Does fire lapping really cure thread choke?

I've fire lapped three single action handguns and my experiences were good. All three guns improved in accuracy, showed less leading and now clean up easier.

By using soft lead bullets at low velocities the embedded lapping compound will abrade only the tightest sections of the barrel. The remaining sections are affected only slightly and from my observation are only lightly polished. (Hence the easier cleaning.)

The forcing cone should not be affected if the cylinder is properly timed as the nose of the bullet should be in or just beyond the leade when the lapping compound, embedded into the bearing portions of the bullet, begin cutting.

I used the NECO product in which you roll the bullets between two hard steel plates over which the lapping compound was spread. The noses of the bullets never got any lapping compound on them. But I never actually checked the forcing cones -- I never thought to check them.

My two Ruger Vaqueros took considerable rounds to remove their frame chokes. Their barrels must be very, very hard. The Italian SAA clone I fire lapped took many fewer rounds to remove its frame choke.

It does take hours at the range to do it correctly with all of the cleaning between the firing sequences and the measuring of the frame choke as it gradually disappears. Not that being at the range all afternoon is a chore.

Everything else being equal, or practically so, Blued or Stainless does not matter. Unless the Firelap people told you different in their instructions.

Um.... what's thread choke? The inference is that it's something that occurs at the end of the forcing cone and beginning of the rifling. But I'd like to see that confirmed.

Um.... what's thread choke? The inference is that it's something that occurs at the end of the forcing cone and beginning of the rifling. But I'd like to see that confirmed.

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Yes. It is where the barrel is often choked down due to tightening in the frame where the threads are.

I have a single action that had a slight choke, and I tried the NECO kit. What a PITA!!!! Be prepared to remove a LOT OF LEADING from your UNLUBED bullets! And, it's not a 'remove the leading when you are done' bit, it is a 'remove the leading every few shots or the rest won't have any lapping effect on the barrel'! Lots and lots of cleaning in the loooong process.

And, what was my result? I was keeping track of the choke by measuring slugs after every stage of the firelapping and in the end was not able to detect any significant difference in measurement. And, I could still feel the bullets hit the choke each time I slugged the barrel. I wouldn't count on firelapping to remove a barrel choke, even a slight one, but other adventurous folks seem to report great results, so I don't know what to say about that. It did, however, make the revolver easier to clean in the end as it was more forgiving to what I fed it as far as what was known to have leaded the barrel before firelapping.

I don't know that I'll ever firelap again. Having been unimpressed (to say the least) with firelapping, I decided to try a different method to smooth the barrel on another single action that I had had reblued and which had started to lead as a result. I simply used the time tested trick of shooting a couple hundred rounds of jacketed bullets through it and this solved the leading issues. Now, jacketed bullets will do nothing to relieve a barrel choke, but neither did the firelapping in my case, and the copper was much easier to remove during the process than the leading from the lead bullets while firelapping. Now that gun is also forgiving of lead bullets, and I have no worries that I ruined any of the fine rifling by using the jacketed bullet procedure.

Just my experiences. Yours may vary.

Ah... I see.

Frankly I would see this as being way out side the realm of a lapping kit. Fire lapping shoudl be limtied to removing any final burrs from the edges of the rifling lands and leaving a nice shiney final polish on those lands to encourage the lead or copper to not pick up and gall as they go by. Actually removing material to open up the bore is a WHOLE other issue. There's no control with abrasive charged bullets flying down the bore like their should be for such an issue. And really there should not BE such an issue on any well made gun. But if there is then this is not the way to deal with it. I'm not a gun smith so I don't know if there is a preferred way to deal with such a situation but I've worked metal for long enough to know that "sanding" up the bullets is NOT the right way.

I don't know much about Firelapping. All I know is it actually helps out accuracy and I know it won't damage your barrel.

