Fouling question???

[drine]

I hid this too deep in one of my other ramblings so I got no response. I got the CETME out again yesterday and fired 2 mags plus of ammo and then it wouldn't fully seat the rounds. This happened after 10 or so rounds before.
The problem is that the chamber is fouled with TAR. South African ammo is sealed with Tar. It looks and smells like tar...so it must be tar. Anyone ever run in to this? Remember, Korean G3 barrel...If the flutes are a bit shallow, would this cause this issue? I can't see what a few 10ths would do for this. That's excessive crap for 50 rounds or so. I'll try to get some other NATO spec ammo and try it. Just wandered what some of you think.

[Teyvareb]

Well, if they're not seating fully, wouldn't the fouling occur mostly around the neck/shoulder area of the chamber? I mean, that would put the case in but not all the way... Though I could see tar buildup at the shoulder side of the flutes also causing problems. Given that the flutes are shallow, I suppose they would fill up faster than original depth. Uh... I suppose try some different ammo after a thorough cleaning of the chamber area and see if it still does it.

[Seattlefungus]

I recall a lot of countries used creosote as a bullet seal, (Including up to the 1960's, the US) The stuff does smell like tar.. I've shot lots of the SA in my M1A1, and HK91 and CETME... All have stock barrels. I have one of those Korean barrels as a spare. I think you may me right that the shallow flutes may well be the issue...

[drine]

A few tenths can make a difference in the line of work I'm in but just wondered about this issue. Even the thick sides of the case have patches of this stuff when it doesn't seat so I know it's coming back further than just the neck. These patches don't have any particular pattern in that they aren't stripes or lines of the flutes. I see Port, Aussie, and Brit ammo on gunbroker. What is the preferred? I figure I'd splurge and get a pack of something since my meager supply of SA is down to less than 100rds. :icon_cry:

[drine]

The bolt face is all crudded too. AND I did start with the rifle cleaned to perfection. It seems to be in the neck area. Maybe the flutes there are the issue? Another thing I plan to do is swap bolts out. I'm using my old stuff after the rebarrel. I have .012 gap with it. With new parts, .020. Maybe some timing changes will help.
It kind of peeves me but considering what I did have, I'm not fussing or going to rebarrel again. It's too accurate to dicker with. Thanks guys. drine

[drine]

AZshooter had a bit of input. SA leaves a little soot. I'm getting "TAR" or gunk. That means something wet! SOOO either I'm not drying out the area good enough after cleaning/lubing or I may as an outside chance be leaching some lube from the barrel swap. It does get better every range trip. I'm going to completely dry it next time except a bit on the rails.
I like this exchange of info. If one is not given an exact yes/no answer then one is usually pointed in a direction to find it! Another plus one for our site.:thumbup:

[M1 Tanker]

Drine, you said its not fully seating rounds...so the bolts not closing, correct?

After reading all your posts and thinking and about it, I truly believe its the out of spec barrel causing your troubles. I'm hesitant to blame ammo, when the rest of us can run SA without the type of stoppage you described. Since your flutes are shallow, maybe that allow the fouling to concentrate and not escape. Maybe the cleaning/lube technique will allow you to fire it longer, but I believe you are going to run into the same problem eventually.

Let us know how your range trip goes.

[Trueno]

Look at the spent casings.

Well, go out in the field and hunt for 'em and then look at 'em :lolgreen:

Check out the soot pattern that the flutes are leaving, are all of the flute marks present? Should have 12 stripes down the side of the spent case.

t

[richl]

tell ya a secret .......

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take a new case .. empty that is ... after you take yer rifle a part make a homemade shaft of some sorts and anchor it on the caseing through where the primer is seated.....


then pack that bastage with mothers polishing compound ... yea you hears me right .. mothers polishing compound ... then insert the casing into the chamber and then hook to a drill or what ever you have , weed whacker , small block Chevy , lawn boy ,, whatever , and SLOWLY spin the casing in the chamber . it will tum black ... great do this for 3-5 minuets.... it will polish the chamber and remove micro pitting in the chamber .. yea you think I'm nuts .. but this worked awesome in my psg1..... it will also allow the chamber to stay cleaner due to the fact the powder residue will not adhere to the chamber due to the polished surface....


and for the record were not nuts..........


oh and dont show anyone this secret .... ok ???

[pigpen]

I'd have to say it has somthing to do with your barrel, cleaning method, or cleaning products. I have shot a boat load(small boat) of SA & have never had a problem like you discribe.

[Trueno]

AZshooter had a bit of input. SA leaves a little soot. I'm getting "TAR" or gunk. That means something wet! SOOO either I'm not drying out the area good enough after cleaning/lubing or I may as an outside chance be leaching some lube from the barrel swap. It does get better every range trip. I'm going to completely dry it next time except a bit on the rails.
I like this exchange of info. If one is not given an exact yes/no answer then one is usually pointed in a direction to find it! Another plus one for our site.:thumbup:

I'll betcha 20rds it's the ammo, not the weapon.

