07-07-2013, 09:27 PM
Shivesy, You may want to give this a try!
From Stokesrj,
The Carbon deposited in the throat is baked on at higher temperatures so as the barrel is cleaned, the solvents soften and remove the carbon from the bore at a faster rate than they do at the throat. The result is a slow build up of hard carbon, easily visible with a bore scope but very difficult to detect without one. This ring adds resistance to the bullet at the critical time of initial acceleration. This can result in rapid increase in pressure, a spike. It can also result in bullets vaporizing before reaching the target. I've seen it more often at 600 yards but have also seen it at 300. I had it happen to me at 300 yards during my rapid prone string at the Nationals one year resulting in a 9 yes, which means they were all in the nine and ten ring but one of the ten didn't make it there. My scorer said he saw a blue puff before the bullet got to the target.
I took my upper in to vendors row where they have a lot of Hawkeye bore scopes and had them take a look. Sure enough a carbon ring had formed at my throat. This was on a Krieger barrel with about 3,900 rounds on it. I JB'd it and inspected again, no carbon ring and none since. I now JB the throat every 200-400 rounds to keep it in top condition.
Here is how Frank White of Compass Lake Engineering says to use JB to maintain the throat.
1. Work the JB into the patch.
2. Wrap the patch around a worn bronze bore brush (not nylon).
3. Using a bore guide, stroke back and forth for 5 strokes in the first half of the barrel. (Breech Half) Push patch through the muzzle and unscrew brush from rod and carefully remove rod from barrel.
4. Remove old patch from brush.
5. Repeat steps 1 - 5 for 5 complete cycles.
Note: A neglected barrel may require this to be repeated up for many more cycles until it is smooth.
Note: The patch will never come out clean as JB is a slightly abrasive compound and is working to polish your throat and bore.
This cured my tight throat issues.
From Stokesrj,
The Carbon deposited in the throat is baked on at higher temperatures so as the barrel is cleaned, the solvents soften and remove the carbon from the bore at a faster rate than they do at the throat. The result is a slow build up of hard carbon, easily visible with a bore scope but very difficult to detect without one. This ring adds resistance to the bullet at the critical time of initial acceleration. This can result in rapid increase in pressure, a spike. It can also result in bullets vaporizing before reaching the target. I've seen it more often at 600 yards but have also seen it at 300. I had it happen to me at 300 yards during my rapid prone string at the Nationals one year resulting in a 9 yes, which means they were all in the nine and ten ring but one of the ten didn't make it there. My scorer said he saw a blue puff before the bullet got to the target.
I took my upper in to vendors row where they have a lot of Hawkeye bore scopes and had them take a look. Sure enough a carbon ring had formed at my throat. This was on a Krieger barrel with about 3,900 rounds on it. I JB'd it and inspected again, no carbon ring and none since. I now JB the throat every 200-400 rounds to keep it in top condition.
Here is how Frank White of Compass Lake Engineering says to use JB to maintain the throat.
1. Work the JB into the patch.
2. Wrap the patch around a worn bronze bore brush (not nylon).
3. Using a bore guide, stroke back and forth for 5 strokes in the first half of the barrel. (Breech Half) Push patch through the muzzle and unscrew brush from rod and carefully remove rod from barrel.
4. Remove old patch from brush.
5. Repeat steps 1 - 5 for 5 complete cycles.
Note: A neglected barrel may require this to be repeated up for many more cycles until it is smooth.
Note: The patch will never come out clean as JB is a slightly abrasive compound and is working to polish your throat and bore.
This cured my tight throat issues.