Neck Tension - Generally Speaking

[MikeMcCasland]

For you guys shooting F-Class, I'm curious... generally speaking how much neck tension do you start your load development with? I'm talking about once fired brass, not new/mandrel expanded stuff.

I know the correct answer is you need to find what the gun likes, however we all know barrels have limited life, and it's better if you can find a load more quickly.

I'm also curious, at a high level, do you typically find most rounds seem to prefer tension lighter or heavier tension?

If you are testing with different size bushings or expanders, at what point in your load dev process do you start this test?

Thanks in advance!

 

[ngb1787]

Mike, as long as they are all the same tension, that is most important thing. I run around 1lb. Also run a mandrel thru your necks the day of reloading. I know guys who run 20lbs of tension and they shoot just as well because they are all the same.

 

[6MT]

I would tend to agree. Consistency should be your goal.

 

[F Class John]

I’ve been running .0005 for a while now and my gun likes it. My buddy has been running .00350 cuz that’s what his gun likes. But as has been stated, consistency either way is crucial and without there’s no point.

I would say in my experience anything around .005 or less is what I’ve seen and allows you to really know how your load is affecting pressure as opposed to using neck tension to bump pressure which is more variable shot to shot.

 

[MikeMcCasland]

Thanks for the responses; I agree with consistency, for sure.

For the sake of discussion, let's assume it is consistent...you're neck turning, annealing every firing, and sizing/seating within hours of each other.

 

[F Class John]

Go test it. Load up some different tensions with all other things being equal and see what happens. You’ll probably be surprised by how much tension affects your groups.

 

[Texas10]

I just tried Moly ( no, not that Moly) on the necks during seating and all I've got to say so far is.....WOW. Can't wait to see how they print.

 

[MikeMcCasland]

Go test it. Load up some different tensions with all other things being equal and see what happens. You’ll probably be surprised by how much tension affects your groups.

I've tested it before in the past, and will do so again this weekend. Most recently, adding a .001 smaller bushing turned a fairly accurate load into a shotgun pattern, so I know it can have a profound impact.

I'm just curious what most F-Classers are starting with as far as tension goes. I suspect most veterans aren't burning up hundreds of rounds in load dev, and they've got to start somewhere.

 

[F Class John]

The bushing is only one part of the equation when it comes to neck tension. You can’t accurately say what you neck tension is until you use a mandrel or gage pin to expand it out (not a ball expander). This is ultimately how you accurately measure your neck tension. Anyway, I’m at .0005 like I said. So is another HM buddy of mine. Another HM of mine has .005 and another .0035. There’s what we do. Others will probably vary quite a bit.

 

[Ned Ludd]

Mike - any eagerness you might have to use minimal neck tension (interference fit) of ~.001" or less might diminish markedly the first time you close the bolt during a match, then decide to remove the loaded round when the wind changes, and dump powder all over the inside of your action because the bullet remained stuck in the throat of the rifle.

When I started reloading for F-TR, almost everyone I spoke with was using .002" interference fit (i.e. neck of round with a seated bullet is .002" greater than before seating the bullet). I have used .002" for pretty much every F-TR rifle/caliber I own and it works pretty well. Although I have played around with neck tension just for the purpose of experimentation, I have yet to find any good reason to routinely test a bunch of different neck tensions with F-TR loads. It simply hasn't been necessary with my various .223/.308 loads. At this point, I would only try different neck tensions as a last resort; there are too many other good and easier methods to tune and adjust a load (i.e. powder, seating depth, primers).

 

[rardoin]

If you start with between 0.0005-0.0015" you should find a 'happy spot'.

 

[MikeMcCasland]

Mike,
As you know, I'm an average shooter on a good day. My experience is that the lighter the neck tension the better the groups, however there is a fly in the ointment. I've also experienced fliers that give me the dreaded 9s and occasionally an 8.

Is this due to neck tension? I believe that it is due to a bullet moving further into the case and changing seating depth. But I can't be sure. I am an alumni of the Stevie Wonder School of Wind Reading, so there is that to consider too.

Joe

Joe,

Hah! I love it. Thank you for the response.

I'm currently enrolled in the same school, but trying to fast-track my learning by taking night classes at the M.J. Fox-Folgers school of position shooting. I think my results are reflective of all that hard work.

 

[fatelvis]

I usually keep my neck tension at .001”, and make sure I never jam.

 

[dcali]

I think neck tension is an over-emphasized variable myself. I’ve used everything from just under .001 to over .003, and never had trouble finding an acceptably good load. Generally I prefer less for reasons that are both practical and theoretical - it’s easier to seat bullets without scraping them up, and I believe that light neck tension is more consistent if you do not anneal, and I don’t. But in reality, I’ve never not been able to make a load work because of neck tension.

 

[D-4297]

On softer brass like Peterson , I've found that .001 - .0015 interference works , and gives me a consistent pattern on target . For Lapua SP , my rifle seems to like only .0005 interference . I use Dry Lube when seating , and none of my loads EVER touch , and I don't JAM . 70 - 75 rounds of 200gr .308 are enough with the load I'm using , without adding to recoil by Jamming a bullet . I use a expander & do not turn . Anneal after every firing .

 

[johnnyi]

For you guys shooting F-Class, I'm curious... generally speaking how much neck tension do you start your load development with? I'm talking about once fired brass, not new/mandrel expanded stuff.

I know the correct answer is you need to find what the gun likes, however we all know barrels have limited life, and it's better if you can find a load more quickly.

I'm also curious, at a high level, do you typically find most rounds seem to prefer tension lighter or heavier tension?

If you are testing with different size bushings or expanders, at what point in your load dev process do you start this test?

Thanks in advance!

.001 is a great starting and finishing point. For me seating pressure is much more consistent lower neck tension. Honestly I have never developed a load that I felt like I needed to adjust neck tension to do any additional tuning.

Measure the loaded neck and pick the bushing .001 under that.

 

[MikeMcCasland]

Thanks guys; really appreciate some insight into what some of you more experienced F-Classers are doing. I don't really have any intention of going back to the drawing board for most of my loads; really just wanted to know for future reference.

I'd been using a .002 smaller bushing as a 'default' for all load development, and hadn't found any issues. For future barrels, it sounds like I'd at least gain some consistency on seating pressures by going up .001 in size.

I appreciate it!