bullet seating problem

25 September 2003, 14:56

jb177

I reload as a hobby, but want to be good at it, so here's my question...

To find the lands of my rifle, I seat a dummy round long and then chamber it in my rifle. This supposedly seats the bullet back until it fits snugly against lands. Correct?

Then I start seating the bullets about .030 off the lands and then start changing the depths for accuracy.

Do I know what I am doing? I do this with every new caliber/bullet combination.

Problem: With bullets that have an exposed lead tip, my seating always varies. How do I fix this problem? I have read about Stoney Point gauges, etc. but don't quite understand how/why to use them.

One other note, I have noticed that even with polymer tipped bullets (Hornday SST), that my COL can change +-.008 from one loaded cartridge to the next. Is that a problem with my RCBS press or die? Or just normal.

Thanks for all of the help you guys have given me in the past, this is my best/only source for real-life reloading information.

25 September 2003, 15:53

Ol` Joe

The problem with chambering a dummy round to set the distance to the lands is it`s possible for the bullet to be jammed in the lands a bit, or stick and pull back out a hair when you extract it, and not be seated "just to" them. If you then back off a few thousanths you don`t really know where you are in relation to the lands.
Smoking the bullet or coloring it with a magic marker and rechambering it will allow you to see if it hits the rifleing.
The Stoney point measures off the ogive of the bullet not the tip. The lenght of a bullet can vary quite a little depending on if it has been damaged or what the tolerance in the lenght is in the factories QC.
The tool measures at a point close to bore diameter on the bullets ogive and is very consistant in measurment you get. I have heard some people have trouble working them but if you follow the directions they work good with a little practice.
One thing to look at if you what appears to be excessive OAL variation is if the seating plug in your die hits the bullet tip or seats properlly off the ogive. This can be a problem with plastic tipped bullets, If you find you have a shallow cup on your seater, drill it out .020" or so with a small drill bit to allow the bullet tip to clear the stem.
Some OAL variation in measuring from base to bullet tip with out a stoney point or other comparator is normal and not a fault of your dies and press. The critical base to ogive measurement should be fine if the die is seating off the ogive as is should.

26 September 2003, 01:33

jb177

Thanks Joe, I usually do smoke the bullet to look for the lands, but I have also got polymer tipped bullets too hot and they melted a little. Just looking for the best way.

I have seen several different Stoney point gauges out there, what exactly do I need? Will one gauge work for all calibers? I want to be as precise as I can be considering all of the factors that work together to get consistency.

Thanks for the insight, I didn't know that the bullet seater worked off the ogive and not the tip. The things you learn. Guess I will have to take my dies apart tonight and take a look.

26 September 2003, 02:20

Bigdaddytacp

quote:
Originally posted by Justin B:
Thanks Joe, I usually do smoke the bullet to look for the lands, but I have also got polymer tipped bullets too hot and they melted a little. Just looking for the best way.

I have seen several different Stoney point gauges out there, what exactly do I need? Will one gauge work for all calibers? I want to be as precise as I can be considering all of the factors that work together to get consistency.

Thanks for the insight, I didn't know that the bullet seater worked off the ogive and not the tip. The things you learn. Guess I will have to take my dies apart tonight and take a look.

.....There are a couple of different Stoney Point gauges that you need.....to find the OAL the OAL tool with a dummy cartridge for EACH cartridge is used with the OAL tool....there is a straight one for single shot and bolt guns and the curved for autos and will work in bolt/single shot....then the BODY of the other tool will use either the comparator inserts to find the ogive distance on the seating depth of different bullets and cartridges...these are caliber specific....then the SAME BODY can use inserts for headspace to check the sizing of the case measured to the datum line on the shoulder of a bottleneck cartridge.......the body works for the two different inserts for bullet ogive distance for seating depth checking and the different inserts in the same body for headspace of the cartridge measurement......the complete kits are cheaper but if you don't load many different cartridges then you can buy the inserts singly......the tools and a good dial caliper..steel..work well for each application after getting the "feel" of the measurements with CLEAN cases and let you set your seating depth and check the consistant seating of your dies and the sizing of the cases with the other inserts to check for need for full length sizing and performance of your die......be sure to clean the inside of the inserts with a clean Q tip or similar and wipe the case clean and the readings are easier to take and then record......HTH...good luck and good shooting-loading!!

26 September 2003, 02:22

JustC

Use a split case and you will get far more exact measurements.

Take a sized case,..and a dremel tool with a cutter wheel (as thin as possible) ans split the neck down past the shoulder/neck junction. This will provide you with just enough "spring" tension to allow the bullet to slide back into the case when contacting the lands, while also providing enough tension to hold the bullet and not allow it to retract as the case is pulled out of the chamber. Do this 3 times and I will guarantee your measurements don't vary by more than .001" OAL. This is the fastest and most accurate way I have found to determine the "at the land" measurement with ANY bullet for ANY caliber. The case is reuseable for any rifle that caliber also,..so it is a tool you will keep. Be sure to size the case after each time,..it seems to provide the perfect tension for me.

26 September 2003, 14:32

Old & Slow

At a 0.008 delta in AOL what is probably happening is the bullet tips are inconsistant. The very tip is the toughest part of the bullet to get consistant. Your die seats the bullet based on a diameter that is part way down the bullet. If the tip is inconsistant you will see this in AOL but the depth to the lands will not have changed. Even on the most expensive benchrest bullets there is inconsistancy in the tips. Some benchrest shooters use a special tool to square up and even the length of their bullets. They are looking for thousanth's of an inch group improvements though.

27 September 2003, 15:35

dodgestdshift

Something else to consider. The length of the cartridge is not the factor that is most important in touching the rifling. Remember the part of the bullet that touches the rifling is not the tip, but a rough circle about 1 caliber in diameter some distance down from the tip. When you measure length you measure to the tip. If the bullet has slight differences on the ogive it can effect how long the cartridge is, when it strikes the rifling.