Gun Hub Forums banner

1 - 20 of 22 Posts

·
Registered
Joined
·
1,186 Posts
Discussion Starter #1
I am now rethinking my rifle cleaning applications and this is what I found or other words this is the first in a series of The Carbon War Chronicles.
One of my target rifles I haven’t fired since 2005 was pulled out and given a once over to see how it is doing and in my gauging now I have added a muzzle gage (got it from CMP) and I inserted the gage in the muzzle and saw it went in a bit far so I put the borescope in and to my shock I saw a ridge of metal build up about 3/8” down inside barrel with a copper build up on it. I remembered last couple of times I shot it that the rifle was not up to par at 600 and this explained it so I decided to whack off 3/8” and get down below the damaged area.
Got it whacked off with cut off saw and started to insert in back of lathe and it there wasn’t enough room to get barrel in back of headstock with action still on so I looked at log book and it had 2800+ rounds on it and the borescope showed it was starting to get tired so I screwed the barrel off and cut off the barrel threads which is known as a “set back”. After rethreading and rechambering it was put back on.

Barrels get most of their wear in the throat about ¼” to ½” forward of the chamber so whacking off ¾” (length of the action threads) will get you into not new but nearly new rifling and remove the effects of high pressure flame erosion.
For years I have liked 26” barrel length to give me good sight separation for shooting long range. Target shooters well know the longer the barrel the further the iron sights are apart and the ability to aim is enhanced with a longer sight radius. This is why you don’t see many guys after age 40 shooting service rifle, especially the AR variety because the older shooter’s eyes won’t accommodate looking close and distant as well as younger shooters eyes will.

Bottom line here is service rifle is a young man’s game but the good news is the NRA Highpower Rules have been changed to allow one corrective lens to be used in rear aperture of a service rifle.

OK back to the set back barrel. To increase sight distance devices known as bloop tubes were developed by an innovative shooter named Scott Medesha which initially consisted of a machined block of aluminum and half of it clamped on the muzzle that was altered to remove taper and give cylinder dimensions about last 2” of barrel.

In the other end of the block a piece of aluminum tubing is inserted which in effect does not lengthen the barrel but the distance between the sights can be enhanced up to a foot. Cap Screws pull the block (slotted in bottom) together and it holds the sight radius extension as the front sight is then placed on front of the tube.
I did not need a foot so I turned the muzzle to .850 and got a piece of stainless steel pipe about 3” long and bored the inside of it to .850”. I drilled and tapped the pipe for the front sight base and then I carefully fitted them together so the front sight was vertical and when it was right tapped it home so now I have a .850” hole at front of barrel and a slightly longer sight radius.
I fired it 20 rounds and the interference fit remained snug and did not move and after confirming the front sight was in the right place I drilled a hole through pipe and into barrel and put a set screw in.


I rechambered the rifle with the same chamber reamer it was put on with in 1990 so all my cases previously fired in first chamber fit the new chamber perfectly so I did not have to pull down the ammo I had loaded for it several years back. On each target rifle I have 200 to 500 pieces of brass that are only fired in that rifle and the boxes are identified by the serial number of the rifle to keep them segregated.
It is a very tight chamber and brass barely moves. Thusly when run into FL die the brass is barely moved returning it to reloadable dimensions. I can reload and fire brass in this chamber using LC Match cases over a hundred times by stress relieving the necks every three shots and cleaning the brass well.
THEN IT HAPPENED ! ! ! ! ! In life you think you know all the answers when you get older but next thing you know all the questions are changed ! ! ! !
It appears I have sort of created a problem in that when the bullet exits the muzzle the gases do not freely go off to wherever but they deposit carbon (our worst enemy besides politicians) on the inside of the tube and the face of the barrel. I zeroed it at 200 yards with iron sights and made an interesting discovery.
I knew that carbon got hard when it cools and never could figure out how quickly this occurred until this past week when I finished the zero session and cleaned it within a few minutes I had ER in the muzzle and the carbon came out rather quickly and easily. I figured if the carbon remained in a heated condition it would remain soft but then again the internal temp of cases run around 3000F and cooling them off to about 120F was too much to hope for. I thought I was good to go until I went to a high power match over the weekend and fired 88 rounds.

