A 30BR likes "neck tension ".... a discussion ensues.

[TommyD11730]

There is only one person I know locally who shoots 30BR. First time out with my 30BR he made the statement you see in my title. I just nodded and didn't say much.

So while I hate the term "neck tension" I absolutely agree your reloading technique can definitely 100% change the force required to seat a projectile.

Other then me pulling on the little arm on my arbor press and noting "yep I have to pull harder " I had no idea what I was feeling.

So I get suckered into the force pack to see if I can "measure" what I'm feeling on the press.

A 325" neck bushing with the dies expander ball was used to "prep" the neck. This results in a easy to seat avg between 20-23 "pounds" of force.

Same brass but a 324" bushing is used. A .3055" mandrel was used vs the .307" dies expander ball. These resulted in a much firmer pull on the press with a 30-33 pound average.

So... I guess I'm just interested in hearing from the fellow 30BR shooters on this subject.

Thanks

 

[Rwfish]

Using a .324” bushing in FL then seating W/ Wilson micrometer die I note my initial is 18”- 20” to get the bullet moving into neck then at seat I’m 30” - 34” also on the force gauge. Anything that appears to seat light on initial or final seat goes in the sighter box. I’m new to 30br so the gauge is more for me to learn what feels right and what is out of the avg. Lapua 6br brass, no anneal w/ BIB 118 10o bullet.

 

[steve210]

I normally use a bushing 3-4 thousands smaller than loaded neck diameter. The only number that matters much is which one shoots better.

 

[Owens85]

For me a tighter bushing has showed to be more consistent and tighter groups with the 30br. I use a bushing with out using a mandrel or expander ball. A 324 bushing with the bullet and amount of neck thickness I have gives me around 40 lbs of force on force pack but that also can change with the condition of the inside of your necks.

 

[jackieschmidt]

I turn my necks to .0098.
My reamer does make a .330 neck.
I use a 325 bushing.

It shoots great, so I’m not going to change it.

 

[Bill Norris]

My chamber neck is .330 - turn brass to .098 - use .324 bushing w/.306 exp. - loaded neck diameter .328

 

[20PPC]

More neck tension in a 30 BR is your friend.

 

[AlNyhus]

I don't use any sort of expander or mandrel. If the necks are turned well, a bushing is all I've ever found to be needed. Smaller bushing gets you more neck tension, larger gets you less.

One thing about bushings...the numbers on them aren't always what they measure with a pin gauge. Make sure and verify this so you're comparing apples to apples when swapping bushings.

 

[ELR LVR]

I use one of these to measure seating force required if it helps you any
Apply the tip to press arm and measure force required
They come in different scales

 

[Chris Edmondson]

So I get suckered into the force pack to see if I can "measure" what I'm feeling on the press.

A 325" neck bushing with the dies expander ball was used to "prep" the neck. This results in a easy to seat avg between 20-23 "pounds" of force.

Same brass but a 324" bushing is used. A .3055" mandrel was used vs the .307" dies expander ball. These resulted in a much firmer pull on the press with a 30-33 pound average.

The force pack is an indicator of peak force which is useful, your 30-33 pound-force average is right about what I shoot for as the neck tension sweet spot, albeit in a different caliber. I've tried the 20's, the 40'a and the 50's I always come back to the 30's.

Even though I can pull more data from this gage, I've convinced myself there's no target-result reason to dwell in the weeds .

 

[TommyD11730]

but that also can change with the condition of the inside of your necks.

That brings up an excellent point. Is friction your friend or enemy? I would be interested to hear how people are cleaning/prepping their necks as well.

For me 1st step after decapping is annealing. I use a dry lube inside the neck when sizing with a mandral. If the case isn't trimmed I will champer and brush the neck. Lastly I Tumble in rice for a couple of hours.

 

[TommyD11730]

One thing about bushings...the numbers on them aren't always what they measure with a pin gauge. Make sure and verify this so you're comparing apples to apples when swapping bushings.

Wow. While that may seem incredibly obvious to some, I never thought of that. An excellent point, thank you!

 

[jobhopper66]

Regarding pin gauges, once you have a set it's amazing all the things you find yourself checking. From sizing bushings to the neck diameter in a benchgun chamber. I have not regretted buying my sets at all.

 

[TIMO]

Regarding pin gauges, once you have a set it's amazing all the things you find yourself checking. From sizing bushings to the neck diameter in a benchgun chamber. I have not regretted buying my sets at all.

Yes, and I use multiple pin gauges to identify neck/bullet interference fit (not neck tension) to segregate and adjust by using a different neck bushing.

Just my .02
Tim

 

[Mulligan]

For all you folks with sets of pin gauges, I'm sure you looked around and sought out what best would meet your needs.
What brand or set do you recommend?

CW

 

[Chris Edmondson]

For all you folks with sets of pin gauges, I'm sure you looked around and sought out what best would meet your needs.
What brand or set do you recommend?

CW

Unless you want to spend a boat load of money, decent M1 and M2 minus pin gage sets on Amazon are most likely the best balance between quality and cost. These for example: https://www.amazon.com/HFS-Steel-Mi...ext&ref_=fplfs&smid=A2QSX0WT38UK5G&gQT=1&th=1

I have M1 and M2 minus sets because I'm a hobby machinist in my own delusional way . If you only need to check a few different calibers and features, it may be possible to buy just the individual pins you need.

It's also not unwise to have a micrometer on hand which resolves to better than the pin gage stated tolerance, or to the tolerance you require; just because a minus pin is stamped .025", it may be .0249 or .0248, if any of that matters.

 

[Oldman1950]

The set listed above is the set I have. I have had the set for 6 or 7 years and have used them often. I use them to make sizing push thru dies on my lathe as well as checking bore size on many different barrels.

A. J. Palik

 

[jackieschmidt]

This is kind of an opinion, but of all of the tuning tricks we use, neck tension is the one with the least affect.
1st is powder charge.
2d is seating depth, possibly equal to powder charge if both are in the ball park.
Third is neck tension, often having no affect at all.

I have shot matches where some of the bullets seated with hardly any noticeable effort, others seemingly much tighter.

They all shoot the same.

I’m not saying that some of the stuff everybody pontificates about does not have merit, I’m just saying it doesn’t seem to show up on the target at 100/200 yards.