Register a SA Forums Account here!
JOINING THE SA FORUMS WILL REMOVE THIS BIG AD, THE ANNOYING UNDERLINED ADS, AND STUPID INTERSTITIAL ADS!!!

You can: log in, read the tech support FAQ, or request your lost password. This dumb message (and those ads) will appear on every screen until you register! Get rid of this crap by registering your own SA Forums Account and joining roughly 150,000 Goons, for the one-time price of $9.95! We charge money because it costs us $3,400 per month for bandwidth bills alone, and since we don't believe in shoving popup ads to our registered users, we try to make the money back through forum registrations.
«62 »
  • Post
  • Reply
Captain von Trapp
Jan 22, 2006

I don't like it, and I'm sorry I ever had anything to do with it.

Proper Kerni ng posted:

The funtime ingredient in Liquid Drano is sodium hypochlorite, which is aces at rapidly pitting and corroding both stainless and high carbon steel. If someone was gonna try a Better Living Through Chemistry approach I'd definitely recommend trying some non-chlorinated brake cleaner first, since that's what The Cool Kids use to clean gas tubes already and anyone who's ever worked on brakes knows that poo poo will eat through blue shop towels like a hungry goat.

Ah, didn't remember it had chlorine. Yeah brake cleaner might do it. Does lye eat metal? That might work too.

Adbot
ADBOT LOVES YOU

Styles Bitchley
Nov 13, 2004

FOR THE WIN FOR THE WIN FOR THE WIN

Proper Kerni ng posted:

Uh, did nobody point out to them while they were trying to be all CHECKMATE, LIBS about gas tubes that the barrel is, in fact, a tube which experiences north of 50,000 psi with every shot? I'm probably not the only dumbass in here with multiple green and yellow boxes in the house, and some of that dirt cheap bulk mystery meat plonkin' ammo out there was pretty clearly loaded in a Slavic basement.

Yeah but your barrel is rifled and has press fit lead and copper streaked down it under heat and pressure. The gas tube is smooth and only subject to dirty gas that should be blown clear. There really isn't any surface for debris to accumulate on. Any remaining filth that somehow goes up the gas port instead of down the barrel ends up in your bolt carrier, upper, and surrounding areas.

A Real Hologram
Jun 22, 2018

Moo!


Yeah but the barrel makes physical contact with metal sliding down its length while the gas tube does not, so there has to be some sort of difference there.

Edit: beat

Cyrano4747
Sep 25, 2006



Plus a gas tube is both cheap and not that difficult to replace.

If gas tubes clogging was an issue the solution would be to put a new one on every 5k rounds or whatever.

Reuben Sandwich
Jan 27, 2007



Or if there was an issue, it would've been blown out of proportion and clung onto for years, much like the early issues of Vietnam. Which makes me wonder even with the powder fouling and overpressure of those early rifles whether gas tube problems were reported.

While on gas tube, someone told me it was designed with the gas tube purposely the weak point in the system for safety. It makes sense on engineering sense but I don't know if factual.

Anonymous Robot
Jun 1, 2007

Lost his leg in Robo War I


Whatís good AR thread. Iím thinking on finally getting a proper long gun. Iíll realistically only ever have one, so I want it to be a practical 5.56 carbine. I also live in MA, so a lot of the compelling reasons to select an AR-15 (big magazines, extensive modifications) are void. I also think the average AR-15 is ugly as sin, which isnít a reason not to select a firearm but does make it feel like a chore and not a pleasure to buy one.

For these reasons, and the fact that my state has specifically called out the Mini-14 as ďnot an assault weapon,Ē for all thatís good for, I was intending on going with a Mini-14. But Iíve been reading up on issues with weather resistance, reliability, and difficulty of takedown with them that is making me reconsider.

Iím not interested in building my own rifle, but if itís head and shoulders the better route to go then I can be convinced. Iím comfortable spending up to $1500 for a boxed solution.

I like the look of the FightLite SCR with the walnut stock, which is presently sold put everywhere but seems like a good compromise. My only hesitation right now is, I havenít seen a wealth of opinions on them, and Iím wondering how difficult it would be to put a light on one if I donít go with the version that has an M-LOK handguard. I could get that version, if itís the only sensible way to affix a light, but I love the appeal of the full walnut handguard.