We only had three relays so the barrel never cooled off and I ran ER on a bronze brush through it about 30 passes after 66 rounds when we left the 300 yard line and went to 600 yards and shot 22 more followed by another cleaning. I estimate the barrel got to about 130-140F during the rapid fire stages and never cooled down below 115F all day.

I noted a goodly amount of carbon build up on muzzle so I left the range with a patch soaked down with ER packed in against the muzzle in what I THOUGHT would be the thing to keep the carbon wet and soft.

I got home and did not get to look at the muzzle again till Sunday afternoon and to my shock when the soaked down patch plug was removed the carbon was STILL HARD and there was build up adjacent to every groove and I inserted a scraping tool and it was too hard to scrape off. So basically the ER soaked it for 24 hours had not kept it soft.
I next tried Mobil 1 Synthetic Motor oil as I know it keeps the internal parts of my engines very clean so I soaked another rag plug with Mobil 1 and left it 6 hours and the carbon came right out with a minimal of scraping.
Went out and ran some testing and fired another 35 rounds and laid the Mobil to it again and it cleaned right up.
Bottom line here now is I will be doing more work along this line in the Carbon Wars to see which tactic works best. I also have some other stuff that is advertised to be a carbon remover and will try that as well but it is extremely expensive for a quart of it and Mobil 1 is like 6.35 a quart. I will try some other things as well but the traditional stuff has never seemed to work in the past.

Bottom line here is if carbon is this hard to remove from the muzzle you can just imagine it loading up inside the barrel round after round and that is a much longer surface to deposit on and it if builds up and packs hard at the muzzle just imagine what is happening inbore as additional rounds go downrange.
 

·
Registered
Joined
·
1,186 Posts
Discussion Starter #2
UPDATE:
After I got through cleaning last time I left wet patch with Mobil 1 up against the muzzle. Shot it yesterday and before shooting I ran patch through bore and picked up a trace smear of carbon. The carbon left on the muzzle was soft and easily removed.

I shot 27 rounds testing at 300 yards yesterday afternoon and came in and cleaned it within five minutes of cease fire and carbon came right off with just a little effort. I made 15 passes with bronze brush initially and patches and then another 5 passes before I got a clean patch. Left the bore sloppy wet with Mobil 1 stored muzzle down.

Next time before I shoot it I will run a clean patch down bore to see if it floated up anything else.
 

·
Premium Member
Joined
·
7,055 Posts
I uderstand you using Mobil one as a followup to conventional solvents but what is the harm of carbon inside the tube?
 

·
Registered
Joined
·
1,186 Posts
Discussion Starter #4
Charlie,

It hardens up and becomes abrasive and bullets coming down embed the carbon in the soft copper jacket and carry it downbore lapping merrily away. Then again this may be a good thing based on some barrels I have borescoped lately that look like they were rifled with a mill bastard file and a brick. haha.

Examine expander balls of your loading dies used in the normal manner and you will most likely see scoring from the carbon residue inside the case neck. Cases cleaned well and carbon removed do not embed carbon on expander balls and thusly the inside of case necks are not scored.
 

·
Premium Member
Joined
·
7,055 Posts
Maybe I misread your post because I was thinking about the tube you added. I certainly understand the evils of carbon in the bore but if the tube is so much larger than the bore does that matter?
 

·
Registered
Joined
·
1,186 Posts
Discussion Starter #6
You are absolutely right, the tube (front sight holder) being larger has nothing to do with accuracy unless you want to count increased sight radius helps in aiming. If it could not be cleaned then the build up would actually not affect anything which is exactly what lots of highpower shooters do. They never clean them.

