short range VS. long range neck tension

[rmist]

short range VS. long range neck tension...I just read in another thread about short range guys using about .002"-.003" neck tension and long range prefer about .001" neck tension.

Why !! If the short range guys get fantastic groups with more tension why wouldn't the long range guys do the same ? Or vice versa ??
Thanx again

 

[mshelton]

It all has to do with what your rifle and component likes, nothing to do with the distance you're shooting at.

A lot of the short range guys use N133 in a 6ppc, N133 really likes neck tension.

 

[rmist]

So Varget, RL15, and the rest in a 6 br like less tension ? Besides seeing why works in a particular rifle.

 

[BoydAllen]

This is one of those things that individual shooters should be fully equipped to investigate on their own. All that it takes is a few sizes on neck bushings, some targets and a chronograph, things most serious shooters already have.

IMO one of the reasons that long range may need less neck tension is that the bullets typically used have higher sectional densities , and this may provide all of the resistance that is needed for powders to burn optimally. On the other hand, with some short range powders, 133 for instance, and the much lighter bullets that are usually used (that have lower SDs) case necks need to come into play to accomplish the same thing. There is also the matter of powder characteristics. I have shot short range powder that did not "care" about neck tension. This also gets into such things as seating depth, with some powders seemingly giving better results with bullets into the lands, and others doing better with a little jump.

Experiments to determine these sorts of things are generally expedited by loading at the range, something that a lot of shooters resist with all sorts of excuses. It seems to me that the real reason that they don't is that they have a built in resistance to any sort of change. If you want an example, look for a wind flag or barrel mirage shield on any range that you care to, except when a short range benchrest match is being shot. Most of us know that the wind moves bullets, and that the heat waves that come off of barrels distort the image that we see through the scope, but for most, the need to conform is much stronger than the desire for better results.

 

[amlevin]

And then there are those who use NO neck tension. Only enough "interference" to keep the bullet in place while being handled and chambered. Seated long and the rifling and bolt push the bullet back to a perfect OAL (for that rifle) every time.

Didn't Gale McMillan once say "Monkey See, Monkey Do."?

 

[Hanbleceya]

It all has to do with what your rifle and component likes, nothing to do with the distance you're shooting at.

A lot of the short range guys use N133 in a 6ppc, N133 really likes neck tension.

Interesting. Didn't know that about N133.

 

[ClassCat]

Interesting. Didn't know that about N133.

It's ALL about the pressure curve and vibration characteristics of that rifle

 

[Hanbleceya]

It's ALL about the pressure curve

I understand. Been sticking with Hodgdon but seeing such results from VV that seriously considering. thanks for the info ClassCat

 

[Tim Singleton]

Interesting. Didn't know that about N133.

Ive heard this "133 really likes a lot of neck tension" for years but never a lot of explanation
one of the biggest reasons is guys are shooting heavily compressed loads of 133 this causes the need of additional tension to keep the bullet seating depth from being all over the place the powder will push it out. this also has a lot to do with the migration of alot of ppc shooters to the .268 neck

 

[Hanbleceya]

Ive heard this "133 really likes a lot of neck tension" for years but never a lot of explanation
one of the biggest reasons is guys are shooting heavily compressed loads of 133 this causes the need of additional tension to keep the bullet seating depth from being all over the place the powder will push it out. this also has a lot to do with the migration of alot of ppc shooters to the .268 neck

I understand. Yet I wonder if the additional cost is worth it?? If a person wants a full case for efficiency, could they not get there with H322 or Benchmark? I haven't done a PPC yet. Just trying to understand.

 

[Tim Singleton]

A lot of guys are looking for a accuracy node up over 3400fps with the ppc. you can get there with other powders and we do use other powders but there are days when 133 is out shooting the others
the PPC is not like any other cartridge, think of it as a top fuel dragster
most times it has to be tuned hour to hour through out the day to shoot the kind of groups that will win. sometimes its 133 sometime Lt32 sometimes Lt30 or H322

 

[ClassCat]

F Y I Running a 262 neck with a 35 reamer for a PPC. The cases are cut to 25950 and using a 258 neck bushing with a Redding SB die.

30 grains plus or minus of 133 Sometimes it works and sometimes it doesn't

 

[BoydAllen]

A couple of decades back I was told about using more neck tension with 133. I was using a .258 bushing with a .262 neck chamber and less neck clearance than I do today. I changed to a .257 and my groups improved. It was noticeable and that was the only change. These days I cut my necks for more clearance and have moved to a .256 bushing. These things are easy to test, and I like doing experiments, they are no big deal, especially when loading at the range.