Discussion in 'Handloading and Reloading' started by Jackiesman, Nov 18, 2021.
That said, .005 of bullet creep isn't likely to hurt anything.
Two things: I crimp my 06 and 338 with a light roll crimp. And I use a heavy crimp for my 375 H&H that I use in Africa. But with those I'm only dumping 1 or 2 rounds down range. Second thing is that I only fired 6 rounds through the 300AAC and had that much creep, and I agree with you that doesn't seem too be excessive. But comes the time when I 'm dumping a 30 round mag what are the ones at the bottom doing. That said, I have and use a cannelure cutter when I'm intentionally loading long or short, but with the wide range of bullet weights available for the 300 the factory cannelure sometimes is nonexistent or falls outside the LOA that I'm loading. I hope that better explains my concern for the very minor bullet creep I'm seeing. The pacesetter dies came with a factory crimp die which I could use if I need to put a little crimp to the rounds.
I use a lee factory crimp die setup to just barely crimp the round to make sure the cartridge is loaded within spec.
The collet style rifle FCD would certainly stop creep, may not be good for accuracy, just have to try. Have you run 28 through and checked number 29 & 30?
Measuring Length OverAll might not be the best way to see if the bullet is moving in the case.
First, tip to base, is not always consistent from one bullet to another. Like these SMK’s, for example.
So measuring Length OverAll with these to will show a .005” difference, despite the two being seated to the exact same depth.
You could also very easily distort the tip on soft point bullets so a way to measure from some point on the ogive would likely be more enlightening.
They sell tools that amount to a hole that becomes your “datum” or reference diameter. This one has 6 different diameters to choose from.
You can also get them where they attach to the blade on a caliper. A bit easier to use if your all thumbs.
Or you could just remove the seating stem from your die and use it.
Those methods would at least let you know if they are moving vs having different lengths to start with or are being distorted only at the tip.
FWIW, I don’t crimp my 300 blk at all.
I understand what you are saying and think it is me that isn’t relaying the information properly.
If you take a bullet out of the package, it should be in pretty good shape. Like the one on the right below. Have the tip contact anything during chambering, recoil and ejection for the subsequent measurement and it can be damaged, like the one on the left. Even if the bullet did not move in the case the OAL measurement will be different but ogive to base will be the same.
This is why I was suggesting ogive to base measurements, it removes tip distortion as a factor in your measurement.
The latest occurrence was today when I loaded some 130 grain Speer PHP varmit bullets. I loaded to 2.135 OAL (well below the max), With a slight crimp. I always chamber a few rounds to verify fit. This time the first round would not manually eject. After finally getting it our of battery it showed that the bullet had contacted the lands. Resized it to 2.1 and got the same results, with two sets of rifling marks on the bullet. Finally got the rounds to properly function at 2.085 LOA And they went into battery just fine, and shot well.
That said I'm wondering if anyone else has experienced this condition with that particular bullet? Or maybe others?
It's the same bullet and once I reduced the LOA to 2.085 it feeds and shoots very well with good accuracy.
This is really dependent on what you're using for brass? If you've converted your own, and it's not been annealed, the spring back is going to cause you to have reduced neck tension. 300 AAC shouldn't need a crimp, if you've got bullet movement, first place to look is neck tension, which is a pretty common problem as a lot of people don't anneal converted brass.
Some magazines, especially polymer, don't have the front relieved enough for reliable feeding of rounds in 300 BO. So far, I have found D&H mags to be good for 300 BO.
D&H on the left, and Del-Ton on the right.
Excellent piece of information. Thank you.
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