Knurling Bullets

[Bratch]

In one of my other threads I was asked about knurling my bullets, at that time I was unaware of knurling. Tonight I bought two bastard files to give it a try.

My question is are you guys knurling every bullet you shoot in a sabot? In my original post I was shooting XTPs. I picked up some Barnes Expanders and SSTs and was curious if you’d recommend knurling them as well.

 

[ElDiablo]

I knurl everything I shoot in a sabot. I’ve seen it make a big difference in some loads. If you find that it increases the loaded (bullet in sabot) O.D. too much making it tough to load, then I’d only knurl it very lightly.

 

[MrTom]

I knurl everything I shoot in a sabot. I haven't seen much of an improvement in my .50's but in both .45's, one smokeless and the other a BH shooting gun the knurling has been a good improvement in group size.

 

[Old No7]

Interesting idea...

I know my twin knurls the lead balls that he shoots in one of his smoothbores, and it helps. I never thought to try it with the XTPs that I use.


Old No7

 

[TransYank]

I shoot SML that needs a .0452 sized to bore. I recently started shooting solid cooper Barnes in .0451 with a good knurl. There too hard to downsize. Very accurate to 300 yards

 

[LBAhunter]

In one of my other threads I was asked about knurling my bullets, at that time I was unaware of knurling. Tonight I bought two bastard files to give it a try.

My question is are you guys knurling every bullet you shoot in a sabot? In my original post I was shooting XTPs. I picked up some Barnes Expanders and SSTs and was curious if you’d recommend knurling them as well.

In my experience, sometimes it helps, sometimes it don't. It depends on the situation.

 

[eekjellander]

I knurl everything I shoot in a sabot. I’ve seen it make a big difference in some loads. If you find that it increases the loaded (bullet in sabot) O.D. too much making it tough to load, then I’d only knurl it very lightly.

I would expect if you have a Hankins sizer die it's a non issue , but if not I'd be concerned with different dimensions . Variation is the enemy of accuracy !/Ed

 

[ElDiablo]

I would expect if you have a Hankins sizer die it's a non issue , but if not I'd be concerned with different dimensions . Variation is the enemy of accuracy !/Ed

It’s mainly about the sabot gripping the bullet for consistency in spin up.

 

[eekjellander]

It’s mainly about the sabot gripping the bullet for consistency in spin up.

I know why it's done ,my point is any change in diameter changes the dimensions of your bullet .Unless you can by hand duplicate that 100 times for 100 bullets ,I spend considerable time to cast identical bullets same dimension/same weight /same base (SHARP) edges and all having a BHN identical till the pot is empty . I do have a fairly low reject rate but that comes with superior molds/techniques and experience . Store bought often come with variables /hardness /weights I would not accept . Guess everyone has different expectations , Ed

 

[ElDiablo]

I think casting lead bullets is a different ballgame from shooting modern jacketed bullets in sabots….

 

[eekjellander]

I think casting lead bullets is a different ballgame from shooting modern jacketed bullets in sabots….

You'd be wrong ,the same principle applies for store bought !!! It is more pronounced by casting your own but the same result applies . Change any of the conditions I listed and your bullet changes accuracy for the worst in most cases . Sabot performance might improve but the projectile (ALWAYS) goes down hill ,you can't group with variables . Sameness is what we all try for in velocity /trigger pull/projectile weight/powder weight /bore condition /rest /grip for good groups ,anything else could be a flyer or just maybe a variance in your shooting . Sameness equals accuracy again in most cases ,most long range shooters count on it . If knurling is done by hand pressure and file it will be different ,just a question of degree /Ed

 

[Mnt monkey]

