Hey There,
Building up my first AR SBR with a dedicated can. During a course this weekend one of the guys told me that the AR will foul quickly and Iwill have nothing but problems after a couple of hundred rounds due to the fouling generated by the can.
True? If so, any mitigation? Would a piston gun be a better choice?
Thanks,
Damien
You will see increased douling. Piston guns are not cleaner because most of the blowback comes back through the barrel. Adding oil when the gun starts malfunctioning will usually make it run again.
This is true if you have a piece of shit put together by Bubba D. Smith in his garage. If you have a quality SBR and can you shouldn’t have any issues. If you lube it properly and shoot some decent ammo you will be fine.
Piston guns are better in some cases. Read through some of the previous threads. Full auto, and SBR suppressor use are some of the times when it will be beneficial.
Isn’t it true in both piston and DI ARs, that the bullet has exited the bore by the time the bolt has completed unlocking, and thus any additional gas present in the bore at that point will blow forward?
Nope. Hell piston guns unlock faster and you can get more fouling down the bore.
Yes the bullet is out of the bore. But the can will still have gas pressure in it.
Think about it that is how a can works it captures the gas and releases it in a controlled manner. A little bit of the gas will blow back through the bore hence soot on the ejected cases. Gas takes the path of least resistance if its waiting in line to get out through the can and the gas seal is broken when the spent casing is being extracted out of the chamber some of the gas will go that way.
I have read a lot about this, and one thing I have consistently seen solve the problem was the addition of an enhanced BCG from LMT. It has different configured gas ports to allow for a longer dwell time.
My SBR is a 10.5in LMT and it is suppressed 90% of the time with an AAC M4-2000.
More fouling into the weapons with a suppressor, absolutely.
Does it cause problems, absolutely not.
If I shoot 20-25 rnds out of a 30 rnd magazine, with the suppressor attached, and do a tactical reload the rounds are much dirtier than than without the suppressor attached; so yes more gas is entering the receiver.
It is rarely cleaned, and ran wet (I wipe down the BCG and patch the barrels, not a detailed strip,scrape, & polish like many believe the AR needs). She is a dirty whore, and loves being ran hard…
Use quality components and you should have no problems.
Good luck, with your build.
Smart man.
You still get some blow back even using the LMT enhanced carrier with a can. I have shot both with a 10.5’’ noveske switch block. No scientific testing but seat of the pants the switch block made the biggest difference. But the enhanced carrier does cycle slightly slower [ smoother feeling]. The best recoil wise is with a switch block, suppressor and the enhanced carrier all working together. I will add the sbr worked fine with the std carrier but the enhanced did soften it up a tiny bit.
Thank you gentlemen, for the detailed and patient explanation to one with minimal experience with suppressors.
As an intentional torture test, I ran about 900 rounds through my RR M16A1 with 11.5" 6933 upper/M42K suppressor without lube or cleaning. I’m running a BCM Ion-Bonded BCG FWIW. No malfunctions or noticeable cyclic rate change during the test. Squirted some lube in it and ran another 300 before I cleaned it. Firing was mainly with Federal 55gr FMJ in 100 round Wal-Mart packs.
As stated, if you use quality components you’ll be fine.
I built up my 10" Noveske, and it runs suppressed about 100% of the time. The only ammo it wouldn’t run was Fiocchi frangible.
It gets dirty, it runs. It stays lubed. I’m sure it will stop some day, but about every 2000rds I get in there and scrap the crap out of the lower, and the recesses of the upper. It just keeps running.
SBR’s and cans these days are pretty reliable if you go with the top names. LMT, COLT, Noveske, KAC and Daniel Defense would be on my short list.
Any idea why LMT doesn’t recommend the enhanced bolt/carrier for barrels less than 14.5"?
quote:“Enhanced bolt carriers are to be used with a 14.5” barrel or longer."
Because it was optimized for carbine gas system with 14.5’‘-16’’ gas system and dwell timing, firing 5.56 nato pressure ammo.
Any thing after that you are going past the manufactures recommendations SO BUYER BE WARE . Now after saying that I have run one in a 10.5’’ noveske switch block with the gas setting set on suppressed and with OUT the suppressor attached[not running the suppressor cuts back on the gas cycling the action] the sbr still cycled but it was on the cusp of short stroking it would go through a 30 rd p-mag but fail to lock the bolt back on the last round with the suppressor attached it worked fine the BCG would lock back on the last round . All of my testing with this set up was done with 5.56 nato pressure M-855 ammo PP & LC to be exact I didn’t try it with .223 ammo. In my 14.5’’ LMT I normally use the enhanced carrier with H-buffer and sprinco blue spring and it will cycle PMC bronze and 62 grain wolf with out a problem. But I did run 1k of M-196 5.56 through it before I tried the .223 ammo the BCG loosens up a considerably after about 500 rounds. I have read some reports of it being used in a mid-length gas system no first hand experience so I couldn’t recommend it. BTW I have close to if not 4k through the 14.5’’ LMT with a enhanced carrier.
More info can be found on this subject by looking up the ultimate sbr thread started by Grant.
Frangible through a suppressor is always a bad idea…
Agreed. I’d never fire frang through a can. There are several flavors of frangible… all with their own downside risks.
Thanks, Thomas M-4.
Yep, I hear it is. No issues. Except the gun wouldn’t run. :sarcastic:
This arena is where a FailZero BCG really shines