Military Arms Review: HK MR556A1
- Thread starter MilitaryArms
- Start date
Starscream
CGN frequent flyer
- Location
- Southern Alberta
Because they're already deemed an AR15 variant, so may as well go all the way and make it AR15 lower compatible. Getting parts from HK's factory is akin to having one's teeth pulled, and being able to source local replacement parts for at least some of the rifle would be desirable.
CarbineOne
Regular
Most of the parts are interchangeable, even in the MR's. Unless you mean the BCG and gas system. But that goes for virtually every piston AR. But you've got a point. I'd dump that HK lower that doesn't fit PMAG's in a heartbeat.
And really, how often does anyone actually swap uppers on guns?
Here in the States people want swappable uppers because a registered machine gun lower could then be used with a MR556A1 upper. Although with the lack of chrome lining or nitrite treated barrel the wear would be pretty nasty. I don't expect HK to make replacement barrels easily accessible or even affordable.
Not on that barrel and the type of steel they used, that thing will hold up well to full-auto fire from what I have been told by insiders. Better than most barrels out there.
Parts are available and by the time any MR223 are needed new parts there will be abundance of availability. If you are willing to pay, you will get what you want.
CarbineOne
Regular
I meant in relation to how Canada can only have the MR223 with the displaced rear takedown pin.
In the US, totally makes sense. One FA lower with multiple uppers. Saves on paperwork and cash.
The HK416 uses a chrome lined barrel to improve the service life. This is from the HK website:
If HK is chrome lining the bore of the 416, that means they've not come up with a superior method of hardening steel in the MR556A1 against wear, otherwise they would use it in the 416.
I'm not aware of any process outside of chrome lining or nitrite treating that yields steel as hard or resistant to wear as chrome lining is. Apparently HK hasn't figured out a process either since they're chrome lining their 416 barrels.
The barrel also tapers on the MR556A1 which means as the bullet travels down the bore the friction increases. With increased friction comes increased wear. It would stand to reason that the muzzle end of the bore would wear faster than the chamber section or middle section of the bore. Again, I don't see this as being conducive to a long service life under extreme conditions (machine gun fire).
HK416 uses a chrome lined barrel because that's what their military customers wanted, not because it increases barrel longevity. A poster on hkpro.com who was involved with the original design of the HK416 (G3kurz) has this to say:
"These guys don't understand barrel/HK barrel production and/or materials. Chrome lining in most cases improves the wear and corrosion resistance of steel, in this case barrel rifling and chamber, which is why it is used. However it is not required IF the material used and the production process produces a wear and corrosion resistant surface without it. That is the case with HK GmbH produced cold hammer forged barrels made from the unique barrel steel employed by HK. In fact, chrome lining often has an adverse effect on accuracy if it it not applied uniformly, which is why it is often not used on "Match-grade" barrels. The HK CHF method provides a degree of wear and corrosion resistance =/> chrome lined bores and decades of evidence with HK barrels proves that. It is more than just the presence or absence of chrome in the bore that determines its performance. Example would be the M4 barrel. It is chrome lined but is also well known to have a service life of under 10,000 rounds (before it exceeds the accuracy requirements of 5" at 100 yards w/ M855 ammo). There are countless examples where non-chrome HK barrels have exceeded 25,000, 40,000 and even 100,002 rounds in the case of the HK MG4 fired in Yuma during desert testing. Or the single HK416 10" fired in the first lot acceptance test that fired 15,000 rounds in 2 days and still fired sub-1 MOA groups at 100 meters (and again at 20,000 rounds, and 25,000 rounds).
The barrel of the MR556 is hammered at HK GmbH in the same way and with the same materials as the HK416 and MG4 barrels. It is imported and then the outside contour finished in the US to meet barrel import requirements. Thus it is a true HK-made CHF'd barrel in the classic style from the AD material.
Let the uninformed rant about how superior a chrome lined bore is versus one w/o. It is a good selling feature if you use cheap (soft) steel and other than CHF barrel production process.
G3Kurz"
The above from post #7 of the following thread:
http://w ww.hkpro.com/forum/hk416-hk417-hq/139968-mr556-getting-bashed-other-forums.html
It still eludes me why no one complained about compatibility of HK9X series and SL8 with the military counterparts, yet people are constantly zeroing in on MR556/MR223 lower. EMag exists because not every weapon on this planet can use PMag. The 416 exists before the Pmags - why don't we question the wisdom of magpul of creating webbing on a magazine that only fits a certain lower?