Usertag, when used to remove any corner burrs on the lands and polish to a final shine yes. But they're talking about actually shooting enough of them to open up the bore where it passes through the frame by a very significant amount. Because there's no control over where the abrasives actually cut I'd be guessing that the lands would be pretty rounded over for the whole barrel by the time the choked area was opened up correctly.

I don't know much about Firelapping. All I know is it actually helps out accuracy and I know it won't damage your barrel.

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Well, might want to make that read ".....MIGHT help out accuracy...."
Some report good success with their particular revolver, and good for them, but in my case the accuracy of my particular revolver was actually better before firelapping than after, and another reason I was totally unimpressed with the results of the procedure which could have likewise been achieved using the far less aggressive jacketed bullet method while probably retaining the accuracy. There are just so many variables at work when it comes to revolver accuracy that there is no one cure-all panacea.

Because there's no control over where the abrasives actually cut I'd be guessing that the lands would be pretty rounded over for the whole barrel by the time the choked area was opened up correctly.

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To be fair, the corners of the lands probably do not round much anywhere but at the leads in the forcing cone. I only surmise this because as the soft lead of the bullet cuts around the lands in the forcing cone the areas of the bullet contacting the tops of the lands and the bottoms of the grooves will retain the lapping compound, while the or "cliffs", if you will, that are cut along the sides of the lands will be fresh lead devoid of compound.

The basis for using firelapping to improve accuracy and reduce leading in a revolver barrel by removing a barrel choke seems perfectly valid in theory. The bullet will swage into the choke, where the most abrasion will take place. Once the choke is removed, the bullet will continue to lap the barrel, the abrasive acting most on the first portions of the barrel, creating a tightening taper to the length of the bore, which is a condition that is definitely known to give exceptional accuracy. However, that is the theory, but I didn't find that even the first step of removing the choke was attainable using a reasonable number of the abrasive-coated bullets, and the choke in my gun was slight to begin with.

SAA said:

Yes. It is where the barrel is often choked down due to tightening in the frame where the threads are.

I have a single action that had a slight choke, and I tried the NECO kit. What a PITA!!!! Be prepared to remove a LOT OF LEADING from your UNLUBED bullets! And, it's not a 'remove the leading when you are done' bit, it is a 'remove the leading every few shots or the rest won't have any lapping effect on the barrel'! Lots and lots of cleaning in the loooong process.

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not a criticism, but did you check the hardness of your lapping bullets? i noticed that the NECO kit i saw on their website does not come with bullets, so if one happened to then pick bullets that were too hard, the lapping process will not work (worse, lapping with too-hard of a bullet can even ruin your bore)

i have a lapping kit from Beartooth bullets and it comes with 100 hardness-tested, soft bullets and literally a book on cast bullet shooting. i would recommend that kit to anybody wanting to lap their gun.

also, somebody else asked about stainless steel and how it compares to carbon steel--carbon takes 20-40 bullets for proper lapping whereas stainless can take upwards of 60+ bullets for proper lapping (I think I've read that Ruger's stainless is particullarly hard and can take closer to 100 bullets )

not a criticism, but did you check the hardness of your lapping bullets? i noticed that the NECO kit i saw on their website does not come with bullets, so if one happened to then pick bullets that were too hard, the lapping process will not work (worse, lapping with too-hard of a bullet can even ruin your bore)

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Actually, the NECO instructions don't go over hardnesses, though they do say that the kit can also be used with jacketed bullets, so I would assume that hard lead would be permissible according to the instructions. However, I used relatively medium/soft bullets alloyed from one part wheel weight to two parts pure lead. I did everything according to the instructions.

funny you bring this up now. i am in the middle of fire lapping my ruger blackhawk. trying to cure a severe leading problem. after 29 fire lap rounds through the barrel, the leading is gone from the forcing cone and the first quarter inch of the barrel. i'm going to continue to 50 rounds through the barrel. will let you know the results leading-wise and accuracy-wise.

am using the beartooth bullets kit. am following their directions. so far so good. just slow and messy. the lapping compound gets all over everything. never cleaned a gun so much in my entire life!

murf