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Old March 23, 2014, 07:59 PM   #1
Panfisher
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Filthy AR empties?

Since I am still new to the AR life, is it "normal" for the freshly fired cases from my R-15 to be filthy dirty. Is it a byproduct of the DI gas system. Just used to cases extracted from my bolt rifles being almost as shiny as they went in. Was sighting in for some new Barnes TSX 55 gr bullets for a possible hog hunt and was noticing that all the cases were horrible looking after firing.
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Old March 24, 2014, 09:49 PM   #2
bfoosh006
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What do you consider filthy ?



If it looks like the brass on the left... then ...yes,
that is normal.
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Old March 24, 2014, 10:15 PM   #3
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Think real hard about how it all works,you tell me,is there any way DI does it?
I don't think so.

Tell me what powder you load with.Seems like part of the early M-16 problems had to do with loading BallC-2.

Actually,you do have something right,just backwards.

Dirty burning ammunition can be a problem for a DI rifle.

That is an ammo problem,not a DI problem.

Your brass will heat discolor but should not soot up.If you have powder residue,find a different load.
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Old March 25, 2014, 06:22 AM   #4
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Does the rifle function properly with your load? Any signs of pressure or other problems? Just clean the brass and enjoy shooting.
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Old March 25, 2014, 08:35 AM   #5
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Buy a box of factory ammo and try that. I'd be willing to bet that it will come out clean.

Brass has too functions. One is to hold all the components (Powder, primer, bullet) together so you can shoot it.

The second, and most critical is to act as a seal to contain the pressure from burning powder so it can push the bullet out the barrel.

The brass swells up sealing the chamber. If there isn't enough pressure in the brass, it fails to completely seal, allowing gas to escape back toward the bolt, leaving a smoky residue on the neck and shoulder of the brass.

My thinking is you're not putting enough powder in the case, or the primer isn't hot enough to get the powder burning properly.

Best way to test this is to fire factory ammo in the rifle and examine the brass.

You may or may not be using the recommended load from a loading manual. They call them "guides" for a reason. All guns are different and require different loads to work properly.

If, the factory brass doesn't smoke (get dirty) then you need to go to a hotter primer or increase the powder charge. One at a time, don't do both at once. If you're using standard primers switch to magnum primers without changing the powder charge, If that doesn't work, increase the powder charge 1/10 of a gr at a time until you stop getting smoking of the brass. Watch for pressure signs. You also try using heavier bullets with the same charge. But again, only make one change at a time.

Then again, if you like the accuracy of your load, DONT WORRY ABOUT IT.
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Old March 25, 2014, 08:35 AM   #6
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Loads are with BLC-2 powder, the empties are "sooty" looking. Everything functions great, shoots accurate and I take care to give it a quick cleaning after shooting. If its a powder problem and it begins to cause functioning issues I will change loads. Wasn't sure if it was common or not. Thanks
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Old March 25, 2014, 10:24 AM   #7
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I'm not an M-16 history expert,but if I recall correctly one of the sources of trouble with the M-16 in the early days
Eugene Stoner designed the rifle around a different powder,and somebody made the decision to load the 5.56 ammo supplied to troops with Ball C2.

The way they make those little balls burn slow is by coating them with a deterrent that does not like to burn.The deterrent can make some nasty fouling.

While I could just "get over" dirty brass,a problem is the dirty fouling is also collecting in your gas tube and bolt carrier.

I also agree with kraigwy's comments about good ignition and enough pressure to seal the brass
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Old March 25, 2014, 03:03 PM   #8
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It's normal. Comes from the unburnt powder and exhaust coming out of the barrel and back into the chamber via the gas tube.
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Old March 25, 2014, 03:29 PM   #9
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Hmm the first reloads I had were pretty mild, will try some of the more recent ones that are hotter. Then possibly a primer or powder switch after that.
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Old March 25, 2014, 06:13 PM   #10
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I just went and looked closer at the empty cases, it appears that is soot, wipes off easily. For giggles I tried one of the empties in my NEF Handi Rifle, wouldn't close on it, so there may be some chamber dimension issues along with semi-normal dirtier brass from an AR. Once I finish with the current jug of BLC-2 I will look for a cleaner burning one.

