AR 223 OAL test increments?


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gregj
December 20, 2011, 10:17 AM
I tried searching, but couldnt find what I was looking for.

I'm trying to find suggestions for an acceptable/established method to test OALs in my AR. I know an OAL of 2.362" results in the bullet touching the lands in my AR. I also know 2.260 is max for loading from a mag. I also know to test rounds longer that this will be single fed/fired.

If I start at 2.360 and go down to 2.250, with steps of .005" that means 23 loads to test. Steps of .01" would be 12 rounds, steps of .02" would be 7 rounds.

It seems best to test the 7 loads with .02" increments, then test with .005 increments on both sides of one that shows the best 5 shot group.

Sound reasonable?

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243winxb
December 20, 2011, 10:42 AM
4 , longest, shortest, and 2 in the middle.

gregj
December 20, 2011, 10:55 AM
4 , longest, shortest, and 2 in the middle.


And then try .002 variations above and below the best of the 4? Or just go with the best of the 4? I picked 2.250 as the minimum as it was listed in some of my manuals. Is this an appropriate minimum OAL? TIA

243winxb
December 20, 2011, 11:22 AM
The most accurate of the 4 would then be adjusted, in or out by small amounts. Keep in mind, measuring off the nose is not very accurate. Variations in loading equipment can cause .005" to .010" difference between loaded cartridges COL . .002" is not enough to make a difference IMO. If the powder charge does not stop the bullet, you can keep seating it deeper till bullet falls into the case.

NeuseRvrRat
December 20, 2011, 11:48 AM
i'd suggest getting a bullet comparator for your caliper so you can measure off the ogive. much more reliable than the meplat.

gregj
December 20, 2011, 12:00 PM
I've got one, and I use it. Just easier to talk about OAL from the meplat as that's what everyone is used to seeing.

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