Styles Bitchley
Nov 13, 2004

FOR THE WIN FOR THE WIN FOR THE WIN

Reuben Sandwich posted:

While on gas tube, someone told me it was designed with the gas tube purposely the weak point in the system for safety. It makes sense on engineering sense but I don't know if factual.

The only mechanism I can see is during very heavy sustained fire the gas tube will probably be the first thing to go from the heat. Seems unlikely but it may be possible this was an intentional consideration to fail and shut the weapon down before you built up enough heat for barrel burst or chamber cook offs. Off the top of my head I can't really think of any other situation where the gas port would fail first and save you.

Rontalvos
Feb 22, 2006



We've been discussing this SCR in the California thread, join us. https://forums.somethingawful.com/s...r=68&perpage=40

darnon
Nov 8, 2009


Anonymous Robot posted:


I like the look of the FightLite SCR with the walnut stock, which is presently sold put everywhere but seems like a good compromise. My only hesitation right now is, I havenít seen a wealth of opinions on them, and Iím wondering how difficult it would be to put a light on one if I donít go with the version that has an M-LOK handguard. I could get that version, if itís the only sensible way to affix a light, but I love the appeal of the full walnut handguard.

If you're reasonably handy it wouldn't be difficult drill the handguard to add some threaded inserts for a small section of rail or directly mount a light holder. The only downside I see there is the SCR offering is only a carbine length gas so you end up with a lot of barrel potentially obstructing the light throw. Wood M-LOK panels are also a common complement which still gives you the advantage of free-float.

Want to go whole hog on wood? Pair an SCR Walnut lower with a free-float that lets you use some full length wood handguards to build a dissipator upper.

darnon fucked around with this message at 17:01 on May 18, 2020

PookBear
Nov 1, 2008


Nobody exists on purpose, nobody belongs anywhere, everybody's going to die.




I put the handstop on backwards with a VFG directly behind it and really like it.

edit: It helps index my hand between the VG and the backwards handstop. I can bring my hand closer and use the VFG normally or push my left hand further out and use the VFG as a hand stop.

PookBear fucked around with this message at 20:36 on May 18, 2020

DarkHorse
Dec 13, 2006

Vroom Vroom, BEEP BEEP!

Nap Ghost

Styles Bitchley posted:

The only mechanism I can see is during very heavy sustained fire the gas tube will probably be the first thing to go from the heat. Seems unlikely but it may be possible this was an intentional consideration to fail and shut the weapon down before you built up enough heat for barrel burst or chamber cook offs. Off the top of my head I can't really think of any other situation where the gas port would fail first and save you.

That's exactly what happened in some video torture tests I saw, I think of a belt fed AR. It ran until the barrel was red hot and the gas tube was white-hot and it went POP

It's not a reliable mechanical fuse but it's at least something, and the gun will still work if it goes it will just become like a bolt action

Somebody Awful
Nov 27, 2011

Don't let Lowtax go down with the ship. Do your part for these dead gay forums.


Styles Bitchley posted:

The only mechanism I can see is during very heavy sustained fire the gas tube will probably be the first thing to go from the heat. Seems unlikely but it may be possible this was an intentional consideration to fail and shut the weapon down before you built up enough heat for barrel burst or chamber cook offs.

I think Chris Bartocci touched on this in one of his videos on the M4 and the short version was that full auto destruction testing showed the barrel would overheat and rupture behind the FSB before the gas tube failed.

E: this was with the standard M4 profile barrel that's relatively thin under the handguards, not the newer heavy profile.

Miso Beno
Apr 29, 2004


Tryin' to catch me ridin' dirty


Fun Shoe

HELP IM ON A FIXED CARRY HANDLE KICK

Mechworrier
Jul 21, 2003

Victory needs no explanation; defeat allows none.

Me too. Bought one of those a1 parts kits and after agonizing over whether to build a 723 or xm177e2 clone I decided to dishonor its former service and made this instead:



I have no idea how it shoots yet, but it sure is handy.

DeesGrandpa
Oct 21, 2009



Very nice, though could probably lose a little weight with the recoil pad.

