View Full Version : Finally "Broke" an AR
Right up to today, I had been on a pretty long streak with no major functional problems with any of my ARs.
I took my 18" rifle to the range to shoot some groups. It had been a while since I shot it and I was really enjoying what a soft shooter it is right up until it simply refused to function. It would fire and eject, then hang with a new cartridge 1/2 way out of the magazine. I could close the bolt with the forward assist and it would fail to close on the next round. I swapped mags once, then swiched ARs. I did not try to diagnose it at the range.
When I stripped it tonight, it was obvious that I cleaned it very thoroughly and put it away without lube the last time I shot it. The BCG was as dry as the proverbial bone.
I fired about 60 rounds before it choked. I honestly thought my gas block screws had loosened and did not think about lube at the range.
Andy
Make/model?
Btw, that is seriously not good. A dry BCG should go 600 rounds, not 60. I shoot "bone dry" rifle all winter long.
The OP says "enjoying what a soft shooter it is," which tells me it is probably on the hairy edge of being under gassed, and/or under-sprung as it is. And, depending on how dirty the ammunition shot, the brand of ammunition, how clean the magazines were, and the ambient temperature, I can believe 60 rounds.
If I had a buck for every time I went to the range and forgot to lube an AR. It always worked for the load out, I usually leave a skim coat on the bcg after cleaning and returning to the safe. It doesn't matter what's on it and it varies as I cycle through whatever is free.
"An AR will run Dirty and Wet, but won't run Dirty and Dry".
Make/model?
Btw, that is seriously not good. A dry BCG should go 600 rounds, not 60. I shoot "bone dry" rifle all winter long.
Mixmaster/home build - Rainier 18" rifle gas CHF barrel (.89 gas port per Rainier), Sabre Defense receivers, SDI phosphate BCG, and an A5 H2 recoil system with BCM rifle spring.
The rifle is neither new nor a high round count gun. I have shot at least a few hundred rounds through it without issue. That does not mean it isn't on the edge of failure when clean/lubed, of course.
I was convinced the gas block screws must be loose but everything was tight.
600 rounds dry? More than I would have guessed, I certainly thought it was weird mine choked.
It was dry as in zero lube. I had cleaned it with Hoppes, which pretty well strips all lube from it.
Andy
So.....How many of you folks operate your vehicles without oil????
Curious minds want to know........
Dunk the bolt in Froglube and add a touch every other shoot. I never have to lube prior to shooting. That's nuts.
Seems a little light on the gas drive...
Mixmaster/home build - Rainier 18" rifle gas CHF barrel (.089 gas port per Rainier), Sabre Defense receivers, SDI phosphate BCG, and an A5 H2 recoil system.
The rifle is neither new nor a high round count gun. I have shot at least a few hundred rounds through it without issue. That does not mean it isn't on the edge of failure when clean/lubed, of course.
I was convinced the gas block screws must be loose but everything was tight.
600 rounds dry? More than I would have guessed, I certainly thought it was weird mine choked.
Andy
Seems a little light on the gas drive...
You would be the guy to know, but that is the spec Rainier posted on their site for the Mountain series 18" barrels. Purely coincidence - the gun I switched to has a 16" BRT Light Optimum barrel.
Andy
Dunk the bolt in Froglube and add a touch every other shoot. I never have to lube prior to shooting. That's nuts.
I don't lube prior to shooting either, but I normally oil after cleaning. I also normally just wipe the bcg clean without solvent. Not in this case, obviously.
Andy
I had an 18" barrel with a bigger gas port than yours that was still not overgassed. I don't have Clint expertise, but my experiences echo what he's saying.
titsonritz
11-14-22, 12:59
Mixmaster/home build - Rainier 18" rifle gas CHF barrel (.89 gas port per Rainier),
Seems a little light on the gas drive...
I would agree with that, my 18" rifle gas barrel has a .0995" gas port.
Mixmaster/home build - Rainier 18" rifle gas CHF barrel (.89 gas port per Rainier)
You have a very soft shooting range gun. That is smaller than a 20” M16 barrel, .093” gas port.
The MK12 is .102” or .104”, and only used with 5.56 NATO pressure ammo.
vicious_cb
11-14-22, 15:14
And now you know why small gas port guns are for shooting suppressed only and gamer $hit.
