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Very Hot Topic (More than 25 Replies) Mould/bullet recommendation for 28-30, Stevens (Read 3129 times)
frnkeore
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Re: Mould/bullet recommendation for 28-30, Stevens
Reply #30 - Dec 17th, 2018 at 1:53am
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Dave,
Run this bullet and twist combination through your miller program and see if you think it can shoot a .52, point on group at 100 yards.

.321 groove, 15 twist Douglas, using the Lyman 320366 bullet.

Frank
  

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Schuetzendave
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Re: Mould/bullet recommendation for 28-30, Stevens
Reply #31 - Dec 17th, 2018 at 6:58am
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Frank:

Sure it can work under certain weather conditions or at short distances and when you increase the velocities to increase the spin rate.
How does it perform at 300 yards?
Can you verify your barrel twist to decimal one place? Since you are on the edge we need to know your exact twist.

Caliber      0.321      Inches            
Bullet Weight      187      Grains            
Bullet Length      1.18      Inches            
Barrel Twist      15      Inches/turn            
muzzle velocity      1600      fps            
Temperature      100      degrees Fahrenheit (59 is standard)            
Pressure      28      inches of mercury (29.92 is standard)            
                       
Sg =      1.39                  


I prefer to select a bullet and appropriate barrel twist that will perform well over longer distances and under all weather conditions without pushing cast bullets at high velocities.

Caliber      0.321      Inches            
Bullet Weight      235.1      Grains            
Bullet Length      1.299      Inches            
Barrel Twist      11.5      Inches/turn            
muzzle velocity      1470      fps            
Temperature      50      degrees Fahrenheit (59 is standard)            
Pressure      29.92      inches of mercury (29.92 is standard)            
                       
Sg =      1.87                  
« Last Edit: Dec 17th, 2018 at 9:31am by Schuetzendave »  
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Dellet
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Re: Mould/bullet recommendation for 28-30, Stevens
Reply #32 - Dec 17th, 2018 at 9:30am
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Schuetzendave wrote on Dec 16th, 2018 at 11:39pm:
Pretty simple.

Ballisticians state it is impossible to have dynamic stability until you first have gyroscopic stability.

So you need the proper selection of bullet length for your barrel twist before it will be gyroscopically stable.

No bullet shape will restore a bullet that is gyroscopically unstable.


No argument there at all.

But shape will determine the center of pressure which is ultimately what will cause the bullet to tumble.

One of the best examples of this is Berger bullets own calculator and their 30 cal. Flatbase bullets. To say their is a discrepancy between the twist required on the box, and using their own calculator would be an understatement.

The bullet Frank posted will likely fall into that same category and is why Berger posts a disclaimer with heir calculator, advising that it will not be accurate for flat base bullets.

  
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frnkeore
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Re: Mould/bullet recommendation for 28-30, Stevens
Reply #33 - Dec 17th, 2018 at 3:01pm
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Dave,
My Miller program, gives a different out put.

This is what my Sg program says about that bullet and twist rate.

Frank
  

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frnkeore
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Re: Mould/bullet recommendation for 28-30, Stevens
Reply #34 - Dec 17th, 2018 at 3:05pm
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Oh, now I see, you raise the temp to 100 and lowered the pressure to sever storm level.

My programs inputs are both std, default levels.

Frank
  

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Re: Mould/bullet recommendation for 28-30, Stevens
Reply #35 - Dec 17th, 2018 at 3:09pm
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Here are some example of calculators not doing flat base bullets justice. JBM which uses the Miller formula and Berger bullets because they publish the specs needed for the calculator and recommended twist for each bullet.

These are both .243 Varmint bullets # 24313, 24321. Berger recommended twist is 1/12.

