Fire lapping -Help needed.

[buck1]

OK, no lube, no check,softer lead,and unsized brass to be thrown away after use.
5 shot strings ,followed by cleaning and measuring between strings of grit.
And dead slow speed , to keep from damaging the throat. ...Buck

[TCLouis]

First gun I ever participated on was a Ruger 77 SS 338 Mag with a rough spot in the barrel about 3" long.

The owner and I used Unique but . . . BUT FAR LESS than you mentioned and since neither of us had any fine Clover grits (at the time) he used Turtle brand rubbing compound.

We fired a total of 41 shots using rubbing compound in place of the lube on the Lee 220 grain 338 bullet sans GCs (GC grrove also received som compound.
41 is a very magic number and was derived using high level mathmatical equations and some kinda calculus derivatives.

Lets see if I can remember how we derived the number of 41 being the "perfect" solution.

Him: "How many bullets do you have cast in 338?"
Me: "I don't know."
Him: "Grab all you have and meet me at the range with your Lee Powder Dipper set."
Me: "OK."

We arrive at range:

Him: "Look at Unique values on the dipper set for fairly low amount."

Me: Dipper #?? is supposed to be about 7 grains."

Him: "Perfect, load a round using this rubbing compound in the lube grooves."

We loaded a couple of peices of brass until 41 rounds later . . .

Me: "We're outa bullets"
Him: Perfect, look at how shiny that bore is now."

Him: "Wow, the last 10 rounds went into less than an inch and a half at 50 yards."

And never again did that bore suffer a visible patch of jacket material again.

Used the same method on the rough spot in my Super Redhawks barrel.
It took care of the rough patch in the barrel also. I did not use any scientific method on this gun, I just shot til the rough spot smoothed out.

Folks would refer to me as, "Stretcher of the Truth" if I told you what the best 50 yard group was using Lee C429-310 last winter (like others, that is the group I will refer to if ever asked about the gun/load/bullet combination).

Suffice it to say that the worst group it has produced was about 3" at 50 with that bullet and powder (SLOW lot of WC 820).

[waksupi]

A Douglas was the last barrel I lapped for cast bullets. using the LBT, i shot maybe ten shots, cleaning every other one. then cleaned the barrel well. I then put a tight patch on the jag, and pushed it through the bore. It squeaked until about the last eight inches. Fired four more rounds, and cleaned a gain. Ran the tight patch up, and ti squeaked until within a couple inches of the muzzle. Four more did it, it squeaked all the way to the end, and shot well there after.

[Bent Ramrod]

I've never tried JB, but have tried Corbin Bench Rest Bore Lap and found it to be extremely slow in action, almost ineffective in practice. I would think JB would be an even milder abrasive than the Corbin stuff.

I've done my most effective fire lapping with soft (.22 lead) bullets rolled with Clover #320. I may fire as many as 40 shots in a session, cleaning with brush and patch at least every five shots--after as few as every shot if any trace of leading comes out. Any lead deposits will protect precisely those spots in the barrel that are roughest and need the polishing the most, from the further action of the fire lapping, so out with the leading forsooth! The loads are not hot, but not whisper loads either, generally a charge that has done well at +/-1200ft/sec with the cast bullet in question.

After 10, 20, 30 and 40 shots, I fire a string with either the cast loading that did the best before or the ditto jacketed load and look for improvements. If the lapping seemed to help, I may do as many as 20 more fire lap shots, cleaning and testing the same as above. In extreme cases, I'll do another ten, but generally I figure at this point that the continuous shooting of regular loads will further smooth out whatever remains of any problem areas.

I use unsized shells that I prime and load by hand, and discard after the lapping is done. The action gets hosed out with WD-40 before firing any good brass test loads in it. That abrasive stuff does loading dies, chambers and firing mechanisms absolutely no good at all, and it can get pressed into good brass by the action of firing if it isn't completely gone.

I've significantly improved three or four rifles by this regimen and have never made one worse.