.338 LM Neck tension measuring .372-.373

[Ryguy]

I measured the loaded neck diameter and I am getting the stated measurements. Empty case neck walls are measuring .015. Why the discrepancy? According to my math, .015+.015+.338 =.368.
Also, the first round I fired yesterday was not able to be extracted.

Data
300gr Berger OTM, 91.0gr H1000, OAL 3.704, 215M Primer

I am using a .365(largest RCBS makes) bushing which is probably too tight. Do you guys think neck tension can raise pressure enough to cause cratered primers and the brass to jam? RUAG brass claims to be on par with Lapua but who knows. From everything I have read, 91 grains of H1000 is the sweet spot for the Savage 110BA. Thank you

 

[Shadow0341]

Re: .338 LM Neck tension measuring .372-.373

I don't think it's to tight. From what I know, proper neck tension should be .002-.003 less then your neck diameter of .368 to allow for brass spring back.

 

[ChrisGarrett]

Re: .338 LM Neck tension measuring .372-.373

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: JumpDoc</div><div class="ubbcode-body">I measured the loaded neck diameter and I am getting the stated measurements. Empty case neck walls are measuring .015. Why the discrepancy? According to my math, .015+.015+.338 =.368.
Also, the first round I fired yesterday was not able to be extracted.

Data
300gr Berger OTM, 91.0gr H1000, OAL 3.704, 215M Primer

I am using a .365(largest RCBS makes) bushing which is probably too tight. Do you guys think neck tension can raise pressure enough to cause cratered primers and the brass to jam? RUAG brass claims to be on par with Lapua but who knows. From everything I have read, 91 grains of H1000 is the sweet spot for the Savage 110BA. Thank you </div></div>

A few things:

Savage BA-110 rifles have had well documented issues with cartridge cases sticking within the chamber...in the beginning, usually with Hornady brand brass, but also Lapua brand.

Neck tension reaches a limit, where the force acting upon the bullet won't become any greater, even though neck diameter/constriction is becoming smaller.

What are you using to measure your necks? While .015" is probably a good number for most of the necks, you might have less in certain areas, for a smaller than .030" average.

Most of us use a .365" bushing (Lapua/Norma brass) and I have the Redding .364" as well, but I don't use it that much. I'd rather have a .366" TiNi bushing, but Redding didn't (doesn't) make anything larger than the .365" at the time I bought my stuff.

Chris

 

[sinister]

Re: .338 LM Neck tension measuring .372-.373

My limited experience with the Savage 110 BA (a population of two rifles direct from the factory for a magazine article) is they are the STEN of the .338 Lapua Magnum rifle family. It will shoot and go bang, and occasionally stack bullets into respectable/acceptable groups, but that's about it. Hard cycling/functioning (using factory ammo and ammo made from all-new components) has been documented here many, many times.

The comments above are all valid, especially for sizing and brass "Spring back" as it loses elasticity with each work-hardening cycle through a sizing die or bushing.

Did you mic the actual bullet itself? Do you anneal your case necks?

Ruag is excellent brass, and if I didn't have Lapua I would use it before Hornady or Norma.