chamber issue

[Texas Solo]

Not sure how to describe this, so please bear with me:

Awhile back I purchased this toll from Sinclair:
http://www.sinclairintl.com/reloading-equipment/measuring-tools/case-gauges-headspace-tools/sinclair-chamber-length-gage-prod32925.aspx

I discovered that my Shilling barrel in .223 Wylde has excessive length over published trim data. Even without trimming my Hornady brass, I have .020" extra chamber length.
I didn't figure where I can do anything about it.

Last week I decided to try a new bullet (80gr A-Max vs. 80gr Berger VLD) When I used the comparator to get length to the lands, I consistently had to push the bullet through a tight spot to hit the lands. This was very consistent. I think I may have a carbon build up in that extra .020" space between the end of the case & the end of the chamber.
I tried vigorous cleaning to no avail. I think I've heard of this as a "ghost ring", but searches only turn up stuff about sights.

So if I've explained this correctly, could a build up of junk have occurred in this space and how can I get rid of it???

Thanks for any advice.

[dfrosch]

Here's a diagram of a rifle chamber:
http://bisonballistics.com/articles/an-introduction-to-rifle-chambers

Are you sure that you are not feeling the throat? A Wylde chamber would have a relatively long throat.

Scroll down in this link:
http://m14forum.com/ammunition/113998-reloading-wydle-chamber.html

The Wylde reamer is about .013 over trim length and a Clymer NATO reamer is .015 over. By comparison, business cards are .013 to .017 thick.

Depending on the length of your brass, having .020" extra length does not seem too excessive. Your Sinclair tool is very likely measuring to a point on the transition(angle) between the neck and the throat. I would be more worried if you measured any amount too little length.

If you are still worried, take it to a gunsmith that has a bore scope.

[Texas Solo]

I believe that the Wylde & Clymer reamers cut deper THROATS (or leades), but not longer chamber specs as it would pertain to brass length. maybe I'm wrong.
The Sinclair tool measures identical to brass spec, in diameter, and could not be entering any angled portion of the chamber (which I did not know existed)
I should have mentioned that this is a new development. I've never had this issue before. When I built this rifle, I did comparator measurements with many different bullets and never felt this "resistance" spot. Something has changed.

[dfrosch]

Look at the K dimension in my second link. The max length for a .223 case is 1.760". Only the match reamer cuts it that short. The Wylde is 1.7726" and the Clymer 5.56 reamer is 1.7750. This is the neck length. It is cut long as a safety factor. If your brass stretches past trim length and you jam it in the match chamber, the case would hold the bullet a little longer and you'd get an over pressure situation.

The angle I mentioned is between the neck and the throat.

If nothing changed with your comparator, I'd suggest looking at the chamber with a bore scope.

[Texas Solo]

OK, now I see the + .013" from "trim length" and Wylde. I'm convinced that I have a build up in that area, as it's exactly where I feel the tight spot....just before the bullet will reach the lands.

So, how does someone get it out?

[BillPa]

OK, now I see the + .013" from "trim length" and Wylde. I'm convinced that I have a build up in that area, as it's exactly where I feel the tight spot....just before the bullet will reach the lands.

So, how does someone get it out?

FYI, a cast I made of a 25-06 chamber and a dummy round with the bullet seated on the lands.
http://oi59.tinypic.com/2vmzxnq.jpg

The resistance you're experiencing is or may the result of carbon and or other assorted crud (burnt oil,powder-primer residue) building up in the freebore, the area between the end of the case portion of the chamber to the start of the lands. What is loosely refereed to the 'gap space" is the distance from the end of the neck portion of the chamber to the start of the of the freebore.

How to remove it? A few pages on the hows of subject.
http://forum.accurateshooter.com/threads/how-to-remove-carbon-from-chamber-throat-area.3777450/

Prevention is always best cure. When cleaning a barrel the chamber should included as part of your barrel cleaning regiment, not occasionally or when its convenient but each and every time. After the bore I run a patch on a brush with GM T.E.C. (old formula) in the chamber and an inch or so into the bore, allow it to work for a minute or so then patch it out. If I see anything on the patch I'll repeat the process until the patch comes out clean. There are other carbon eaters, Seafoam, Mercury QuickSilver but there are others which work just a well.

Oh, and as far as the case length dohickies are concerned I've been making and using a form of them for years....
http://oi66.tinypic.com/2yzlg8z.jpg

In addition to finding the case overall length they're also a good tool to detect carbon-crud buildup in the 'gap space" If that length was X and now its something less than X its long over due for a good cleaning.

Bill

[Texas Solo]

Ding Ding Ding....I think we have a winner!
Very well explained Bill, and right on point with the issue I think I have.
I do clean the chamber each time I clean the barrel, but with no more the the Wipe Out I use on the bore.
Also, my use of the Sinclair bore guide is probably hindering my actually getting to the problem area.
So it looks like I have some work to do, that's OK, I learned something.
Shooting tomorrow AM, then I'll do the usual cleaning and try some Seafoam on it after the bore cleaning.
How long to leave the Seafoam soak? Any danger of leaving it too long?

Thanks much for the pics and links. They're spot on.

[BillPa]

Also, my use of the Sinclair bore guide is probably hindering my actually getting to the problem area.

How long to leave the Seafoam soak? Any danger of leaving it too long?

Thanks much for the pics and links. They're spot on.

Yes, bore(rod) guides for the most part cover all or a portion of the gap space. Initially I use a undersized brush w/ patch on a pistol rod so the neck portion of the neck portion doesn't squeegee the TEC off, let it soak for maybe 5-10 minutes then patch it out. If I see something on the patch then I'll soak it again until the patch(s) come out clean. The Seafoam is only a recommendation from others, I haven't used or tried it. When GM changed the TEC formula I bought all eight cans of the old stuff the dealer had in stock!:p

I don't think Seafoam or TEC will hurt steel or aluminum, it was designed to remove carbon from cylinder heads, exhaust valves , throttle bodies and... rifle barrels!:p

Bill