Also fixed handles are always the choice, I need to loving get back out shooting so I can get better pics of the perfect AR (I sold the scope thankfully)

MazeOfTzeentch
May 2, 2009

rip miso beno


gently caress yeah carry handles

Mechworrier
Jul 21, 2003

Victory needs no explanation; defeat allows none.

DeesGrandpa posted:

Very nice, though could probably lose a little weight with the recoil pad.

Also fixed handles are always the choice, I need to loving get back out shooting so I can get better pics of the perfect AR (I sold the scope thankfully)



Oh no doubt. It's on that lower because until I get the brake pinned and welded it needs to live on my SBR lower, which normally hosts an early gwot m4 cqb receiver clone. And ya can't claim to be trying to clone one of them without zip-tying a John Masen recoil pad to a car-15 style stock like all the cool guys did back in the day.

Styles Bitchley
Nov 13, 2004

FOR THE WIN FOR THE WIN FOR THE WIN

DarkHorse posted:

That's exactly what happened in some video torture tests I saw, I think of a belt fed AR. It ran until the barrel was red hot and the gas tube was white-hot and it went POP

It's not a reliable mechanical fuse but it's at least something, and the gun will still work if it goes it will just become like a bolt action

It seems possible but to me doubtful if that was intentional if so. Looking at some torture tests here are three where you have one gas tube pop, one barrel pop, and one where the test was stopped due to a cookoff:

Gas tube burst: https://www.youtube.com/watch?v=_WD0W4ry0LY#t=833s

Barrel burst: https://www.youtube.com/watch?v=BSizVpfqFtw#t=630s

Cookoff: https://www.youtube.com/watch?v=tNG7Kkk_s6o#t=513s

But you have who knows what when it comes to commercial ARs compared to the original Stoner specifications.

Shaocaholica
Oct 29, 2002

Fig. 5E



Carry handles Iím helping

Miso Beno
Apr 29, 2004


Tryin' to catch me ridin' dirty


Fun Shoe

your gun is confused.

DeesGrandpa
Oct 21, 2009



https://www.youtube.com/watch?v=P9uny8aCoLc

My fave AR destruction video

Miso Beno
Apr 29, 2004


Tryin' to catch me ridin' dirty


Fun Shoe


oh yes the test that made the AR worse for most users

ArmyGroup303
Apr 10, 2004

If this were real life, I would have piloted this helicopter with you still in it.

Miso Beno posted:

oh yes the test that made the AR worse for most users

"Rounds fired: M4= 535, M4a1= 911."

I kind of agree. It's great that the M4A1 is about 350 rounds more durable than the M4, and there's some value in that. However, both rifles/barrel profiles easily survive twice the 210 rounds a solider/Marine would generally be issued.

It'd be more interesting to see the accuracy of both barrels after 30 and 210 rounds of full auto fire. (Edit: May as well add a test after 420 rounds too.)

Shaocaholica
Oct 29, 2002

Fig. 5E


Robski does accuracy tests after mag dumps to see POI drifts in his torture tests. He mostly does AKs but he might have done an AR at some point.

Good barrels tend to just open up the group when hot while still preserving the same general POI. Thinner pencil barrels open up more than heavier profiles.

Somebody Awful
Nov 27, 2011

Don't let Lowtax go down with the ship. Do your part for these dead gay forums.


ArmyGroup303 posted:

"Rounds fired: M4= 535, M4a1= 911."

I kind of agree. It's great that the M4A1 is about 350 rounds more durable than the M4, and there's some value in that.

Just FYI, whoever put that video together doesn't know what distinguishes an M4A1 from an M4. It's the FCG, not the barrel profile: M4 is burst, M4A1 is auto.

MazeOfTzeentch
May 2, 2009

rip miso beno


Uhh, m4a1 absolutely has a much heavier barrel profile

Somebody Awful
Nov 27, 2011

Don't let Lowtax go down with the ship. Do your part for these dead gay forums.


The M4A1 is getting a heavier barrel profile because operating operators were blowing out standard profile barrels trying to use the M4A1 as an LMG. The heavy barrel was not part of the original TDP.

