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When I use my OAL gauge I push the plunger in until I feel the bullet hit something. If I push not that much harder it sort of pops ( for lack of a better description ) and goes in a little farther to were it won't go any farther. Is that normal or do I have a problem.
I experienced that as well on a 260 criterion once. I would mark the case and try several bullets keeping the index mark at 12:00. It always drug in the same place. so I figured the chamber was not concentric. What I should have done was rotate the tool 180* and compared the orientation of the mark to determine if it was the tool or the chamber. Also check neck RO on the modified case. Unless you have tools to check it you will never know. Hoping others had this issue and found something, I think I gave up to soon.
Could be a couple of things. The bullet isn't square with the Lands when you first touch and a little more pressure squares it up. With that second push you are jamming the bullet into the lands. Hard to say without being there.Quote:
Originally Posted by troutdiver
After I set the bullet past the little catch to were I would have to use a lot of force to go in any farther, I take a wood dowel and push the bullet back and forth with the dowel and plunger on the OAL gauge. When I do that I can feel a little catch before it stops and can't go any farther. It leaves a mark about .11 inches long all the way around the bullet. If I go were the bullet stops after that little catch and back it off .3" and seat the bullet based on that it is close to the recommended COL in the reloading manual.
That would be the throat. Is this a new gun? If not you could have a little carbon buildup. When you clean with a bore guide you skip this area. A chamber brush and a good carbon getter will clean it up.Quote:
Originally Posted by troutdiver
Of.course this is the area of the barrel that gets the.blow torch effect every firing. You can expect it to be a.little rough.
New to me last year, finally had one of those right place right time moments. It was only fired 10-12 rounds, the owner figured he really wanted a 338Lapua and not a 308. Its a Savage BA 10 308, I'm guessing 400-450 rounds at this point, did not start using the OAL gauge only in the last 200-250 rounds. Is there a way to clean that part of the barrel other than when I run the brush down the barrel?
A chamber brush and a good carbon cutter. Do a little search about.cleaning carbon from rifle throat. Too many products and opinions out there. I will let you pick.Quote:
Originally Posted by troutdiver
What I do is clean with bore tech eliminator and periodically clean the chamber well with chamber brush and mop. Doing.this I have not had any problems.
I use a chamber plug and soak the barrel overnight (Savage factory barrels mostly). This usually loosens up the carbon enough to clean out with a nylon brush and patches.
The bullet should hit the lands square when checking your OAL. The only time I had the issue your having, I found a problem with the throat area at the lands.
Dennis
I've been fighting the exact same thing in my 223 Wylde chamber, Shilen barrel. My CBTO readings became noticeably shorter, which seems backward from a growth due to throat erosion.
Exactly as you describe...bullet seems to stop, then with additional pressure, it "pop's" to the lands.
I discovered it when I took the occasional reading as always and it came up way short from the original data.
It started happening at the 1000 round mark. It's definitely a carbon ring build up in my case. This is how I know:
Using a Sinclair tool, I measured my chamber to 1.790 when it was new. My brass is 1.760 (never been trimmed) That leaves a .030 gap for carbon to build up in.
I also have a Wylde chamber, which doesn't help matters.
Research has shown MANY complaints about this issue when using Varget. It gets carbon rings that are as hard as a diamond.
I've tried soaking it in Kroil, brushing, and even Isso paste.
Had I known all this when my barrel was new, I would have done a better job at cleaning the chamber. Using a bore guide, I guess I was totally ignoring this area.
Below are magnified bore scope photos of a brand new Savage button rifled barrel. You may be pushing the bullets through a "speed bump" when when the bullets "pops".
Below the throat.
http://i122.photobucket.com/albums/o...ps60cef129.jpg
And below two inches from the muzzle.
http://i122.photobucket.com/albums/o...ps507846d8.jpg
And below a custom made hand lapped barrel for comparison.
http://i122.photobucket.com/albums/o...ps1da8a9ed.jpg
And this is why I clean my barrels with foam bore cleaner and cotton patches and seldom use a copper bore brush that get eaten by the speed bumps.