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Quote:
Stability
Input Data
Caliber:      0.243 in      Bullet Weight:      69.0 gr
Bullet Length:      0.919 in      Plastic Tip Length:      0.000 in
Muzzle Velocity:      3000.0 ft/s      Barrel Twist:      12.0 in
Temperature:      59.0 F      Pressure:      29.92 in Hg
Output Data
Stability:      1.046


Quote:
Stability
Input Data
Caliber:      0.243 in      Bullet Weight:      69.0 gr
Bullet Length:      0.919 in      Plastic Tip Length:      0.000 in
Muzzle Velocity:      3000.0 ft/s      Barrel Twist:      9.8 in
Temperature:      59.0 F      Pressure:      29.92 in Hg
Output Data
Stability:      1.584      
     


Something that has a shape more like something that you could cast.

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Quote:
Stability
Input Data
Caliber:      0.243 in      Bullet Weight:      80.0 gr
Bullet Length:      0.913 in      Plastic Tip Length:      0.000 in
Muzzle Velocity:      3000.0 ft/s      Barrel Twist:      12.0 in
Temperature:      59.0 F      Pressure:      29.92 in Hg
Output Data
Stability:      1.236      




Quote:
Stability
Input Data
Caliber:      0.243 in      Bullet Weight:      80.0 gr
Bullet Length:      0.913 in      Plastic Tip Length:      0.000 in
Muzzle Velocity:      3000.0 ft/s      Barrel Twist:      10.5 in
Temperature:      59.0 F      Pressure:      29.92 in Hg
Output Data
Stability:      1.614            
1


150 grain .308 #30407, recommended twist 1/15

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Quote:
Stability
Input Data
Caliber:      0.308 in      Bullet Weight:      150.0 gr
Bullet Length:      1.155 in      Plastic Tip Length:      0.000 in
Muzzle Velocity:      2800.0 ft/s      Barrel Twist:      15.0 in
Temperature:      59.0 F      Pressure:      29.92 in Hg
Output Data
Stability:      1.150      


Quote:
Stability
Input Data
Caliber:      0.308 in      Bullet Weight:      150.0 gr
Bullet Length:      1.155 in      Plastic Tip Length:      0.000 in
Muzzle Velocity:      2800.0 ft/s      Barrel Twist:      12.5 in
Temperature:      59.0 F      Pressure:      29.92 in Hg
Output Data
Stability:      1.656      


That's why they don't recommend it for flat base
  
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frnkeore
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Re: Mould/bullet recommendation for 28-30, Stevens
Reply #36 - Dec 17th, 2018 at 3:34pm
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Many modern, long ogive bullets, have a extreme rearward GC (lead core in the rear and hollow jacket forward). It is this CG position that allow them to shoot in slower twists.

As near as I can tell, running comparisons between my program and the Miller. The default Miller bullet is either a cylinder or a VERY short ogive bullet giving the CG about the center.

Frank
  

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Re: Mould/bullet recommendation for 28-30, Stevens
Reply #37 - Dec 17th, 2018 at 4:31pm
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frnkeore wrote on Dec 17th, 2018 at 3:34pm:
Many modern, long ogive bullets, have a extreme rearward GC (lead core in the rear and hollow jacket forward). It is this CG position that allow them to shoot in slower twists.

As near as I can tell, running comparisons between my program and the Miller. The default Miller bullet is either a cylinder or a VERY short ogive bullet giving the CG about the center.

Frank


Another interesting thing to do with JBM is to check bullets with a plastic tip.

This is a 178 grain Hornady Amax with a plastic tip.
Quote:
Stability
Input Data
Caliber:      0.308 in      Bullet Weight:      178.0 gr
Bullet Length:      1.318 in      Plastic Tip Length:      0.138 in
Muzzle Velocity:      1600.0 ft/s      Barrel Twist:      12.0 in
Temperature:      59.0 F      Pressure:      29.92 in Hg
Output Data
Stability:      1.489      


Same bullet with the tip length at zero
Quote:
Stability
Input Data
Caliber:      0.308 in      Bullet Weight:      178.0 gr
Bullet Length:      1.318 in      Plastic Tip Length:      0.000 in
Muzzle Velocity:      1600.0 ft/s      Barrel Twist:      12.0 in
Temperature:      59.0 F      Pressure:      29.92 in Hg
Output Data
Stability:      1.209      


So clearly the shape and weight distribution have meaning when it comes to stability, but getting the accurate data points needed to predict it is difficult.

