338 Lapua loaded neck size please

H

Hoverp

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Oct 20, 2009
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#1
for those using the 338 Lapua brass could you please tell me the mic'ed neck diameter of a loaded round.


Im trying to get my redding neck bushing bought and but I dont have any loaded rounds to measure yet.

I have one .366 but want to know what your average loaded round measurement is. I will be shooting 300 SMK or 300 Bergers.



Thank you
 
#3
Re: 338 Lapua loaded neck size please

The .366 for the first 4 firings then if you don't anneal you will need a .365. I would get a .365 now just in case your run of brass is on the thin size. This should give you about .0025" of neck tension.

This is with Lapua mfg brass

Jeff
 
#4
Re: 338 Lapua loaded neck size please

Thank you Broz. Good info.

I was at the reloading store at Angeles Shooting Range today and picked up the TiNi .364" and .365" bushings. My one size fits all FL Neck die is sizing the brass down too far then having to work it out with the expander ball.

Last week I ordered the Competition Bushing 3-Die Neck Sizer Set only to find out it has no expander ball. I think I would have rather ordered the less expensive Type S Match Bushing 3-Die Neck Sizer Set. Oh well.
 
#5
Re: 338 Lapua loaded neck size please

I have through much Hipower shooting, and Long range competition found that using a Carbide neck turning mandrel, those are found at Sinclairs, do a much more uniform resize. I like to use a FL or neck sizer with the expander ball removed, sizeing down the necks about about 2-3 thous. then take the carbide mandrel for one run through the neck. let it sit for about 5 seconds while inserted. Yes it is one more step but that long straight mandrel does a nice job for a unifrom and concentric final product.

Dont buy the "expander" mandrel as this will be too big. Buy the neck turning carbide mandrel and the holder for it. once you use it I dont think you will go back.


Just my .02.

thanks for the info on the loaded round size.

Patrick
 
#6
Re: 338 Lapua loaded neck size please

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: dstewart51</div><div class="ubbcode-body">Thank you Broz. Good info.
Last week I ordered the Competition Bushing 3-Die Neck Sizer Set only to find out it has no expander ball. I think I would have rather ordered the less expensive Type S Match Bushing 3-Die Neck Sizer Set. Oh well. </div></div>

I use the comp set now. I never use expanders, they seem to introduce way to much run out for me and why over work the brass? I think once you start using the new set you will be pleased.

Jeff
 
#7
Re: 338 Lapua loaded neck size please

I am just getting into reloading the .338 LM. I plan on using a regular FL die for decapping and sizing the case. Then I plan on using a Wilson style micrometer seater on my mini press. I have a Lee single stage press for my FL & decapping work. Any suggestions on the dies I should buy? Then I will need to buy a neck bushing to match. I also plan on loading 300 SMK or 300 Berger Hybrid along with some 250 grn bullets. Thanks
 
#9
Re: 338 Lapua loaded neck size please

I measure 2.190" head to shoulder on all my factory Lapua loads. My once fired brass is coming out at 2.1925" so I have been bumping the shoulder back to 2.191", just enough to know Im touching the brass at the shoulder. The reloads seem to feed and extract nicely.

Edit, using the 20 deg Sinclair Bump Gage Insert to measure.
 
#10
Re: 338 Lapua loaded neck size please

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: dstewart51</div><div class="ubbcode-body">I measure 2.190" head to shoulder on all my factory Lapua loads. My once fired brass is coming out at 2.1925" so I have been bumping the shoulder back to 2.191", just enough to know Im touching the brass at the shoulder. The reloads seem to feed and extract nicely.

Edit, using the 20 deg Sinclair Bump Gage Insert to measure. </div></div>

What is the datum line measurement on the 338 Lapua brass?
 
#11
Re: 338 Lapua loaded neck size please

Are you asking what is a datum line measurement or what a typical datum line measurement would be?

