Knurled lapping bullets

[f3]

I was getting ready to roll some lapping bullets today and had an idea. What if I knurled them before hand. Seems like you could more effectively and quickly embed the lapping compound. So I rolled the bullets between two files a couple of times. No more than a couple seconds of work. I typically set a timer for two minutes when I am rolling the bullets between the plates. I checked at 30 seconds and it really seamed like It was working faster. I still did them for two minutes. Tomorrow I will shoot them and see if for some reason it increased leading. Seems like a sound theory to me. Any thoughts? Don't really have a way to see if it is more effective unless I drastically reduce the rolling time. 

[cherokeetracker]

IMHO It is not needed at all ( the knurling) I have lapped 22 pistols and all you do is put some compound on the bullet. You do not roll them between plates like you do on larger bore pistols. The 22s work fine. so it is just something you want to do then go for it. Lapping is enough work as it is without increasing work. For what that was worth,,,

[f3]

Oct 11, 2016 22:48:34 GMT -5 cherokeetracker said:

IMHO It is not needed at all ( the knurling) I have lapped 22 pistols and all you do is put some compound on the bullet. You do not roll them between plates like you do on larger bore pistols. The 22s work fine. so it is just something you want to do then go for it. Lapping is enough work as it is without increasing work. For what that was worth,,,

I wonder if knurling alone would accomplish whats needed.

[f3]

With lapping compound obviously.

[cherokeetracker]

It should not have to be required since the lapping bullets are soft lead. That is the idea behind them to obturate and fill the barrel properly, therefore lapping the lands and grooves.

I will add that we usually do this for the removal of thread choke. Now if a person was just wanting to polish their barrel, then, that could be a different approach. But for polishing I will stay with the felt plugs and the JB compound.

[cherokeetracker]

You just might get by with a reduction of shots fired through your pistol to accomplish the thread choke removal. Let us know how this works out. Be sure to keep count of shots and show us end results.

[f3]

It seems like it would save a lot of time especially with a stainless ruger. A couple seconds of knurling with lapping compound.

[Fowler]

I fear the only thing this will do is reduce the diameter of the bullet and you want an oversized bullet for firelapping. Bigger bullet are used to push the lapping compound into the metal for better cutting, the same reason you use very soft bullet so the bases will push up and seal the bore with the very reduced loads.

You certainly won't hurt anything and I sure don't know how much oversized of a bullet you are starting with. It might work great but that was my thought process.

[ChiefTJS]

Only fire lapping I've done was on a .357 and I used Hornady HBWC's that were already knurled. Thought occurred to me at the time that the knurling may hold the compound better.

[Deleted]

I should have thought of trying this. The idea of embedding the lapping compound is to keep it from being displaced as the bullet travels through the bore. This would make the lapping more uniform. However the idea of knurling the bullet appeals to me, and I'll try it the next time I get a bore that needs attention. BTW, you can knurl any cast bullet by rolling it between a steel plate and a file. Just be sure to be certain you don't make the bullet diameter too small. I'm not excited about using Hornady swaged bullets for this application though. I've found them to be undersized in most cases. Apparently Hornady counts of obturation to make the bullets shoot accurately, and they are a bit soft to begin with.

[f3]

Oct 12, 2016 6:54:22 GMT -5 Fowler said:

I fear the only thing this will do is reduce the diameter of the bullet and you want an oversized bullet for firelapping. Bigger bullet are used to push the lapping compound into the metal for better cutting, the same reason you use very soft bullet so the bases will push up and seal the bore with the very reduced loads.

You certainly won't hurt anything and I sure don't know how much oversized of a bullet you are starting with. It might work great but that was my thought process.

The 15 I knurled had their diameter increased roughly .002. But then again its common for knurling on a lathe to increase diameter.

[2 Dogs]

I've fire lapped a good number of Sixguns myself. I don't see that it could hurt to try your idea. But to prove it better than the existing process you might have to fire lap a bunch of Sixguns. I've had some lap right in at 15 rounds. Others took 10 times that many. Let us know what you find out. Good luck.