Kraigway thanks for the tip on the primers, I never considered needing a magnum primer in the .223 cases, but it makes sense as the cases are pretty full with that powder, especially if the powder is coated to slow the burn rate. Any favorite powders for .223's.
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Old March 26, 2014, 06:26 AM   #11
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Kraigkw is correct. Bump up your charge and try again. I had the same issue until i switched powders and loaded 1gr below max. My brass is much cleaner and my ar15 and ar10 are much easier to clean because theres less build up. Try using IMR4064 AND IMR 3031. Also, ive used magnum primers in my 308's. It works but you have to becareful not to flatten or blow out primers. Start by changing powders first.
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Old March 26, 2014, 07:05 AM   #12
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Panfish, the Handi rifle is probably chambered for .223 and has a tight chamber to boot. As long as I did not use 5.56 mine ran ok otherwise It was necessary to punch the cases if I got one mixed in with .223 ammo. I doubt you will find many AR fired cases that will drop into the chamber of the Handi without resize.
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Old March 26, 2014, 08:05 AM   #13
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My AR is .223 Chambered also, let me slightly re-phrase that, it is a Rem R-15 and is stamped .223 Rem not 5.56, however after reading about 5.56 vs. 223 chambers ad naseaum, I cannot say for sure what it actually is reamed to.

Newest loads are 1/2 grain below max, haven't tried them yet.
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Old March 26, 2014, 12:31 PM   #14
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I started out loading heavier bullets,so my experience is with 69 gr +

Brother has a 60 or 62 gr Nosler Ballistic tip load using Benchmark.
Best accuracy so far from that rifle.If you should try 69 gr bullets,Like a MK or Nosler Comp,Varget works great.Benchmark is like Varget,but one step quicker.They both burn clean.

I have no experience with it,but H-335 has a good reputation.

Thinking about it a little more,to get soot around the outside of the brass,dirty gas has to travel between the chamber and the case.(The Quickload folks can give you a percentage of burn for a given load.With appropriate powders,its usually something like 95% to 105%.That occurs before the bolt unlocks.If the case seals early on,as it should,no soot on the brass.There is not a lingering fire in the barrel during extraction.

The DI tube gives impulse to the bolt carrier,and the gas is mostly inside the BCG.There is no contact with the brass case.

After the bullet is long gone,the BCG has traveled the dwell time in the cam,the bolt turns,pressure has to have dropped enough for the case to de-obturate and extract.The gas tube remains telescoped into the BCG till the bolt is unlocked and extraction has begun.How can gas and flame still be spewing out of the gas tube to smoke the brass?

So,for your brass,I think kraigwy's answer is better than mine.

But,still,for your BCG and gas tube gunkying up,I'd choose another powder.
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Old March 26, 2014, 01:30 PM   #15
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OP if you don't mind I'd like to jump on to this thread with my own question .

These are my first reloads for my AR . LC case , CCI #400 primer , 55gr FMJ-BT , 25.5gr IMR-4895 . It appears I get powder residue 3/4 of the way down the case . Cases on the left ( before ) cases on the right ( after ) Click on image to zoom
http://imageshack.com/a/img34/9527/qqbk.jpg

This is a close up of a single after case . What's up with the rings on the neck ? They are not on all of them .
http://imageshack.com/a/img716/3671/ipgd.jpg

What do you guys think . Do I need more powder or am I gtg . These shoot real good and the guns function fine .
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Old March 26, 2014, 05:19 PM   #16
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Jump right in Metal God.

I went to look at my loading manuals when I got home today, couple thing I noticed. 1. missed the * that denotes magnum primers with BLC2, and one of the manuals listed IMR 4895 as a powder for the .223, since I usually have plenty of that for .22-250, .243 & 7-08's, I will give it a try next. Have 500 55 grain dogtown bullets on order to test with.
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Old March 27, 2014, 03:48 PM   #17
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Panfisher, be advised that BL-C2 is kind of tempermental / spooky at max pressures and higher temps. I haven't had good luck with max loads of it .... all of a sudden the primers were FLAT... just an FYI.

