.001 vs .002 neck tension...thoughts

[Davehc130]

Decided to change my reloading process... rather than use expander in die when resizing I am going to expand neck with mandrel after resizing... now for hunting with 6.5 creed and 6.5 PRC I need to decide.001 or .002 neck tension... goal is to get better concentricity and lower SD/ES ...

thoughts???? Concerned .001 might not be enough for recoil on bullets in mag during shots...

 

[spife7980]

Then go with .002, most people do.

Expander mandrels are .001 under caliber size, turning arbors are .002 under caliber.

 

[Dave62677]

go with .002, u also need to put the neck thickness into the equation. a very thick neck with .001 tension might have more tension than .002 thinner neck case.

play around with it and get some actual data.

 

[kthomas]

Try it out and decide for yourself, bushings are inexpensive.

I went through the same thing with 6BRA, but between 0.002 and 0.003 neck tension. Was curious if there was any difference in SD/ES. I found out there wasn't. Stuck with 0.003 as it was the last bushing in the die.

 

[RTH1800]

Not sure what you are going to be hunting but reliability trumps getting the last few FPS off the SD.

 

[Milo 2.5]

Neck Tension

Ok first off I’m no newbie to reloading but I always love to know how others are doing things. Question: How do you know when your neck tension is correct or enough and how do you go about checking it? Once I get enough answers, I’ll let you know what the Ballistician’s say.

www.longrangehunting.com

Read this if you can get through it w/o your head exploding. One guy is extremely vocal, but provides no answers.

go with .002, u also need to put the neck thickness into the equation. a very thick neck with .001 tension might have more tension than .002 thinner neck case.

play around with it and get some actual data.

Good post and thoughts !
You fire new brass one time and necks are thinner. So initial measurements may not be relevant. I play with what I consider neck tension more that most to tighten group size.
But after reading my linked post, I question my theory, I never measure, and go off felt seating force. The most vocal guy in that post makes good points on seat force, as friction may be part of it. He goes on to say bullet release happens in X amount of time, I would like to know who came up with that exact number. Late this summer, I processed some dasher brass for the 4th time, annealing each firing(AMP), and on the 5th firing, after my seating force felt inconsistent, it did not shoot well. My cure was to sonic clean it, and for some reason my seat force felt more acceptable, and so did my downrange results. Thankfully, I test 10 pcs of brass before I process the rest of it.
So as you say., getting your own data is the key

 

[kthomas]

Don't be afraid of more neck tension. Some record setting benchrest shooters and gunsmiths use up to 0.006 neck tension or more.

You aren't limited to 0.001-0.002 for a precision rifle.

 

[Feif64]

I use .002 for my 6.5 creedmoor in Lapua brass

 

[Davehc130]

go with .002, u also need to put the neck thickness into the equation. a very thick neck with .001 tension might have more tension than .002 thinner neck case.

play around with it and get some actual data.

Thanks. I neck turn everything to .145

 

[918v]

Neck tension is one of several variables affecting bullet release. Others include neck diameter BEFORE you expand it, neck inner surface condition, neck hardness, and neck thickness. So when taking advice from others, take those variables into account.

 

[spife7980]

You are being redirected...

 

[memilanuk]

Don't be afraid of more neck tension. Some record setting benchrest shooters and gunsmiths use up to 0.006 neck tension or more.

You aren't limited to 0.001-0.002 for a precision rifle.

I routinely run 3 thou neck tension - measured with pin gauges - on my competition FTR gun. Not sure if that counts as 'precision rifle' or not

 

[gnatmm]

Look at xxicsi.com mandrel sets. You will be able to tune your tension with 0.0005 granularity

 

[JWHanks]

Disclaimer: I'm relatively new to this level of reloading so take that for what it's worth.

I recently changed from .001" tension to .003". I do not have anything other than a caliper to determine this so I'm not sure how reliable that is. I have, however, seen my groups and SD tighten up and become more repeatable. I went from a .289" bushing down to a .287" (on redding dies) to give reference. The best I can tell; the factory rounds I measured were .290" below the top of the brass and any crimp/chamfer (where I understand the neck tension is measured).

 

[ThePretzel]

I run 2-3 thousandths of neck tension, but I don't know the exact number. I actually use a bushing die with an expander ball. The bushing I use would create ~6 thou of tension on its own, but then that's followed up with an expander ball 0.001" undersized. Leaves me with ~2-3 thou of neck tension.

