What is the groups opinion on lapping a "finished" barrel. By "finished" I mean a barrel that is ready to be installed on the rifle, but was never hand lapped.

If it is a good idea, any suggestions on techniques for a person with a small machine shop?

Regards,
Kory

According to most barrel makers, you cannot correctly lap a barrel on the gun. Most of them, lap the barrel blank and then cut off each end.



I have, however, used JB bore paste and at times, Flitz to polish a stubborn barrel with good results. I would try that first.

YOU CAN USE TUBB'S FIRE LAPPING KIT CALLED FINAL FINISH BORE CONDITIONING SYSTEM IT IS SOLD BY CABELA'S MY GUNSMITH HAS USED IT AND SO HAVE I IT HASN'T HURT THE ACCURACY AT ALL AND HAS HELPED IN MOST OF THE TIME. HAVE A GOOD DAY WELLS

Firelapping is indeed an option, but if you have not done it before, be a bit careful. In some cases, it can smooth out rough barrels quite nicely. It can, however, also move the throat of the barrel forward a good deal. Whether that is a problem or not depends on how much freebore your rifle currently has. I've also seen velocities drop some in firelapped barrels, probably because things loosened up a bit. Again, this may or may not be a problem to you...
- mike

I would recommend JB Bore Paste before fire lapping.

I use a patch jag w/ a good bit of JB on a patch. You need to change patches about every 25-50 Round trips down the barrel.

It may only take 50 round trips but, it could take several hundred if the barrel is rough.

I would shoot the rifle before lapping a whole lot. You may want to lap alittle before the barrel is installed but, I wouldn't lap any more until fouling was a problem and accuracy was suffering.

Good Luck!

Reloader

You get what you pay for. If you have a barrel that did not come lapped, you didn't buy a quality barrel. I know, some feel that Douglas is great, and they can be, if they lap them. Otherwise you're gonna have a time with fouling.

As another poster said, they should be lapped before chambering. Actually, they should be lapped after contouring, fluting, threading for a break, etc. This way, when they lap it, it is true all the way thru. Anytime metal is removed from the OD, it can change the ID dimension.

If it hasn't been chambered yet, send it back for lapping. It's not a big thing to do, but you have to KNOW what you're doing.

I'm a machinst and have done a lot of lapping, but none of them rifle barrels. As an experiment, I was thinking of buying a $135 Green Mountain barrel for a 10/22, check the group size, hand lap it and then check the group size again. I am going this really as fun experiment. Otherwise, I would just buy a $315 Lilja barrel and call it a day. I'm interested in reducings the group sizes rather than reducing fouling.

Regarding fire lapping: all of the information I've seen points to hit or miss results. I've actually seen things get worse after fire lapping.

Regards,
Kory