300wm neck tension

[zorak]

Reloading my 300wm and doesn't seem like they much neck tension. Is this normal is a die issue? Im.using RCBS dies.

 

[jfseaman]

Don't know, however, mine is the same. Not much seating force required. Shoots great.

 

[Bart B.]

Minimum neck grip on bullets typically means smaller muzzle velocitiy spreads.

It's a combination of things. Diameters of bullet, die neck, expander ball if used and case neck wall thickness. Plus brass hardness. If you're using a die neck .002" smaller than loaded round neck diameter, that'll end up with about a .001" interference fit, or tension as its sometimes called. Brass springs back a smidgen or tiny amount.

Ideally, the sized case mouth diameter should be about .001" or less smaller than bullet diameter. It depends mostly on brass hardness.

Hunting bullets may need 20 to 30 pounds of force to get them out of the case. Then they'll resist setback from recoil as they slam into the n
Magazine wall. And survive rough handling. Only bad side is muzzle velocity spread increases with release force.

Match bullets need only 4 to 5 pounds. Less is best if accuracy is most important and rounds are single loaded.

 

[retired]

MY HUMBLE OPINION is that it is based on desired accuracy, and how close
to the lands you are.
a bullet engraving into the lands is a lot more resistance than a neck tension resistance.
if you are jumping, neck tension is significant, if you are at or in the lands, not so much.
that does not mean your tension can be all over the place just because you are on the lands.

 

[Zero333]

If you have less than 0.001" I would spin the expander ball in a drill and sand it a hair to get at least 0.0015" to 0.002" bullet to neck interference.

Like Bart said... different brass can have different interference with same die and bullet.

If I remember correctly, the 300winmag RCBS die I have sizes F.C. brass where the neck (near the middle) measures around 0.335".

Next time I reload those F.C. 300winmag cases I'll take some measurements and write them down so I don't have to go of off memory.

 

[zorak]

I'm using Norma and Nosler brass and they both seem to have same lite tension. I'm assuming they're right around 4-5lbs like Bart was saying.

 

[Steve Ladino]

Reloading my 300wm and doesn't seem like they much neck tension. Is this normal is a die issue? Im.using RCBS dies.

I unloaded a few rounds of new Federal .308 Match 168 grain rounds and the bullets were lightly seated in them.

 

[muleman69]

Minimum neck grip on bullets typically means smaller muzzle velocitiy spreads.

It's a combination of things. Diameters of bullet, die neck, expander ball if used and case neck wall thickness. Plus brass hardness. If you're using a die neck .002" smaller than loaded round neck diameter, that'll end up with about a .001" interference fit, or tension as its sometimes called. Brass springs back a smidgen or tiny amount.

Ideally, the sized case mouth diameter should be about .001" or less smaller than bullet diameter. It depends mostly on brass hardness.

Hunting bullets may need 20 to 30 pounds of force to get them out of the case. Then they'll resist setback from recoil as they slam into the n
Magazine wall. And survive rough handling. Only bad side is muzzle velocity spread increases with release force.

Match bullets need only 4 to 5 pounds. Less is best if accuracy is most important and rounds are single loaded.

Are you saying brass hardness makes a difference on tension? How much difference in pounds are you thinking? Is that one of the biggest reasons to anneal more often?

 

[muleman69]

Don't know, however, mine is the same. Not much seating force required. Shoots great.

Loaded some 300 win today with both norma and Nosler using Redding dies ,seems like they seated fairly easy but when I tried pushing them in against my bench they would not move. Apparently your expander ball is larger than mine?

 

[Bart B.]

Are you saying brass hardness makes a difference on tension? How much difference in pounds are you thinking? Is that one of the biggest reasons to anneal more often?

Soft case necks expand easier than hard ones; release force will be less.

The difference in bullet release force will vary with how hard the brass is and how much the neck has to expand; the interference fit dimension.

It may require annealing. I've never annealed case necks; never had a reason to.

You'll need to measure your bullet release/pull force to see exactly what your ammo has. With a collect type bullet puller, you can usecachand scale to measure the press arm force needed to pull the bullet. It will be a relative measurement good enough for comparison, but the linkage arm lengths would have to be used in a leverage formula to get actual release force.

