Neck sizing vs FL sizing and POI.

[GQshayne]

For the first time ever, I find myself in the position of making handloads using a neck sizing die on once fired cases. I have always prioritised fast loading of rounds in the field over accuracy and case life, so full length sizing has been my go to method. I started loading .243 in about 1986. It occurred to me yesterday that I don't own a neck die. Might have to get one.

And now I have two rifles where fast loading is not such a priority, and reloading for accuracy will be done for them. In my case, one of my .243's, and a .17Rem. I have a neck die for the .17 already.

Accumulating once fired cases for neck sizing will take a while, and in my rifles, FL sized loads shoot very well, so it is no big deal. But it occurred to me today, that the point of aim may differ between the two handloads. Anyone have any experience with this?

[Blr243]

I think it’s entirely possible that a factory cartridge floating around somewhere in the chamber could shoot to a different poi than a snug fitting neck sized cartridge but how much poi change can really only be discovered after a test shoot. Rabbit hunters at 300 m get right into this but for me it rarely matters. I find the biggest contributor to me hitting my target in the field is my ability to aim and shoot my rifle correctly ......On my last hunt I noticed when checking my scope zero my neck sized 243 handloads with 87 v max were shooting exactly same poi as my purchased factory ammo ppu 90 gn soft points .... And these are two completely different products ....... so we can get lucky sometimes.

[bladeracer]

For the first time ever, I find myself in the position of making handloads using a neck sizing die on once fired cases. I have always prioritised fast loading of rounds in the field over accuracy and case life, so full length sizing has been my go to method. I started loading .243 in about 1986. It occurred to me yesterday that I don't own a neck die. Might have to get one.

And now I have two rifles where fast loading is not such a priority, and reloading for accuracy will be done for them. In my case, one of my .243's, and a .17Rem. I have a neck die for the .17 already.

Accumulating once fired cases for neck sizing will take a while, and in my rifles, FL sized loads shoot very well, so it is no big deal. But it occurred to me today, that the point of aim may differ between the two handloads. Anyone have any experience with this?

I find significant velocity differences between neck-sized and shoulder-bumped due to the difference in capacity. Whether that translates to a significant shift in impact will depend on the specific load, but it's certainly possible.

[Stix]

Ive found not too much difference really.

Im basing that on a load thst works in your average FL sized case, then loaded & shot in that same case thats been neck sized...

By not much difference, i mean you'd be well n truly on the target.

The load might need tweaking, &/or have a diff point of impact.

I ususlly measure the diff in fl sized to fired case...if there's a huge diff in the measurment to the shoulder--like what you used to get in factory chambered rifles back in the 70's & 80's, (5, maybe even 7 thou or more diff) then re test in .3gr increments out to atleast a grain higher than the load you use for the fl sized case...

If its a modern chambered rifle, (eg, new Tikka), i usually find the load is pretty close to what worked in the fl sized case (well within a grain diff).

I dont have a 17, but the two 204's i have dont shift all that much on paper, nor does the load change much.
So if you have a neck die for the 17, id think you wont have too much of a diff in point of impact, nor in the load for the neck sized case...infact at worst you'd likely be very close still at 200m...

I guess its all somewhat relative to free space in the case/pressure...

Hopefully the other more experienced guys will correct or add to what ive said...

[JimTom]

Mate I neck size and then FL size about every 5th reload. Although as some have already suggested, a change in POI is possible, I think if you are just hunting then the shift in POI would be negligible at worst.
Put it this way, I haven’t noticed any difference at all but I am not the worlds best shot either.

[marksman]

if you want to use your fls die to neck size when you set it up instead of lowering the die to shell holder put a washer around 1-2mm thick inbetween and it will not size the body, or it shouldn't, it will leave a portion of the neck not touched that will center the case neck in the chamber

lMHO l would be buying a lee collet die

[GQshayne]

Thanks fellas, looks like experience has shown that it will depend on individual circumstances. I had a hunch that it SHOULD be much the same, and any difference would be minimal, but was interested if anyone had an opposite experience. Strange things happen sometimes.

And as for dies, as mentioned above I do not have one for the .243, so had a look last night, and mostly for sale were the collet dies. They can be bought as low as $36-40. A normal Hornady die was about $60. I have never used a collet die, but they seem to be well regarded. Shame I didn't buy one for the .17 when I bought the normal die for it.

[bladeracer]

Thanks fellas, looks like experience has shown that it will depend on individual circumstances. I had a hunch that it SHOULD be much the same, and any difference would be minimal, but was interested if anyone had an opposite experience. Strange things happen sometimes.

And as for dies, as mentioned above I do not have one for the .243, so had a look last night, and mostly for sale were the collet dies. They can be bought as low as $36-40. A normal Hornady die was about $60. I have never used a collet die, but they seem to be well regarded. Shame I didn't buy one for the .17 when I bought the normal die for it.

Just checked my logbook.
I tested neck-sized alongside shoulder-bumped by alternating them in the same set of five cases in .223Rem.
55gn RooMax on 26.5gn of AR2206H at 2.290".
Bumping the shoulder gives me 3326fps average with an ES over five rounds of 67fps.
Neck-sized gives me 3233fps average with an ES over five rounds of 39fps.

[Blr243]

Blade. Can u tell us if you got better groups with one bunch? Or if there was a poi difference.? Or perhaps you don’t have that info?

[bladeracer]

Blade. Can u tell us if you got better groups with one bunch? Or if there was a poi difference.? Or perhaps you don’t have that info?

Sorry, no I don't.
I was shooting a case life test using ten cases bumped and ten necked to see if there was any difference in case life.
I noticed the difference in velocities though so I did a test with the same five cases alternating between bumped and necked. But I was only recording the velocities unfortunately, just shooting into a dead tree outside my office, reloading them, and shooting them again.
I could do the test again though I guess and put them on paper.

[Blr243]

I can’t imagine how much legal trouble I might get into if I started shooting my rifle into a dead tree outside my office so back to you blade but only when u have time.

[bladeracer]

I can’t imagine how much legal trouble I might get into if I started shooting my rifle into a dead tree outside my office so back to you blade but only when u have time.

Actually, I did group them at least once.
https://enoughgun.com/forum/viewtopic.php?f=3&t=10133

Neck vs FLSb.jpg (53.07 KiB) Viewed 3185 times

I didn't record any difference in POI so it was probably not significant or measureable.
It would depend on where the load sits in the node, if you're close to the edge of a node, that 100fps could push it well out of the node.

[GQshayne]

Blade. Can u tell us if you got better groups with one bunch? Or if there was a poi difference.? Or perhaps you don’t have that info?

I think it is well accepted that accuracy is improved using only neck sized cases. My comment to you on another thread somewhere was that I FL resize when my priority is for fast follow up shots. This is often done for hunting dangerous game, or with lever actions. Basically where quicker is more important than accuracy.

So I think if you rule that out as unnecessary, and accuracy is your focus, then once-fired cases in the actual rifle concerned, then neck sized, are the most accurate. It makes sense that a method considered to provide better accuracy would also provide less variance with velocities. So you can expect group to tighten up. But maybe not move the average point of aim.

I am prepping (case tumbler going as I write this) my remaining unfired cases for the .17. My test groups were about half MOA, so no need to worry about fire forming. I will just use them normally and neck size down the track somewhere.