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COAL, ogive, off lands ... yup, more Q's

2K views 10 replies 7 participants last post by  MikeG 
#1 · (Edited)
Soooo, I'll be loading for a 223 shortly and took some time recently to review my set ways from reloading for my 30-06. Now the 30-06 is my hunting rifle and I've always loaded it as such being sub-MOA performance isn't required. Now the 223 will be mostly a target rifle with the odd varmint here and there so sub-MOA performance would be nice.

Now, after reviewing numerous postings retrived from the search function, I've found out the "cleaning rod" OAL method to the tip of the bullet isn't the best way so on to the question.

Using my previous method I assume I'm getting a fairly consistant "off the lands" distance but it may not be the absolute distance I think it is. So now I switch to the ogive to case measurement which will put me closer BUT when seating the bullets with the Lee bullet depth die how much error will this introduce being it doesn't seat by pressing on the [edit] shoulder point?

Also, tell me if I'm getting to picky just to get sub-MOA loads. :)
 
#2 ·
My experience, which is limited, is you don't know what may be the thing that gets that little extra out ou your rifle or load. For target shooting , crimp or no crimp has been a big deal in my H&R 308. Seating to lands has not. I think most folks find projectile and powder combo to be the big factor in load development. You just never know.
 
#3 ·
On the other hand....in my .22-250 Ruger #1, seating depth turned out to be everything, other than loosening the foreend screw. I fight with too many variables to test, even after I've picked my powder and bullet. Powder weight and OAL are both huge, and require a lot of test shots to learn much unless you dial in on something pretty quick. I have alway subscribed to the method of seating the bullet loosely in the cartridge and carefully closing the action. Smoking it's helpful to see the marks. Then start backing off a tad and run your tests. Clearly, different rifles like different seating depths, and some are more finicky than others.
 
#6 ·
ranger335v, that was the first question I started off with .. is the cleaning-rod method good.

Just for fun I measured the last four .308 bullets I had which ranged from 1.191 to 1.195. So a difference of only .004 which didn't seem too bad though a bigger sample would have been nice. I also measured each bullet with the seating die in place. The maximum difference dropped to .0035 which isn't much of a gain but it also wasn't from the longest bullet either, the distribution changed. But in the end what is a .0005 difference gonna get you in accuracy?

Out of curiosity I grabbed a new box of .224 bullets, pulled 4 out and they showed a max difference of 0.0065. Now this I thought was interesting as the .308s were hunting bullets and the .224 are target ... I would have guessed the target would have had tighter tolerances. Now the surprising part, the .224s measured with the seating die dropped to a max difference of 0.0005.
 
#7 ·
can06 said:
ranger335v, that was the first question I started off with .. is the cleaning-rod method good.

Just for fun I measured the last four .308 bullets I had which ranged from 1.191 to 1.195. So a difference of only .004 which didn't seem too bad though a bigger sample would have been nice. I also measured each bullet with the seating die in place. The maximum difference dropped to .0035 which isn't much of a gain but it also wasn't from the longest bullet either, the distribution changed. But in the end what is a .0005 difference gonna get you in accuracy?

Out of curiosity I grabbed a new box of .224 bullets, pulled 4 out and they showed a max difference of 0.0065. Now this I thought was interesting as the .308s were hunting bullets and the .224 are target ... I would have guessed the target would have had tighter tolerances. Now the surprising part, the .224s measured with the seating die dropped to a max difference of 0.0005.
You can always seat a bullet (non-crimp, non-loaded of course) just enough to keep it from being too loose, work the bolt closed then carefully extract and measure. That should tell you what OAL will put you in contact with the lands. If you neck size your rounds this will work well as you can just size lightly and the bullet will be loose in the neck enough to permit the chambering without giving inaccurate measurement. Try it and see what your OAL is. I've done this with my .270win.

Also, if you load anywhere close to max loads be sure to back off slightly and work up for safe results. It's possible to spike pressures with the bullet tight against the lands.
 
#8 ·
Perferator, that's the exact method I use, I put enough neck tension to hold the bullet firmly. Thinking about it this can lead to two problems, one I've actually measured, 1) bullet is too loose so the extraction causes a change in length (seen this) and 2) bullet is too tight and gets forced into the lands.

Now the difference I've seen with issue #1 wasn't all that big (don't have my notes handy so I can't post them) but is wasn't as repeatable as the cleaning rod method with collars.

Now if the bullet is too tight in the neck how much can it be pushed into the lands?
 
#11 ·
What you do is have the bullet make very light contact with the lands - then, record that measurement, and try adjusting the bullet seating stem down another 0.010".

After you get the perfect spot figured out, keep a dummy round in the die box to check setup.
 
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