The M4 and M4A1 entered service in the mid-1990s. The SOCOM heavy barrel didn't appear until well after we got balls deep in Operation Worthless Dirt.

Wa11y
Jul 23, 2002

Did I say "cookies?" I meant, "Fire in your face!"

MazeOfTzeentch posted:

Uhh, m4a1 absolutely has a much heavier barrel profile



I'm not sure that's always the case, but I haven't found a good clear answer on versions of the M4 like you can for the M16.
I think the only difference between the M4 and M4A1 is the burst/auto, but then there is the M4A1 SOCOM variant that has that heavier barrel you pictured (any maybe some other differences, but also maybe not, possibly only related to available accessories?).

If there's the possibility of a good clear rundown of differences, I'd love to read it, but I think there have been SO MANY variants by the different branches, and different groups in the different branches, that it would look like a conspiracy theorists yarn board (M4, M4A1, M4A1 SOCOM, M4 Block 1, M4 Block 2...).

Ygolonac
Nov 26, 2007

pre:
*************
CLUTCH  NIXON
*************

The Hero We Need


Hrng. Long-term builds of the two shortys are being delayed due to low or no availability of the specific receivers I want, plus being a broke-rear end goon. :V The LaFrance is easy, pre-ban Colt Grey (or early XM, see below), standard deflector/assist uper and full-fence lower, yadda.

The bitch is really the 601 slabside lower for the N-23... the 80% ones (as well as the completed lowers)are sold out with a projected 2021 availability. The other half is getting the early XM Grey anodizing - sounds like US Anodizing is the one place that for sure does it, when they accept small orders, and $fuckyou pricing. Brownell's has the retro upper in that grey, but there's been complaints about it not being the correct grey, and/or not coming close to matching. (Some Arfcommer even got black instead of grey.)

There's a really nice moly coating available, but I'm not that trusting of my painting skilz - plus, I'm wanting to develop wear (some of it even legit).

In short,

ArmyGroup303
Apr 10, 2004

If this were real life, I would have piloted this helicopter with you still in it.

Shaocaholica posted:

Robski does accuracy tests after mag dumps to see POI drifts in his torture tests. He mostly does AKs but he might have done an AR at some point.

Good barrels tend to just open up the group when hot while still preserving the same general POI. Thinner pencil barrels open up more than heavier profiles.

Yep. Honestly, I wish I had the time, money and legal ability to do a side-by-side of a pencil barrel with a heavier profile (and maybe some in-between, such as Faxon's gunner) because it'd be fun and enlightening to see the data. I know there's been some demonstrations on YouTube with an AR/M4, but almost all of them are just destructive testing with no associated accuracy/precision testing.

PookBear
Nov 1, 2008


Nobody exists on purpose, nobody belongs anywhere, everybody's going to die.


I'm willing to bet the army has a lot of hybrids where as the marines didn't start using m4s outside of squad leaders and up until pretty late. I deployed 2011 and had to ration them to shorter marines first and then team leaders.

Miso Beno
Apr 29, 2004


Tryin' to catch me ridin' dirty


Fun Shoe

Somebody Awful posted:

The M4A1 is getting a heavier barrel profile because operating operators were blowing out standard profile barrels trying to use the M4A1 as an LMG. The heavy barrel was not part of the original TDP.

The M4 and M4A1 entered service in the mid-1990s. The SOCOM heavy barrel didn't appear until well after we got balls deep in Operation Worthless Dirt.

There are three M4 barrel profiles. OG M4, M4A1 "Mid" profile, and M4A1 Heavy profile.

Shaocaholica
Oct 29, 2002

Fig. 5E


ArmyGroup303 posted:

Yep. Honestly, I wish I had the time, money and legal ability to do a side-by-side of a pencil barrel with a heavier profile (and maybe some in-between, such as Faxon's gunner) because it'd be fun and enlightening to see the data. I know there's been some demonstrations on YouTube with an AR/M4, but almost all of them are just destructive testing with no associated accuracy/precision testing.

Didnít InRange do a test of a pencil barrel for their WWSD project?