I had a batch of SA a year or so ago that left tar (+ soot) on spent shells. Others with the same lot # had the same experience, nasty random gooey smears down the side of the case.

t

[drine]

Like I said, it gets better each trip. I already polished it a bit with a scotchbrite pad but richl's advice seams to get it done quicker and easier. If you could see what I pull out, it is obvious something WET is also present, otherwise I'd have just the normal soot. It shoots fine for 50 rounds or so. No issues with it BEFORE that. It just builds up. Good stripes on the cases until the crud forms. Being that it is wet and the shear volume of what I get, I still have to say I'm leaving too much lube or it's leaching out from the rebarrel.
I'm going to keep trying. Like I said, it's too accurate to "F" with anymore. I still intend to get a spare barrel, "just in case". thanks for all the input.

[drine]

I'd agree. What I get is making its way down past the neck to the main body of the case and leaves spot here and there. In my line of work, I have to pin-point root causes for failure and I'm having a time with this one. Now the worst news is I have about 50 rds of SA left!!!!!!! Hope nobody invades soon! This will cause me to try PORT or Aussie that I see on gunbroker. I'll pay a bit to just try something else. Anybody want to suggest the absolute best? Winchester white box?

[pigpen]

I'd agree. What I get is making its way down past the neck to the main body of the case and leaves spot here and there. In my line of work, I have to pin-point root causes for failure and I'm having a time with this one. Now the worst news is I have about 50 rds of SA left!!!!!!! Hope nobody invades soon! This will cause me to try PORT or Aussie that I see on gunbroker. I'll pay a bit to just try something else. Anybody want to suggest the absolute best? Winchester white box?


I'd sugjest IMI, TC or LC stamped cases. Stay away from commercial.

[drine]

I've got 60 rounds or so of the LC from CTD. I've all but flamed it! I know there is good LC but what I got ain't it! I'll try two or three different ones since I won't be getting a case.
About the commercial, I don't shoot it........much. Just one round to kill a deer. Functioned fine and the other deer flinched and looked where the shell landed and not at me!
Winchester white box is the mil-spec stuff still, isn't it?

[grifter95]

I would try some of Winchesters Nato Whitebox from Midway. Its almost as cheap as SA is now. Its $99/200rds of NEW, RELOADABLE, NATO, 7.62x51 ammo.

OOPS....sorry but now its $135.00/200....they went up since I ordered.
But it is good stuff.

[richl]

OK let me enlighten you on why i do this on every rifle i own .....................................

due to mass production and slop in tolerance's there is never ever a exact fit... ever...... when you do what i have recommended it to a extent helps form the chamber to a closer than before tolerance , even though it is a few thousandths it will help seal the case against the flutes... scotch brite or steel wool is a huge no no ... it cannot maintain the shape as it was first entered .... if you have any further questions... e mail me .. I'll give you my phone and discuss this with you over da phone .........

as me fingers cannot keep up with me mind ...........

[drine]

:icon_biggrin: Now I'm just kiddin', educated guess.
We've talked before. Good man. The scotcbrite I did try but won't dare do the steelwool. The case method you described sounds perfect. I'll see how she does next trip. Thanks

[robocop10mm]

+1 on creosote. Tar like. Nasty. It is possible some is being blown back into the neck/shoulder area. If others are not having the problem, I would look in two directions. 1- Lot of ammo has an larger than normal amount of creosote. 2- Your barrel is on the loose side of normal, allowing more to blow back.

[drine]

Since I'm the only who can see it, I'm leaning at this point toward I left too much lube in it. The gunk was very wet.
I bitched about having to work on it before. I actually enjoyed it afterward when the first rounds went down range.
I've got a reload/armorer friend who still thinks some measurements needed to be taken on the barrel. Bolt gap or not, the chamber length should have a seperate spec. That sounds logical. It wouldn't work if it was 1/2 long or 3 " long to go to extremes.
It can't be far off anywhere judging by the accuracy and feeding. You ain't heard the last from me! Thanks again all.

[Trueno]

Go ahead, take it apart etc etc etc etc etc etc...or simply try one round of another brand.

Bet still stands...

...and I'll raise ya another 20rds the lot is marked 091 B07/81.

You gonna call or fold? :icon_biggrin:

t

[drine]

I forgot to look. The plastic MRE lookin' pack is long gone. I'm still partially blaming myself for leaving excess oil in it somehow. The lot code will be a hoot if it matches!

[Trueno]

I forgot to look. The plastic MRE lookin' pack is long gone. I'm still partially blaming myself for leaving excess oil in it somehow. The lot code will be a hoot if it matches!

I found one round in a box by itself, thinkin' it's the only one I have left from that batch, kept it for reference I guess.

Headstamp is B81

t

[drine]

203W A11/80
Headstamp is WA 80.

Now what do you owe me? he he!