It is only mentioned as a highly visible evidence of just how much carbon deposits are left in the barrel where they are not readily seen. We see evidence of carbon down inside cases and their turning black on first firing and now I am getting carbon at the muzzle so it stands to reason the entire surface of the barrel is getting its share of carbon deposits.

The only way I know to remove the carbon from the inside of the cases is to tumble it in the stainless steel media that has become so popular. It makes my cases look just like new never loaded internally and I know the carbon is gone as it turns the gallon of water in the tumbler to black ink with only 100 308 cases.

My theory is if I can find something that removes carbon effectively and quickly from where I can see it then I must conclude where I can't see it will be removed as well. Removing it from the muzzle is a quick effective manner just confirms how well the Mobil 1 works in removing carbon from everything I have ever used it on.

Then to confirm it I run sloppy wet patches in afterwards and let them sit a couple of days and see if anything else breaks loose. So far the Mobil 1 seems to be removing the carbon exceptionally well the first time cleaning session.

We all know as gas burns in engine it turns the motor oil black from the fuel being burned. Conversely engines run on propane leaves the oil clean for a long time. As well if we are using the wrong oil these will allow build up as sludge in engines. The Mobil 1 seems to be outstanding in keeping engines clean and I have run it about 700,000 now.

Right now I have 192K on one vehicle and 258K on another and looking down inside valve cover the internal area is clean. I change my own oil and filter between 15,000 and 19,000 miles and I always look for deposits on tip of drain plug and down inside filter and every time the end of the plug is clean in the internal surface of the filter is bright and shiney. I have dropped oil pans on other vehicles and found black carbon sludge deposits on bottom of oil pan.

I have a tanker garand and it has Mobil 1 in gas cylinder and if I leave it wet when I pull it down the carbon wipes right off. I once ran 250 rounds through it without taking it down for a good cleaning and I was plasantly surprise to see the carbon wiped off easily.

I have even found a way to recycle it. I use it for cutting oil on my lathe and have chambered half a dozen rifles using Mobil 1 with 15 to 19 k on it taken from engines. Last thing I used it for was poor mans termite treatment and put it in post holes before packing dirt back around them. I know several guys that do this on fence posts and so far have not had to replace any posts form termite damage.

Haven't tried it on fire ant mounds yet. ER works well on them though.

Oh yeah wear old clothes when using it for cutting oil as spots of it slung on your shirt is there forever! ! ! !
 

·
Premium Member
Joined
·
7,055 Posts
I'll rush out and get some... always looking for better cleaning ideas...

Some time ago I had a marketing type call me to tout a new bore cleaner. The BS was getting pretty deep but when he told me that it "dissolves carbon" I told him he needed to re-take chem 101 and call me later...
 

·
Registered
Joined
·
1,186 Posts
Discussion Starter #9
I don't see why or how it could hurt. You might have to let it "soak".

Went to a match today. 3 600rd matches and did my thing with Mobil 1 and it worked like a champ. As soon as I got throught with a string I had the Mobil 1 dripping from a 30 cal bronze brush and making 15 passes initially. The first two strings I shot 4895 and last string I shot WC852. It was somewhat harder to clean. I did three sessions with bronze brush before it all came out. The crud on the face of the muzzle and inside the barrel extension cleaned up easily as well. I did not have anything sharp and soft to work at it with me so I left it soaking with Mobil 1 on a piece of sponge packed in barrel extension to keep it in contact with it on the say home.

When I got home I found a brass pin that allowed me to get to edge of the barre and it wiped right out.

I check barrel with erosion gage and I have advanced almost a full ring but funny thing the OAL of the bullet did change. I next checked the OAL by soft seating a bullet and chamber the round and closing the bolt letting the barrel place the bullet right where it wants to when bolt cams in. I then compared the overall length and it is still the same as I chambered it a couple weeks back.

Now has 226 rounds and for all practical purposes the throat did not move.

Most interesting is running borescope in chamber end there is no copper at all for first part of barrel but looking in muzzle end there is a goodly amount and more than I like to see so I laid the Mothers to it.


