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Discussion Starter · #1 ·
i had to aquire the H/L regulator for my ACR recently. let me add that i am the first to bust out any company when i get bad service but when i talked with BM on this is was pretty good. despite some phone tag and i got routed to the wrong person. my big issue was i didnt want to send it back in. i just dont like doing it. basically its a bullet launcher with my name on it. anyway i talked to them at noon on a monday and got my regulator the very next day!!! very impressed it came way sooner than expected! now i had to get the H/L regulator cause my ACR started jamming just like the guys on youtube. i couldnt go 20 rounds without a few "stove pipes" and a stove pipe really isnt a stove pipe in the ACR it will double feed on a normal tap and rack. I did go out and try it and it worked just fine but guess what i threw the U/S regulator on and WHAM JAM!! so i throw on the H/L. WHAM WHAM no JAM. my serial number is quite low too. i wonder if this is just happing with a certian lot number of these rifles or if they all could possibly be affected? cause i kinda wanna get another one but im tempted with this whole gas regulator thing because theres a pretty big difference is the U/S and H/L regulator. what has everyone heard or experienced?
 

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Do you remember what ammo, (make and type) you were using when it jams?
Any idea what your round count is?

Also, if you have the means, could you measure the ports on the new regulator for diameter please.

For the 1st time, I had 2 stove pipes last range session and it's only been happening with Fed XM193 brown box. I have also noticed that the brass mark pattern on my brass deflector has moved forward and brass ejection pattern has changed.
 

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Discussion Starter · #3 ·
i was useing the same type ammo the xm193. my round count was about 1000 when this started occuring. i was just doing normal failure drills with only 20 rounds in the mag and i couldnt get through a mag without 2 or 3 jams. i only went through 120 rounds and called it a day. i was frustrated. but i did measure my U/S regulator and i only measured the one hole and it was .088. i need to measure the H/L reg still. and thats how mine started with 2 stove pipes and i did notice a difference in ejecting. the barrel is a 5.56 barrel but i dont think the regulator was designed for 5.56 ammo whick wouldnt make sence to me. its a fantastic solid rifle and i want to get another one but this gas regulator thing makes me a bit nervous.
 

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Do you remember what ammo, (make and type) you were using when it jams?
For the 1st time, I had 2 stove pipes last range session and it's only been happening with Fed XM193 brown box. I have also noticed that the brass mark pattern on my brass deflector has moved forward and brass ejection pattern has changed.
Something like that would make me think low gas but XM193 is pretty hot. Weird. Is your gas block gummed up maybe? You can also try a detail strip of your bolt and scrub out your extractor. Take some gunscrubber or some other good degreaser and blow out your ejector. Put a couple drops of oil around the ejector then work the ejector. You can use a punch to do this or just take a fired case and hook under the extractor and rock it back and against the ejector.
 

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Discussion Starter · #5 ·
im not also wondering if the heat has anything to do with it. i mean metal expands when it heats up. all the heat is getting channeled where the regulator is at. maybe the holes expand and let to much gas through? cause when i slow fire the rifle with the U/S reg and allowed some time for it to cool i didnt have issues. when i started doin drills and heatin it up a tad i had issues 2,3,4 jams in 20 rounds! and i wasnt putting an ungodly ammount of ammo through the rifle like i said that one day i stopped at 120 and even then i still kinda slacked off some during that time. i dont know just a theroy.
 

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Discussion Starter · #6 ·
i strip mine down after ever range session and clean it especially when its new. the xm193 is hot and is cycling the bolt to fast and isnt allowing it to eject like its suppose to. with the new H/L reg i goti noticed a difference in ejecting as i was shooting.
 

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i was useing the same type ammo the xm193. my round count was about 1000 when this started occuring. i was just doing normal failure drills with only 20 rounds in the mag and i couldnt get through a mag without 2 or 3 jams. i only went through 120 rounds and called it a day. i was frustrated. but i did measure my U/S regulator and i only measured the one hole and it was .088. i need to measure the H/L reg still. and thats how mine started with 2 stove pipes and i did notice a difference in ejecting. the barrel is a 5.56 barrel but i dont think the regulator was designed for 5.56 ammo whick wouldnt make sence to me. its a fantastic solid rifle and i want to get another one but this gas regulator thing makes me a bit nervous.
First of All I wasn't aware that a H/L was available as an option... I'm glad you got one. Secondly, it's interesting that you started getting the jams after the 100 round count. And lately, it will be interesting the dimensions of the high and low gas port holes. You might be able to determine whether or not BM made any changes on the fly with older serial numbers.
 

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i strip mine down after ever range session and clean it especially when its new. the xm193 is hot and is cycling the bolt to fast and isnt allowing it to eject like its suppose to. with the new H/L reg i goti noticed a difference in ejecting as i was shooting.
How hard did you have to ask for the H/L GR? Or was it offered to you without any hesitation?
 

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Discussion Starter · #9 ·
i kinda had to argue with the guy cause he really wanted me to send it in and i wasnt gunna send it in AGAIN. then he connected me to a BM gun smith and i told him what the deal was and took my info and sent it out. but it did get here fast!! gotta love that!
 

