Bench Rest Seating Dies Stem cup is flaring

[Stan Malinky]

Just picked up some new seating dies with the floating die barrel allowing for axial alignment. The gun is a 300 WSM the Brass is Norma fire formed and prepped, FL sized with the sister die, and the bullet is a Barnes TTSX 168 Gr. I have now flared the bullet cups on two seating stems one of them after about 5 to 8 rounds and the newest one after 2 rounds. The manufacture is working diligently in an effort to solve the problem. They think that the Norma Brass is causing the problem. First question, has anybody ran into this problem and what was the solution? Second question, does anybody think turning the necks will help? Thanks in advance!

 

[Mikecr]

Either your seating forces are way too high, or the stem design is flawed.

 

[Stan Malinky]

Either your seating forces are way too high, or the stem design is flawed.

The issue about seating forces are way too high. I agree with this statement. However, if I am using the sister FL resizing die the manufacture just checked and said it were good to go, how can I reduce the seating force???

 

[Laelkhunter]

Is it possible to post pictures of the affected pieces (brass, bullets, and seating stem?)

 

[Stan Malinky]

Is it possible to post pictures of the affected pieces (brass, bullets, and seating stem?)

When inspecting the seated rounds I did not find anything out of the ordinary. However, you did provoke a thought, the next time I run into the problem I will pull a bullet and see how scored it is!!!

 

[Mikecr]

how can I reduce the seating force???

With caliper measure a neck OD with and without a bullet seated. How much difference is there?
Are your neck insides clean or dry lubricated?

 

[Stan Malinky]

With caliper measure a neck OD with and without a bullet seated. How much difference is there?
Are your neck insides clean or dry lubricated?

Just received the new polished seating stem yesterday. Last night I set up the die using a brand new prepped piece of Norma Brass and when I seated the bullet the seating pressure was normal. I will be loading a couple of fire formed brass and I will report back.

The diameter change after I seated the bullet was .001 +/- .0005. Neck average inside diameter .3035, bullet diameter as expected 0.0308, neck thickness 0.016. I did not want to take apart the FL dies from the same manufacture at this time so I measured the expander button from another die set (RCBS) and found the diameter to be 0.305.

I do use an inside neck lubricate, (graphite) when I size the brass and I do not brush it out.

I have to get a block of brass fire formed and set up before the opener. Once I reload the fire formed brass in a couple of days I will post the results.

 

[Mikecr]

The diameter change after I seated the bullet was .001 +/- .0005. Neck average inside diameter .3035, bullet diameter as expected 0.0308, neck thickness 0.016.

If you're seating .308 bullets into .3035 interference, with necks .016 thick, that will take a lot of bad effort. Too much

 

[Stan Malinky]

I am reporting the problem solved. It appears that the Norma Brass necks was the problem. I took 20 pieces of brass fired 3 times and Turned the necks. When I loaded them up and seated the bullets there was a definite difference in the resistance as compared to the brass that the necks were not turned. Lesson learned turn all brass necks as part of the initial Brass Prep.