Tubbs Final Finish

[jsthntn247]

The throat in my 243 tactical rifle erodes much more quickly than I'm used to. Considering shooting 2 or 3 of these bullets through it every 300 rounds to keep the throat smooth and possibly prolong the life of the barrel. Anybody on here use them in your target rifles?

 

[Toolbreaker]

I used one of the Tubb kits several years ago on a factory barrel that fouled badly. It'll definitely smooth the barrel out, but the abrasive will also push the throat out with it. If I remember right, it pushed the throat forward around .035". Something to keep in mind if you're limited on your COAL from a mag-fed rifle & can't chase the lands.

 

[CatShooter]

The throat in my 243 tactical rifle erodes much more quickly than I'm used to. Considering shooting 2 or 3 of these bullets through it every 300 rounds to keep the throat smooth and possibly prolong the life of the barrel. Anybody on here use them in your target rifles?

If you are not happy with your throat moving forward, then these bullets will make you cry...

Throats don't move forward because they are not smooth... they move because the steel is being burned away every time you pull the trigger... adding abrasive bullets will just remove more steel, and move the throat further forward.

 

[jsthntn247]

The throat in my 243 tactical rifle erodes much more quickly than I'm used to. Considering shooting 2 or 3 of these bullets through it every 300 rounds to keep the throat smooth and possibly prolong the life of the barrel. Anybody on here use them in your target rifles?

If you are not happy with your throat moving forward, then these bullets will make you cry...

Throats don't move forward because they are not smooth... they move because the steel is being burned away every time you pull the trigger... adding abrasive bullets will just remove more steel, and move the throat further forward.

I was thinking a rough (pitted, jagged) throat would allow the burning powder and bullet more to "grab" onto under pressure and cause faster erosion. Must have read that a while back because I wouldn't be able to come up with that myself, lol. Seems in my two F/tr rifles I don't see much erosion until around 5-700 rounds and then they start to erode around .002 every match. This 243 started eroding right out of the gate at .004 per 100.

 

[Webster]

Measuring the erosion by determining the increase in OAL to touch with a particular bullet ignores the fact that the erosion continues many inches down the bore. The rough metal may not even touch the bullet? I cross sectioned a 6mm Rem barrel with about 7K rounds down the tube. 6" down the barrel you could only see a hint of rifling. I took scanning electron microscope pictures of the bore from the case mouth to about 6". I posted the pix about 2 years ago. Very nasty. There comes a time you have to scrap the barrel. No-one said it's an inexpensive sport. The 6mm Rem still shot groups about a little under 1". Still killed many GH.

 

[ARK]

I used one of the Tubb kits several years ago on a factory barrel that fouled badly. It'll definitely smooth the barrel out, but the abrasive will also push the throat out with it. If I remember right, it pushed the throat forward around .035". Something to keep in mind if you're limited on your COAL from a mag-fed rifle & can't chase the lands.

I had similar experience, but it helped to seat bullet longer, out of the dreaded doughnut!

 

[mikecr]

I use 10 FF for break-in, and a 5 TMS every few hundred rounds (dress up lands and restore lapping).
This little bit has not hurt anything.

For rough factory barrels, the full FF kit reduces copper fouling.

 

[urbanrifleman]

I shoot 1 TMS per 100 rounds.

 

[INTJ]

I would try Iosso on a rough throat first.

 

[Straightshooter1]

I use 10 FF for break-in, and a 5 TMS every few hundred rounds (dress up lands and restore lapping).
This little bit has not hurt anything.

For rough factory barrels, the full FF kit reduces copper fouling.

Ditto, for factory barrels. I find the kit works really well.

 

[fkimble@charter.net]

I'm old school. A quick touch-up with JB every 300ish round to keep the throat smoothed out. Frank White(Compass Lake/CLE) even mentions this with new barrel purchases(AR 223 competition barrels).
A 243 is considered a barrel burner!

Frank

 

[rijndael]

I'm old school. A quick touch-up with JB every 300ish round

Which JB? Bore Bright or Cleaning Compound?

 

[fkimble@charter.net]

The original, not sure it's actual name. And I am a XTC guy if that matters to anyone.

Frank

 

[mikecr]

Which JB? Bore Bright or Cleaning Compound?

What works great: J-B® NON-EMBEDDING BORE CLEANING COMPOUND
What ruins a bore: J-B® BORE BRIGHT

Their bore bright polish should be removed from a gun related market.
A friend with the best shooting barrel I ever seen, directly ruined it, with a mix up between the two.
He didn't know there were two different kinds of J-B.
A few years later I tried similar with Flitz polish, just for the learning, with identical disastrous result.
It causes extreme copper fouling.

The damage from use of polish was so bad that I could not recover normal lapping, even with Tubb fire lapping products. This surprised me, as Tubb FF works so well with copper fouling bores.
A bore too smooth is even worse than a bore too rough.

 

[BoydAllen]

What works great: J-B® NON-EMBEDDING BORE CLEANING COMPOUND
What ruins a bore: J-B® BORE BRIGHT

Their bore bright polish should be removed from a gun related market.
A friend with the best shooting barrel I ever seen, directly ruined it, with a mix up between the two.
He didn't know there were two different kinds of J-B.
A few years later I tried similar with Flitz polish, just for the learning, with identical disastrous result.
It causes extreme copper fouling.

The damage from use of polish was so bad that I could not recover normal lapping, even with Tubb fire lapping products. This surprised me, as Tubb FF works so well with copper fouling bores.
A bore too smooth is even worse than a bore too rough.

Not so much of a reply, but more as additional related information: Barrel manufacturers use coarse abrasive to put the final finish on their barrels because that is necessary to prevent unsolvable jacket fouling problems. The probable reason for the problems that mikecr reported is polishing that roughness away. That is one of the reasons that I only use fine abrasives on an as needed, just enough to get the job done basis. My current favorite is Thorroclean, with Thorroflush to remove it. Evidently it is hard enough to remove fouling, but soft enough to avoid over polishing, but I really have not used it enough to actually prove that, but it seems that others may have.

 

[Longtrain]

I’ve used TMS on a few barrels, I believe they worked to smooth out the throat, but they certainly extended it a bit also. Is that a problem? It depends on your load’s seating depth. If you’re not jumping bullets a country mile and need to be close to or in the lands you can run out of neck.

I just put a new Brux barrel on my Dasher and had a chance to fire a few rounds to check functionality and start the break-in process. When I cleaned it, I got the expected amount of copper from the rough throat and reamer marks.

Bore scoping after firing showed pretty sharp reamer marks in the throat. I decided to run a bit of JB on a patch over a nylon brush. After two rounds of JB, the reamer marks have lessened. Break-in isn’t done of course, I’ll have have to wait until Spring to comfortably sit at the range and enjoy the process.

I’ll just go the normal route for break-in and cleaning and save TMS for an aged barrel whose throat needs a little smoothing out.

Here’s two photos, first after firing and the other after two JB sessions.