choke in revolver barrel

[5of7]

I have a Smith model 67 that has choke in the barrel just muzzle-ward of the forcing cone. Have any of you guys ever lapped the choke in a revolver barrel?

I am interested in how long it takes and can a lay-person do the job? Or do I need the services of a gun smith? Please.... 8)

 

[GP100man]

DougGuy is thee man to talk to . But he may have to have the 67 inhand to answer your question.

Taylor throating or firelapping is bout your only options short of a new barrel.

Have you measured the amount of choke?? or just feel it during cleaning/slugging the bore??

GP

 

[5of7]

Just slugging the bore. The slug went in easy until it reached the part of the barrel that is screwed into the frame. I don't think it is much, perhaps just a few tenths of a thousandths but enough to make shooting cast bullets problematic. 8)

 

[Jimbo357mag]

I found this video on barrel lapping very interesting. Seems to me this technique would be good to use on a thread choked barrel.

https://www.youtube.com/watch?v=ml-9oLLKYsM

 

[rkrcpa]

Here is a link that may answer some of your questions.

http://www.gunblast.com/FerminGarza-Firelapping.htm

 

[GP100man]

That is an excellent write up on firelappin a barrel & I agree with the pins slippin thru the whole barrel length, but the draw back is the cost of the pins !

I`d fire a few /clean/fire a few more until groups titened, then change over to regular loads & fire a few of those & go from there.

 

[5of7]

My brother in co-owner of a tool and die shop and has a complete set of pins. I am sure that I can use his. 8)

 

[jgt]

The guy on you tube is showing you a good way to ruin a barrel. He didn't even have guides on the rod to center it except that lame washer that could scratch the heck out of the bore. The fire lapping method described by Fermin Garza is a much better solution.
I have hand lapped a revolver barrel that had thread choke, but only enough to get the guide on the end of my cutter to go down the barrel. Then, I Taylor throated it using three rod guides to center the rod in the bore while pulling the cutter into the barrel from the breach end. Brownell's sells the proper tools (rod, rod handle, bore guides) The Taylor throating reamer came from Clymer's. Pin gauges and a micrometer are also essential tools. As is lapping compound of proper grit abrasiveness. If you are going to take the trouble to fix what is not right with a barrel you might as well do it with proper tools and technique. Otherwise why bother?

 

[medicdave]

Just for curiosities sake how's the gun shoot now? Had a few guns with such naggling glitches, but they shot so well as is I wasn't going to fix what wasn't broken. If it's not shooting well I would have at it.

 

[5of7]

Just for curiosities sake how's the gun shoot now?

Not so good. 8)

 

[DougGuy]

I do not have a Taylor throat reamer for .35 caliber barrels. If the restriction is not too severe, firelapping will mostly remove it. This may be the best choice you have under the circumstances. Be thankful it is blued steel and not stainless as the lapping procedure can be as much as 6x slower on stainless barrels.

One customer sent his NM Blackhawk .45 to be Taylor throated as he felt it was thread choked. When I received the gun I did his cylinder work but upon closely inspecting the barrel, I found a .4425" pin gage slid smoothly into the barrel and came out the forcing cone with no restriction. The "choke" he had been feeling was simply lead building up in the barrel caused by the undersized cylinder throats. I did recut the forcing cone to 11° and after removing the lead it was determined that he had a pristine bore, and what should now be a very good shooting revolver.