Bangbangman wrote:What abrasive do you use and do you need to "go through the grits" from coarse to fine?
I use Clover brand silicon carbide grease, purchased from a machining supplier. I happen to have 150 grit (very coarse), 280 grit, and 500 grit. I don't know if Clover is available in the UK but you should be able to find something equivalent.
Auto parts stores sell valve grinding compound, but often it is coarse, 150 grit or so.
You may be able to find lapping grit on ebay, too. Sometimes it is sold in powder form, and I suppose you could use the powder to make your own grease, just mix the powder with oil.
The 150 is very coarse and I've only used it on very rough barrels. Normally I start with the 280 and then follow with 500, which leaves a mirror finish.
If you only buy one grit, I would suggest 280-ish.
Several shooting outfits sell lapping kits with several different grades of grit, but they're $40 or so.
How do I know how many shots to fire?
When there are no more tight spots in the barrel ?
I'm instinctively afraid of "grinding-out my throat and rifling!"
I don't blame you. I am not a big fan of lapping myself because it can make long throats longer and big throats bigger. However, since you are starting out with a nearly throatless barrel, that would actually be an improvement.
Is there any reason I can't get on with ordering a mold as already discussed?
No reason, since I don't recommend making the bullet a "glove" fit in the throat, anyway.
