Neck tension confused on what I need to get???

[elktaker]

I am having issues with neck tension.

I have a 7mm wsm pacnor barrel. I went to range yesterday to check what my drop was a at for 300 yd.

I happen to have 5 once fired cases that I saved for 300 group. Others had been fire 3 to 5 times a neck thickness was noticeably thicker and bullet seat with different pressure on press. I wanted to establish that my 100 yard zero was right so I fire 3 of older brass after one cold bore shot. Group was just over an inch. Load development showed 1/2 groups. Another group yielded the same 1 in. Groups were very vertical

I moved to 314 to check my with newer brass group measure .71 moa (5shots) which I am happy with. All group were shot off atlas bipod prone.

Does this correlate with a neck tension issues, correct?

What do I need to properly adjust the tension uniformly? I am Planning on get a neck turner.

I need to be able to bump shoulders back also if that makes a difference (.001 in) full length sizing with a redding die currently.

 

[Mikecr]

Couldn't suggest it's tension, or thickness, while these things are not being measured.
Do you seat bullet bearing near neck-shoulder junction?
Do you FL size necks?
Are you heavily body sizing?
Are you changing or removing carbon residue from the necks?

 

[elktaker]

Bullets are 168 vld seated to fit mag i believe this places bullet very near or past shoulder in 7m wsm I will have to load one with my seating die to get length.

I tumbled them until they are shiny and have not attempted to clean necks anymore than that.

I full length size the necks and bump shoulder by running them through redding fl die.

Body also is full length, I am not sure how to bump shoulders back without heavily sizing the body.

This is COW fire formed 270 wsm brass.

 

[Mikecr]

Have you seen trim length changing with those FL sized ~4times?
What did you use for load development?

 

[elktaker]

Yes they grow and need trim most of them every time. If I run them through fl without bumping shoulder the shoulder extends +.oo2. Is there a way to bump shoulder without heavily sizing the body? Guess I am growing them to +.oo2 then pushing the shoulder back to -.001.

Did what you suggested on another forum seating then did a OCW all at 100. Was happy with .5 moa groups so did not try to fine tune seating.

 

[Dr. Vette]

You can use a body sizing die to ONLY bump back the shoulder:

Redding Body Die 7mm Winchester Short Mag (WSM)

and then a neck sizing die to size the neck.

This actually works quite well, and depending on what neck sizing die you use can also significantly decrease how much your neck is worked during resizing (i.e. bushing die).

 

[Mikecr]

+1 Dr. Vette. I myself use body dies for bumping only followed with bushing/partial neck sizing.
And early seating is good.
What was the brass situation with powder testing?

It sounds like you have bullet bearing crunched into fully downsized donuts by now. Like you're bringing donuts heavily into play.
This playing havoc with tension.

 

[elktaker]

If I switch to body die for shoulders and neck only should I go ahead and do it with fresh brass?

Seems like the thing to do and if so I will have locate brass too. Is Neck turning worth investing in at this point. I am currently loading for this (7mm wsm), 6x223 and planning to get another savage with a barrel with a longer barrel life for longer range (308 or 7mm08)

 

[elktaker]

Found body die on sin Clair in stock. What neck die should i get for this process?

Would it better if I just got a whidden custom fl die? Cost of a body die and a neck die will put me close to the cost of the custom? Time is not too much of an issue since I have no rifle hunts this year.

 

[Mikecr]

Well, depending on your chamber clearances, amount of barrel steel around that chamber, and load pressure, you may not have a lot of choice about FL sizing the body. You might have to squish the crap out of it, leading to constant trimming and donut building.
This is a pretty common scenario for folks. You may or may not be there.
But you need to understand your seated bullet relationship to donuts, and manage this.

I'll say this - DO NOT FL SIZE NECKS -ever. Any advice you get to do so is bad advice.
As far as recovery with the old brass, it's too late to neck turn. You would have to ream out any donuts now. To keep donuts out of play, next time, have the chamber throated appropriately for the intended bullet, so that bearing is well clear of donut area. Everything about preventing donuts comes down to sound gun/cartridge design and rational sizing allowed by that.

Redding body & Redding bushing die. New brass. Maybe a bigger magazine & new full seating testing to bring the bullets out a bit.

 

[rcoody]

Here is what I would do. Trash the brass and start over new. If you can get lapua brass do it.

just full length resize the new brass, load it and fire it.

from then on just neck size. Use the lee collet neck sizer. No donuts!

don't bump the shoulders

Once the brass is tight to chamber then full length resize again

annealing really helps things. I recommend after every third firing. Keeps neck tension constant and extends the life of the brass

 

[elktaker]

Well, depending on your chamber clearances, amount of barrel steel around that chamber, and load pressure, you may not have a lot of choice about FL sizing the body. You might have to squish the crap out of it, leading to constant trimming and donut building.
This is a pretty common scenario for folks. You may or may not be there.
But you need to understand your seated bullet relationship to donuts, and manage this.

I'll say this - DO NOT FL SIZE NECKS -ever. Any advice you get to do so is bad advice.
As far as recovery with the old brass, it's too late to neck turn. You would have to ream out any donuts now. To keep donuts out of play, next time, have the chamber throated appropriately for the intended bullet, so that bearing is well clear of donut area. Everything about preventing donuts comes down to sound gun/cartridge design and rational sizing allowed by that.

Redding body & Redding bushing die. New brass. Maybe a bigger magazine & new full seating testing to bring the bullets out a bit.

Goal of gun is magazine fed to use for hunting purposes. Bullets are currently .030 off lands so extending them out is not an option.

 

[elktaker]

Here is what I would do. Trash the brass and start over new. If you can get lapua brass do it.

just full length resize the new brass, load it and fire it.

from then on just neck size. Use the lee collet neck sizer. No donuts!

don't bump the shoulders

Once the brass is tight to chamber then full length resize again

annealing really helps things. I recommend after every third firing. Keeps neck tension constant and extends the life of the brass

No lapua wsm brass. Have to bump shoulder after 2nd or 3rd reload or I will get resistance when chambering.

B

 

[Coach Hunt]

Hello elktaker,

I've shot 7 wsm since it came out in 2002. I've burned up four barrels on mine, and I'm shooting fairly consistently with it. I've reloaded it and worn out 300 rounds of ammo shooting it. All that to say I have lots of experience with shooting it, and loading for it.

May I suggest something that might help. Take a flashlight, or other strong light... shine it into the necks... check out to see if the brass is marked by vertical streaks. This is especially evident after a clean case comes out of the sizing die. I found that my Winchester brass had numerous imperfections inside the neck that could be measured with a very, very sensitive ball micrometer. I took the path of least resistance, literally. I use two electric drills, one with a worn bore brass brush coated with brass wool (available at furniture refinishing locations) and the other drill has a Sinclair Driver (#749-003-251sy) and Caseholder (#749-002-490sy). Put driver in its drill, put a case in it, put the brass brush in the other drill, put the brush in the neck, turn on both drills and polish the inside of the necks for 15 seconds or so. The idea of two drills opposing each other is that the even-ness of the case neck thickness is not compromised that way. No polishing more on one side than on the other in other words.

Question... have you measured your neck dimensions after coming out of an "expanderless" sizing die? It could be that your full length die neck dimension is squeezing your neck dimension way too small. That happened to me with RCBS dies, but was quickly "fixed" by going to Forster dies. Forster bullet seater is great by the way.

These two simple techniques have been key parts of my reloading for the 7wsm. Hope this helps, and if interested in more, send me a pm.

Good shooting.

Coach