Another hard seating inquiry - 7 SAUM

[BOB LEE SWAGGER]

I have a 7 SAUM that shoots very well for me. When I first loaded my virgin 7 SAUM brass I just chamfered the neck for prep. I loaded on an arbor press with a force dial. Average psi was 40-50 when seating 180 Berger hybrids. My reamer has a .190 freebore and a .319 neck. Loaded rounds are .315. No chambering or extraction problems and no pressure signs. After a SS tumble I FL & neck size with a .313 bushing. When I loaded once fired brass again I would have exceeded the 100 psi warning on the dial. I instead used a mallet to tap the last remaining space in the Wilson seating die. I do not see a doughnut (although I am not saying it isn't there) but want advice before I proceed. Will annealing help? Inside reamer? I have never experienced a doughnut loading for dasher, brx or 6.5x47 so I am ignorant on this subject. Thanks for any help!

 

[dkhunt14]

I think the main problem is the SS tumbling cleaned the necks too hard. Try dipping the cases in powdered graphite before seating. Could also maybe need annealing. Matt

 

[21shooter]

Hi, How long did You tumble? I never tumble more than 30min. It doesn't take much longer to start to peen the mouth of the case, this will make the entrance smaller. Thanks,John

 

[BOB LEE SWAGGER]

I must admit that I usually tumble over an hour, but... this has never been an issue with other calibers.

 

[DHD]

Here is what I do for the same issue (except ultrasonicaly cleaned not SS pins). I chuck up a STIFF nylon brush and spin the heck out of the necks. I don't know why the nylon brush works where a bronze brush just makes it worse, but you have nothing to loose but a little time. Then dip those necks in the Redding graphite.

 

[rayjay]

Your seating die is also your 'time to anneal' indicator. Anneal a few fired cases and then reload them. The bullets will seat like a hot knife through butter [ like they should every time ]. You will go 'wow'.

 

[ballison]

What is your neck diameter after sizing? Reason I ask is that ALL my Redding bushings produce necks that are less than the printed value. For example, my .336 bushing produces necks that are .335" in diameter. It can be even worse if you are sizing the neck more than .004" at a time. If your .313 bushing is giving you .311 or .312 necks, this along with a very clean inside neck could be causing your high seating force.

 

[M99]

That is the reason I stopped using Stainless pins for tumbling and went back to walnut shells. Look at the necks under a magnifying glass and you will see very small indentations on the inside of the necks. That was causing uneven seating pressure and sometimes even small scratches on the bullets. I chamfered the necks again and went back to walnut shell tumbling and the problem went away.

 

[338rumshooter]

Hey BLS, two things. First, what brsss are you running? And the necks got hard after just one firing? I've loaded all three brasses, Rem, Nosler and Norma and have had no problems at all. And, I've never annealed any of them. FTR has a point about the bushings not sizing to the numbered size. My 316 bushing sizes 312 so over working the brass is a possibility. And I never ss pin tumble anything. Walnut all the way. Hope this helps.

 

[wwbrown]

That is the reason I stopped using Stainless pins for tumbling and went back to walnut shells. Look at the necks under a magnifying glass and you will see very small indentations on the inside of the necks.

This is exactly what I did after I found the peening, I may have run them too long in the tumbler as some have said, but it seemed to me that you would get some level of peening no matter how long you tumbled.

 

[fguffey]

That is the reason I stopped using Stainless pins for tumbling and went back to walnut shells

And then there is the acid. I use vinegar once for the worst of cases for a maximum of 15 minutes. Who knows? Is it the acid that cleans or the pins? Use the pins without the acid when determining if the acid is required. I never started with the pins.

F. Guffey