Please critique my plan for setting neck tension

[precision.riflecraft]

Well EK is a smart guy..

But consider this’ start with plenty and work your way towards optimum by testing side by side .001 at a time, you may find that light hold produces erratic groups as well as too much hold.

Cheers, I'm looking forward to experimenting. I'm also curious whether .001-.002 tension is enough to withstand fast cycling from a magazine without disturbing the bullet when it hits the feed ramp.

 

[acloco]

0.001 neck tension on a round with recoil?

 

[precision.riflecraft]

Probably not.

Interesting, guess I'll find out.

 

[precision.riflecraft]

0.001 neck tension on a round with recoil?

Yeah, a .300 PRC, but in a heavy, braked rifle. I guess you're saying I'll need to single-feed them if I want that little tension?

 

[acloco]

Maybe. Sorry....but that is the answer.

As you reload your brass X number of times, you might have to anneal every 6th load, 3rd, of ??? Brass composition is a variable as well.

I give a light crimp on the heavy recoiling rifles, braked or not. Some barrels/brass/bullet combos like a light/medium/heavy crimp, but, some do not like any crimp.

You are on the right path, control the neck tension, what your barrel/bullet/powder/primer/brass combo will like.......well......let us know what you find out!!

 

[precision.riflecraft]

Maybe. Sorry....but that is the answer.

As you reload your brass X number of times, you might have to anneal every 6th load, 3rd, of ??? Brass composition is a variable as well.

I give a light crimp on the heavy recoiling rifles, braked or not. Some barrels/brass/bullet combos like a light/medium/heavy crimp, but, some do not like any crimp.

You are on the right path, control the neck tension, what your barrel/bullet/powder/primer/brass combo will like.......well......let us know what you find out!!

Cheers man! I'm looking forward to experimenting, keeping notes and learning more. I plan to anneal after every firing, using an AMP induction unit for consistency.

 

[338 dude]

Hi everyone, my first set of dies is on its way! I ordered a Redding Competition seating die, VLD stem and Type S FL die for the Cadex .300 PRC that's in the works. I also have a box of Lapua brass on the way. I have Retumbo, 250 gr A-Tips and CCI primers ready to roll.

I was planning to set neck tension with just the bushing in my FL die, but I saw a video that showed how the Type S dies produce up to .003 of runout with that method, whereas doing so with an expander mandrel caused less than .001 using the same brass (can't recall which brand).

So now, my plan is to bump the shoulder and size the neck down with the Type S FL, then open up the neck to its final size using a 21st Century expander mandrel die. Here's my question:

What should I set the initial tension to? My idea is to set it to .002 with the bushing, then push a .307 mandrel down to get to .001, which I've read will be about .0015 with springback. My thinking is that this will reduce working of the brass compared to a non-bushing FL die, especially with thick Lapua cases.

Is this what you guys would recommend, or should I use a tighter bushing, say, setting initial tension to .003 before opening it up with the mandrel? I'm relatively new to precision handloading.

.001 is fairly light I like to shoot for at least .002 then end up with .0025 because don’t forget when you size with a bushing it Springs out (bigger)when you size with a mandrel the spring back is inward (smaller)

 

[Coyotefurharvester]

#17 o ring under the lock nut/ring slightly compressed is supposed to allow the die to "float" self center. Reducing neck runout from sizing die. I don't have run out measuring equipment, but I have used it with my 17 rem, and 22-250(only custom barreled rifles I have). I FL size everything.

 

[PracticalTactical]

I have yet to find runout on a fired case. The more you size the case after firing, the more you screw it up. Run tight necks and then you don't have to size much... Ergo, you will get really great runout.

 

[Dusty Stevens]

Make sure the bushing rattles a tad before you install the die. Forget the runout and start with .003 neck tension for that round

 

[fatelvis]

Make sure the bushing rattles a tad before you install the die. Forget the runout and start with .003 neck tension for that round

Way too much is made of runout IMO. I sold my Accuracy One gauge after playing with it extensively and finding that I was worrying too much about it, and it didn't affect my groups noticeably. With the recoil of the PRC cartridge, and if you're feeding from the magazine, I'm with Dusty, I'd go with .002" Minimum, and probably closer to .003" neck tension. And also make sure the stamped size on the bushing is facing down.

 

[mikecr]

Tension is not interference.
Measure loaded neck OD, pull the bullet, measure free neck OD. The force of that springback (~1/2thou) against an area of bullet bearing was your tension (in PSI).
Down sizing to greater interference will just be undone with bullet seating (using your bullets for expansion).

Rational tension is available with .5 to 1thou interference, from normal hardness necks.
It's best adjusted with LENGTH of neck sizing against seated bearing, and not beyond.

If concerned that this grip won't hold under recoil and rough chambering, then lightly crimp into bullets with a cannelure for this, or increase sizing length slightly beyond seated bearing length.
I would never do either with a bolt action.

 

[precision.riflecraft]

.001 is fairly light I like to shoot for at least .002 then end up with .0025 because don’t forget when you size with a bushing it Springs out (bigger)when you size with a mandrel the spring back is inward (smaller)

Thanks, I'll remember that. I think I'll start with .0015 with the springback, then run through a five round mag, removing the last round after chambering it to check OAL and runout to see if running it up the feed ramp (as well as the recoil of the previous four firings) affected the bullet. If it does, I'll move up to .0025 and try again.

 

[precision.riflecraft]

Way too much is made of runout IMO. I sold my Accuracy One gauge after playing with it extensively and finding that I was worrying too much about it, and it didn't affect my groups noticeably. With the recoil of the PRC cartridge, and if you're feeding from the magazine, I'm with Dusty, I'd go with .002" Minimum, and probably closer to .003" neck tension. And also make sure the stamped size on the bushing is facing down.

Thank you - I'll experiment and report back.

 

[precision.riflecraft]

Tension is not interference.
Measure loaded neck OD, pull the bullet, measure free neck OD. The force of that springback (~1/2thou) against an area of bullet bearing was your tension (in PSI).
Down sizing to greater interference will just be undone with bullet seating (using your bullets for expansion).

Rational tension is available with .5 to 1thou interference, from normal hardness necks.
It's best adjusted with LENGTH of neck sizing against seated bearing, and not beyond.

If concerned that this grip won't hold under recoil and rough chambering, then lightly crimp into bullets with a cannelure for this, or increase sizing length slightly beyond seated bearing length.
I would never do either with a bolt action.

Cheers, lots to learn, but I definitely won't be crimping or selecting a bullet with a cannelure. I chose the 250 gr A-Tip. No compromises I'll experiment with neck tension and report back.