I do not knurl, for the exact reasons eekjellander mentioned, I understand helping grip the plastic I just have never have been able to be comfortable with doing knurling by hand with files, it would not be consistent enough for me bullet to bullet, and this is just me but I won't as little scratch ,scarring ,and friction on the outside of my jacketed bullet as possible as it flies through the air I guess that's silly but it's just me if I feel like I have a bullet that's too small in diameter for my bore I'm going to get a different bullet ,most likely or I'm going to switch plastic, I'm going to find another way to address the issue ,because by switching bullets or changing my plastic I stay more constant, if I have a machine perhaps that gave me the exact amount of knurl on my bullet every time I might play with it or experiment more,, still the part of my thought process that doesn't want the jacket of my bullet roughed up and scratched up will win out. I want my bullet flying through the air with this little friction as possible

 

[ENCORE50A]

You CAN NOT provide the identical amount of force by hand knurling. Won't happen.
I agree with both posts above.

 

[ElDiablo]

I want my bullet flying through the air with this little friction as possible

There’s a boundary layer of air around the bullet as it flies, so in theory, a slight knurl (or rifling impressions) shouldn’t meaningfully affect friction (drag). Especially at traditional hunting ranges.

 

[eekjellander]

There’s a boundary layer of air around the bullet as it flies, so in theory, a slight knurl (or rifling impressions) shouldn’t meaningfully affect friction (drag). Especially at traditional hunting ranges.

Please define traditional distances ,dam sure what your discussing is( not) never was traditional
(theory or otherwise) . Lots of theory short on facts ,going back to groups or the lack of proves my point /not theory /Ed

 

[Mnt monkey]

I agree and understand there's just a boundary layer of air that runs around the top of my brain that layer is called consistency and I just can't get away from it.

 

[ElDiablo]

Please define traditional distances ,dam sure what your discussing is( not) never was traditional
(theory or otherwise) . Lots of theory short on facts ,going back to groups or the lack of proves my point /not theory /Ed

The OP (in this post and others) says he is trying to develop a load for whitetails at “up to 200 yards.” I think that fits the definition on traditional hunting ranges nicely. Knurling his bullets won’t significantly increase his dispersion (and it may significantly improve it) at 200 yards.

When I measure my knurled bullets they are within a thousandth of each other. That’s more than consistent enough for good groups. There are other variables that will have a much greater affect on dispersion. If it makes someone feel better they could run their knurled bullets through a sizer. But I don’t think it would make any difference.

 

[Mnt monkey]

Consistency bullet to bullet no matter what range should always be the goal, there are some bores I have ask Dennis at Fury bullets to knurl for me, only because I trust him to do that consistently and not myself ,Diablo if you're getting that consistency then I would agree with you out to 200 yards that should be sufficient ,it's that constantness that I'm always concerned about.

 

[Mnt monkey]

If I had my mind set on one particular bullet and if I was shooting that particular bullet and it was loose in the plastic and bore then I would consider knurling, for me personally though when I run into that situation there's so many other bullets to choose from I instantly just switch to a different bullet because I would always rather have a tighter fit, and if anything use a sizing die to size down

 

[MrTom]

I do the two-file knurl job on all of my .40 bullets regardless of maker along with all of my bullets for the .50 cals and in every instance, at a range of 100 yards, there was group improvement.

I'm not leaning on the files, but just enough to imprint on the bullet. With the bullets for the .50 cals, I know that groups pulled in a bit but honestly neither gun is putting the bullet out at over 2050 fps so I'm not going to say that knurling was a true benefit. Both the the 45's are hustling the pills out at or more than 2300 fps and the groups in both guns tightened up by at least 1/4".

My hunting is , as a rule, well inside that 100 yard shooting distance and I am not hyper anal about things as a rule, however even at the 100 yards I try to remove as much from the load equation that can be a trouble spot as possible and bullet slippage within the sabot was just another thing that the knurling addressed in a positive way for me. Again, I just put enough pressure on the files to leave enough of an imprint to eliminate any chance of bullets slippage in the sabot. I can see where using a tool designed to knurl bullets could make things more absolute but in my shooting I have seen nothing but positive with the file method. I think too many people get hung up on this one size fits all stuff, especially if people are not going to long distances.