Seating depth Issues

[6BRinNZ]

Hi,

Quick Intro, I have just moved from a .223 to a 6BR for varminting in New Zealand and have been following this site for about 6months...awesome site, none better!

Anyways in my search for the perfect match of speed and accuracy I purchased a Redding Instant indicator die set, and I have been using it to measure the seating depth of each projectile loaded. I have found that the depth can vary by up to 6 thou! I am using laupua Brass (no neck turn) and a Redding bullet seater with mircrometer. The variance occurs across new or fired brass, V-maxes or Berger projectiles.

Am I making some dumb newbie mistake or....?

Thanks in advance for any help.

PS I can post my results for 88 FB HBC Bergers where the seated depth was changed by 2 thou increments, if anyone is keen to view, I was shocked at the change.

 

[groupshooter22]

That is why I sort all of my bullets by length to the ogive, Bergers, Bibs, Sierra etc. None are perfect but the Bibs have been the most consistant.

 

[oneflyer]

Sort all bullets base to give before seating and then hope that the seating stem approximates the same location on the ogive.

 

[NorCalMikie]

One thing to check is that the hole in the
"seating stem" is deep enough. A Berger VLD will bottom out in most stems where other style bullets won't. That will give you fits!! (Been there, done that.) If the point of the bullet hits the botton of the hole inside the stem, you'll never get an accurate reading. If needed, drill the hole a little deeper.

 

[limbic]

I find that lapua scenar varies the least. If I'm loading a compressed load I find more variance than non compressed. Also SMK often vary several thou.

 

[JRXCR]

I've been using the technique from High Power Rifle Accuracy by Arnold. Set depth to 10 though more than what you want as a final measurement, seat the bullet, measure with your comparator, and then dial in the amount needed to get you to your final base to ogive measurement. This cracked the problem for me and my SMKs all have the same base to ogive measurement. I would reccomend the book, it has a lot of good information on working up loads and some good tips for loading with max accuracy. It is definitely a slow process though!

 

[6BRinNZ]

Hi Thanks, to everyone for the info. I have been busy with Xmas so I haven't had a chance to measure anything yet, but I will and I will post with my results. I did end up resorting to setting the seater short, measuring each loaded projectile and then adjusting the seater again for the final seating depth. Everything came in exactly as I wanted but it is slow. Interestingly enough, this left a little ring on the projectile from the seater which wouldn't be anywhere near the ogive from my understanding. This may explain the 6 thou variation as I wouldn't have thought that even cheap bullets would vary by 6 Thou at the ogive?

I have included the results from my seating depth changes. The two largest groups are seated two thou longer and two thou shorter that the smallest group. I used the Redding instant indicator die to measure the seating depths. This result is what lead me to make this post as I was shocked that two thou would have such a significant impact. The conditions were perfect so I am confident wind played no part.

 

[cliffy]

I find .223 Remington plants itself best at 2.250" C.O.L. and most .243 Winchester bullets work best at 2.687" C.O.L. yet nothing is written in stone regarding individual variables. Some .243 Winnie prefer 2.600" C.O.L. due to Ojive dimensions, so THERE! Handloading is both frustrating and perfecting combined. I have my favorite rounds through many near-misses. Downrange at 200 yards is where you'll find what your rifles likes and dislikes. My favorites come from way too many spent rounds at 100-200-300 yards of frustration, but when a round comes together, it, somehow, all seems worth the effort, sweat, and tears. Cliffy

 

[6BRinNZ]

Hi, I have checked a bunch of the Berger projectiles and I can't find any significant variance, also I have checked the seater stem and it easily has enough room to seater the Bergers. Not sure where to go from here, could it be neck tension? Loaded rounds measure .271+ and I am using a .268 neck bushing.

 

[tenring]

I like the Redding Instant Indicator for checking shoulder bump, but not OAL. I set my micrometer seater die to load about .005" over my desired length. Usually load 20 or so at a time. Measurements are made with Davidson nose cone and base in a Mit digital caliper. There will be variances of .001-.005" in each batch. I set them in a loading block, lowest to highest, and turn micrometer down a thou at a time as needed to bring all of them to exactly the same OAL. If those loads are not fired within a few days, OAL's will change.

 

[6BRinNZ]

Hi Lynn, I chose not to go down this track as it seems more work than just adjusting for each projectile.

What I have done is purchase a wilson seater, when I used this it really showed up the amount of force needed to seat the projectile, and even using the Wilson seater I had the same problems. Sooo, I went from a .268 bush for the redding die to .270, this has pretty much solved the issue, I loaded over 20 rounds using the new neck tension and the redding seater and they were all within .001". I was using 75 V-maxes in this particular case.

The other aspect that I think is causing some issue is - the Berger 88s when seated to just touch the lands; seat so that the base of the bullet is exactly at the neck shoulder junction. I cut a case open and I suspect that there is the tiniest of donuts (scraping a pin over the junction tends to indicate a slight bump...I don't turn my necks) and when seating I suspect that this is causing some issues for a consistent seating depth when using the Bergers, no problem for the 75 -vmax as they are a boat tail.

So for now, my conclusion is - too much neck tension and keep well away from the neck shoulder junction.

Oh well maybe I will need a new barrel to seat them out ;-)

 

[squirrelsnpr]

6BR-
I am having the same kind of results with my 223 using 75-Amaxs. I found that when I seated the bullets I could feel different pressures required to operate the press. I noticed this more with cases I had fired a few times. I have started to anneal my cases and it seems to help quite a bit. If you have read about annealing, this will put the elasticity back into the cases. I am not as knowledgable as most on this site, but it helped for me. I don't know why the new cases are doing the same thing. I just bought my first batch of new Lapua brass and did not have this problem. But, I didn't even neck size the Lapua brass. Who knows if this problem will occur after a few firings.
Best Luck,
Mitch