I'm pretty new to reloading. Right now I'm reloading 300 win mags. I'm using winchester cases and sierra 180gr. game kings. 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

You are probably measuring to the tip of the bullet. That's a no-no.

Where should I measure to then? I know the bullets arent all exactly the same length, but there is more than a thousandth or two difference between the overall length and the differnce in length between the bullets was only a thousandth or two.

Get a comparator (sp?) Russ Hayson's Shooter's Supply 253-857-7557.

Russ sells a comparator that fits the popular calibers up to and including 30 Cal.

quote:

Originally posted by Andy2590:
Where should I measure to then? ...

Hey Andy, There are quite a few different ways to accomplish this task. I prefer to convert Overall Cartridge Length(OCL) to Overall Die Length(ODL) and repeat it every time I open a new box of bullets.

Best of luck to you.

The length of the individual loaded rounds will vary because the actual shape and length of the individual bullets vary, especially those with exposed lead tips like the Sierras.

The stem in your seating die bears on some portion of the bullet ogive that matches its diameter. Hopefully, this is reasonably consistent from bullet to bullet so that the effective seating depth of each bullet (the bullet's full diameter in relation to the start of the lands) is essentially the same. DO NOT attempt to make all of the overall lengths the same, since this will cause your effective seating depth to vary.

Set your die so that the longest bullet does not exceed whatever your desired overall length may be, and let the rest of the bullets "fall where they may" short of this length.

HOWEVER, I think you may be under the misimpression that what your are striving for is some predetermined overall length, rather that a proper relationship between the bullet's bearing surface and the lands. The only thing that overall length concerns is whether the cartridge will fit into the magazine. All other length considerations revolve around performance and accuracy, which is related to the bullet-land relationship, not the bullet-magazine relationship.

This mostly applies to match ammo that is loaded into single shot rifles but can be applied here also. The neck tension of the case has alot to do with this inconsistency of the overall length. Hard to understand but I've tried many different things and neck tension bugs me the most. With a light neck tension set up my overall length doesn't vary much at all but change that and I have the same problem. I double seat most of my high neck tension loads and it seems to help. JMO

StoneCreek has it explained pretty well. This link will take you to Midsouth and the Stoney Point bullet comparator set. It goes on your calipers and will measure to the ogive of the bullet rather than the tip. The tip is what is giving you problems with your measurements. If your seating stem is seating from the tip of the bullet you have a problem, but I'm betting that it is seating properly off the ogive and that is where you should be checking your measuements. I'm sure Stoney Point will have web site explaining all the gadgets they have. I use their overall length gauge and the comparator often.

Thanks for all of your help.

Andy

That pretty well covers this problem.

Set a bunch of your bullets on a flat surface next to each other and compare them. This will give you some idea how much they'll vary.

Also, IF your powder charge is highly compressed. This can and may push your bullets out some to relieve the pressure.

I generally lightly crimp all my loads whether they need it or not. Just to take the sharp edge off the mouth. I ripped a finger one time digging in a pocket for shells while hunting once. Seems to work fine for me. Not everyone agree's with anyone else all the way. You'll find that out.

Make sure those loaded shells are all real closely the same before you shoot them. IF some have pushed bullets out, you could have a pressure problem. It's doubtful with a case that large, but, the theory is there at least and in some place's you'll read about it.

Wish you well,

George