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Posted: 9/14/2010 2:23:46 PM EDT
[Last Edit: 9/14/2010 2:26:02 PM EDT by Boosted98gsx]
So I have a redding competition match seating die, trying to seat 77gr SMK's into UNIFORM cases (I am talking about they are ALL 1.750" +- .0005, and I can NEVER get the bullets to seat to the same depth, and there are huge variations in seating depth from one to the next. I get one bullet to 2.260, then I try to seat the next, and it's at 2.250 or something.

WHAT THE HECK???
Link Posted: 9/14/2010 2:57:54 PM EDT
You're checking COAL and not to the ogive, correct? The nose length of bullets vary. Seating dies contact the ogive of the bullet, so they're all seated the same in relation to the rifling––-even though they appear to be different.
Link Posted: 9/14/2010 2:59:34 PM EDT
It is fairly common to have different OAL with BTHP bullets because the seating dies use the ogive of the bullet (ensures each bullet starts the same distance from the lands), not the tip. You need to get a comparator gauge like this one that measures OAL from the ogive.
Link Posted: 9/14/2010 3:01:32 PM EDT
Most imperfections in the bullet manufacturing process occur in the top third of the bullet, so various COALs are common.

Were you to acquire an Sinclair/Hornady/Stoney point bullet comparator, you'd see that the actual ogive length is very uniform, which as Martha might say 'is a good thing'.

Chris
Link Posted: 9/14/2010 3:18:22 PM EDT
Are you measuring cartridge overall length with dial calipers? The hollow points on the SMKs' are a little uneven around the edge of the jacket, no big deal really. To get true loaded bullet to beginning of rifling measurement you need a tool that measures the bullet length from where the bullet touches the rifling. I think Lyman makes a tool for this. To be honest, it is a nice tool, but unless your reloading match loads for a bunch of different calibers its' not worth the expense. As long as the groups are tight and the pressure is safe, just shoot it.
Link Posted: 9/14/2010 3:32:13 PM EDT
Link Posted: 9/14/2010 3:49:31 PM EDT
Thank you guys!
Link Posted: 9/14/2010 8:13:22 PM EDT
You are already happy with the answers given, I was going to say measure the bullets, (since your brass is all exactly the same length) then you will see why the COAL is different.Just for fun you could file or sand them all (bullets) to the exact same length, then check COAL next time around and see what you get, now that would be fun..... wouldn't it?
Link Posted: 9/14/2010 8:27:17 PM EDT
[Last Edit: 9/14/2010 8:30:28 PM EDT by EWP]
A melplat uniformer for the BTHP bullets is the only way you'll ever get even close to the same measurement at the tip, like the others have said get the Hornady bullet comparator set and you will see the ogive is uniform from bullet to bullet but the tips are way off(unless you uniform them which will help with accuracy as well with minor loss of bullet BC.)

Meplat uniformer

My choice and easy to do With these you just buy a new body for $15 for other calibers and it's an easy swap.
Link Posted: 9/14/2010 8:43:29 PM EDT


That doesn't look right, I got one for .277 for my 6.8 and it swallowed the whole bullet like yours shows(which is not the ogive) and they sent me a 6.5mm for free that works perfect. My .22 cal insert does work right and it's not so close to the case mouth even with 69gr SMK & H-75gr BTHP which have long ogive's.
Link Posted: 9/14/2010 8:54:23 PM EDT
Originally Posted By EWP:


That doesn't look right, I got one for .277 for my 6.8 and it swallowed the whole bullet like yours shows(which is not the ogive) and they sent me a 6.5mm for free that works perfect. My .22 cal insert does work right and it's not so close to the case mouth even with 69gr SMK & H-75gr BTHP which have long ogive's.


it works with a bare bullet.


that seems rather pointless though but whatever. I'll be getting that bullet depth checker once its off backorder at Sinclair lol
Link Posted: 9/14/2010 10:55:44 PM EDT
[Last Edit: 9/14/2010 10:56:41 PM EDT by EWP]
Originally Posted By danpass:
Originally Posted By EWP:


That doesn't look right, I got one for .277 for my 6.8 and it swallowed the whole bullet like yours shows(which is not the ogive) and they sent me a 6.5mm for free that works perfect. My .22 cal insert does work right and it's not so close to the case mouth even with 69gr SMK & H-75gr BTHP which have long ogive's.


it works with a bare bullet.


that seems rather pointless though but whatever. I'll be getting that bullet depth checker once its off backorder at Sinclair lol


Your missing the point, you are NOT measuring from the ogive with that insert from the looks of the pic and it was meant to be used on loaded rounds not just bullets(but you can), the point where your insert is contacting the bullet is almost at the shank of the bullet, it should be 1/8" or so(little more than half way up the ogive like how you are using it backwards, not right where the ogive and shank almost meet) down from the shank on the ogive to get a proper ogive reading.

I plan to get the Redding Instant Indicator($83.99 vs 79.95 for the sorting stand just to measure bullet base/ogive length), I want the one that will fit your press and measure seating depth off the ogive using bushings or set just after your sizing die will give you exact measurement of shoulder bump and will also sort bullets from the base to ogive, this is done to sort bullets before using a meplat trimmer mostly because as we know the factory tip doesnt matter but once bullets are sorted and trimmed using a meplat trimmer you will even have accurate ogive to tip measurements for improved flight characteristics. It's quick and with a good dial gauge so you can see the results fast and keep moving

I like all Sinclair's little tools, they are so nice with heavy anodized bases(I have the concentricity gauge I love & a Redding neck thickness gauge that is nice as well, just wish it had a base like Sinclair's) and the one to quickly sort bullets with the dial gauge will sure to come soon also but the Redding tool does the same plus more so I'm going for it first since I'm not meplat trimming/uniforming my bullets yet, so that sorting is useless as long as the bullets are seated at the same ogive distance regardless of ogive to bullet base distance.
Link Posted: 9/15/2010 4:07:01 AM EDT
The product description says "These inserts are not intended to measure rounds seated to magazine length or shorter"

I had bought it anyway hoping it would contact just the way you mention but it doesn't.
Link Posted: 9/15/2010 5:41:37 AM EDT
[Last Edit: 9/15/2010 5:44:46 AM EDT by EWP]
Originally Posted By danpass:
The product description says "These inserts are not intended to measure rounds seated to magazine length or shorter"

I had bought it anyway hoping it would contact just the way you mention but it doesn't.


My .277 one for the 6.8 is loaded out to 2.30" and way above mag length and it still swallowed the whole bullet up to the shank but the 6.5mm insert works great.

What length are you seating to?

I seat to 2.260" for most all .224 bullets and mine works fine, the Hornady comparator insert really works better on loaded ammo but your Sinclair insert should still work better than it does for you, what bullet was that in the pic, maybe I can compare mine with the same bullet?
Link Posted: 9/15/2010 6:21:06 AM EDT
[Last Edit: 9/15/2010 6:22:14 AM EDT by danpass]
77 SMK loaded to mag length

likely an issue of tolerance stackup as loading to mag length brings the ogive pretty far down
Link Posted: 9/15/2010 6:29:33 AM EDT
Originally Posted By danpass:
77 SMK loaded to mag length

likely an issue of tolerance stackup as loading to mag length brings the ogive pretty far down


The closest I can come to matching that bullet loaded to mag length is a 69gr SMK or a H-75gr BTHP just to show where the comparator stops on the ogive at mag length.
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