Badlands Precision Bullets thread - From BC to terminal ballistics

[nralifer]

.105" jump to .115" jump. Mag feeding in my 300wm with the 205gr sbd2's

Interesting. The head spacing on the WM is generally at the belt so there could be a difference in jump requirement when you head space at the shoulder, although we have had guys tell us that jumps as long as 0.050-0.075" work well for them. Good info. Thank you very much.

 

[jasent]

Interesting. The head spacing on the WM is generally at the belt so there could be a difference in jump requirement when you head space at the shoulder, although we have had guys tell us that jumps as long as 0.050-0.075" work well for them. Good info. Thank you very much.

I never tried anything shorter than .095" jump. Started at .020" short of mag length and backed it up from there.
Feeds great, shoots great and kills fast. Won't feed it anything else. Switching all my rifles over to sbd's as time allows
243 is next

 

[nralifer]

I never tried anything shorter than .095" jump. Started at .020" short of mag length and backed it up from there.
Feeds great, shoots great and kills fast. Won't feed it anything else. Switching all my rifles over to sbd's as time allows
243 is next

What barrel brand do you use?

 

[nralifer]

That is crazy to me that such a small difference in seating depth change could make such a big difference. You could rack up a hell of a component bill running such minute adjustments. I would probably need to invest in a better set of calipers...

Jasent has taken the jump issue to high levels of precision, and his information is very noteworthy. work.

 

[jasent]

What barrel brand do you use?

This one is a McGowan 28" 1/8 twist SS with their match 300wm chamber

 

[FEENIX]

There are two generalizations you can make about monos vs C&C. The latter are much softer and don't penetrate as well at high speed impacts. Monos (all copper) bullets are etched by rifling where C&Cs "squeeze into the rifling. Our bullets generally will need a jump between 0.020-0.30". They shoot 1/2 MOA right off the bat in the 6.8 Western that has tight clearances in the lead/ free bore portion of the throat. Typically from my guns I can get sub-MOA groups at those jumps. If not then I do 2 shot jump ladders at 0.010" increments starting 0.005" off the lands. I have one Proof carbon barrel in a 308 Win with a short throat that gives me more trouble than the other barrels though.

I agree; however, the DRT (https://drtammo.com/) terminal shock projectiles use compressed copper metal powder core instead of solid copper material and act similar to a C&C/lead core frangible bullet.

 

[FEENIX]

Jasent has taken the jump issue to high levels of precision, and his information is very noteworthy. work.

WHOA!

 

[Roninco]

There are two generalizations you can make about monos vs C&C. The latter are much softer and don't penetrate as well at high speed impacts. Monos (all copper) bullets are etched by rifling where C&Cs "squeeze into the rifling. Our bullets generally will need a jump between 0.020-0.30". They shoot 1/2 MOA right off the bat in the 6.8 Western that has tight clearances in the lead/ free bore portion of the throat. Typically from my guns I can get sub-MOA groups at those jumps. If not then I do 2 shot jump ladders at 0.010" increments starting 0.005" off the lands. I have one Proof carbon barrel in a 308 Win with a short throat that gives me more trouble than the other barrels though.

At what distance do you shoot your jump ladder?

 

[nralifer]

At what distance do you shoot your jump ladder?

I do it at 100 yds mostly because I have a target set up to which I can shoot from the garage even in the winter. Seems like a convenient distance the results of which can be applied to longer distances.

 

[RH300UM]

@nralifer
I want to try HBN coating the 250 sbd-2. I'm wondering if the the tips concentricity will be affected by the vibratory process for the coating application?

 

[nralifer]

@nralifer
I want to try HBN coating the 250 sbd-2. I'm wondering if the the tips concentricity will be affected by the vibratory process for the coating application?

I doubt the tips will be affected

 

[FEENIX]

@nralifer
I want to try HBN coating the 250 sbd-2. I'm wondering if the the tips concentricity will be affected by the vibratory process for the coating application?

I doubt the tips will be affected

That would be wicked.

@nralifer, congrats. Good luck with your continued success. Keep up the excellent work.

Ed

 

[xsn10s]

@nralifer
I want to try HBN coating the 250 sbd-2. I'm wondering if the the tips concentricity will be affected by the vibratory process for the coating application?

@nralifer my thinking is if the bearing surface is very short the HBN coating my not be as effective as bullets with a higher amount of surface contact. After reading of some of your velocities I'm guessing that the surface contact is low on your bullets so the HBN coating might not be needed. What are your thoughts or findings on this?

 

[nralifer]

@nralifer my thinking is if the bearing surface is very short the HBN coating my not be as effective as bullets with a higher amount of surface contact. After reading of some of your velocities I'm guessing that the surface contact is low on your bullets so the HBN coating might not be needed. What are your thoughts or findings on this?

If you have any of our bullets you can estimate the total bearing surface for that bullet by taking a sized brass piece and using it to mark the bearing surface bordering the ogival and boat tail ends and subtract 0.10" from the linear measurement between the marks to account for the copper relief grove.