Need some input on a problem I've been noticing. I have a Rockchucker press and use the standard RCBS dies. While loading for my 22-250 and 17 Rem recently, I'm having a very hard time holding my bullet seating depth consistent with this setup. After measuring all my 17's tonight, the OAL varied as much as .013 from what I wanted it to be. Sometimes deeper, sometimes shallower. Everything is locked down tight, I'm using polymer tipped bullets (V-Max), the die is clean, the shells have all been prepped properly, and the die sits about 1/4 turn off the top of the shell. Am I expecting more accuracy out of these components than they can give? It's getting quite frustrating and time consuming when I have to measure every round and adjust the seating depth on each shell.

If you measure OAL from the bullet tip you'll never get consistent readings, as individual bullets from the same box vary in length. The correct way to measure OAL is from the ogive, i.e. bullet to land position, like when using a Stoney point or Sinclair gauge.

jethro
For what it worth, here's a technique I used back when we were exchanging our cataputs and ballistas.....
Make a dummy round, seat bullet out too far, smoke the bullet with carbon from Bic lighter. Try to chamber, turn seating stem in push bullet deeper into the case, smoke bullet again,keep repeating until dummy round chambers. Once you have determined this you can experiment to find what bullet length your rifle likes.
With one of my rifles the bullet gets really jammed into the rifling lead for best accuracy, others like a bit of space before engaging the rifling.
Jim

I have a Stoney Point gauge to measure the OAL, but you measure from the bullet tip, not the ogive. Is there a way to measure from the ogive without buying extra tools? If not, what tool do you recommend?

What you want is the Stoneypoint comparator tool. They are sold by www.Midwayusa.com or www.grafs.com
The Stoneypoint web site shows them and I believe you can order from them also www.stoneypoint.com
The tool is a must if you want a good reliable measurement. Sinclair and a few others make comparator type tools but the stoneypoint is the cheapest and easiest I`ve used.

I forgot to add the tool takes caliber specific inserts. You will have to order one in each caliber you load for ie; 308, 7mm, 257, ect.

.013 sound a little bit to much...

The easiest way to reveal problems with your seater or perhaps even your press, is to make dummy rounds as suggested above, but without smoking them. Make the rounds so long that you can see see the marks from the rifles. Chamber them and compare the lenghts of the rifle marks on the different rounds.

I'f you can't see any differences than you can be confident that there are no differences when you are seating them at normal depths either.

[ 05-03-2003, 18:56: Message edited by: Olimahtes ]

That's pretty innovative Hotcore. I like the way you think.
I was looking at the Stoney Point Comparator and I like the fact that you can buy inserts for it to cover all calibers, rather than a whole new unit. I may just go that route to make it easy. You can buy a kit that comes with 6 inserts for $22. Of course, the odd ball 17 isn't one of them, but the inserts are only $2.68.

jethro,
One thing I do is too load a dummy case. This case is then used for all future seating depth changes. Since the same bullet is always used, measurements too bullet tip always reflect the correct change in seating depth ghanges. Good luck.

[ 05-04-2003, 01:48: Message edited by: BigBob ]

Hey jethro, I'd originally listed the wrong Drill Bit size, so I went back and EDITED my prevoius post.

Good luck with the Stoney Point.

Hot Core is all over it, Sinclair's comparator is about $16.75, most time saving tool on the bench. The comparator looks like a big hex nut with holes drilled in the flats, the holes fit directly on the ogive of the caliber they are drilled for, way easy and consistant. Hot Core, they came out with the comparator with the .17 in the last catalog I think,just got mine(gotta have a gadgit ) Also watch going lot to lot even in the same part number bullet, from one run to the next can vary a great deal. If you really want to make it easy on yourself use a Redding competion seater. With a comparator from Sinclair and Redding's die's going from lot to lot or even bullet to bullet takes a matter of seconds. A few thousands variance in seating depth measured at the ogive is not uncommon due to inconsistencies in jacket thickness etc. The quest for the perfect bullet continues, that's why the custom bullets cost so much, the perfect bullet is a tall order. I agree the Stoney Point is the long way around the barn to get the job done, by the time you get all the calibers it's much more expensive than Sinclairs unit and doesn't work as well.---Shoot Safe---montdoug

Don't be misled by OAL. It can vary considerably from one bullet to another in the same box. The bullet point isn't touching anything anyway. The ogive measurement is the key. You can get the needed tools from the Sinclair catalog. Stoney Point and Sinclair both make excellent equipment for measuring to the ogive. Best wishes.

Cal - Montreal

I do two things to get consistant O.A.L.'s and it
works very well for me.
1) Trim all cases to exactly the same minimum trim
length.
2) When you open a new box of bullets, measure
each bullet to within +/- 0.003". Depending on the manufacture and type of bullet you will end
up with about 85% of a box all falling into this
range. Lead tipped bullets will have the most
variation due to deformation and some polymer
tips will fall into the high 90% consistancy area.
Cull these into size ranges and set the seating die to adjust for each size range. When shooting
these you will see better groups and less flyers.
3) Take one of the average sized bullets in the
largest group measured and make a dummy round
as stated above to get the length to lands and
set your seating depth accordingly.
This whole process only takes a few extra minutes
but your O.A.L. will be consistant! If you only
want to load say 10 rounds you probably will get
10 that measure the same before measuring 15 rounds. Nosler BT's seem to vary less than all
the others except for Sierra Match Kings. I have
found my most accurate loads were with those two
bullets. I have measured factory loads and found
they vary as much as 0.018" and they do not group as well as reloads. That's why I reload! BLR7

Whichever method you use be sure to check when changing between batches of the same bullets. I have experienced lot to lot variation (even with BTs)that would make a 10 thou off lands load on the lands with attendant pressure problems.

PS loading near the lands much over rated IMHO.