Are these barrels available for purchase from you in 5.56 of course?
I’m still on the fence between 5.56 and 6.8. I REALLY don’t need to jump off in another caliber, but the ballistics on the 6.8 Spec II look pretty good even in SBR form.
I run an M6A3 12.7’’ in 6.8 with an AAC M4-2000, M6A2 12.7’’ with an AAC SPR/M4, and a KAC SR-15 E3 IWS 11.5’’ CQB with an Ops Inc. 15th Model CQB MBS.
Of all of them I do prefer the LWRCi M6A3, for many reasons.
A - For some reason the recoil is more comfortable to me. (As is the weight, it’s a bit heavier though. 3 oz. to be exact.)
B - My M6A3 is quieter than both of the others. (By 1 or 2 full dBs, when the gas system isn’t off)
C - The carbon build up isn’t caked on the bolt carrier like the KAC. (Still just as dirty.)
D - With the LWRC M6A3 I get the option to turn the gas off completely making it quieter due to the action not cycling.
E - I know I’m not going to have to swap bolt carriers every 2000 rounds with the piston system.
F - I can perform over the beach operations if need be. (I live in Oregon, there’s a lot of water here.)
Over all. No you don’t need a piston system, I can run my KAC a LOT and it’ll be fine, I’ve ran my KAC 2000 rounds without cleaning it. (Had to swap the bolt carrier out after though, it was through it’s life span anyways.) It functioned okay.
I prefer the piston system though, for the reasons stated.
And if somebody says ‘‘I’m not impressed with the piston system.’’ bring up two things.
Service life, and OTB. (Over the beach)
Actually, OTB can be done with some DI guns if you live in a wet state.
(Oregon, Washington, Virginia (Virginia gets a lot of rain right?)
Did you sound meter this or are you just speculating? Just curious how you came up with the measurement.
Can you clarify the “swapping bolt carriers” comment for me, please? How many rounds did your KAC carrier have total before you needed to replace it? What symptom or wear evidence led you to believe the carrier needed replacing? Lastly, if you could describe the type of use the KAC carrier experienced that would help better understand how it came to needing replacement.
Thanks in advance for your additional info. I like knowing expected life of certain items compared to what I see in my own guns.
Take care,
Mark
No, not currently.
C4
Yes I sound metered this.
Swapping Bolt Carriers: Needing a replacement bolt and bolt carrier - end of service life.
I think it had like 5-6 thousand or so. I don’t exactly remember how many rounds it had through it suppressed but it had a lot. More than half.
Wear or evidence that it needed replacing: I’m looking at it right now. Honestly I think I could shoot it more, but it looks like it has been shot more than it has, this is because I’ve shot it a lot suppressed, through a short barrel, and because the gun as a whole has seen a lot of abuse.
How was it used: Shot a lot suppressed.
Also: The KAC bolt carrier has a longer service life than any DI carrier I’ve ever used. It’s amazing.
Interesting results, I’ve never experienced a piston gun that wasn’t noticeably louder than a same barrel-length DI gun…
If you’re using that meter you mentioned in the other thread, it maxes out at 130 dB, which is generally lower than the SPL from a 5.56 gun suppressed… Plus, the gunshot is too quick I think for it’s 500 ms response time.
To be accurate, you really need a meter and mic that are specifically built to handle the levels and duration of a gunshot… unfortunately, they cost around 50 times more than the SL-4013.
FWIW
I didn’t use my SL-4013 on that sound test, as that was done before I bought mine.
I’m actually only using this until I can find something more fitting. Money isn’t really an issue, I just needed a meter fast, because I’m in the market for good .45 and .40 sound suppressors.
Jason, any recommendations for a good meter and mic?
That is interesting. I have bolts and carriers with a lot more rounds through them than that and much of the use has been full-auto fire with a 11.5" barrel hosts. I have one Sabre Defense barrel that has specifically been shot to try to get a 50K documented round count through it. We’ve been using that barrel for over two years now and use it frequently for LE demos. We let them run the gun as hard as they can do it using their ammo. The round count through the gun is well over 30K rounds at this point. It is still using the original bolt and carrier. I can’t say the same for the gas tube, gas rings, cam pin or firing pin retaining pins though.
Go figure. Perhaps I just got lucky. 
Thanks for the extra info. Take care.
Mark
Were you using it suppressed, full auto?
Yes. I have an AAC M4-2000 with 20K+ rounds through it that was used most of the time with the Sabre.
The first time that suppressor was shot was when we were stress testing the (then) new Blackout mounts. We destroyed an older (but then current) Phantom mount through full-auto testing with that particular rifle. When the mount failed the M42K that was on the gun also was destroyed. The next day we put a new Blackout and brand new M42K through more than double the abuse that failed the Phantom mount. So, the very first weekend I shot that rifle we put 2500 rounds of VERY HARD use full-auto through the weapon. After that I used that weapon in several classes and then almost weekly at LE demos.
A friend gave me a Beta mag as a gift and I even ran a few Beta full-auto dumps through the weapon. Well, I didn’t but I let friends do it. All Beta dumps were with a suppressor attached.
That is why I was more than a little surprised when you were replacing KAC carriers at only 5-6K rounds. It is also why I asked how you knew there was excessive enough wear on the bolt/carrier to warrant replacement. You never really answered what signs of wear were on those parts and I’d still love to know if you would be kind enough to post some extra info. Even pictures would be great if you could swing that. I like knowing how things got to a point of failure (or close to it).
Thanks,
Mark
Sorry I don’t own a camera so I can’t post pics.
I have replaced the springs, and now have a Crane O-Ring, black extractor, and 5 coil extra power extractor spring.
I will put the (Not bad, but more than I am comfortable with) worn bolt back in the gun, and run it to the point of failure. Here I go.
It will now be the gun I take out instead of my trusty M6A3. ;D
It looks at 8 (I put 1000 through it today) thousand rounds what a normal bolt (BCM, Colt even) looks at 10 thousand rounds unsuppressed.
The signs of wear that I mentioned before, was a small fatigue crack on the bolt face. (Now gone. Or I don’t notice it.)And I was having failures to extract after 5000 rounds.
I’ll post an update at 10 thousand rounds, and every 2 thousand after that. Until failure.
I will be comparing it to my LWRCi bolt. My 5.56 gun has about five thousand rounds through it suppressed, with no signs of wear whatsoever. No carrier tilt to speak of.
Also, it’s nice to know that my AAC M4-2000 will go through 20k rounds fired, even full auto mag dumps and still be functional. Thanks for doing that so I don’t have to.
Yeah, the M4-2000 will take a lot of abuse but make no mistake after the abuse I’ve put it through you can see significant erosion in the core.
I forgot about extractors. I probably replaced the extractor on that high round count bolt once or maybe even twice. I’d have to check my logs to be sure. Same with the extractor spring. Oh, you might also try #60 o-rings. For me they work just as good as “Defender” or other high priced rings. They don’t last quite as long but very, very close and you can get them for pennies each.
Mark
Where can you get them that cheap?
Does your AAC still offer significant sound reduction?
How many decibels do you think?
I will also replace the gas rings, I may have worn those out.
Where can you get the #60 o-rings? Just about any hardware store. I get mine in a bag of 20 or 30 at Home Depot for maybe a buck or two.
Yes, that M42K still is very quiet. It is a bit louder than a new one but not too much. I have not sound metered it.
On the gas rings I extend the bolt from the bolt carrier and stand it on a table. If the weight of the carrier isn’t supported by the bolt (and gas rings) the rings are shot and I replace them. That is an easy way to look for worn rings.
Take care.
Much appreciated.