I have the cases tumbling now in the stainless media cleaning the carbon out of them. I am hoping they will be ready about 2200 hrs
 

·
Registered
Joined
·
1,186 Posts
Discussion Starter #11
Went to a 600 yard practice match on Saturday and tried three different loads with three different bullets and two propellants.

With the 4895 the clean up was as normal. 15 passes with wet bronze brush immediately aftering firing followed by patches and another five passes with bronze brush.

The last load was using WC852 (milsurp ball) and it was harder to clean. I initially did 15 passes followed by 5. To get the last of it I did another 10 passes and got it out.

In the muzzle extension the carbon from 4895 came out easily. The WC852 took out about 95% of it immediatley but I did not have anything to get to the very edge that would not scratch the muzzle so I left it wet till I got home and a bronze pin took it right out.

Then an amazing thing happened. I ran the erosion gage in and it showed I have a movement of about 3/4s of a ring so I figured I would have to change seat depth. Normally on a new chamber job I have about 1 to 1.5 rings of movement in first 100 to 150 rounds.

I arrive at seat depth by soft seating a bullet longer than I had previously and closing the bolt and let the throat put the bullet where it wants it. To my great surprise the seat depth at 226 rounds is the same as it was at 0 rounds ! ! ! The reamer I cut this with gives me a short throat so OAL with 173 bullets is 3.297" and normal 30.06 chamber is 3.340".




I had another surprise as well. I borescoped it and there was absolutley no copper in barrel as far as I could see in front of chamber which is about 6 inches. I ran bore scope in front end and it was copper to XXXX and gone last 16" of barrel with build ups six inches from muzzle. I had never defouled it and at 160 rounds with was still shooting well at 300 yards. During the first strng I had a massive zero shift vertical at the 12th round and had to come down 1.5 MOA to get centered again and it stayed there. This barrel is a tight bore and and a .2984 plug will not enter muzzle. Note:: LC 173 match bullets run large and spec .308 to .3089 with hard jackets.

So I laid the Mothers to it and it took it right out quickly. 3 patches of it was all it needed and copper was gone.

Loaded up another 200 rounds for it yesterday but will lay the Mothers to it after every match from here on out. I would have never realized this without a bore scope. That is one of the best investments I have ever made.
 

·
Registered
Joined
·
1,186 Posts
Discussion Starter #12
Found a good source for oil/bore cleaner bottles. www.usplastic.com has 4 oz and 8 oz tilt top bottles so I ordered 6 of each. They are only .63 for stock 60148 (.4oz) and .74 for stock no 60149 (8oz). I have used their bottles before and they are good. I have already filled one with Mobil 1 0W20 for the bore cleaner I will use at tomorrow's match. I have several of them around with ER in them. :D
 

·
Registered
Joined
·
1,186 Posts
Discussion Starter #13
Went to a match at Mid Carolina on Sunday. With sighters I fired 69 rounds and did not clean all day as firing was over fairly quickly.
Tried to clean at range but the bronze brush I had was crappy so I could not clean till I got home.
I left the muzzle and inside of front sight extension wet with Mobil 1 and when I came home it came out easily. I let a new shooter use an AR match rifle I had taken for another new shooter to use and it stays wet with Mobil 1 all the time.

When I got home I got a good brush and barrel cleaned up as normal finally giving birth to clean patches. The best part was the bore scope. As before there with just a trace of copper here and there first six inches and then I went in front end and fouling was about 1% of what it had been before if that much.

The Mothers took it right out.

Interesting to note the erosion gage shows maybe .005" movement forward and I reloaded ammo to get ready for next match and check the seating by putting round in chamber and closing bolt and a lightly seated bullet and the seat depth has been adjusted about .020" out. (Note) this seating method is nice as it is so gentle the lands don't even mark the bullet! ! ! !

