Thread: bore, polishing?

Speaking of lapping. I have a new MAB barrel and I heard they aren't lapped. Does anyone know if this is true? If so how should I lap it? Autosol and tight jag like Spanners has suggested?

Originally Posted by Normie

Speaking of lapping. I have a new MAB barrel and I heard they aren't lapped. Does anyone know if this is true? If so how should I lap it? Autosol and tight jag like Spanners has suggested?

I would shoot it first. If it shoots and doesnt copper up then it will be sweet. A barrel does not have to be lapped to perform. Otherwise give the jag and rag a go.

Thanks will do.

I have had 2-3 MAB barrels and they all shot really well. Still got one on a remmy .308. I never lapped any of them.

That's good to know. Thanks

Probably not lapping as such but I got a new 303 barrel and i could see the burr at the start of the lands from chamber reaming.
It was very tight on a patch at that spot and you could see where it was tearing the patch.
Half an hour with JBs on a tight patch short stroking the first few inches smoothed it right up.
Haven't got around to fitting the barrel yet cant make up my mind which one to put it on.

JB's every 200 odd rounds gets rid of carbon build up. I've got to clean mine after 20+ rounds otherwise accuracy = rubbish. That is with a 22-250 doing around 3600fps

I have a marine industrial product I'm going to try for carbon removal. By all accounts it whips it off cylinder heads and injector nozzles pretty good without damaging metals.

That sounds interesting spanners, crc carb cleaner was great for that also.

Originally Posted by 7mmsaum

That sounds interesting spanners, crc carb cleaner was great for that also.

This stuff makes carb cleaner look like water
Need to do some testing on barrel off cuts long term to see if it does any damage

There is 'something' in brake clean and carb clean which can fuck some finishes on guns - i know of a pistol that it started to remove what is normally a hard coating.
Little bit wary of it myself

It contains carbon tetrachloride that is very agressive, I finished my heavy trade diesel apprenticeship in 1987 and can still remember the msd sheets info on it. Then went on to get qualified in petrol as well and they hardly used the stuff.