OAL question

[Jcobb]

Quick question on OAL.

I'm new to reloading and am trying to soak in everything I can. How important is consistancy with OAL to accuracy? For instance, I loaded 10 rounds this afternoon. Winchester brass, CCI large pistol primer, 5.0 grains Bullseye, and speer 230 grain TMJ. When I checked the OAL with my digital micrometer, I get the following:

OAL Crimp


1 1.264 .471
2 1.272 .471
3 1.273 .471
4 1.275 .471
5 1.266 .471
6 1.273 .472
7 1.275 .471
8 1.268 .471
9 1.270 .471
10 1.269 .471

Variation
.011 .001

Is this typical or something to be concerned with? I am using a Lee Pro 1000 with Lee Dies and Lee Factory Crimp. Should I try for less variance? If so what do I need to do different? Thanks

[kart racer]

The crimp is excellent range wise,but the oal varies a bit more than what I see on my stuff.The oal seems a bit long-but as long as it fits in the mag and feeds all is well.

I usually load my 230 fmj/tmj at 50-55 oal.They usually vary in that same range,but that's with zero brand bullets and assorted brass.

If it was varying that much in my 9mm loads I'd be concerned,but the 45 is a little more forgiving.I'd check the dies and make sure they are tight-if you're using the factory die rings,that could be part of the equation.

[Jcobb]

Originally Posted by kart racer

The crimp is excellent range wise,but the oal varies a bit more than what I see on my stuff.The oal seems a bit long-but as long as it fits in the mag and feeds all is well.

I usually load my 230 fmj/tmj at 50-55 oal.They usually vary in that same range,but that's with zero brand bullets and assorted brass.

If it was varying that much in my 9mm loads I'd be concerned,but the 45 is a little more forgiving.I'd check the dies and make sure they are tight-if you're using the factory die rings,that could be part of the equation.

The OAL I was shooting for was 1.275, out of the Lyman 48th edition.

What I am hearing you say is that I need to tighten the dies tighter than just finger fight, which is what the directions stated?

The factory crimp die is brand new (bought yesterday). I do not know the age of the other dies as I purchased the press and other dies from Lee as factory refurbished. If tightening the dies doesnt work, should I chalk it up as worn out dies and purchase new ones?

[jdavionic]

The variance in the OAL is much more than what I get. With respect the importance of the variance, we've got some experienced experts that may have more to add. But I'll offer my opinion.

I would have 2 concerns with OAL variances. The first being whether or not some of the rounds would cause feed problems. Not necessarily the difference from round to round...but whether one on either extreme simply is a dimension that doesn't work well in your gun.

The second concern would be a slight variance in accuracy & pressure from round to round. As long as neither extreme goes beyond the load recommendations for the powder / bullet combo, you should be fine with the exception of maybe some minor variances in accuracy.

[fredj338]

If you are seating & crimping in the same operation, this can cause variations due to brass diff. I can't help on the Lee, I use Blue.

[Jcobb]

Originally Posted by fredj338

If you are seating & crimping in the same operation, this can cause variations due to brass diff. I can't help on the Lee, I use Blue.

Seating on one, crimping on the FCD.

[Tard]

I agree the OAL variation seems high. My variation is +/- 0.001 w/ my Dillon Square Deal and .45ACP with mixed brass.

[Nicadflyer]

Today I was loading some 45ACP's with my Pro 1000. I'm using Rainier 230 GN with Bullseye. I checked ten reload's and they were 1.230-> 1.233, and .471-> .472.
Make sure that the dies's are tight in the turret. You should not need to replace them for many years.

[Jcobb]

Originally Posted by Nicadflyer

Today I was loading some 45ACP's with my Pro 1000. I'm using Rainier 230 GN with Bullseye. I checked ten reload's and they were 1.230-> 1.233, and .471-> .472.
Make sure that the dies's are tight in the turret. You should not need to replace them for many years.

At the bottom of the down stroke, when the shellplate meets the dies, should the turret move upward any? I am getting some upward movement, maybe .016 of an inch. Should I try to shim this up?

[ichy_trigger]

Sometimes while using copper COATED, not jacketed, bullets, the FCD can "squeeze" the bullet up a bit. Kind of like if you squeeze something slippery, it will shoot up through your fingers. I have not heard of it happening with FMJ bullets though. I would make sure that your shell plate is clean and adjusted, your dies are TIGHT, finger tight never did much for me, and make sure that you use a consistent stroke when seating them.

Also try seating 10 bullets but dont crimp them, mic them and see what the consistency is. By checking it before you crimp them, you will likely find out if your crimping station is your problem.