How is knurling a bullet accomplished?

I see a lot of reference here about knurling bullets to increase the diameter for a tighter fit in the sabot or bore - (I assume). I understand the setup in a lathe but I would think the size of the knurl has to coincide with a specific diameter, otherwise it wouldn't match after one revelation - it would just knurl over itself on the next revolution. Can someone explain how this is done? Thanks.

Take 2 10 or 12 inch Mill files, sharp ones are best. Lay one on the table and place the bullet on it near the end then lay the other file on top. Apply a little pressure and using the top file roll the bullet across the bottom file one end to the other. Learning consistency seems to be the key and I have not practiced enough the accomplish that yet.

tpcollins said:

I see a lot of reference here about knurling bullets to increase the diameter for a tighter fit in the sabot or bore - (I assume). I understand the setup in a lathe but I would think the size of the knurl has to coincide with a specific diameter, otherwise it wouldn't match after one revelation - it would just knurl over itself on the next revolution. Can someone explain how this is done? Thanks.

Click to expand...

Using what Shawn has written...which is basically what I do...

Here are some pictures...










when I first started I used the mil files but then later moved to the rasp.... You can see the wood rasp in the top picture. They make a heavier Knurl...

See if this helps any....

viewtopic.php?f=13&t=24664

I have been able to get it pretty consistent with 2 double cut bastard files. When I was still getting the hang of it I snapped one of the files.

Thank you sabotloader the photo's are a great help. If I persue this sabotless thing I needed this info.

That is just too simple. In addition to sabotless, I assume one could do that to make a bullet fit a bit tighter in a sabot? Thanks

Yes they still work in sabots too. Sometimes better even if you barely increased the OD. It seems to help them grip the sabots a bit more.

It cut my groups almost in half with my sabots. I am shooting the 200gr sst out of a .45 Encore at close to 2400 fps. Went from about 2" down to 1" groups at 100. I do believe the sabot hold them more consistently with the knurling.

Here's a link to a video on bullet knurling.
http://www.youtube.com/watch?v=NncCcscSQa8

vabowhntr said:

It cut my groups almost in half with my sabots. I am shooting the 200gr sst out of a .45 Encore at close to 2400 fps. Went from about 2" down to 1" groups at 100. I do believe the sabot hold them more consistently with the knurling.

Click to expand...

X2 for my conversion also. I lightly knurl all sabot bullets now. Helps the metal grip the plastic to get spin. The Encore conversions are 1/20 twist and that is a pretty hard spin.

I even lightly knurl the 300 Speer and 300 SST and 325 FTX I shoot saboted in my MLII mada a good improvement in group size and flyers eliminated.

These are my results and your results may be different. W

I saw something like this on youtube channel, some wilderness survival guys, one of the more prominent ones on youtube. They knurled a roundball they cast over a fire from shot and the knurling was used as it works with a golf ball to keep it flyong true? I offer this, not because I know anything about it, but because it seemed similar.

Sent from mobile......

vabowhntr said:

It cut my groups almost in half with my sabots. I am shooting the 200gr sst out of a .45 Encore at close to 2400 fps. Went from about 2" down to 1" groups at 100. I do believe the sabot hold them more consistently with the knurling.

Click to expand...

I'm going to have to give that a try this season.

How exact of a process is this when doing it for a saboted bullet? Do I need to be super careful to do each bullet the exact same or can I be only reasonably careful?

It's not an exact kind of thing. I use 1 file. Put the bullet on a metal plate and run a 12" bastard over it about 5-6 times, depending on the pressure used. The object is to get the entire surface that goes in the sabot knurled. When you put the bullet in the sabot it shouldn't slip out. I think smooth bullets may slip inside the sabot not rotate on their way down the barrel at the same twist rate as the sabot (especially in 1:20 twist barrels). Knurling makes the bullet slightly bigger and rougher to rotate with the sabot. In my Omega .45, an older SS gun, knurling has made a big difference in accuracy.

https://m.youtube.com/watch?v=9nIF82SlYpc

This guy uses strips of foil and wraps the bullet before putting into a sabot. My be the ticket.