Do powders have an affinity for a particular neck tension?

[Mulligan]

In the short range group arena, I have heard several times that LT powders prefer (shoot smaller) with lighter neck tension and N-133 has a preference for more or higher neck tension.

Do these affinities for more or less tension follow the powder through all the nodes? To say this differently, If N-133 shows a preference for more neck tension at a lower charge (28.2 for example), does it generally have the same preference at say 29.2 or 30.2?

The reason for the question is, I am seeing conflicting data on the targets and any time I start to question or make excuses for data outliers, I get a bit twitchy.

Your experiences?

CW

 

[Fuj]

Speed of the powder can come into play. A slower burn rate
powder may need a bit more tension. Like anything, It falls into
the test and tune category.

 

[BoydAllen]

While I have tested133, and LT32 for this in the past, I have not done the same with LT30 and would not assume they were identical in this respect. This is so easy to test, especially if you are loading at the range, shooting over flags and the wind is not challenging. Let us know what your results are. The nodes you mentioned would be specific to only one powder, given that 133, LT32 and LT30 have different burn rates. How did you come up with those numbers?

 

[Beiruty]

from the test I saw, 0.002" below the bullet diameter would be ideal. However, I am not certain that powder burn rate would affect the need for more or less neck tension.
The best way is to test with the powder you would like to use.

 

[Joe Maisto]

from the test I saw, 0.002" below the bullet diameter would be ideal. However, I am not certain that powder burn rate would affect the need for more or less neck tension.
The best way is to test with the powder you would like to use.

A complicated topic, and perhaps no single answer. Most of us in SRBR in MI. at the Holton range were using a .262 neck chambering with a case neck thickness of .258. for 20 or so years. A few tried heavier cartridge case necks as in...269, but seemed to have returned to the previous. That was then...fast forward to 2021. A recent call to one of our competitors there informed me they have for the most part gone to a .268 cartridge neck. My thinking is that it was such a pain to turn the necks down TWICE to try and eliminate heat buildup it grew old. I certainly understand that, especially using the recommended lubrication for the "pumpkin" tool,( which resulted always having to remove it from inside the neck as well.

I do believe most of us have decided to let the barrel tell you what it wants. If conditions are good, and you do your part, the rifle will talk to you. SRBR can be a real "bugger" if you do not stay on top of your game. I know of 3 HOF shooters at Holton that go to the line with 3 different loads . If they don't like what they see with 2 rounds on the "sighter", they go to the next load.
By this time... we already have got other things kind of figured out pertaining to neck tension, bullet "jump"... or none.. At this point in the game, it often times comes down to dropping or increasing the powder a bit. Fwiw...I had a HART barrel that was on this new PPC back in '98. It could do no wrong no matter what load I used. It is referred to as a HUMMER.

 

[moondog]

Funny to see this. I was doing some load development for my 300 prc earlier this summer. I had about 7 that seated with more pressure than I normally like. No problem, I'll just use them for foulers.
At 1200 yards they shot much tighter. Go figure.