Changing Oal?

[kimber45acp]

I apogolise if this has been discussed before, didn't see this on other posts/topics.

I am handloading Rainier 230gr RN 45's, and I have noticed if I chamber a round, then eject it, the OAL is .006" -.008" less than it was prior to being chambered.

Wondering if I have enough crimp, my crimp is set at .469 using a Dillon 550B. I tried it with Factory Winchester's and the same thing happens... Does this sound right? Anyone else notice this?

[pskys2]

Your crimp sounds right. I have ran into this a few times. Some set back is normal when your round hits the feedramp, which it usually does.

Make sure you are using a good quality Sizing Die, Dillons works good. If your sizing die is oversize it will not provide the friction needed and you can have extensive setback.

Does this happen on the first round or all rounds? On a Slide Lock loading?

If you're worried you can try the following:

Measure 4 rounds (record the exact measurements) then load all 4 into a magazine. Use a marker to write 1-4 on the case head and match those numbers with your measurements.

Then chamber your first round by grasping the slide and pulling it all the way back and releasing it. Then rack the next one into the chamber.

Fire the 2nd round and allow the 3rd round to be cycled into the gun.

Remove the Magazine, eject the 3rd round and pull the 4th round from the Magazine (without it having been cycled).

Now measure rounds 1, 3 and 4.

#1 will probably be the shortest (.005 isn't bad at all).

#3 may be a little short, but probably not by much.

#4 should be the same as the original measurement.

If this is what happens, don't sweat it. If #1 is shorter than .010, check your magazines for weak springs, bad followers, dirty, etc...

If #2 is as short as #1 you may have a worn Mag Release, incorrectly installed barrel, or a bad magazine.

I don't know what the limits are, but a little set back seems normal.

Your crimp sounds ok, unless at any point you can rotate the bullet in the case, then you may need to check your measuring tools. Too much crimp can be worse than not enough.

Note, that when you load on a progressive, overall length will vary.

I.E. there is usually a .005 difference in length if there is no case being sized, or if the case is new and not providing friction. If the case in the sizing die is bulged, or real hard to work, you can get .005 longer overall length.

I always record my overall length off of the 3rd or 4th case ejected from my Dillon. Setting up the first one I usually try to make them about .005 shorter than I want.

Now if you still have concerns, I'm sure someone can come up with some more ideas. Then again, if it works, is accurate and nothing else is acting up Shoot It Now and worry later.