What are the advantages and disadvantages of each? I have a Marlin Guide gun that has significant tool marks at the start of my barrel. Which method should I use? I'm far from a gunsmith..is this something that I should leave to a more experienced person?

Any opinions would be appreciated,

Do a web search for a product called Final Finish.
I would stay away from the NECO fire-lapping process.

The best way is to just shoot it, that is better than any of the above methods, lapping is in simple terms "wear"...and I am sure the practice won't hurt you or anyone else.

"Tool marks" lapped out may damage the barrel to a great degree..Lapping is for minor burrs etc.

With the 45-70, a rough bore is not likely to hinder its shooting capability to any great degree..the big slow bullets are not as prone to sincitivity as the faster calibers.

I guess I'm saying if it ain't broke, don't fix it. Why create a non existant problem, unless your just bored.

The problem I'm having is bad leading with anything about 1600 fps or higher with hard cast lead bullets. Even Gas checked bullets. If I fire 3 bullets and then take a look up the bore you can tell that the leading is starting where the tool marks are. After 5 or 6 shots with a 1800 fps bullet the accuracy is so bad I can't hit paper.

[ 08-06-2002, 19:48: Message edited by: KY23 ]

I think Ray's advice is best. Shoot a 100 jacketed rounds then see if leading is still as bad. Clean to bare steel every 5 or 10 rounds.

I do have a NECO lapping kit, and have used it on occasion on some very rough factory rifle and pistol barrels. The NECO process is a pain, and I won't use the brass again because the grit will likely be embedded in the case neck.

You could try to give the rough part a good polishing with a tight patch and some JB, but I would still shoot it a bunch with some jacketed bullets.

Good luck.

Steve

[ 08-09-2002, 18:01: Message edited by: Need Just 1 More Gun ]

Send it back to marlin and politely but firmly tell them that this is a manufacturing defect and you expect them to make it good.

I've had quite alot of experience with barrels that fouled badly. Let me say once again that the FINAL FINISH is just that the Final Finish of your spending money on a losing proposition. Believe me, there is nothing that you can do to fix such a barrel. Don't spend another dollar or minute on it. Send it back to Marlin and tell them they sent you a defective barrel and you want a new one. All these Lapping methods do is wear out the throat of your barrel. I have a borescope and I can even take pictures of the wear induced. Fire lapping and Final Finish are just marketing gimmics for people who just don't want to face the facts. I will probably get ten E-mails from peple who swear this works, but I every time this subject comes up, I find that none of them have ever looked down a borescope ( it's scary even with a good barrel). Most Marlins shoot great with cast bullets and don't foul perceptively until you exceed 2000fps. I hope this helps.-Rob