I have no Idea what a 6920 is.
http://colt.com/law/lecarbine.asp
To be honest, the ammo you listed reads like the who’s who of underpowered ammo with Wolf being the worst.
C4
I agree. You have to pay attention to what ammo your using and use the proper buffer.
I ONLY run M855 so my H3 buffer and ISMI spring runs great.
C4
Having a gun that will only run on a single type of ammo that may or may not be available to me when the SHTF is sort of like having an automobile that won’t run on pump gasoline.
Who says I’m going to fight with my own ammo? (Analogous to Clint Smith: “Who says you’re going to fight with your own gun?”).
If I KNEW that I would always have a ready supply of Mk262 or 5.56 TAP, and if I knew that those I might be swapping mags with when Murphy comes calling would ONLY have the same ammo, then I might be comfortable knowing that my rifle would not work with “the who’s who of underpowered ammo.”
It baffles me why someone would spend hard-earned dollars on a precision barrel and then shoot ONLY SS109 bullets through it. 
I believe that there is probably a certain degree of buffer/spring envy that gets promoted by these forums. “My carbine must be inferior; I don’t have an H/H2/H3/9mm buffer. While I’m at it, I might as well replace that cheap spring. I just know that it’s shrinking.” :eek:
What most fail to realize is that all of the components work together as a system that must be in balance in order to ensure reliable function. Changing the spring RATE, buffer mass, carrier mass, friction due to gas ring(s), friction due to lube, ammo pressure, gas port diameter (modification or erosion) and any of a host of other factors can have a direct influence on the delicate balance.
Notice that I said “spring RATE”. Changing the spring rate (e.g., force required to compress a coil spring a specific distance) changes the system balance. I have no issue with using superior spring materials from a fatigue (spring life) standpoint. The concern I have is that many may not understand that all available springs are likely NOT providing the same spring rate.
Ever put shorter/stiffer springs on a car? Ever install “sport-tuned” shocks/struts/dampers? Ever switch to low-profile tires? Ever add a significant amount of weight/load on a truck? Did these things affect the ride/handling? These are crude analogies to how changing carbine components might affect function (and they will affect function).
I agree. That is why I shoot all my weapons with TAP, BH, XM193 and Federal. All work well for me.
You would be amazed how well M855 will shoot out of a Noveske barrel. 
I don’t follow the spring/buffer envy comment. We are all here to try and build the most accurate/reliable weapons. This takes trying various things to find out what works and what doesn’t. I am kind of happy to see people trying different things (buffers and springs) instead of just accepting the norm.
I personally am against extra power springs in both the extractor and the buffer. I do however like springs with longer life (less likely to cause a malfunction due to loss of tension).
I was speaking with the guys at Tubbs that other day about spring life. They explained to me that a normal SS buffer spring is at about 90% of its useful life right out of the gate. :eek:
C4
FWIW the Canadian Forces when switching to the C7A2 (20" bbl and telestock) ran testing to see which buffer was the best for NATO ammo in various barrel lengths (many units are issues two uppers of different barrel lengths - some three - and inside CANSOFCOM 6+)
The H2 buffer was found to cycle the most reliably throught the NATO 5k testing program in the following lengths 10" (flat 10 not 10.3 or 10.5) 10.5, 11.5, 14.5, 16, 20, than the other weights.
As a result Canada standardized the H2 buffer for all telestock equipt gun in conventional force inventory.
(I’ve seen H2’s used in 4"-6" M16FOW based PDW’s as well)
I predominately use H2 buffers in all my guns –
IF the end of the world happens – at least they will work with M855/SS109 stuff
Interesting Kevin. It appears that everyone has switched to the H2 buffers.
C4
Brownells has standard power chrome silicon springs for carbine and rifle length in 3pks for less than $12 for people who want to use an H2 and an ISMI is too powerful.
Brownells
078-000-087 M4 Recoil Spring (CS), 3-Pak $11.76
078-000-102 AR-15 A2 Action Spring (CS), 3-Pak $11.76
They have extractor and ejector springs in chrome silicon as well.