The Sinclair bump gauge insert I have measures from the shoulder angle and not necessarily from a "datum" line. The Stony Point (now Hornaday) headspace gauge set measures from a datum line.
http://www.hornady.com/store/Headspace-Gauge-Bushings/
The Datum line is just a fixed reference point somewhere near the middle of the shoulder.
 
#12
Re: 338 Lapua loaded neck size please

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: dstewart51</div><div class="ubbcode-body">Are you asking what is a datum line measurement or what a typical datum line measurement would be?

The Sinclair bump gauge insert I have measures from the shoulder angle and not necessarily from a "datum" line. The Stony Point (now Hornaday) headspace gauge set measures from a datum line.
http://www.hornady.com/store/Headspace-Gauge-Bushings/
The Datum line is just a fixed reference point somewhere near the middle of the shoulder.

</div></div>

I have the Hornady headspace guages .350, .375 but in the caliber list I dont see what guage to use for the measurement for the 338 Lapua, is it the .420 ? I dont see the datum line shown on the pictures I can find on the Lapua, so I was wondering what diameter guage you use . for example For my 6XC It calls for the .375 guage, and that is also listed in the cartridge drawings of the case.

Thanks.


Patrick
 
#15
Re: 338 Lapua loaded neck size please

There's some good info on bushing sizing in Redding's Tech Tips,
http://www.redding-reloading.com/tech-line-a-tips

They mention some of the issues you can run in to if trying to neck size more then .008 to .010 down from a fired case.

When I first ordered my dies they shipped a 362 and 363, after measuring everything I found I needed 364 and 365. Just to be on the safe side I later ordered a 366 and 367. I may never use the 362 or 363 but they where cheep (steel), 364-367 are TiNi. May as well just pick up a 368 on my next order just to complete the set.

I measured .368" average on new factory Lapua 300gn Scenar ammo and .367" on some of my 4th cycle reloads with 300gn SMK's. The chamber in my Savage seems to be OK, fired brass is coming out at .371" to .372".

Just a note, I also measured a few pieces of new Lapua brass at .365"
 
#16
If you (we) are measuring new Lapua brass at .365, then the first time a bullet is seated, the projectile is acting as an expander ball and sizing the neck at .367 or .366 was just a wasted stroke. I use Redding Competition Dies and after first-firing I size to .367.

Base-to-Ogive should always be measured with the same equipment. There can be a slight differences in each comparator insert if you own TWO for bearing-surface measuring. Mark one with a marker and always use it for B2O measurements.

I sometimes gasp when I see someone else's headspace measurement, but then remind myself that they are not using my insert. (Whew)

I've got three close friends with Sako TRG's, and our Chambers are near identical, as they should be. It's our measuring equipment that is subtly different.
 
#17
Original poster - You should be getting a measurement of .338 + .30, for .368. Lapua brass runs .015 thick, give or take .oo1, but you will be safe with .367, .365 and .364 bushings.

Sorry, got caught up in the thread and failed to notice your original question. LOL

I am not the authority here, however... just one of many.
 
#18
I have an Accuracy International AX338MC. I've just shot my first ladder. I used Lapua brass but I also have some PPU that I use to warm up the barrel. I've taken the calipers to the outside neck width of the once fired case and found an average around .3735 with variances at the shoulder near .3780 and the tip at .3705.

I just got an outside neck measurement from an unfired Lapua .338 case and found it was .366.

Everyone in the thread and forums suggest I get the 365, 366, and 367 neck bushings for my Competition Redding Neck Sizing die. Why is that? Should I still get these or get something around .3735?

Also, from my reloading manuals, the case dimension for the .338 Lapua neck outside width should be .3710 at the tip (according to Nosler). Are things different for my rifle? Explain which neck sizing bushings I ought to order and why. Finally, if I buy the three suggested, then which of the three do I run my brass through?

Thanks so much!

-Torrentuser
 
#21
I got the following advice: Measure the neck of a loaded unfired round and then subtract .002-.003" for bushing size. Measure a few to get an average.
I did and I consistently got .3675 inches. With that, advice, I'd get ordering:
366, 365, .364

Agree?
 
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