 

[muleman69]

I unloaded a few rounds of new Federal .308 Match 168 grain rounds and the bullets were lightly seated in them.

Soft case necks expand easier than hard ones; release force will be less.

The difference in bullet release force will vary with how hard the brass is and how much the neck has to expand; the interference fit dimension.

It may require annealing. I've never annealed case necks; never had a reason to.

You'll need to measure your bullet release/pull force to see exactly what your ammo has. With a collect type bullet puller, you can usecachand scale to measure the press arm force needed to pull the bullet. It will be a relative measurement good enough for comparison, but the linkage arm lengths would have to be used in a leverage formula to get actual releace force.

Good info,So how do you get around not annealing? Doesn't the brass get to hard? I will exsperiment with the neck tension, maybe start by pulling a factory round and go from there

 

[Bart B.]

Good info,So how do you get around not annealing? Doesn't the brass get to hard?

Never thought about annealing because brass never got hard enough. Not with 46 cycles on the same case.

 

[tuttlefarm]

Minimum neck grip on bullets typically means smaller muzzle velocitiy spreads.

It's a combination of things. Diameters of bullet, die neck, expander ball if used and case neck wall thickness. Plus brass hardness. If you're using a die neck .002" smaller than loaded round neck diameter, that'll end up with about a .001" interference fit, or tension as its sometimes called. Brass springs back a smidgen or tiny amount.

Ideally, the sized case mouth diameter should be about .001" or less smaller than bullet diameter. It depends mostly on brass hardness.

Hunting bullets may need 20 to 30 pounds of force to get them out of the case. Then they'll resist setback from recoil as they slam into the n
Magazine wall. And survive rough handling. Only bad side is muzzle velocity spread increases with release force.

Match bullets need only 4 to 5 pounds. Less is best if accuracy is most important and rounds are single loaded.

Bart, where do you get your information on neck tension and accuracy.......... Everyone loads to match what the rifle wants. My 300 wsm's want and need more neck tension for 1000 yd competition.

 

[Bart B.]

Bart, where do you get your information on neck tension and accuracy.......... Everyone loads to match what the rifle wants. My 300 wsm's want and need more neck tension for 1000 yd competition.

Bullet release force in my and others tests for accuracy.

Please explain how a rifle "wants" anything. None have a nervous system nor a brain to think and have emotions.

 

[tuttlefarm]

Bullet release force in my and others tests for accuracy.

Please explain how a rifle "wants" anything. None have a nervous system nor a brain to think and have emotions.

Come on now. Your rifle will tell you what it likes or does not like. Apparently you have never tested at long range.

 

[dmoran]

..... None have a nervous system nor a brain to think and have emotions.

Mine do.... and they tell me exactly what they like and what they dislike....

IME, a lot of differences to loading "acceptable accuracy" ammo and "highly precision" ammo.
Donovan

 

[dmoran]

.... My 300 wsm's want and need more neck tension for 1000 yd competition.

As I'm sure you already know, but you and your 300-WSM's are not alone on needing more.
Donovan

 

[Bart B.]

Come on now. Your rifle will tell you what it likes or does not like. Apparently you have never tested at long range.

Only several hundred rounds. Most were loads others used. They shot as well as theirs; about half MOA or better.

 

[tuttlefarm]

Only several hundred rounds. Most were loads others used. They shot as well as theirs; about half MOA or better.

Let me know when you get up into the thousands of rounds and wear out 8 or 9 barrels in 300 WSM. If you want to know what works, listen to guys like dkhunt14, dmoran, 4x4fun, mikegaiz, and a handful of guys that have been shooting 1000 yard for 30-40 years.

 

[Bart B.]

Let me know when you get up into the thousands of rounds and wear out 8 or 9 barrels in 300 WSM. If you want to know what works, listen to guys like dkhunt14, dmoran, 4x4fun, mikegaiz, and a handful of guys that have been shooting 1000 yard for 30-40 years.

If anyone has kept all record groups from a given barrel under 5 inches at a thousand, then I'll consider it.