Author Topic: bullet seating (Read 455 times)

Andy2590 · « **on:** June 27, 2006, 10:36:48 AM »

I'm pretty new to reloading. Right now I'm reloading 300 win mags. For some reason when I go to seat the bullet every one comes out a little different in overall length. The max oal is 3.340, and I'll set it so the first one is right on that, and then the next one will be anywhere from around 3.335 to around 3.345. Each time I put a round in I have to adjust the seater adjustment screw so that its around 3.340, but when they come out less than that I have to just leave it so my final overal lengths end up ranging from 3.335 to 3.340. I've tightened the ring right below the adjustment screw so that the seater adjustment screw can't move, and I've watched it and it doesn't move, but they still come out different. If anyone can help me because as you can see I have no clue what is going on. I loaded 40 rounds like this and I'm gonna go shoot them the next chance I get, although that could be anywhere from this weekend to a month from now.

Thanks in advance
Andy

Iowegan · « **Reply #1 on:** June 27, 2006, 10:56:37 AM »

Try measuring a batch of your bullets before you load them. It's very normal for the tips to get deformed slightly, thus their measurements can be several thousandths off from longest to shortest. Your seating die stem holds the bullet back from the tip and seats to a very uniform depth, assuming you are pulling the handle through a full stroke.

Andy2590 · « **Reply #2 on:** June 27, 2006, 11:01:42 AM »

I measured the bullets and they are all within a thousandth or 2 of each other, but the overall length of the full cartridges end up being off a few hundreths so that can't be the problem.

KN · « **Reply #3 on:** June 27, 2006, 11:46:47 AM »

You didn't say what bullet you are using but if the bullet profile/oglive(spelling) varies that will account for your descrepencies. The seater seats from oglve not the end of the nose. So if that varies any, so do your over all lengths. I have found plenty of brands of bullets that don't repeat OAL any better than +/- .005. You may also not be starting your bullet perfectly straight in the case mouth when seating. The bullet can cock a little in the seater and cause variations also. I like to gently turn the case in my fingers as I start the seating opperation. It seems to straighten the bullet out some what. Especially in long cases. KN

Bad Irv · « **Reply #4 on:** June 27, 2006, 01:32:13 PM »

Yep, KN is right, the overall length will vary several thousandths with all but the best bullets. It's really nothing to worry about, as the distance of the ogive to the rifling is more important than the OAL. It's also a good tip on turning the case a few times as you seat the bullet a little at a time. This will help to minimize bullet runout. I use Forster in-line seater dies, and they are really worth the extra money if your goal is accurate reloads.

Irv

savageT · « **Reply #5 on:** June 27, 2006, 01:53:06 PM »

Andy,
Have you measured the length of each case? That could make a big difference in OAL. The case will grow in length after firing so make certain you also check case length before loading and bullet seating.

Jim

Andy2590 · « **Reply #6 on:** June 27, 2006, 03:50:40 PM »

I'm using sierra 180 grain game kings. I understand that they can vary a few thousandths, but they are varying a few hundreths. The dies I'm using have a sleeve that makes sure the bullets seats straight also. Thanks for all of the help so far.

PaulS · « **Reply #7 on:** June 29, 2006, 05:53:23 AM »

Quote from: Andy2590

I'm using sierra 180 grain game kings. I understand that they can vary a few thousandths, but they are varying a few hundreths. The dies I'm using have a sleeve that makes sure the bullets seats straight also. Thanks for all of the help so far.

Andy,
there are a number of variables that can cause bullets to vary in seated length and I will list some here and how to correct them.

Play in the equipment you are using. Some of the cheaper presses can flex enough to allow the distace to vary .010 or more. If you have a good quality press this is probably not the cause.
If your seating dies are loose or the lock-ring is not properly tightened it can allow enough play to affect your seated depth.
Dirt or lube build-up in the seater punch can cause variations in seating depth - clean your dies with "brake parts cleaner" from any auto parts store to be sure that this is not your problem.
Your technique in using even the best equipment can cause variations in the finished product. make sure that you are going "full stroke" on each operation of the press.
A die that is adjusted so that the built in crimper of the seating die is not seating in the cannelure or if the cases are of varying lengths this will interfere with the seating depth of your bullets. Back your die out one turn and then readjust the seater stem and see if that changes your results.
Dirt on the shell holder could cause variations in seating depth. Clean the ram and shell holder with brake parts cleaner.
If the shell holder hits the bottom of the seating die it will cause variations so make sure that the die is properly adjusted.
Unless you are seating your bullets very close to the lands the .010 variation that you are seeing is going to cause no signifigant problems in accuracy or pressure. After checking my compponents and equipment to make sure that I had covered all these probable causes I would not be overly concerned with .010 variation. If this is going to bug you until you find out why it is happening you may find that it is just a combination of all the vaiables within your equipment and components.