Just passing on my experience with it... keep your eyes open for pressure issues.
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Old March 28, 2014, 07:47 AM   #18
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Thank you sir, so far no noticible signs but have had a ton of use with it yet.
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Old March 28, 2014, 09:20 PM   #19
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OK here's a before and after pic from today . The residue is clearly getting all the way down to the head just about . You can see the powder line where it appears to stop . FWIW these are the same loads as I said in my other post and eject at 2:30 -3 o-clock

http://imageshack.com/a/img822/4168/xz9h.jpg

It sure seems like I'm getting to much blow back to me .

Primers look good
http://imageshack.com/a/img18/528/4oer.jpg
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Old March 28, 2014, 11:12 PM   #20
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It has nothing to do with it being direct impingement.

First, look at the cases on any blowback gun -like the .22, or a .380 pistol. They get dirty, too. It happens because as the case pushes against the slide or bolt it retracts, which allows barrel gas to vent backwards out the chamber.

Next, have a buddy with a HK roller locked action show you his brass. When I owned one, that was my first observation - "Wow, this brass is nasty." It was shooting off beat import .308 from Pakistan, but it was also because the timing of the bolt retracting is early enough that the chamber will pass barrel gas past the cartridge into the action.

Then, see what happens with an AK - we finally get to an action with a piston, but it's way out over the barrel. Fire it, check the brass, it's dirty, too.

All this of course depends on the powder used, but the point is, a manual action gun doesn't pull the brass backwards out of the chamber while their is still pressure in the bore. Self loaders that blow back have to, and timing on most self loading actions allows it, too.

Now, check the action on the AR - the gas tube vents into the key which directs the gas into the chamber in the bolt carrier. As it expand and rotates the bolt to unlock, it uncovers the gas ports on the side of the bolt allowing it to escape out the ejection port. The overlap of the gas tube to key is enough that as the bolt carrier moves to the rear, the brass unchambers, and like all the other self loading actions, there is enough bore pressure to exhaust past the brass casing.

It's NOT the gas tube - which is mounted much higher above the bolt face. Gas from the tube is what leaves residue in the upper receiver channel, not on the bolt face - and by then, with a barrel open on both ends, the gas pressure is gone.

DI doesn't have anything to do with dirty brass or the bolt face getting dirty, it's all about the gas from the barrel passing by the case and exhausting at the bolt. That happens in all self loading actions, rifle or pistol.

What we have is a lot of shooters who aren't familiar with self loading actions unless they have shot modern military rifles - and that is a much smaller pool in the population. Veterans were 1 in 10 back in the early 60's, it's now 1 in 100. The knowledge and experience aren't being shared nearly as much.
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Old March 29, 2014, 04:53 PM   #21
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I didn't mean to denigrate the DI action, I should have stated it more along the lines of "does is have something to do with the gas powered action". I have lots of experience with autoloaders in shotguns, pistols, and .22's but not AR's thought maybe something was "different" with it. I have noticed sooty empties on my .45 and .22 empties and have pretty well decided that it is a combination of powder choice combined with wrong primer and it being a gas operated system, not necessarily a DI system. You all have been great, just gotta get a little time to make up a few test loads with IMR 4895 and see if it is a noticeable difference. If it doesn't I can live with a little more cleaning as the rifle shoots very well, and I don't fire more than 20 rounds at a time usually not that many, just a trip to the back yard with the big bale backstop to shoot a few for "mental health" purposes.
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Old March 30, 2014, 02:07 PM   #22
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First of new recipe. Loaded 5 rounds with 25 grains of IMR 4895 and fired them today. Shot pretty well, and with plenty of authority. Grouped dead center. Soot was pretty well confined to the upper third of the case and not as heavy, seems as though I have found an answer there, thanks gentlemen. Also the new Caldwell bag/shell catcher worked perfectly.
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Old April 1, 2014, 12:30 AM   #23
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It's completely normal. I wouldn't worry about it.
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