Miso Beno
Apr 29, 2004


Tryin' to catch me ridin' dirty


Fun Shoe

It's also worth noting that the guns are failing under heavy sustained fire which is an unusual situation to be engaged in. Carbines shouldn't be doing the job of a light machine gun.

ArmyGroup303
Apr 10, 2004

If this were real life, I would have piloted this helicopter with you still in it.

Shaocaholica posted:

Didnít InRange do a test of a pencil barrel for their WWSD project?

They did, but not quite to the scale that I'm referring to, which is an accuracy test cold bore, followed by a test after 30 rounds full auto and another test after 180 rounds. If we're feeling really generous, let's do one more accuracy test at 420 rounds.

Miso Beno posted:

It's also worth noting that the guns are failing under heavy sustained fire which is an unusual situation to be engaged in. Carbines shouldn't be doing the job of a light machine gun.

I'm guessing the regular Army considered that the heavier profile barrel was worth it because:
1) The accuracy holds up *significantly* better than the other lighter profiles overall - both in normal courses of fire and extreme ones. (A main reason for the combined heat stress/accuracy test above.)
2) The lifetime cost of the heavier barrel ends up being cheaper, i.e., fewer replacements over time.
3) The handiness of the weapon isn't a high priority compared to overall accuracy and lifetime cost. (Edit: This sucks or is at least annoying if you have to carry the thing all the time with "force-multiplying garbage," to use an InRange phrase, and I'll also assume which Miso Beno was getting at by the "making the AR worse" comment earlier.)

ArmyGroup303 fucked around with this message at 20:41 on May 19, 2020

Styles Bitchley
Nov 13, 2004

FOR THE WIN FOR THE WIN FOR THE WIN

Always wondered why they didn't go with a fluted barrel under the handguards, aside from costs.

Miso Beno
Apr 29, 2004


Tryin' to catch me ridin' dirty


Fun Shoe

ArmyGroup303 posted:

They did, but not quite to the scale that I'm referring to, which is an accuracy test cold bore, followed by a test after 30 rounds full auto and another test after 180 rounds. If we're feeling really generous, let's do one more accuracy test at 420 rounds.


I'm guessing the regular Army considered that the heavier profile barrel was worth it because:
1) The accuracy holds up *significantly* better than the other lighter profiles overall - both in normal courses of fire and extreme ones. (A main reason for the combined heat stress/accuracy test above.)
2) The lifetime cost of the heavier barrel ends up being cheaper, i.e., fewer replacements over time.
3) The handiness of the weapon isn't a high priority compared to overall accuracy and lifetime cost. (Edit: This sucks or is at least annoying if you have to carry the thing all the time with "force-multiplying garbage," to use an InRange phrase, and I'll also assume which Miso Beno was getting at by the "making the AR worse" comment earlier.)

I bet the army went with it because they saw a video and thought machine gun go brrr.

Android Apocalypse
Apr 28, 2009

The future is
AUTOMATED
and you are
OBSOLETE





Illegal Hen

Barrel fluting sounds expensive compared to having a barrel profile of various thicknesses.

Now I'm thinking of a barrel with radial/lateral fluting. I assume that type of fluting is more structurally weaker than traditional barrel fluting?

Android Apocalypse fucked around with this message at 21:22 on May 19, 2020

Cyrano4747
Sep 25, 2006



ArmyGroup303 posted:


2) The lifetime cost of the heavier barrel ends up being cheaper, i.e., fewer replacements over time.


Does it? The main thing that kills barrels is throat and muzzle erosion. FA is way worse for a barrel in that regard than even rapid mag dumps semi due to heat, but is the heavy profile going to soak enough in the chamber and at the end of the barrel to make that big a difference?

Adbot
ADBOT LOVES YOU

Somebody Awful
Nov 27, 2011

Don't let Lowtax go down with the ship. Do your part for these dead gay forums.


Miso Beno posted:

There are three M4 barrel profiles. OG M4, M4A1 "Mid" profile, and M4A1 Heavy profile.

Right, the SOCOM profile isn't a heavy barrel in the sense of an HBAR build, just heavier than the government profile. My point was just that a heavier barrel isn't what defines an M4A1.

  • 1
  • 2
  • 3
  • 4
  • 5
  • Post
  • Reply
«62 »