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Posted: 4/29/2008 11:32:35 AM EDT
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I'm trying to spec out a suppressed SBR build, shooting for reasonably light weight and decent balance, which is kinda hard with a big can hanging way out there on the barrel. I'm not set on AAC, but I'm looking at them at the moment. Comparable suggestions welcome of course. The two cans I'm looking at right now are the M4-2000 (QD, better suppression, 6.625" long, 16.25 oz), and their Ranger 2 (threaded, a little louder, 6" long, 16 oz). So the difference is nominally .625" and 1/4 oz, but I suspect the real-world difference is a little higher due to (a) those are can lengths, but there's also the back edge of the QD flash hider (~0.25"?) vs direct thread mount (0), and (b) the extra weight of the QD flash hider itself. I'm assuming the Ranger doesn't go back past the step for the barrel threads in all of this, but I didn't see anything definitive on AAC's site about that. I'm leaning towards the Ranger because I don't really plan to shoot it without the suppressor, but the length/weight differences sound small enough to almost be trivial. I don't know why they would even make the thing if it wasn't a decent difference. If I would really notice it I'd rather go Ranger. OTOH if I wouldn't, then why not go M42K and get a few extra dB's? Based on my limited experience (a 5.56 QD M4-96D on an AR-15 and a 9mm threaded pistol can on a G34), I'm also wondering about the practical implications of going threaded on an AR-15. I'm assuming I would have to either loctite the threads (or is suppressor/barrel heat too high for loctite anyways?) or torque the can down to some high value when I screw the can on to prevent it working loose during use. Then that makes me wonder, will it be a real PITA to unscrew it for cleaning? Or is the norm just to not remove the suppressor for cleaning very often (if ever?), and run a rod through the barrel+suppressor and clean them both together? |
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Don't forget to consider price. I don't have any thread mount cans, but from what I've read the procedure is normally to attach it tightly by hand and retighten as needed as it warms up. Loctite would be worthless at those temps and rockset would be too permanent. |
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The new '08 M4-2000 cans are even lighter weight and quieter. We just got these in Friday. They weigh less than 16 oz (that's without the mount). To me a can is a life time purchase. For the difference in basically the cost of a quality case of ammo I'd step up from the Ranger II into a fast-attach can for an auto-loading gun. I'm not a fan of thread-mount cans on ARs, but it really depends on how you plan to use it. Mark |
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What is your barrel length? Length and weight are certainly a concern if it is a 14.5" SBR. I run an 11.75" barrel and SPR/M4 can. The barrel is a SOCOM profile under the handguards. It is light and reasonably balanced though I do want to put a UBR on it to get a better balance when suppressed. I am a weight/balance freak and the longer barrel, heavier barrel, heavier mount and heavier suppressor do not combine to creat an heavy or front heavy rifle. The rifle also has midlength rails on it that are about average in weight. While longer barrels make the suppressor length and weight a HUGE issue due to the cantilevering effect from being so far forward it is not as big a deal on very short barreled rifles like a 10.5" or 11.5" barreled upper. If you are going to run a government profiled 10.5" I would not think twice about weight and length issues as small as you are describing. Again I am a huge weight and balance freak and I still would not go with a 10.5" barrel and M4-2000 over my 11.75" SPR/M4 combo... I really dislike backpressure and gas in my face far more than 2 ounces and an extra inch in barrel length/overall length. That can (SPR/M4) also adds no more length than an M4-2000 other than the extra barrel length itself. Also keep in mind your experience with a previous silencer was an M4-96D which was over 24 ounces in weight... far heavier than my SPR/M4. And ridiculously heavier than an M4-2000 as well as being over an inch longer than the M4-2000. |
Well it isn't built yet, (I'm trying to get this all sorted out on paper before I start buying things) so the barrel length isn't set in stone yet. I'm considering using a factory LWRC M6A2 10.5" piston upper for this build, but it's probably heavier than building a DI system with a lighter-contoured barrel. Jury still out on all of that I guess, this stuff is complicated 
I think I saw some posts by you re: this setup over in the LWRC forums, with the screw mods etc, right? It sounds pretty ideal (11.75 + SPR/M4), but it also sounds like there's some things I would have to sort out re: getting someone to build such an upper for me (I could take a stab at everything but the actual barrel chopping and threading, but I'd rather not trust my meager gunsmithing skills).
