Why doesnt my OAL I set it to remain the same

[lucas]

e.g. I set it to 1.170 on the button then with a differ bullet in same case confirm it again that it is set at 1.170.

I start loading and my OAL is always longer e.g. 1.174 to 1.183.Not one at 1.170.This is not a functioning problem for me everything runs fine,but why?

Could it be when the other stations are in use during loading like the powder die and crimp die they are ajusted in a way that they are preventing the same OAL?

[scribble]

e.g. I set it to 1.170 on the button then with a differ bullet in same case confirm it again that it is set at 1.170.

I start loading and my OAL is always longer e.g. 1.174 to 1.183.Not one at 1.170.This is not a functioning problem for me everything runs fine,but why?

Could it be when the other stations are in use during loading like the powder die and crimp die they are ajusted in a way that they are preventing the same OAL?

Yeppers I was told to always set belling and AOL with all stations filled.

[L9X25]

You have to adjust the overall length "on the fly" while there is a case at every station. Once you set it using that method, your lengths should remain very consistent.

I personally leave the shell plate loaded, after I finish reloading, so that I can resume loading and everything will be consistent. If you clear the shellplate, the first few, and the last few, will be slightly different.

Edited May 1, 2008 by L9X25

[el pres]

While all of the above is !00% I have found also that mixed brass can cause

a slight diiference. For instance, Federal brass seems to get a little shorter, not

as resilient or something..

[lucas]

When you say all stations filled you mean with a empty case.

Edited May 1, 2008 by lucas

[BritinUSA]

Typically the one station that seems to affect all the others is the resizing station.

When setting OAL I just keep a case in there and adjust the seating die. It always seems to work for me and I never have to adjust once there is a case in each station.

[kevin c]

I don't know if it's changed, but years ago Dillon advised me, on the old SDB I still use, that I should set the OAL 0.005" shorter than what I want if measuring with just a case and slug in the seating station. They were right on.

Also worth noting that, even with good quality same lot bullets, OAL from round to round may vary. For me, with good bullets, +/-0.002", with bad stuff, +/-0.015".

[redbird1976]

There are a couple of things that can affect overall length. There is some variance in the length of the bullet itself usually + or - .001. The length of the brass will also affect the OAL. If you set your OAL with brass that is long, then you can expect the OAL to vary depending whether the length of your other brass is greater or shorter than that length. Set the OAL with the with the shell plate full. This will help remove any variance from play in the shell plate.

[CocoBolo]

The seating die insert you are using can affect this inconsistent length. I have a flat and a cupped insert and find that one or the other will work better depending on the bullet profile being loaded JHP is more conistent with the cupped insert. In your case, with the .010-.014 variance this is more likely the stations not being full.

[steel1212]

Set seating with rounds in all stations. Check to make sure your shell plate is down as far as it will go and still allow the brass to move around, this will also help you get good primer seating in a SDB/550/650. If your using mixed brass this will have an effect on it as well, if you want good match brass with as close to the same OAL use only once fired/new brass. If you use mixed brass and mixed times fired you'll get all kinds of OAL and you'll get all kinds of readings at the chrono.

[Graham Smith]

I find that I can reduce that variation by prepping my brass in advance much like you would with rifle brass. I have a separate tool-head with an EGW "U" decap/sizing die and I run it through that as a separate operation first. This eliminates the problem of having variable amounts of resistance (due to variable amounts of bulge) when running the brass through the actual reloading process. It is extra work but not that bad as the chore of cleaning and prepping brass is a pretty mindless task that I can relegate to rainy weekends along with other tasks I rather not have to do. As a result, I have a nice big pile of clean prepped brass ready for the press.