The two main reasons I like the expander ball:

• I like that I am smoothing the brass out both inside and out - you can't fix even small dents in the neck by squeezing from the outside alone
• I don't have to worry about neck turning my brass to get consistent neck tension

The only real downside to it is that you work the neck a little bit more during the sizing process by oversizing and then expanding. I'm not too concerned about that though, especially since there are a few local guys who can help me out with annealing if I need it.

 

[Frankk]

I bump my brass with a Forster full length sizing die that has been custom honed for me at the factory. I run it without the expander spindle. I had neck portion of that die honed to 4 thou under final neck diameter of my particular brass with bullet installed.

Then I use a separate expander mandrel die (1 thou under) to expand my necks.. But I expect my actual holding tension is about 1.5 thou because of springback.

 

[memilanuk]

I expect my actual holding tension is about 1.5 thou because of springback.

Pretty easy to actually check with pin gauges...

 

[Tokay444]

I bump my brass with a Forster full length sizing die that has been custom honed for me at the factory. I run it without the expander spindle. I had neck portion of that die honed to 4 thou under final neck diameter of my particular brass with bullet installed.

Then I use a separate expander mandrel die (1 thou under) to expand my necks.. But I expect my actual holding tension is about 1.5 thou because of springback.

And what are your results down range?

 

[PracticalTactical]

Pretty easy to actually check with pin gauges...

Reading through this thread it's interesting how guys think they are maintaining closer neck tension tolerances that you really are.

milanuk eludes to the point regarding pin gages in his post and if you are not checking every case with pin gages, you really don't know how much neck tension you really have, and that is regardless of expander ball, mandrel or bushing.

Without neck turning and running a tight neck... Maintaining a 0.001" neck tension tolerance is harder to do than you would think when you consider variations in neck wall thickness and variations in individual neck hardness.

Hard necks have more spring back and require more stretch to get where you want to be than softer necks.

Another factor is how far you are re-forming the neck. There is an elastic effect where a small move has more spring back than a larger move.

You can test this yourself with bushing dies, by starting with a bushing that is 0.002" larger than what will hold a bullet. Size all the necks in a lot of 50 cases and check if any will hold a bullet. Then reduce the bushing to the next smaller size and do it again.

Separate any cases that are small enough to hold a bullet, and size the rest to the next smaller bushing.

I do not know the technical term for it, but by about the third or fourth bushing the rounds will suddenly move farther than 0.001 smaller and that is because its overcoming spring back.

And to the Ops question... this is more about what happens to the loaded round between the mag and the chamber than it is a ballistic performance question. Look closely at what the bullet bumps into coming out of the mag before it enters the chamber and you will see that more neck tension is a better place to be to keep the bullet from moving during that feeding process.

Single shot hand fed rounds can work really well with very little neck tension, but that is not practical when feeding from a mag.

 

[Pge]

Reading through this thread it's interesting how guys think they are maintaining closer neck tension tolerances that you really are.

milanuk eludes to the point regarding pin gages in his post and if you are not checking every case with pin gages, you really don't know how much neck tension you really have, and that is regardless of expander ball, mandrel or bushing.

Without neck turning and running a tight neck... Maintaining a 0.001" neck tension tolerance is harder to do than you would think when you consider variations in neck wall thickness and variations in individual neck hardness.

Hard necks have more spring back and require more stretch to get where you want to be than softer necks.

Another factor is how far you are re-forming the neck. There is an elastic effect where a small move has more spring back than a larger move.

You can test this yourself with bushing dies, by starting with a bushing that is 0.002" larger than what will hold a bullet. Size all the necks in a lot of 50 cases and check if any will hold a bullet. Then reduce the bushing to the next smaller size and do it again.

Separate any cases that are small enough to hold a bullet, and size the rest to the next smaller bushing.

I do not know the technical term for it, but by about the third or fourth bushing the rounds will suddenly move farther than 0.001 smaller and that is because its overcoming spring back.

And to the Ops question... this is more about what happens to the loaded round between the mag and the chamber than it is a ballistic performance question. Look closely at what the bullet bumps into coming out of the mag before it enters the chamber and you will see that more neck tension is a better place to be to keep the bullet from moving during that feeding process.

Single shot hand fed rounds can work really well with very little neck tension, but that is not practical when feeding from a mag.

Hello!