Yeah, the M4-96D is on a 14.5 barrel, and it's a beast, which is certainly coloring my thinking on this build  |
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A can on an SBR balances a whole lot better than on a longer barrel. A QD can, (with a GOOD locking system), is a better choice than a thread mount can, because tightening a loose can that is really hot sucks, ALOT. I run a AAC M4-2000 mod 06" on a 10.5" barreled SBR, gun balances well for me. My rig, after an overhaul, it actually looks clean!  
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The blackout mounts weigh 2.7 ounces. I don't think that's a huge deal if the can weighs less than 16 though. It is when the can weighs 22 that it's more of an issue. My thread mount cans are going to have wrench flats (which are ugly and hurt overall length specifications on the sheet, but delete these tightening issues.) I just wouldn't want to shoot without peace of mind. I'd always be wondering when the can was going to come off without properly torqueing it on. The QD system is only beginning to be worth having with 16 ounce cans. at 20 and 22, the mounted cans are heavier than it is worth in my opinion. |
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Ok, you guys have convinced me that the threaded ones are too much PITA for the miniscule weight/length savings (thanks). At this point I'd probably just get an LWRC 10.5 upper and put an M4-2000-08 on it and be done (well, after all the waiting on LWRC + BATFE), except that DevL's posts about the SPR/M4 setup having less gas in the face have me thinking about that setup now. Looks like doing that on an LWRC 10.5 would at the very least require the "screw mod" and moving the LWRC gas port/block back up under the rail. Hmm... Or I could just stick with the M4-2K and try to do a really good job sealing up the charging handle I guess, and the build won't be nearly as complicated. |
Get a PRI Gas Buster CH to push some of that gas away from your grape. |
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If you don't have other suppressors, you may enjoy the ease of transferring the can to different platforms with a quick detach. I have one 9mm can, and it's a whore. It goes on everything I own that 9mm comes out of. If I had an assload of suppressors, I'd leave them on their designated hosts most of the time. |
I have one on my M4-96D setup. It definitely helped a bunch, but the amount of gas coming at my face is still annoying. I'm considering trying the do-it-yourself RTV route to see if it's any better. I should probably try that now on the M4-96D setup and see how much difference it makes. |
I like my Ranger... because it will screw on to anything with 1/2-28 threads.  To tighten it, all I do is hold the rifle between my legs while tightening the suppressor with both hands. It's never come loose on me. I don't use any kind of washer or spacer either... the can just gets tightened right up against the shoulder of the barrel to insure perfect alignment. Any time I've tried using a lockwasher or crush washer, it kicks the suppressor off-center risking a baffle strike. 
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ph713, I don't want to convince you to go with one system or the other, however, don't let people tell you the Ranger can will always loosten up on you and that you have to constantly tighten it. That is simply not true in my experience. I have a Ranger on my 11" upper because I wanted a light dedicated can that was going to stay on that upper and why pay for a QD system if you are never going to use it. It has NEVER loostened and I do mean NEVER. I do carry a fireproof "pot holder" in my range bag and have checked it every now and then just for the hell of it, but it has always been rock solid. In fact the can is "almost" too hard to remove sometimes requiring someone to hold the hand guard while I use both hands to take the suppressor off. I can do mag dumps and fire 500 rounds per session and the can will never budge. Just my .02, not that it means anything, MadDog 
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You need an 11.5" barrel and the custom LWRC gas block they sell to use a SPR/M4... 10.5" is too short to have room between the thread shoulder and gas block. Jesse made my barrel and modded my screws and he can provide the screw mod and barrel length to you if you like. If you go 10.5" you will HAVE to use the M4-2000. I still want to use the the silicon trick on my upper and it has SPR/M4, gas piston, AND the Gas buster CH to try to get rid of gas and smoke. I still get smoke slowly seeping out the holes in the rear of the Gas Buster and under my shooting glasses... it may even be worsethan a regualr handle since there are more holes for the smoke to seep out of in the rear but it does not have velocity pushing it into your face like the M4-2000. LWRC is considering a factory 12.5" CHF barrel which allows the use of the SPR/M4 and unmodified midlength handguards... a consideration if you are still waiting on picking out the rifle and dont like custom work. If you wanted to you could order a factory 14.5" M6A2 and cut the barrel to 11.75 to save time but it voids your warranty. I can give you the AAC spec sheet for the screws and free screws to modify the rail if you decided to go this way. You simply remove some of the threads off the screw shafts. |
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