Chuckster wrote on Jun 3^rd, 2022 at 10:49pm:


Back when NECO introduced to fire lapping kits  I bought one. Mr. Martin recommended the finest grit for breaking in the throat of a cast bullet gun.he  told me to use short for caliber  jacketed bullets so it wouldn't wash out the throat as soft cast tended to bump up and enlarge things. I tried it and it "seemed" to work but I can't say it was a scientific experiment.

rafter3c wrote on Jun 4^th, 2022 at 9:57am:


I don't have anything to add to this other than to say I asked the same question on another forum years ago and some Wise Donkey (think of the more common name we use for such animals) posted a video of a couple yahoos tossing a rifle accross a field of cobbles.  He thought it was funny.  I thought it was a fairly unimmaginative stab at humor.  Anyway, since then the reponses I have received to this question all seem to say go out and shoot the rifle and let everything else take care of itself.

JLouis wrote on Jun 4^th, 2022 at 9:21am:


IIRC  the NECO fine grit was 1200 grit and very high quality.Not Clover valve grinding compound grit😀

Like you though I do nothing special to a new barrel but shoot it.

Some thoughts: First, confirm the barrel is button rifled.  Hammer forged barrels have little of no burrs or sharp edges and need no break in.  Second, my understanding is the primary purpose for break in is to smooth the sharp edges and burrs left by button rifling. It is only done with jacketed bullets, and includes a wire brush bore cleaning after a series of 5 shots - 7-10 times.  You should feel reduced resistance to the bore brush as bore imperfections are removed/smoothed.  Third - do not use lead bullets for break in - they are not hard enough to remove/smooth imperfections, and will lead quickly.  Just my thoughts and understanding from experience (mine and others).  Good luck!

My barrel break in is a little different than what has been put up here. 
First I never put a jacketed bullet down a bore meant for cast bullets NEVER.
My method is to clean the barrel and then put some of my bullet lube on a patch and run it down the bore and work it into the lands and grooves. Then fire 10 shots and clean it just enough until I see cooked lube on the patch. then fire 10 more and repeat for 50 shots. Then fire it like normal.
Cleaning is important again I clean it until my patch just shows lube and stop. I believe that cast bullet barrels have more in common with rimfire barrels than jacketed bullet barrels.
The only time i deviate from that is if I get leading. Then I lightly lap the barrel with a lead lap and some ultra fine diamond paste. then go back to my original routine.

40 Rod

How does one determine whether a bore needs breaking in or not?

Leading? One cause of leading is gas cutting. I had a barrel that was recut and it leaded at the last ten inches at the muzzle. I've had barrels that were installed backwards. Barrels with no detectable taper in the bore. I chambered a barrel once that had a ridge of metal in the throat when I got done. I have a Goodein barrel that still has roughness in it but shoots very well. All those defects I was able to correct but it was not through breaking in. My .32MS didn't shoot a tight group until fifty rounds had been fired through it. I don't know if it got broke in or I happened to run into the right conditions. I think some barrels will shoot more accurate after a careful lapping. 

I fire lapped two barrels, one it had no effect. The other was improved a great deal. 

Seasoning a barrel? My barrels get cleaned with Hoppes after every shooting session so I doubt any seasoning remains after cleaning.
Some barrels can be just plain mysterious. I have a Borchard with a perfect bore. I win BR matches with it at Hamilton but came in last place at Spokane.

Mysterious.