misalignment with the gas block?

My thinking has been, either the gas block is misaligned or the gas key is leaking air. I experienced the latter in a PSA gas block I bought years ago because it was a "steal". Years later, I put in a gun I built mostly out of spare parts and played hell trying to get it to cycle. I applied all my learned knowledge and the last thing I tried was the bolt carrier(I really could have saved myself a lot of trouble if I had tried that first ). I pulled the gas key, honed and sealed the new one and the gun ran like a top!

ETA: The problem, in the case of the OP, we haven't been able to establish an ejection pattern to help with the diagnosis.

 

[trickg]

My thinking has been, either the gas block is misaligned or the gas key is leaking air. I experienced the latter in a PSA gas block I bought years ago because it was a "steal". Years later, I put in a gun I built mostly out of spare parts and played hell trying to get it to cycle. I applied all my learned knowledge and the last thing I tried was the bolt carrier(I really could have saved myself a lot of trouble if I had tried that first ). I pulled the gas key, honed and sealed the new one and the gun ran like a top!

Interesting - I hadn't even thought about the gas key, but that makes sense too. That's something to file away in the brain for later use - it might just come up at some point.

 

[outrider58]

Interesting - I hadn't even thought about the gas key, but that makes sense too. That's something to file away in the brain for later use - it might just come up at some point.

Normally, in new builds, if the gas key has proper screws and passes the 30 in/lbs torque test, I leave it alone, unless there is a problem. Nowadays I only use Toolcraft chrome phosphate carriers with 158 carpenter steel bolts. I have yet to come across any issues with them.

 

[Russ D]

I’ve been known to plug barrels with my fingers and blow into the muzzle to determine if there are restrictions and misalignments with the gas block. If you know what it “should” feel like you can get a good idea. Also there are some powders that just do not create the right gas pulse to properly function an AR in some situations. You have to verify and gas flow and try some factory rounds to go much further here.