That makes a lot of sense! So you set yours to .001 to keep the bullet tight while chambering the round. Or are you using .002? I can't locate previous info from your thread response. I wondered also about bullet contact while running out of the mag.

Thanks!

Thanks!

 

[PracticalTactical]

Hello!

That makes a lot of sense! So you set yours to .001 to keep the bullet tight while chambering the round. Or are you using .002? I can't locate previous info from your thread response. I wondered also about bullet contact while running out of the mag.

Thanks!

Thanks!

It depends on the rifle and intended use.

For single shot events like F Class I use the least possible neck tension. Just enough to hold the bullet and no more. The thinking is that variations in neck tension will adversely affect velocity spreads. So if there is less neck tension then there is by default, less variation in neck tension.

Now light neck tension doesn't work well when feeding from a mag, so in a mag fed rifle, I'm more concerned about the bullet staying in place as it comes out of the mag and the tip of the bullet bumps into the feed ramp.

In mag feed rifles I use 0.002" neck tension regardless of what might produce the most consistent velocity spreads.

In mag feed loading I need to be just as careful as for F Class. When loading for a match I just run all cases through a bushing that is too large and then incrementally cycle all rounds through progressively smaller bushings until a bullet will stay in place by hand, then drop two more bushing sizes and pull that case out of the batch.

I just keep cycling through until all cases are 0.002" smaller than what bushing it took to hold the bullet.

It can also help to use gage pins if you prefer. You can use the same method and just go until a gage pin 0.002" smaller than the round cannot be pushed into the neck. Then put that case aside and continue with the rest.

If your necks are turned, then the bushing will reflect neck hardness, with the larger bushings being used on softer necks. The rounds that require the smallest bushing are most in need of anneal.

You can get a cheap set of gage pins off ebay out of china for about 40 bucks. Then you can use them to test for primer pocket expansion as well.

Note: When using this much neck tension, it can be hard to seat a bullet if you do not put a nice lead chamfer on the inside of the neck. For this I use a cone shaped carbide burr... none of that cheap crap RCBS or Lyman sells for this. Its a 1/4 inch shank cone shaped carbide burr. They come two ways... one with solid flutes and others have interrupted flutes... they call those chip breakers.

Just chuck it in a drill and its goes quickly.

 

[Pge]

It depends on the rifle and intended use.

For single shot events like F Class I use the least possible neck tension. Just enough to hold the bullet and no more. The thinking is that variations in neck tension will adversely affect velocity spreads. So if there is less neck tension then there is by default, less variation in neck tension.

Now light neck tension doesn't work well when feeding from a mag, so in a mag fed rifle, I'm more concerned about the bullet staying in place as it comes out of the mag and the tip of the bullet bumps into the feed ramp.

In mag feed rifles I use 0.002" neck tension regardless of what might produce the most consistent velocity spreads.

In mag feed loading I need to be just as careful as for F Class. When loading for a match I just run all cases through a bushing that is too large and then incrementally cycle all rounds through progressively smaller bushings until a bullet will stay in place by hand, then drop two more bushing sizes and pull that case out of the batch.

I just keep cycling through until all cases are 0.002" smaller than what bushing it took to hold the bullet.

It can also help to use gage pins if you prefer. You can use the same method and just go until a gage pin 0.002" smaller than the round cannot be pushed into the neck. Then put that case aside and continue with the rest.

If your necks are turned, then the bushing will reflect neck hardness, with the larger bushings being used on softer necks. The rounds that require the smallest bushing are most in need of anneal.

You can get a cheap set of gage pins off ebay out of china for about 40 bucks. Then you can use them to test for primer pocket expansion as well.

 

[Pge]

Understood!

I reloaded a lot 40 years ago. 7mm Mag, 30-30 etc.

I am doing PRS Matches now and have been using factory loaded Hornady 147 ELD. 500 so far. And, they actually worked great. Shooting out to 1100 yards. But recently the FPS dropped almost 200 FPS! Not cool.

I had been gathering reloading equipment again for about 3 months now just because of cost and wanting to have absolute control over consistency. Then this last production factory batch fell of the cliff! I've contacted Hornady but no reply yet.

That sped up my reloading needs!

Now trying to decide is I should start with 147 in my reloads or go lighter and faster.

 

[Rocketvapor]

Ammo or Throat?

 

[Pge]

Sorry... Bullet

 

[LR51]

Graphite on the inside of the neck Is a thing as well