Inconsistent Oal 650

[boo radley]

Very strange....I've had my 650 for a couple months, loading .40 Zero brand 180's JHP's, just perfectly.

I converted to .45acp, loaded a thousand, then went back to.40, and had a couple problems -- broke the indexing ring, crushing primers, etc. -- but all is finally working again, smoothly....

This time I am loading Montana Gold 180 JHP's. My dies are Lee -- the 4-die set. However I'm starting to notice some unusual variance in OAL. Previously, I'd set it to 1.135" and have everything between 1.130-1.140, though most were dead on.

Now, I'll set it to 1.135, and one will be 1.120, and the next 1.153, or something....What could be going on? The shell plate is tight -- tighter than I used to have it, in fact. I'm working the handle smoothly, and the bench configuration hasn't changed. Could the profile of the Montana Gold JHP be irregular, and not seating to the same distance?

Thx

[straightshooter1]

I'm sure someone will reply who has more knowledge of 650s than I do, but the first thing that came to my mind was whether, when setting OAL, you had a case in every position on the shell plate? Not doing so can make the OALs inconsistent.

Bob

[n2ipsc]

I'm sure someone will reply who has more knowledge of 650s than I do, but the first thing that came to my mind was whether, when setting OAL, you had a case in every position on the shell plate? Not doing so can make the OALs inconsistent.

Bob

+1 on that. If you painstakingly single-load a round to get your OAL, as soon as you start encountering resistance from resizing, seating, and crimping, the OAL will grow dramatically.

The other thing that will jack .45 ACP OAL's around is mixing commercial and military brass. Been there, done that. Try separating a lot out by headstamp and see if the issue goes away (I've also encountered this with 9mm's...).

Could be that the bullet diameters are inconsistent - have you mic'd a sampling to see? MT Golds have been very consistent, in my experience, but...

[boo radley]

Good points....N2IPSC, I'm actually loading .40 S&W...

I do initially set the OAL with a single case in station 4, but tweak it once I'm under-way. As you say, it differs slightly, once cases are in every stations.

I'll check the bullet diameter. The only other thing that's a little bit different than the way I normally load, is that I have belling from the powder die set to a bare minimum. I don't normally like a lot of bell at the case mouth, but this is almost to the point where the bullet barely sits by itself, before being sized....

I'll increase that, and see what happens, but who knows. Maybe the Lee sizing die just doesn't handle the MG profile well? Did fine with Zero, thoguh.

[Intel6]

If you are using the Lee Factory crimp Die I have found that that will cause some variance but it is small and I ignore it.

Neal in AZ

[pandashorts]

Great post. I too have been having problems with my OAL. There can be a difference of .040 or more. I thought I was losing my mind and was about to rip my hair out. I was also seating the test rounds one by one. I'll go back and try it your way (with a shellplate full of brass). Most of my brass is commercial (CCI and PMC seem to be the majority), and I'll mic my rainier .40s. I'll get back with you all if I keep having problems. Thanks for the fixes

[boo radley]

Well, I had to sh*t-can almost 400 rounds, but I have the problem solved.

The shell-plate tension, the Lee sizing die and the FCD-die MUST exist in a Holy Trinity. Or else.

Near as I can tell the root problem was that the Lee sizing die wasn't screwed down tight enough, although the stem pressed the bullet in to the correct OAL. This -- combined with a questionable setting for the FCD, and shell-plate tension, resulted in wildly varying OAL. *Worse*, I discovered I could easily cause set-back, in some of the shorter rounds, by simply pushing the round into the side of my bench with my thumb. Didn't take much effort at all, and enough rounds were like that, I ended up dumping a couple-hundred. <FUME>

Reset everything exactly according to the specs, battled a couple other issues, like the bushing-arm adjustment (which isn't documented in the manual), but now I'm churning out perfect ammo. My OAL is 1.135 and variance is +/- 0.004, AFAICT.

Man.