DMPS GII with a sig SRD7.62 silencer.

Let me start off that I not a big fan of the GII, since it uses a long stroke action in a short stroke receiver, and this ends up with the face of the bolt retracting back past the back of ejection port window.  Hence spent case on an AR is when the bolt is as the back of stroke, and this can end up with the spent case tagging the inside and even edge of the back of ejection port, to end up with stove pipe jams.  DPMS did make stride in the ejectors to try to prevent such, but as the spring weaken, your back to the problem at hand.

Hence the old slab side 308's had the same problem, but you could mill back the back of ejection port to solve the problem on these.  With the GII having a ejector port cover, pretty much takes milling of the back of ejector window off the table.

Next lets talk about suppressors.

Way, way back, they where swiper type units, with the bullet cutting through the swipper discs to keep most of the blast within the swiper sections.  The problem with this, the bullet was touching the swipers so caused some longer range accuricly problems.

The next gen of suppressors used conical/K type sections.  This allowed the bullet to pass through the sections untouched, while the gases in each section where diverted to roll back and in to the previous baffle section.

But the problem with both designs, it that it increases the bore residual pressure, and in fact cause a back blast of the fouling as well.

So the first mods to the conical/K baffle design, was to add in a expansion section before the first baffle, and was born the reflex design suppressors.

Granted that your still going to get the back blast off the baffles back down the bore, but this gives the can a great deal of volume to divert the initial blast section gases from all being directed straight back down the bore instead.   As for the problem with the reflex design, since you have so much volume area with fresh air, you can get some nasty first round pops to begin with.

So since its the evil of the back pressure from the barrel sections redirecting the spent gas wave off them and back down the bore, the next gen suppressors uses a different type of barrel system, and which is to reduce the back blast off the blast section and baffle to prevent as much pressure being sent back down the bore when using conical/K type barrels.  Hence the back blast of pressure increases the residual bore pressure, and makes the gas port acted as it was greatly increased in size, which causes the bolt to unlock faster and cause over function problems.

Here is your can, and remember that the direction that the gas build up is in a straight angle baffle, the gas rebound will be straight back in the opposite direction (back down the bore).


So let me stop for a second, and go back to your rifle.  
Hence some of the ejection problems are being caused by the bolt unlocking sooner from the increase residual bore pressure from the baffles to increase the bolt unlock speed, and this can be causing problem with the spent cases tagging the back of ejection window edge, even with the bolt extractor/ejector spring still be good.  
So a quick fix, is to just increase the mass/weight of the buffer, to slow the bolt unlock timing back to normal.

But since you still have that back blast wave still coming back down the bore to the chamber, lets move into the next gen of suppressors.
On these, they do not use convectional conical/K baffle designs, but a turbine effect to redirect the blast gasses isntead. This greatly reduces the back blast wave back down the bore again, and which helps to solve the need for a heaver buffer when supressed, while greatly reducing the amount of fouled spent gas being pushed back down the bore to the chamber as well.

Here is a good write up on the OSS suppressor that the government is moving to.
http://www.defensereview.com/operator-suppressor-systemsoss-mission-muzzle-cans-almost-no-back-pressure-less-problems-and-more-hits-on-target/

NG2 has also come up with a zero back pressure suppressor as well.


So to wrap it up, your rifle and suppressor as it, you need to increase the buffer mass/weight to slow the bolt unlock back down, which should everything short of the additional action fouling problems.

As for better mouse trap (rig), that would be a different action that is long stroke action, with lock stroke receiver so the face of the bolt does not retract back past the back of ejection port window on back of stroke when the spent case if being pivoted off the bolt face, and then a next Gen zero back pressure suppressor that will not have an effect on bolt unlock speeds, nor increase the amount of fouling that the suppressor it shoving back to the chamber as well.

Suppressed rifles get fouled up quicker than unsuppressed, there is no real way around it.  That blow back of the gas pressure will get into the magazines, resulting in fouling build up in the magazine and on the ammunition.  As already mentioned, when reloading the magazine with rounds still left inside of it, remove the dirty rounds and wipe them off, then use those rounds on top of fresh rounds.

As already mentioned, slowing the timing cycle by adding a heavier buffer and/or action spring will often times help.  When teaching armorer courses, and building AR308 type rifles, we use and recommend buffers from http://heavybuffers.com/.

To answer your question a chamber brush, you can get AR10 chamber brushes, which are larger than the AR15 chamber brushes.
Dewey AR-10 Chamber Brush

Brownells AR-10 Chamber Brush

You should also scrub out the magazines, and my suggestion is to run them dry as any oil or solvents left behind can attract fouling.

Do not lubricate the ammunition, run it dry, as any lube or solvent on the ammunition can cause casings to get stuck in the chamber, get deformed, and if the lube is heavy enough you could possibly cause pressure issues.

You mention that you have been cleaning with Hoppe's, and lubing with RemOil, and are now wiping everything down with CLP wipes.  When teaching Armorer Courses, we teach doing maintenance on the AR15 & AR308 type rifles, as viewing it as a high performance engine, so you may need to consider cleaning and lubrication different when compared to bolt action rifles and shotguns, as the AR15 / AR308 type rifles run hotter and dirtier.  Running a suppressed rifle will mean that it gets hotter & dirtier quicker than unsuppressed.


Here is an quick description of a cleaning method we use on the AR15 / AR308 weapons system that you can adapt to your rifle if you wish:
What we teach in armorer courses & instructor courses is to use the proper cleaning equipment, and to give the entire rifle a thorough cleaning when you either need to or want to. To dispel any possible myths, the rifle doesn't need to be spotlessly white glove clean, it will run clean or dirty as long as the friction surfaces of the bolt carrier assembly are wet.