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Discussion Starter · #10 ·
i measure the holes. the 2 hold at the end of both the regulators are the same .090 but the single hold on the H/L is .046 and the S/U is .088
 

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i measure the holes. the 2 hold at the end of both the regulators are the same .090 but the single hold on the H/L is .046 and the S/U is .088
Thank you for the measurements. That would explain the possibility XM193 is overgasing the rifle and there's to much bolt speed. Hmmmmm, my round count is at 2800 and the problem started last range session and my round count at the start of the session was 2500. Something changed, cuz prior to this last outting, XM193 gave me no problems. During the same session I shot alot of m855 and it cycled perfectly.

Digging further is in order. Woundering if all the little cracks and crevices that allowed some gas to escape when the rifle was new have now sealed up and that extra gas is causing an issue. (just thinking out loud)
 

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Something like that would make me think low gas but XM193 is pretty hot. Weird. Is your gas block gummed up maybe? You can also try a detail strip of your bolt and scrub out your extractor. Take some gunscrubber or some other good degreaser and blow out your ejector. Put a couple drops of oil around the ejector then work the ejector. You can use a punch to do this or just take a fired case and hook under the extractor and rock it back and against the ejector.
All excellent suggestions and already part of my regular maintenance. (some old m16 habits are hard to break :) ) Something changed, don't know what. After next range session, (@ 3k round count) I going to break rifle down as far as possible and detail clean everything. As I said earlier, I'm woundering if everthing has finally sealed up and allow all the gas to hit the piston. I did notice some carbon build up in that space on the side of the barrel where the gas block stradles the barrel. Maybe the piston / BCG spring are getting little weak and need to be replaced. Maybe the action has smoothed out so much that the bolt speed has increased.......(again just thinking out loud)

We'll figure it out eventually :)
 

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cjt50- I don't know. My thinking is that there isn't enough gas. Or alternatively, something is binding up now. Are your empties creeping closer to your firing position compared to when you started?
 

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losman- I don't know. My thinking is that there isn't enough gas. Or alternatively, something is binding up now. Are your empties creeping closer to your firing position compared to when you started?
Can't speak for losman, but mine have gone from consistantly 5-10 feet at the 2-3 o'clock position, to launching them bout 20 feet at the 1 o'clock position when using xm193. Using m855 or .223 ammo it will still leave the rifle bout 10 feet at 2-3 o'clock. The stoppage is a new round is chambered, but the stovepipe won't let the bolt close. Moving the bolt back enough to relieve pressure on the stove pipe will clear the issue. Yes, I would agree a stovepipe stoppage is a classic undergas, but all other signs point to the opposite. (I think)
 

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Oops, pay no attention to the man behind the curtain. I fixed it...lol!
 

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I haven't had much trouble with mine. It's an early S/N with the S/U regulator. I have only put about 300 rss through it including zeroing but I bought it second hand. Not sure how many the previous owner ran through it.

I have only had one malfunction. It was with American Eagle XM193 black box. It was the same stovepipe with the casing getting crimped and stuck parallel to the chamber.

The only other thing is the ejection. The XM193 had a forward ejection to them that I wasn't used to. When I switched to some Herter's 55gr steel case .223 FMJ, I noticed less felt recoil and a rearward ejection.

I'm not sure if I'm gonna need to get that H/L regulator in the future or not, but I'm glad to hear that you were able to get it without sending in the whole rifle. I feel the same way, Matt.
 

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Actually, mine was trouble free up until this last 300 round range session. It only happen twice outta 160 rounds of XM193, but I did notice that my brass ejection pattern changed drastically using it. Hopefully it's an annomily and not a trend.
 

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Discussion Starter · #18 ·
Thank you for the measurements. That would explain the possibility XM193 is overgasing the rifle and there's to much bolt speed. Hmmmmm, my round count is at 2800 and the problem started last range session and my round count at the start of the session was 2500. Something changed, cuz prior to this last outting, XM193 gave me no problems. During the same session I shot alot of m855 and it cycled perfectly.

Digging further is in order. Woundering if all the little cracks and crevices that allowed some gas to escape when the rifle was new have now sealed up and that extra gas is causing an issue. (just thinking out loud)
well they changed the design of the gas regulator when magpul sold it to BM and it prolly wasnt tested like it should have been. something of the nature
 

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i measure the holes. the 2 hold at the end of both the regulators are the same .090 but the single hold on the H/L is .046 and the S/U is .088
I measured my S/U GR purchased in Dec 2010
the two holes measurement = .0885 -.090 (so that's consistant with matt2636's measurement)
single hole measurement = .063 (mine is different from both Matt's S/U and H/L)

it would be interesting to get other dimensions of the single hole of their S/U GR's. Maybe BH has been adjusting the size of these ports all along the way?

So what size is your hole, Gas Regulator wise?

I'm still puzzled, but maybe the small size port is so that the BCG is slowed down!?

Matt, my serial number start with BL049xx purchased in 12/2010, I don't want to know your complete S/N but was your rifle an earlier production?
 

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Finally got around to measuring my GR, .065 or there bouts, (close enough) My serial number is BL019XX and it was given a home on 7/2010.
 
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