I am ok with a range/gamer gun, I guess. It may not work in sub zero temps and it definitely needs to be lubed, but I have other ARs that lean towards reliability.
On the other hand, the rifle has been problem free with a wide variety of ammunition when it is lubed. I researched the barrel a bit before I purchased it and all the reports I read (including here) were positive.
I should also note that this barrel is from the CHF chrome/phosphate Mountain line that Rainier discontinued, not the current series.
Andy
I'd be curious to the affect using a LMT E-carrier would have on opening up the operating envelope via increased carrier speed. I may be thinking of this incorrectly, but perhaps an E-carrier and stepping down a weight to A5H1 would combine well.
I'd be curious to the affect using a LMT E-carrier would have on opening up the operating envelope via increased carrier speed. I may be thinking of this incorrectly, but perhaps an E-carrier and stepping down a weight to A5H1 would combine well.
It would be difficult to determine since the rifle normally runs just fine.
I could send it off to have the gas port drilled larger and pin the gas block if I needed a 24/7 duty gun - the barrel is CHF chrome lined and the gun is built with quality parts.
For my intended uses of the rifle, remembering to lube it will suffice. The rifle is not built for gaming or fighting - it is built for shooting at the range and perhaps thinning a few prairie dog towns or plonking one of Bambi's parents.
Andy
It’s not just lube, temperature plays a big part as well.
It would be difficult to determine since the rifle normally runs just fine.
Not really; just run it dry again. It's easy to swap buffer weights to try A5H1 or A5H0 configuration. Perhaps it doesn't degrade the feel but runs longer dry.
I was also wondering if it would continue to run with an A5-H1 or 0.
My last step to cleaning a rifle or pistol is the application of lube. Until lube is applied, it doesn’t go into a safe.
My last step to cleaning a rifle or pistol is the application of lube. Until lube is applied, it doesn’t go into a safe.
Well, I can almost say the same. I am pretty sure I got interrupted and did not get back to it.
Andy
It’s not just lube, temperature plays a big part as well.
If I head back to the frozen wasteland of SD this winter, I will drag it along and see how it acts in the cold.
Andy
I don't clean my ARs until they get at least 600 to 800 rounds through them. So not shooting for lack of oil is not really a problem because they almost never have fresh oil. I treat them the same as my AKs if they don't function dirty I don't want them around.
With that barrel I bet it will shoot softer and be easier to run faster with a lighter buffer
With that barrel I bet it will shoot softer and be easier to run faster with a lighter buffer
The rifle started life with a 20" barrel, hence the A5H2 buffer. I swapped it for an 18" with a new bcg some time ago, and round count has been pretty low on it since then.
Should I drop back to an A5H0 or H1 first? I have a plethora of steel weights on hand.
Andy
Yes. Less weight will give you a little less recoil but also a little more margin of function. (Except closing when dirty)
Colt Carson
11-24-22, 01:48
Why would anyone run their firearms without lube???
Why would anyone tell that they did that???
Why would anyone run their firearms without lube???
Why would anyone tell that they did that???
In my case how, not why.
Because I feel the outcome is interesting.
Andy
When I clean my BCG's they go, disassembled, into an ultrasonic cleaner for 10 minutes.
When they are done, I shake them off and immerse them in Kerosene. Once I've done the requisite further brushing, I lather them up in a liberal coating of G96 before putting them back together and they are stored like this until my next use. I'm sure I've run some drier than others, depending on time between cleaning and shooting.
As far as I can remember, I've never experienced a lube related stoppage.
Technically, you didn't break your AR, you found its operating limit, due to the gas issue.
Dropping to an A5H0 should help, but may not be enough to make it fully reliable.
We'd probably still touch up the port to 093 to avoid any future issues.
The rifle started life with a 20" barrel, hence the A5H2 buffer. I swapped it for an 18" with a new bcg some time ago, and round count has been pretty low on it since then.
Should I drop back to an A5H0 or H1 first? I have a plethora of steel weights on hand.
Andy
hotbiggun42
11-26-22, 14:25
My first AR was a oly arms car15 bought it in 1994. Shot about 1000rds through it in one day until it began having failure to feed and extraction issues. I had no idea i needed to oil the bcg.
