.300 WM Loading Questions

**JDog** · #1 07-27-2012, 05:09 PM

So I loaded up some rounds in January, fired 'em and found a promising load. I did 5 rounds per charge and tried to make the cases per group as close to the same length as possible. Most were in the 2.620 which is the max length, but those that were 2.615 I'd group together, etc.

So after that range trip, I'm just now getting back to loading up two promising charges from that previous range trip. Not surprisingly my cases have exceeded max case length and are now 2.650 or so. No big deal, and I trim them all up. My trim gauge ends up trimming them all to anywhere between 2.614 and 2.616. They're actually more uniform than before. So my question is this, how important for accuracy is it that the case length of my promising load was 2.620 and now the case will be 2.614? I'm looking for sub MOA (or hopefully 1/2 MOA) accuracy but at 100 yards. I'm not a long range guy so will this case length difference be negligble? I got 3 shots in one hole and then pulled one in January, so I'm REALLY hoping this recipe is a winner.

**Reloder28** · #2 08-01-2012, 01:57 PM

No, the .006 won't make any difference in your accuracy. You'd have to work up a new load every time you trimmed if it did. Trim lengths are quite forgiving.

**JDog** · #3 08-01-2012, 02:13 PM

so switching calibers, for my .223 my trim lengths are 1.748-1.551. Again, you're saying I don't really need to sweat .003, or any probably any differences under say .01. Man, I'm driving myself crazy trying to get these things to be exact.

**davidb** · #4 08-07-2012, 02:40 PM

Just trim all to the shortest length. Usually .005 under maximum. Check the manuals.

Uniformity is the most important aspect. Only a real problem if your pushing the maximum length, this can jack up pressures and won't do much for accuracy.

Bullet run out is a much bigger accuracy factor. If they are loaded straight they go out the barrel straighter.