Variations of lube grooves in cast bullet at the back of the bullet, will play with the stability just as the plastic tip does in the front.

You can get an idea, but ultimately, you're going to have to shoot them.

  
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JLouis
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Re: Mould/bullet recommendation for 28-30, Stevens
Reply #38 - Dec 17th, 2018 at 5:26pm
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Very knowledgeable information Dellet your interest intrigues me. If you don't have Mann's book on The Bullets Flight I think you might be one of the very few who would enjoy it as much as I have.

JLouis
  
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Re: Mould/bullet recommendation for 28-30, Stevens
Reply #39 - Dec 17th, 2018 at 5:56pm
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Not sure if this is still available but if anyone has an interest it would be hard to beat this price.

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JLouis
« Last Edit: Dec 17th, 2018 at 6:24pm by JLouis »  
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Re: Mould/bullet recommendation for 28-30, Stevens
Reply #40 - Dec 17th, 2018 at 9:48pm
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Dellet one of our competitors and a close friend has been swagging his bullets now for quite sometime. He gets his Dies from I believe Blackwell and all though the lead wire is 1-30 and and the hardest I believe he can use. The knurled bullets and the means for the bullet lube thus not having any lube grooves have actually been shooting quite well.
  
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Re: Mould/bullet recommendation for 28-30, Stevens
Reply #41 - Dec 17th, 2018 at 10:10pm
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Also not sure if you received my last PM that might be of some help to you and if not please let me know and I would be more than happy to re-send.
  
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Re: Mould/bullet recommendation for 28-30, Stevens
Reply #42 - Dec 17th, 2018 at 10:18pm
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JLouis wrote on Dec 17th, 2018 at 9:48pm:
Dellet one of our competitors and a close friend has been swagging his bullets now for quite sometime. He gets his Dies from I believe Blackwell and all though the lead wire is 1-30 and and the hardest I believe he can use. The knurled bullets and the means for the bullet lube thus not having any lube grooves have actually been shooting quite well.


Are those by or similar to the ones that Dave Bennett does?

I have seen some write ups of those and they are interesting, any real different results that you have seen?
  
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Re: Mould/bullet recommendation for 28-30, Stevens
Reply #43 - Dec 18th, 2018 at 12:59pm
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Yes similar to Bennett's but I believe the nose forming die he uses is different. I think the big benefit is the lack of having the air pockets that can be cast into poured bullets creating unbalanced bullets. All the bases are flat, the edges sharp and probably more identically the same. A poured bullet shrinks after being poured and can shrink out of round. And there are no lube grooves to disrupt the air flow Dellet and he does quite well with them. The only thing I don't care for is I like a harder bullet and one of 1-16 tin and lead alloy. I feel it helps greatly to keep the unsupported spitzer nose from slumping off center from both shrinking in length to fill the grooves and the centrifugal forces being applied to it. In Mann's testing the X factor he could not eliminate was the lack of achieving perfectly balanced bullets.

JLouis
« Last Edit: Dec 18th, 2018 at 1:07pm by JLouis »  
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John Boy
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Re: Mould/bullet recommendation for 28-30, Stevens
Reply #44 - Mar 26th, 2019 at 5:03pm
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Quote:
Any thoughts or if you have something available appreciated.

Old thread but for what's it worth for consideration:
* Accurate Molds has a 120gr clone of the Ideal 28-30-120 Stevens bullet .... (You need to Login or Register to view media files and links)
The bore on an original 28-30 Stevens is 279/282


  

Regards
John
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