Anyone with experience firelapping a bore?

Josey1

I was interested in the technique involved in firelapping.I see where you can improve accuracy up to 40% but I'm not so sure as it was in a G&A article which we all know G&A is an advertisers dream.I read that you have to "Slug your bore" first? Then you fire sequences of higher to lower grit lapping rounds until you get to the 10 polishing rounds.My question is,where does the rifle sluggin come in?In my understanding you have to plug the barrel and pour molten lead into barrel and let cool thus making a "Slug of the rifles rifleing?What is this for?I've got my PSS shooting .85" groups at 100 yards after an extensive breaking in process.I cleaned after every round for 10 rounds then after every 5 for 50 rounds.I shot all groups off a sighting bench rifle vise and before cleaning groups were in the 1.5" MOA,while I am happy with the increase in accuracy I was told by a longtime benchrest shhoter that if I was to firelap the bore I could cut that .85" in half.What do you all think,is it worth it?Is this something a person who never fire lapped a bore should take on?Thanks for any/all responses,Josey.

boeboe

Josey, It's been a while since I slugged a bore, years in fact, but the means you described is not how I learned it. I might be wrong, but as I learned it, you start with a slightly oversized lead bullet and simply force the bullet through the barrel with a dowell. I use to slug .44 mag and .357 mag handguns back when I was reloading. I did this to most closely match the diameter of the reloaded bullets with the bore for peak accuracy. For example, on the .44 mag, I would generally start with a .431 to .432 dia bullet. After the bullet is forced through, I'd mike it, generally it would be .429 to .430 range. Then I'd select the bullet diameter to reload for that handgun. I didn't pour molten lead down the barrel, but perhaps others do and there might be a reason for it. But I think starting off with just a bit larger lead bullet would save some labor. As far as the fire lapping, I've heard some say it works, and others say it's a waste of time. I don't know because I've never done it. No doubt, the objective of slugging a bore prior to fire lapping is to determine the correct diameter bullet for that particular firearm, which in itself will help the accuracy.But maybe I'm all wet. I'll be interested to hear what other say.

Orphanedcowboy

If you plug the barrel then pour molten lead in it you have just plugged it, not slugged it, how would you remove it without heat?

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Orphanedcowboy@msn.com

dennisw

To slug a barrel wad up a small ball of paper (spit ball), place in end of barrel, pour a small dollup of lead in barell, equal to a slug; drive out with dowell.To plug a barrel pour in more lead, Not a recamended procedure

lugee00

Josey1, there are several methods to "slug" a barrel, the easiest is to drive an oiled slightly oversize soft lead cylinder through the barrel with a wood or brass rod so as not to damage the bore.The other is more involved, usually slugging a bore is done to determine the correct diameter cast bullet for the bore, normally this is .001 to .002 over nominal bore diameter. There are two schools of thought, first is to determine the maximum diameter of the bore then size to that. Second is that the throat area is the critical dimension as that is where the cast bullet is first mated to the rifeling. To slug the throat area use an empty case, cut a steel or brass dowell to fit inside the case to within about 1/8" or so of the case mouth. Insert the case in the chamber and close the action. Then use a slightly smaller than bore diameter soft lead cylinder about 1" long, drop it in the bore then use a brass rod and mallet to tap it untill it expands to tightly fill the bore. Usually the plug will eject with the case, it will give you the throat and bore groove dimension.You are correct on using lapping compound to "fire lap" a barrel. There are kits available to do this, Brownells have them. Often this will help a marginaly accurate barrel using jacketed bullets. It does help reduce leading using cast bullets. I've built several rifles for use with cast bullets that leaded with brand new barrels, after fire lapping the leading was nearly eliminated.

inplanotx

I would definately NOT pour molten lead down a barrel to slug the bore. Brownells sells a kit called CerroSafe that you can clog the bore and pour into it. It has a known coefficient of expansion and will not adhere to a barrel or chamber. If you've ever shot lead bullets and had a barrel lead up on you, you will find out how many hours it takes to clean the bore. Plain base lead bullets sometimes melt during their little trip down the barrel and deposit "molten" lead down the bore. It is a nightmare to get clean. Just use a bullet of the diameter you shoot, cut a wooden dowel that will fit down the barrel in two pieces, insert on piece in the chamber, insert bullet in other end and use the rest of the dowel to push it to the inserted dowel half. This will make it expand to the barrel and then you can measure it. Hope this helps.

chuck

I fire laped a 22-250 remington 700. I did not notice any change in accurcy or ease of cleaning

robsguns

I have firelapped a couple of my firearms, and they were new before I did so. I cant tell you about accuracy differences, cause I didnt care about that and didnt test them before. However, I can tell you that I have noticed that those guns are extremely easy to clean,and have less copper fouling present. I shoot Barnes bullets only, and this is a very big benefit for me. Also, the 338 Win Mag is a less than a MOA shooter, but it may have been anyway, who knows.

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SSgt Ryan E. Roberts, USMC

dheffley

Josey1,Before you firelap the bore, try this. Use JB Bore Cleaner. It is actually a fine lapping compound. Clean the bore and run it through on a patch per instructions. If you see metal fines on the patch, you need to continue doing it until the patch has no metal fines at all on it. It is as good, and less abrasive. I swear by it, and it will greatly improve the accuracy of a new barrel by removing the broaching burrs.

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edharold

I don't know what purpose slugging the barrel would serve. I fire lap the barrel of new rifles as a part of the breakin procedure. I'm not sure either one of them really does any good.