Lapped with JB test

[ntsqd]

I must admit to chuckling a little at the comments about JB not being a lapping compound. I guess all of those mechanisms that I've smoothed with it weren't lapped?

Maybe it is not a barrel lapping compound, but it is a fine abrasive. From experience with it and various Clover compounds I'll guess in the 1200 to 1500 grit range. So about equal to most toothpastes.

 

[bdyal1972]

The barrel makers will luv you. Suggest you use 60 grit compound and fire lap to speed it up even more.

A 210 gr @ 28-900 is normal to fast for a 24" 300 WM.

What do you need a 210 gr for ?

David Stubbs FIRE LAPPING SYSTEM HAS NEVER FAILED US!!!

 

[bdyal1972]

I must admit to chuckling a little at the comments about JB not being a lapping compound. I guess all of those mechanisms that I've smoothed with it weren't lapped?

Maybe it is not a barrel lapping compound, but it is a fine abrasive. From experience with it and various Clover compounds I'll guess in the 1200 to 1500 grit range. So about equal to most toothpastes.

Job works for me fore fine LAPPING polishing!!!

 

[FilippoMo]

Lapping will not increase velocity at all,if done properly it will increase accuracy , if not done by the barrel maker, you should consider fire lapping :NECO sells lapping kit and David Tubbs also offer kit.
Speed however is the wrong reason
Filippo

 

[MLN1963]

Two different animals. The red is a fine polish. The blue cleaning compound wouldn't do much in the way of lapping IMO.

 

[DJ Fergus]

David Stubbs FIRE LAPPING SYSTEM HAS NEVER FAILED US!!!

You have saw good results from firelapping? I'm just curious. I have never tried it. I usually just rebarrel and will probably stick with doing that.

 

[FilippoMo]

I received one of the first kit from Merril Martin of Precision Shooting magazine (No longer available) as a tester before marketing from NECO.I did use it according to instructions with cast bullets and I did notice an increase in accuracy in my Remington 700 308 W.
I would not use it on a custom barrel though (it voids warranty)
Filippo

 

[Alex Wheeler]

Lapping has to be coarse enough to actually cut. Otherwise you end up with a polished surface that's still irregular.

 

[MLN1963]

True, but I don't recall JB compound being a metal cutting compound like used for lapping a barrel? Is it?

 

[ntsqd]

An undulating polished surface still had some material removed. It may have been from abrasive polishing and it may have been from a process like Electro-Polishing.

The older black label JB (my only tub of it) slowly turns from light brown/tan to black when used on steel and I'm pretty sure that it is not induced by heat. So what does cause the color change if it is not microscopic pieces of steel emulsified in the paste?

 

[Huntz]

What are you expecting to get?Don`t get so worried about FPS ,rather worry about accuracy.If you get good accuracy you can dope out your ranges and an extra 100FPS will not mean much.As far as lapping,you only need to do that if your throat is scaling.Bore scope a Savage barrel once and you will wonder how they shoot so well with all the machining marks in them.

 

[JAYgs8163]

Some have asked I'd anyone has had good results with Tubbs Final Finish. I can attest to the 2 times I've used it both were factory Savage rifles that would foul terribly. One a 6.5-284 and one a 7 Mag. The 6.5 I did the entire process as instructed, and the 7 mag I did half of the recommended amount on the more abrasive and then the full set on the last 2 strings. Both resulted in much better cleanablity, more velocity but not dramatic, and slightly improved accuracy. The most improved by far was the lack of fouling. I could shoot longer and cleaning became a much less time consuming process. The 6.5-284 saw the most improvement. Just my experience for what it's worth.

 

[6.5-300 BEE]

I have fire lapped several that had issues. A 700 300 WM that was frosted in last 6", a 308 98 from Israel with bad pitting and a 30-40 Krag with moderate pitting. The 700 came out great and shot moa with minimal fouling. The 308 was so bad that when done we used .311 bullets and it shot 2 moa with irons. The Krag got better, shot no better but fouled less.

From another angle, have an 1899 96 in 6.5x55 that I bought in a pawn shop. Cleaned it w/Hoppes and shot it with 160 Hornady RNSPs. After scoping it, it was a MOA rifle. Then I read all the propaganda and cleaned it down to bare metal and bought a borescope. Lotsa pitting and 3 moa groups After 80 rounds groups went back to 1 moa. It will never be "deep cleaned" again.

 

[Alex Wheeler]

Throats are critical. JB and other abrasives have to be used correctly. When the throat looses its sharpness accuracy goes away. This is why guys set back barrels, it restores accuracy. The reason is the sharpness is returned. JB and other abrasives do remove small amounts of steel, you would be there all day to measure it though. They are useful but you have to use them correctly, or they will shorten the barrels accuracy life.