Treating Inside of Barrel

I completed the next step in my work to clean up and seal the bore of my rifle. I shot the 50-bullet series in the Tubb's Final Finish kit, cleaning the rifle in the field using Bore Tech Eliminator after each grit classification as per Tubb's instructions. After getting home, I did a final clean using Bore Tech CU+2. For the cleanings in the field and at home, I still seemed to get a fair amount of copper out. I'm not sure if the Tubb's bullets themselves deposited some copper or if the scrubbing action of the abrasive bullets released some copper that had been embedded in the bore. Looking at the bore with my borescope, it appears that the Tubb's Final Finish did clean up some marks in the bore. The attached file shows before Tubb's (BT) and after Tubb's (AT) pictures at the same points in the bore. I used tape on the borescope flex probe to mark the location of the before pictures so I could get to the same point in the barrel for the after pictures, although it's difficult to assure I reached the exact same spot. However, in places I had seen some transverse marks in the rifling before firing the Tubb's bullets, I could find no such transverse marks afterwards. The Tubb's bullets did not remove much of the pitting (and I didn't expect then to), it appears that some of the pitting now looks a little more subdued and a little less pronounced. My next step will be to acquire and apply the JTI Bore Shield I noted in post #18 of this thread to seal up some of the micro pits of the barrel.

Nature Boy said:

That made a noticeable difference. Now the $64 question remains: does it show up down range

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I don't know yet. My time at the range was solely to run the Tubb's bullets through so I could see how things changed inside using my borescope.

gotboostvr said:

Hows the actual muzzle look? Sometimes even a little damage there can make groups awful. The bore itself might not be the issue.

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The muzzle looks good. That was the first thing I checked. I re-lapped the crown just to make sure, but after getting a borescope and looking inside, I found extensive copper fouling and a lot of pits and other marks in the metal.

earplug said:

What does your crown and last couple of inches of barrel look like? As this rifle has to be cleaned from the muzzle it may be damaged by years of trying to remove the copper and pits your messing with.

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Actually, about the last 3" of the barrel has the cleanest rifling and almost no pitting. I have not observed any noticeable wear of the rifling in this area of the barrel from being cleaned from the muzzle.

Prior to running the Tubb's Final Finish bullets through my rifle, I had established the length at which the bullet would just touch the lands in my rifle. For my measurements I used the Hornady Bullet Comparator, which measures off of the ogive of the bullet, using Speer 150 gr. flat nose bullets. I measured 5 dummy rounds and used the minimum length of the 5 rounds. I repeated this process after running the 50-round series of Tubb's Final Finish bullets and observed that the bullet now touches the lands at a length that is 0.0225" longer than before. This makes sense since the Tubb's bullets would have 'ground down' the leading edge of the rifling at the throat. The before and after pictures of the throat taken with my borescope seem to show a more gradual slope in the leading edge of the rifling after firing the Tubb's bullets.

After starting this post a month and a half ago, here are the final results from all my efforts. After determining I could not get 100 yd. 5-shot groups of less than 5-6 inches with very random pattern, even with the rifle fired from a machine rifle rest, I spent efforts doing the following:

• Did a thorough and extensive copper fouling removal (and there was a lot)
• Fired the 50-shot series of the Tubb Final Finish bore lapping bullets
• Re-crowned the barrel
• Coated the barrel with the JTI-Bore Shield product I noted in post #18 of this thread

At the range I fired three 5-shot groups at 25 yards and one 5-shot group at 100 yards, all from sand bag rests using a red dot sight. One of the 25 yard groups was just off target (I had a larger backer paper so I could see the shots) since all the work I had done had apparently shifted the the bullet impact point about 5 inches higher from the previous zero of my red dot. My 94 Winchester will never be bench rest quality rifle, but I think all my work paid off.