Seating depth changes after seating a bullet?

I partial seat them. Put them on some type of vibration. I have used the washing machine. Then Complete the seating. This was with Barnes LRX and H1000, seated to fit in a magazine. After this they did not move.
not a 338 though, a 300 wm.

thanks for the advice
 
As an alternative to a drop tube, you try an ultrasonic -type toothbrush. I got mine from Walmart for about $5. Shakes the powder down settling it in the case. Works great. You cna actually watch the powder settle if you do it before seating the bullet.
I've also used the sonic toothbrush method, seems to do the trick. I touch the loading tray with the brush
and do them all at the same time.
 
I partial seat them. Put them on some type of vibration. I have used the washing machine. Then Complete the seating. This was with Barnes LRX and H1000, seated to fit in a magazine. After this they did not move.
not a 338 though, a 300 wm.
I like this idea of setting a loading tray with partially seated bullets on the washing machine for a cycle (I don't put loaded rounds in a tumbler for any reason btw).
 
Lee factory crimp dies set for a light crimp that does not dig into the bullet works for me. Does not jack up pressure compared to a tight crimp.
 
are you using a drop tube funnel ? if not get one it really helps settle the powder . I use this one .

Yep, on loads I know will be compressed I use a drop funnel.
While the load may still be compressed at least it will be "less" compressed.
 
My loading procedure is to weigh each charge. Then I seat the powder funnel on the case, pinch the case and powder funnel with my index finger and thumb, tilt the case enough that the primer doesn't touch the bench, and rapidly tap the case on the bench as I slowly pour the powder in the case. The more coarse the powder, the greater the settling. The slower the pour, the greater the settling.

I have gotten into trouble with compressed loads in my 10mm, because they will bulge the case wall.
 
I had this issue so bad with my 338-416 Rigby Improved 45* with H50BMG, I had to change powder. As soon as the rounds came out of the press, they would start backing out while in the loading block!
My 300WM has this issue with 230gr Berger OTM's with just about every powder I put in there. I haven't lengthened the throat yet, and it is a SAAMI chamber, I will probably set back and run the A191 reamer in to fix it, but I just re-seat prior to shooting them.
I will also add that there is an important part of the loading procedure often overlooked. It is called the "Powder Packing Scheme". If you just dump powder into the case, especially powder that will be compressed, each dump of powder will be a jumbled random height in the case, the level of compression will also be different. This changes the burning of the powder between shots, which affects ES.
The best technique is to swirl the powder into the case with a powder funnel, no drop tube is required. This technique stacks the powder so uniformly that it is more consistent than a long drop tube. I did a test with clear 1/4" plastic pipe, as dumped loads varied in height quite a lot, the swirled charges practically stayed exactly the same height each time.
My ES dropped on untuned loads without even doing seating depth tests first using this method. Now this is only useful on loads that will be compressed, whether only slightly or heavily, although it works best on bulky powder loads like RETUMBO, RE33 & H50BMG or ANY compressed loads.

Cheers.
 
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I read an article a long time ago about someone using a tumbler to polish old loaded rounds that he had for a long time. Someone advised against it because if you (shake) them to long they could rub coating off the powder and change the burn rate of that powder. I just wouldn't do it to long.
Never did it, just repeating a word of caution if it's TRUE.
 
Tighter neck tension or try vibrating (use a shaver or powered tooth brush) after powder is dropped. Works super getting them little buggers in line. Been there done that successfully.
 
After reading this thread initially, I wasn't 100% convinced. I went back and remeasured my rounds I loaded the week before and found no movement or variation (Moved on).

I recently returned from Wyoming. I flew out, and flew back. I went to the range today to verify my zero. Needless to say my zero had shifted (Separate Issue).

After getting back home tonight, I decided to measure all my leftover rounds that I had taken to Wyoming and noticed they had moved out .001 - .002 thousands from 2.989. Ran them back through the seater, all good to go.

So that being said, I believe something happened to my rounds in flight. Not certain what if any effect pressures would have on ammo being transported onboard a plane.
 
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