bullet seating on 40 cal

[rob45cal]

i finally bought a reloading press after about 6 months of reading many different books and reading online. ive got most of it down pretty easy. i have a Lee single stage press, so there has been alot of work done in the steps before the actual seating part. i am worried about the amount of pressure needed to seat the bullets. ive read thru the 3 books that i have and none of them give a definative answer. I have a factory bullet that i compared to the 10 bullets that i started to seat and some of them are the same size (by eyeball), but some are a little longer and some are a little shorter. How important is it to have a caliper to measure with. The people at the gun shop said that for .40 its not really needed.

So my questions are:
1. How much of a margin do i have over and under to the 28.83mm? Im very cautious of using any bullets not to the specified measurements even by the smallest amounts. so please let me know what are the safety limits that you follow.

2. What do you use to measure the length of your bullets mafter reloading?

I really enjoy this hobby and would like to be able to continue doing it. i have about 3000 rounds that are cleaned and primed just waiting to be charged and seated.

thanks you very much for your help.
Rob

[agalindo]

Once you set your seating die the OAL length shouldn't change. I measure the length against a dummy bullet I've seated at the desired length. Unless your loading at +P+ pressures ,just eyeball it against the dummy round. Again once you've seated the die and locked it the length will not change.

[fredj338]

Actually, over all length (OAL) is quite important in the 40s&w. It is one of the reasons you hear so many KB stories about this round. In factory form, it is already running at max pressures (there is no such thing as +p or +P+ 40s&w) & depending on the powder used, there is little room for error. I always set my OAL to the max. the magazine will allow. In case I have bullet setback (bullet pushes into the case, rasing pressures dramatically) there is a little margin for error. Check your loading data for min. OAL & calipers are the best way to measure this (sorry, but most data is in inches not mm).

[ichy_trigger]

Load 180 grain bullets to 1.135-1.145 and you will be good to go.

[KEVWYO]

Originally Posted by rob45cal

How important is it to have a caliper to measure with. The people at the gun shop said that for .40 its not really needed.

In regards to the 40 round (which I have been reloading now for 5 years) this might be the most negligent statement ever. Shame on those gun shop guys. The 40 round operates at very high pressures ... in fact, in most cases double or better pressure than the 45 ACP. Once you have your seating die set for the most part your rounds should be pretty uniform in over-all length. I have my turret press really dialed in and the uniformity of OAL is excellent. However, I grab a round every 25 or so just to make sure it doesn't exceed the max for OAL. Fredj338 said it very well above regarding loading rounds to their max OAL.

When reloading you and you alone are the quality control. You maintain excellent quality control by being very careful about your loads (amount of powder) and by being meticulous about the seating depth of the bullet.