Variance in seating depth

Started reloading two weeks ago or so. I feel pretty confident and rounds shoot good at 25, but I feel like there is too much play with the seating depth. I’m aiming for base to shoulder (45acp) of .920 and rounds are all over the place from .915-.930. Is this normal? If not is there something I should look into to fix this. 
Dillon 750XL, Dillon dies, SWC shoulder seating insert, using brazos 200gr, all virgin starline brass.

I’ve noticed a variance of .010 with Brazos 200s as well.  They still shoot fine.  I bet the cause is variances in the mold manufacture.

He is seating on the shoulder and any difference in the length of the bullet should not matter. Shell plates on most machines move so try this 
Make sure the decapping and sizing die hits the plate according to spec
Load each station and remove the first 2-3 that are finished and set aside. 
Now load 20 and check them. I bet they will be within a few thou or so

Wobbley wrote:I’ve noticed a variance of .010 with Brazos 200s as well.  They still shoot fine.  I bet the cause is variances in the mold manufacture.

No that is not the case.  The molds are waaaay more precise than a 1/100th.

I've noticed different lengths with a partial load on the shell plate on my LNL.  So when all 5 stations are full the flex or tolerance becomes more uniform and OAL is more consistent.

A press that isn't solidly mounted can also produce a variance in OAL.

If your press is wobbling or moving at all when being operated you may see primer seating and OAL issues.

James Hensler wrote:Make sure the decapping and sizing die hits the plate according to spec
Load each station and remove the first 2-3 that are finished and set aside. 
Now load 20 and check them. I bet they will be within a few thou or so

The sizing die was raised off the plate slightly. I adjusted and it appears to have made a large difference in the variance. Went from .915-.930 to .922-.925. Thanks for the help.

Unless you are using a good single stage press .002-.005 is just about the best anyone can get! Sounds like you have that down so now enjoy

I am strong believer in locking everything tight when it comes to reloading.  So, locking dies from both sides of tool head, shimming and locking tool head by any means one has would be my recommendation.  And of course watching for and applying same pressure on lever with each round. 

AP

PhotoEscape wrote:I am strong believer in locking everything tight when it comes to reloading.  So, locking dies from both sides of tool head, shimming and locking tool head by any means one has would be my recommendation.  And of course watching for and applying same pressure on lever with each round. 

AP

Absolutely!

I don't have any of that "locking" stuff for my 650's and my ammo comes out very, very consistent. I do run O-rings under the sizing, seating and crimp dies just to keep upward pressure on them.  And everything is very solid mounted and the shell plate bolt is set very carefully to allow rotation without hesitation and with minimal flex. 

Once the shell plate is loaded up and producing rounds, then you check the measurements.  

I figured that for progressives, its better to let the rounds center in the dies, rather to try and make the dies "center" the rounds since its not a singe stage set up and there are multiple positions on the plate. 

But with all manufactured products there are variances and some will better than others.  Last time I had a 650 rebuilt, it took a while to get everything set up to my preferences again.  Everybody has their own way to get to their own answer.

CR

I'd have to sat the same for my 650. Bone stock with no "tricks" or "upgrades" and ammo is within a few thousandths OAL variation.

It is, however, very solidly mounted to where there is zero movement of the press when operating.