HK has their own magazines to sell - why should they go backwards to make it compatible with a magazine that was designed after they have developed the 416, and plus that Magpul is a competitor to HK in the magazine business.
If people insist on Pmag compatibility - fine - but it is like not buying a car because it won't take the winter tires you have in the garage.
Well from what i herd, was a different spin on it, I can't confirm it, that being said I own the MR223 and it is Chrome lined. From what i have herd from various sources that Chrome lining is not necessary anymore on many high end barrels that are coming out of many manufactures these days. The MIL still require it but that has more to do with ignorance from i have herd and read and witnessed.
Secondly if any one is shooting that Rifle like a "Machine gun" you have a problem right there, the USMC adopted a similar profile for an IAR role as an in between the M249 LMG role, not to replace it. So sustained fire role is definitely not what I would be using that rifle for, but sustained short bursts that would work well, a higher rate a fire than a standard carbine is what that can do. But that is a good point about the barrel profile at the end to muzzle be made tighter, interesting i think that would wear the barrel out faster on full-auto i think. I would have gone a lighter profile than what HK offered it as, but the barrel config does have it's place as well.
Also I noticed in your review you were not impressed with the pistol grip, I have to strongly disagree on that, i find that is an awesome grip, although i would prefer many of the characteristic on the HK 416 & HK 417 Battle Grip Variant 2 which i own as well and that would complete that grip. The back strap would help with stability due to the weight I find. Although muscle memory is key, and I understand the need or ease of the A2, hence we have been trained on that for years, I have gotten use to that grips and would say it works great when getting use to it.
Great Review by the way.
It sounds good, but I've seen nothing in the form of actual tests comparing their proprietary steel alloy to a nitrite treated barrel or chrome barrel, and certainly nothing with regards to the MR556A1 and its tapered bore.
As for other weapons HK has built like their 90 series rifles, they used polygonal rifling that lacks lands and grooves. Their G36 uses a button rifled barrel with chrome lining.
I'm less inclined to buy into the marketing machine of an HK insider than I am to go with what the rest of the military manufacturing community seems to know and use, that being chrome or nitrite with nitrite being the new wonder treatment of the immediate future.
That's not to say I'm right, of course.
As for other weapons HK has built like their 90 series rifles, they used polygonal rifling that lacks lands and grooves. Their G36 uses a button rifled barrel with chrome lining.
I'm less inclined to buy into the marketing machine of an HK insider than I am to go with what the rest of the military manufacturing community seems to know and use, that being chrome or nitrite with nitrite being the new wonder treatment of the immediate future.
That's not to say I'm right, of course.
Actually, what they're moving to is nitrite treatment of the bore. Yes, chrome is going out but nitrite is coming in full swing.
You don't have to shoot it like a "machine gun" (although we have legal machine guns here in the States) to accelerate wear. Take 5 magazines out to the range and run them through the gun back to back... in something like a carbine course. Your barrel will be extremely hot, hot enough to cause increased wear. There's no question chrome significantly increases the service life of barrels in semi-auto rifles.
It's all a matter of personal preference. I prefer the profile of the grip used on the HK416 over the one used on the commercial MR556A1. I've yet to meet anyone that I've showed the MR556A1 to that actually preferred the MR556A1's grip over say a Magpul or even a standard A2. I have no doubt there are people out there that like it, I'm just not one of them.
Why won't people demand to chromeline their Noveske SS Barrels???? The first reason of chromelining is for corrosion resistence and ease of cleaning.
Have you ever looked down the barrel of a chromelined Diemaco C7 barrel or NoveskeN4 and a Bushmaster chromelined(or even LMT) that had gone through the same number of rounds firing in the same manner. The steel under that lining matters a lot IMHO.
Tapered bore is a feature of the CHF processs. It happens because of the manufacturing process - all your diemaco, FN and HK barrels that are CHFed have tapered bored, including the Minimis, HK21 and the MG4. Even your Ruger and Remington barrel are CHFed.
The pistol grip comes from the Americans. They want a pistol grip that is the same angle as the 1911.
Have you ever looked down the barrel of a chromelined Diemaco C7 barrel or NoveskeN4 and a Bushmaster chromelined(or even LMT) that had gone through the same number of rounds firing in the same manner. The steel under that lining matters a lot IMHO.
Tapered bore is a feature of the CHF processs. It happens because of the manufacturing process - all your diemaco, FN and HK barrels that are CHFed have tapered bored, including the Minimis, HK21 and the MG4. Even your Ruger and Remington barrel are CHFed.
The pistol grip comes from the Americans. They want a pistol grip that is the same angle as the 1911.