My version of hell: Not having a neverending supply of Mk262 and having to defile my weapon with M193 & M855:D
Fuck you, ya prick…rub it in, why don’tcha?
OK the truth be told, I did fire about half a case of M855 thru my Mk 18 today, and 750 Win/Ranger thru the Sig. I hurts to type.
And I did it with a stock action spring and H buffer, no suppressor
Slumming, huh?
Edit: don’t mind me - I’m feeling a bit testy today - quit smoking four days ago 
No prob, Bro
And I should add no Crane O Ring, but I was using H&K mags.
All I did was add some lube(Rem Oil) every so often. Didnt even use a chamber brush. I would say the weapon went about 1200 rounds without cleaning the chamber. I had no jams what so ever.
I guess the point im trying to make is that you dont need all the extra bells and whistles, up to the point that the weapon wont run reliably without the extras, then use them to keep the weapon reliable. Just like you dont use “Over 100,000 mile” motor oil on a brand new vehicle.
Yup…sorry for the A-hole Hijack:D
Dude,
You need to hook a brother up! I can help you deplete some ammo!
I just installed the ARES G35 piston conversion on my Mk18’ish LMT and I’m having the KAC RAS2 top rail milled tomorrow to fit over it. I had thought of getting a VLTOR CASV-EL which is cool but probably would require milling to fit as well.
I put an ISMI spring and H2 buffer on my middy a couple of weeks ago and was very happy with the performance. Everything ran great even Wolf ammo. Went to the range today and the crazy thing would short stroke Wolf ammo about every fourth shot or so.
I was highly confused until I remembered that I changed out my stock flash hider for a Smith Vortex after my last range trip. Could a flash hider change make a difference in bolt cycling? The only other thing that changed was the temp. It was much cooler last time I went out.
Ive had the same problem , I was breaking in an m4 with wolf ammo, during multiple range trips. I was new to the game. I think it’s the wolf powder residue, it kinda gums up the gas tube after you let it sit any length of time after you shoot. What I do to resolve the problem is at the end of my range or training session I shoot some good ole high pressure 5.56 to blow the wolf crap out of my gas tube. It’s the easiest way to clean your gas tube. I hope it works for you!
I just read on the David Tubbs website that there CS springs are not recommended for use with low power ammo. The ISMI spring I have seems pretty heavy, it may have the same problem. I will probably go back to a standard spring or one of the Brownells CS springs in my Middy, since I use Wolf ammo alot.
Well guys,
Let me say that I bought some brand new, Black Hills (red box) .223 ammo, in 68gr Sierra Matchking BTHP today, and I “single shot” all 50 rds today, with not a single issue locking back.
The gun performed flawless with the ISMI spring and H2 buffer. I think it was the ammo I had been shooting before.
The problematic ammo, was actually some that I had THOUGHT to be decent ammo, due to many of my buddies having excellent experiences with it. Said ammo was from GA Arms, and yes, I know of the problems some of the board members have had with it, with double powder charges and whatnot.
I too, had a shell that malfunctioned, but that is another thread entirely…
Can anyone here tell me WHAT exactly is considered to be “low power ammo”??? I mean, is ALL .223 factory ammo considered “low power”, and all 5.56 ammo considered “high power”???
Also, can anyone tell me where I can obtain some Mk262 ammo?
I mean, IF not available, then how much different would the .223 Black Hills 77gr Sierra Matchking BTHP ammo be, from the 5.56??? What is the exact difference between the two, and how will the two rounds most likely perform in comparison with one another??? (I realize true testing will only reveal the definite results, so I’m looking for approximates here)…
Mk262 - www.goarmy.com or http://careers.state.gov/
Blackhills was selling seconds IIRC – but those two links are the two ways I have gotten Mk262
I ended up with a few rounds of Mk262 in my kit on the way home from Afghan (accidently I swear) - I chrono’d it over the 77gr Red Box BH stuff I had – aprox 150fps faster the NATO load was over the .223