XL650 COL variance?

[sl33py]

I am wondering if i'm doing something wrong, or if this is part of a "break-in" period for the new press?

I don't think i under-tighten, but definitely am cautious to not over-tighten (into aluminum after all) the seating die.

I noticed it in my 9mm loading, where it seemed to slightly increase COL/OAL as i went. I tightened the seating die down a bit and kept going. iirc they increased about 1.08-1.10 w/ the 135 LFP bullets.

Helping a buddy load some .40 last night - saw the same thing. The COL went from 1.15 to 1.25 with only ~20 rounds. (doing some workups of titegroup at 4.2, 4.4, 4.6 with his xtreme 180 RNFP)

Is this normal? Am i not tightening it down enough, or do they "break-in" and COL will settle?

I will tighten the dies down a bit more and try again w/ my next 100 rds of 9mm. Likely user error, but figured i'd ask the collective here in case it's typical, or something i'm doing incorrectly.

Thanks all!

 

[Reefinmike]

typically any OAL variance is due to differences between bullets. the seater stem in your die is not designed to contact the tip of your bullet, rather on the ogive, or simply put just the sides of the bullet. If the bullets are not extremely consistent, then your overall length wont be. I wouldn't worry a whole bunch unless you are getting much over .010" +/- variance.

you mention a lead bullet- lube and other junk can come off of these bullets and build up in the seating die causing bullets to seat deeper and deeper. sometimes that chunk of bullet lube will come out with a loaded round and subsequent loads will come out longer.

another possibility is that if you are using a soft lead bullet, cases with higher neck tension(thicker brass) may lead to that bullet deforming during seating and not fully seating.

 

[sl33py]

thanks reefinmike!

The .40's he was reloading were xtreme RNFP - FMJ's. I'll measure a couple to see how consistent they are.

I don't quite understand ogive yet - but if it's the profile of the bullet and any variances, that makes sense.

The 135gr FP bullets are hi-tech coated lead. I will check teh seating die insert/plug/spud to check for any buildup. Considering the OAL increased, not decreased, i doubt i will find anything - more than likely the ogive like you mentioned.

Appreciate the info and help!!