As indicated previously I am shooting 173 Match bullets from LC and I thought I would do a little study. I took a Sinclair bullet measurement tool that is attached to a caliper and distance from base of bullet to ogive was measured. That was a real eye opener and the range was about .023 variation. I segregated them into longs and shorts once I figured out the mid range and wound up with 2/3rds of them in the shorter category so I have them marked for shooting 300/600 only. At that they will still vary about .012”.
I started seating them and overall length varies a great deal as well. About .025”. I then used the same Sinclair/caliper tool and check OAL to the ogive and as before it varied as well.

Before seating the bullets I measured them for diameter. The milspec for the 173 gr bullet allows for .308 to .3089 bullets. In the 60 I measured these ran .3082 thru .3088. The good news is the 300/600 bullets had more uniform bases and they measured .3083 thru .3087”.

Though not widely known the 173 design is a excellent design and W C (Bill) Davis told me that the design was a scaled down 50 cal and it was first designed with slide rules. He said LC Match went out of production a while and when it went back on line they had computers and ran the numbers and the computers confirmed the slide rule and there was no design change on the bullets.

So bottom line I have bullets averaging .3085 being fired in a Obermeyer 5R barrel that won’t accept a .2984 plug in muzzle and the finish is so smooth there is just a wee bit of copper.

Bottom line is I should be able to go all day by just brushing with Mobil 1 and then Mothers after final carbon removal. I used three patches of Mothers but most likely one or two would have done the deed.

Oh by the way the AR gas system cleaned up easily as well with Mobil 1. :D
 

·
Registered
Joined
·
1,118 Posts
Super thread. Have a couple of questions:

What is "Mothers"?

Ever tried Flitz for a bore polish? I've had very good results on badly fouled bores.

Any thoughts on using ATF (Synthetic)?

Cheers!
 

·
Premium Member
Joined
·
7,055 Posts
Mothers is a polishing compound originally intended for mag wheels. It has long been used as an additive for brass tumblers. If I recall it is an aluminum oxide.

The gold standard paste bore cleaner is JB but it is a two edged sword because over use can do much harm. It is an abrasive and will remove metal... not just fouling.

I have had very good luck with the Outers Foul Out but it is a pain to use. My normal practice is to clean with Butch's or Shooters Choice at the range when the barrel is warm and then if needed use one of the strong ammonia based solvents like Sweets, Montana Extreme or Super Solvent at home
 

·
Registered
Joined
·
795 Posts
The gold standard paste bore cleaner is JB but it is a two edged sword because over use can do much harm. It is an abrasive and will remove metal... not just fouling.
Gabe McMillian wrote an excellent missive about the overuse of JB. Short version of the story is that a bench rest rifle that Gabe built was subjected to excessive use of JB bore paste. When the rifle was returned he inspected it with a bore scope and could see that the barrel was mirror smooth but the lands had been rounded over. Gabe replaced the barrel on that rifle and changed to warranty on his rifles after that. JB might be OK for an off the shelf hunting rifle barrel for the first twenty rounds but is not something you want to use frequently.
 

·
Premium Member
Joined
·
7,055 Posts
That's the stuff Al. I think Bill Wilson recommended it ages ago but I haven't used it in years. I put a bit of Iosso brass polish on the corncobs.

McMillan isn't the only one who has had problems with over-use of abrasives and routine use is probably overkill for any barrel custom or not.

I don't think taking a bore down to bare metal is necessary anyhow. If you watch the benchrest guys they clean frequently but don't normally use agressive methods.

I don't know how to objectively measure cleaning methods and I've taken the bore scope to the range to look at barrels as I shoot them. It isn't unusual to see a bit of copper even after pretty thorough cleaning but I can't say it hurt anything.
 

·
Registered
Joined
·
1,118 Posts
Agree Charlie. I don't do new rifles much, too many great deals on used ones. I have found (like my recent Interarms Mark X) that some of these used rifles are horrendous. As in bores caked with dust and green fuzz. :grumble: That's when the initial cleaning with boiling water, Mobile One, Flitz, what ever seems appropriate.

:D
 
1 - 20 of 22 Posts
Top