Went back to shooting my Mak 90s.
To continue beating the dead horse, this rifle functioned normally when oiled with all (brass case) factory .223 and 5.56 I tried, plus some mild-ish reloads. Functioned normally meaning ejection direction and distance similar to my 16" mid and optimum gassed ARs, last round bolt hold open, etc.
When I took it to the range without lube after a thorough cleaning, it functioned normally until I changed to some Hornady 55 gr soft point 223 and the bolt consistently failed to return to battery with a live round about 1/2 out of the magazine.
I messed around for a couple rounds, tried a different magazine with no change, then swapped to another gun. The second rifle fired the remaining 10 rounds or so of that ammunition without issue.
Maybe the ammo was a little weak, I don't know. I do know that I will put an oil bottle back in my range bag.
Andy
vicious_cb
11-27-22, 01:30
To continue beating the dead horse, this rifle functioned normally when oiled with all (brass case) factory .223 and 5.56 I tried, plus some mild-ish reloads. Functioned normally meaning ejection direction and distance similar to my 16" mid and optimum gassed ARs, last round bolt hold open, etc.
When I took it to the range without lube after a thorough cleaning, it functioned normally until I changed to some Hornady 55 gr soft point 223 and the bolt consistently failed to return to battery with a live round about 1/2 out of the magazine.
I messed around for a couple rounds, tried a different magazine with no change, then swapped to another gun. The second rifle fired the remaining 10 rounds or so of that ammunition without issue.
Maybe the ammo was a little weak, I don't know. I do know that I will put an oil bottle back in my range bag.
Andy
Congrats you've inadvertently found the sweet spot that race gunners are constantly tuning their guns for, the ragged edge of functionality and softness. Now you can go out, put on a silky shirt and shoot a dozen A-zones at 3 yards really fast. :cool:
Congrats you've inadvertently found the sweet spot that race gunners are constantly tuning their guns for, the ragged edge of functionality and softness. Now you can go out, put on a silky shirt and shoot a dozen A-zones at 3 yards really fast. :cool:
I can't even shoot fast at 3 yards tho.
Andy
Maybe the ammo was a little weak, I don't know. I do know that I will put an oil bottle back in my range bag.
One interesting thing with longer gas systems and less dwell time is that “weak” cycling ammo doesn’t always mean lower velocity. Powder burn rate affects pressure at a rifle gas port that you would never notice in a carbine.
BufordTJustice
11-27-22, 21:18
One interesting thing with longer gas systems and less dwell time is that “weak” cycling ammo doesn’t always mean lower velocity. Powder burn rate affects pressure at a rifle gas port that you would never notice in a carbine.
That is actually very interesting. Can you elaborate?
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Sure, M855 military ammo has a gas port pressure requirement that I’ve seen, they do that to ensure function.
PMC used the wrong powder in their Bronze M193 back in 2000 something. Ran fine in carbines, choked hard in rifles.
https://www.m4carbine.net/showthread.php?7757-interesting-PMC-ammo-problem
Hornady Superformance is basically the opposite. Look at the pressure curve chart they have where the pressure goes up faster, a regular faster powder would also go up faster but then drop off faster after the peak. So it could have similar velocity (area under the curve) as the standard load but lower pressure at port.
https://www.hornady.com/support/superformance-in-gas-operated-firearms
BufordTJustice
11-28-22, 18:06
Sure, M855 military ammo has a gas port pressure requirement that I’ve seen, they do that to ensure function.
PMC used the wrong powder in their Bronze M193 back in 2000 something. Ran fine in carbines, choked hard in rifles.
https://www.m4carbine.net/showthread.php?7757-interesting-PMC-ammo-problem
Hornady Superformance is basically the opposite. Look at the pressure curve chart they have where the pressure goes up faster, a regular faster powder would also go up faster but then drop off faster after the peak. So it could have similar velocity (area under the curve) as the standard load but lower pressure at port.
https://www.hornady.com/support/superformance-in-gas-operated-firearms
Understood. Thank you.
I've used Superformance for several years now (55gr 5.56 GMX) in my 16" intermediate and 11.5" suppressed SBR. Idefinitely moved up one buffer weight compared to nato pressure 55gr.
Pressure under the curve. Interesting.
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