Home Forums Hunting & Shooting Ask The Gunwriters JB, neck tension question

I bet dollars to donuts that most are running more tension than they think.

for getting the right neck tension you should use bushing dies , full length bushing sizing die per cartridge with at least 5 different sized bushings per caliber . not all brass is the same thickness and sometimes even bullets are off some. if you turn the necks for consistency that can change things too but it can help with accuracy. neck tension for the average handloader for hunting ammo you don`t need to worry about neck tension with a hunting rifle just use standard dies.> bench rest target shooters need to do neck tension and bushing dies with their bench rifles or varmint hunting rigs. enjoy handloading and shooting your handloaded ammo , Pete53

Yup. A statistical method is the only obvious approach that comes to mind.

I have an anecdote related to this; In my unenlightened youth, I loaded up some 30-06 just shy of touching that fit in the magbox. When I took the ammo out for hunting and found that it wouldn't fit in the magazine! When I got home, I reseated the ammo and happened to look at the tray of completed reseats...I saw the bullets extending out of the neck as if by magic. The load wasn't compressed, so I can only guess it was air being compressed as I seated the bullet that under enough pressure to ease the bullet out...and inadequate neck tension. ....and that is how I discovered that seating dies have a built in crimp feature! I also became more diligent about removing lube from inside the necks!

I quit crimping most rifle loads a while back, after finding that even with heavier-recoiling rounds such as the .375 H&H and .416 Rigby sufficient neck-tension held bullets in place. Haven't crimped .30-30 handloads in lever-action rifles in probably 20 years. This was after testing all of them considerably.

Elmer Keith, who experimented considerably with crimping and non-crimping in both rifles and handguns, firmly believed neck tension was far more important than crimping.

I find this all interesting. So much of my early shooting knowledge was based on convention. These days I'm going backwards and revisiting some of these conventions. Crimps being detrimental to accuracy has been one of these conventions. (although Richard Lee's assertion and battle with Sierra remain in the back of my mind). Can you quantify the results of your testing? Was your endpoint bullets holding in place?...or was accuracy one of your endpoints?

I've got a situation I'm working through where a crimp may be a step in the solution, so I'm extra interested.

Chris,

Both accuracy and bullets remaining seated in place were the primary objectives.

Crimps will definitely work, but my main point (and Elmer's) was that neck tension has more effect than crimping. I do crimp some loads, but mostly use a taper-crimp--which essentially increases neck tension.

with that thought have you experimented with doing a heavier taper crimp on revolver rounds instead of conventionally done roll cramp...?

Just for reference, 3 year old factory ammo using the method I use described in an above post, .30-06 Fed Gold Medal 168 gr broke tension at 90# and .30-06 Black Hills Gold 178 ELD broke tension at 72#. Of course no visible crimp on either brand. Either brand is supremely accurate in my match rifle. Just counting 10 shot groups, MAYBE the FGGM is a bit better, but there are so many variables, neck tension is the last thing I would consider as a factor.

I recently loaded up some .30-06 rounds with 175 LRX bullet. Starline brass (this is good stuff) was LCD sized to provide .004" neck tension. All 8 rounds had .001 bullet runout. I look for .003 - .004" runout on my hunting ammo, depending on recoil level. My .260 Rem will get .003" and .35 Whelen gets .004". More than .004" in unnecessary IMO. Boat tail bullets don't seem to care much, but a flat base bullet is hard to seat straight with higher neck tension. A 250 Partition in the Whelen is tricky.

All my LCD mandrels are sanded down quite a bit smaller than factory provided so I can control neck tension by how hard I "squish" it against the mandrel. Work hardened brass and thicker necks provide higher neck tension.

I really don't think it's a huge factor in accuracy, especially in hunting rigs. When you look as the forces necessary to start the bullet moving, 50# is nothing compared to the force required to start the bullet moving forward. The start of gas pressure building in the case will cause the neck to expand before the bullet starts moving, making the bullet friction/tension with the case mouth even less significant. Just my $0.02

Neck thickness plays into this a bit - when WSM’s came out the brass was really thick, and when really thick brass hardens things go screwy fast.