Recommended Cleaning Equipment:
Tooth Brush (Military style works well)
Bore Brush with 1-piece cleaning rod
Chamber Brush with chamber rod
Bore guide
Brass Jag in whatever calibers you shoot
Solvent (My preference is Slip2000 725 Cleaner Degreaser, is it loosens carbon & lead fouling, and there's no ammonia)
Copper Solvent when necessary (My preference is Sweet's 762 Solvent)
Cotton Patches
Denatured Alcohol
Brass Jag in any caliber you shoot
Pipe Cleaners with Bristles
Gun Lubricant (My recommendation is Slip2000 "EWL", as it runs well in the AR15 / AR308 weapons system)
Bolt Carrier Scraper

Start by separating the upper receiver from lower receiver, as it is easier to handle when cleaning. Next remove the bolt carrier assembly and charging handle, and set aside.

Remove the buffer and action spring from the lower receiver. Scrub the buffer and action spring with a solvent and tooth brush, then either rinse or wipe them off, and run them dry as they are low friction and won't rust, and lube will find its way onto them as you shoot the gun as it will come off the bolt carrier assembly.

Scrub the inside of the lower receiver using a good solvent and tooth brush, scrubbing loose any fouling build up inside the magazine well and trigger group area. With the fouling loose in the lower receiver, rinse of wipe away all fouling. Lubricate the trigger group and sear engagement surfaces, the lube all steel parts like the safety selector and pivot/takedown pins to protect from corrosion.

Scrub the inside of the upper receiver, making sure you get the area where the bolt cam pin rotates into when the bolt locks into battery with the barrel extension lugs, which is on the left side when working with a traditional right side ejection port. Rinse or wipe away all fouling.

Scrub the charging handle inside/outside with a tooth brush and solvent, then wipe away all loose fouling. Before you reinstall it back into the cleaned upper receiver, apply lubricant so the exterior rails are good and wet.

Clean the chamber using a chamber brush, and good solvent. Do this by inserting a solvent soaked chamber brush into the chamber, and give the solvent soaked brush about 5-6 rotations to get the fouling loose. Rinse or wipe away all fouling.

Insert the bore guide into the upper receiver. Using a solvent soaked bore brush with cleaning rod, insert the brush into the upper, and through the bore guide, allowing the bristles of the brush to scrub the bore. My preference is to scrub only one direction, from chamber towards the muzzle only, and not to scrub from rearward or back and forth, as by only going from chamber to muzzle you reduce the potential of causing damage. Once you have the fouling loose inside the barrel, use solvent soaked patches on a jag to remove all fouling, repeat using fresh solvent soaked patches through the barrel until they come out clean. Once clean, remove all solvent by dry patches, then my preference is to follow up with a few patches soaked in denatured alcohol to remove any solvent present. If you need to clean out copper fouling, follow the copper solvent makers directions, specifically making sure not to leave any ammonia based solvents soaking inside a barrel for more than 15-minutes max, and I prefer to rinse with several patches soaked in alcohol to remove any solvent.

Remove the firing pin, cam pin, and bolt from the bolt carrier. Scrape the inside of the bolt carrier to loosen fouling at the back where it is hard to brush. Scrub the inside and outside of the bolt carrier with a brush and solvent, once all fouling is loose you can either rinse or wipe it away. Remove the extractor, and clean the entire thing, making sure the lip where it grabs the ammunition is clean. Scrub the firing pin track with a solvent soaked pipe cleaner, then rinse and wipe dry. Scrub the outside of the bolt, lugs, tail, extractor area, and bolt face, getting all fouling loose, then rinse of wipe the fouling away. Scrub the cam pin and firing pin, and scrape away any carbon build up. Lubricate the bolt carrier, ejector channel, extractor, cam pin, bolt, and reassemble the bolt carrier. Lube the entire bolt carrier assembly liberally so it is glistening like a glazed donut, making sure the 7 bolt lugs and rails of the bolt carrier are good and wet.

With a clean chamber, barrel, upper receiver, charging handle, bolt carrier assembly, it is time to put things back together. Insert the lubricated charging handle, and bolt carrier assembly into the upper. Put the upper receiver and lower receiver assemblies back together, and manually cycle the action a few times. Function check to make sure everything is good internally. Scrub the outside of the rifle, once clean, wipe all steel surfaces with a lube for corrosion protection.

From there clean & inspect the magazines. Use quality ammunition from a USA Reputable Manufacturer. Lubricate all steel parts that could rust, using a lubricant that has corrosion protection. Lubricate all friction points.

CY6
Greg Sullivan "Sully"
SLR15 Rifles
TheDefensiveEdge.com
(763) 712-0123

Granted that I can make one, really never felt the need for one.

Hence pull the B/C down to cleaning level, hit it with some fresh CLP, including in the carrier gas section, and by the time you finish cleaning the upper and barrel and it has been soaking, any fouling in the B/C gas section cleans right out with a Q tip.

The inside walls of the bolt carrier can easily be cleaned with a brush and good solvent.  The inside back end of the bolt carrier is where getting at the carbon build up can be a little harder to get at, keep in mind that it doesn't need to be white glove clean, and you may find a heavy carbon build up here, so the bolt carrier scrapers are nice to help knock off the large chunks.

When teaching Armorer Courses we supply several different scrapers.  The ones that have done thousands of bolt carriers in our classes are

Brownell's AR15 Carrier Scraper
Brownell's AR308 Carrier Scraper



I have one in the collection that was labeled Bushmaster.  Here is a video showing how to use it


CY6
Greg Sullivan "Sully"
SLR15 Rifles
TheDefensiveEdge.com
(763) 712-0123