Discussion in 'Handloading and Reloading' started by Kfaulkn, Jul 2, 2017.
I'm new to reloading.
Any ideas what I might be doing wrong. Using mixed used brass fmj 115 gr 9mm.
OAL variation is caused by:
- Variation in bullet nose profile and/or dirty seating die
- Bullet tilt during seating
- Shell plate deflection from loose shell plate bolt or resizing of overly expanded brass
Make sure your shell plate bolt is tight and the seating die is clean.
To rule out shell plate deflection, try seating without a case under the resizing die. If you are still getting significant OAL variation, you may be tilting the bullet during seating. Roll your loaded rounds on a flat surface and see if nose tip wobbles. If it does, bullet is not loaded straight.
Use enough flare so bullet base sets just inside the case mouth and ensure bullet is not tipping as bullet enters the seating die. If you see bulging of case neck on one side, bullet is not being seated straight - You should see even slight bulging around the case neck.
Winchester 115 gr FMJ showing one sided bulging indicating tilted bullets
Even slight bulging around case neck showing straight bullet seating and no wobble of bullet nose tip when rolled
All my 9mm is mixed brass, so when I'm setting the seating & crimping, I'll take several different brands of cases & set the die for the shortest allowable length.
I am sorry but I fail to see how variation in case length can cause variation in OAL when press ram/shellplate pushes the loaded round to same height in the seating die (of course unless there is shellplate deflection).
Only thing I could think of is different length case applying different neck tension but if that affects OAL, there may be other issues with the press.
If you set it with just one case once all 5 are full it will change your OAL
I have never found that the tightness of the shell plate bolt effects seating depth, when seating, the case is forced down on the shell plate platform not the shell plate.
.044" is a lot, are you sure you are stroking the handle all the way down until it stops?
That's only true on the 550, the SD, 650 and 1050 the case sits inside the shell plate, the 550 has no effect except extracting the case from the dies.
How the others act depends on how the rest of the shell plate is loaded and why you want to double check initial settings once all stations are full.
Doesn't matter though those differences would be a few thousandths max, not 44.
Even if it is loose it would still be forced down onto the platform by the force of seating.
Any chance that you can post a couple of pics of the problem rounds?
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