bullet seating variations

[TackDriver284]

My .308 Lapua cases are fired 2x, and neck sized with Redding Competition Die, and trimming is not really needed because its around 2.005 case length, some are from 2.003 to 2.006, so no big deal. Now when I seat the 168 SMK, I measured the ogive on each bullet, and there is a variation up to .008" on base to ogive. Why is that? My RCBS press is about 25 years old, don't you think it might be some wear? It's frustrating when you spend a couple of hours prepping cases, fill and seat bullets and find out at the end that there is a seating variation.

 

[waveslayer]

What dies are you using to seat the bullets? Most likely the dies

My wife thinks I only have 3 guns

 

[kraky1]

.008 might be a little excessive for the bullet jacket itself having variation.... but I sure wouldn't expect them to be perfect and I would think you could have up to at least .005 in the jacket?
Any amount of compression on the powder could have a lot to do with this also.

 

[truck driver]

I have the same problem with .358 200gr ABs so I just set the Micrometer seater stem to seat them long and adjust to where I want them. I have no problems with Partitions just ABs.

 

[TackDriver284]

waveslayer, using Redding Competition Seating dies, took it apart and checked the seater cup / stem, looks fine and bullet seats in the cup just fine, not on the tip.

kraky, I am using 42.9 grains Varget in .308, powder is filled to the bottom of the neck, don't feel any powder crush. I last shot the .308 and shot .2 MOA, just varying COAL lengths in .015 increments to find the best load and to fit the mag. Shooting the GAP Crusader, 60 rounds down the tube.

 

[TackDriver284]

I have the same problem with .358 200gr ABs so I just set the Micrometer seater stem to seat them long and adjust to where I want them. I have no problems with Partitions just ABs.

How did you adjust them?

 

[truck driver]

I have the same problem with .358 200gr ABs so I just set the Micrometer seater stem to seat them long and adjust to where I want them. I have no problems with Partitions just ABs.

How did you adjust them?

I would screw the Micrometer seater down to seat the bullet deeper till I got the length I wanted.

 

[kraky1]

Deleted....I see you checked the seating stem relationship!

 

[Guy Miner]

.2 MOA and you're looking for better... :grin:

Cool. You're into the rarified air of benchrest or long-range competition at this point... Enjoy!

Guy

 

[TackDriver284]

.2 MOA and you're looking for better... :grin:

Cool. You're into the rarified air of benchrest or long-range competition at this point... Enjoy!

Guy

Call me picky. :grin: Even if it shoots .2 MOA, its great, but I wanted to figure out why the variation.

 

[Guy Miner]

Go for it!

You're past the point in accuracy where I've long since just loaded up a mess of 'em and burned out a barrel or two, learning the wind and learning my own limitations.

But for handloading perfection, it's guys like you who push the envelope and improve things for the rest of us.

Regards, Guy

 

[TackDriver284]

Went back to the reloading bench to try a different bullet, used the same cases, same powder measurement and this time I used 165 Nosler Ballistic Tips, i measured all the bullets, base to ogive, they all about .001 " of each other, then loaded 20 rounds and measured loaded round length from base to ogive and now they are all right at 2.229", no more or less. Just not sure what the cause of the variances from the other day, but shot those rounds earlier this morning, and they shoot .2 MOA still. Soon I will go back to loading the 168 Sierra MK again and see if I can find what the cause of those variances were. Hopefully its just human error on my part.

Yes, you are right, I get anal about little things sometimes, but if it shot good like this morning, I'll let it pass and move on and worry about the bigger problems.

 

[kraky1]

Years ago my buddy bought two boxes of 308 federal match grade 168 mk ammo. We sorted them over my rcbs run out checker and were shocked to find 1/3 had over. 006 run out...some as much as. 011!
We sorted them into 3 groups.....003 and under.....004 to. 006.... and the rest over. 006. When he shot them at 330yds there was no difference in groups....all hovered around 2.5". Sometimes I think 98% of accuracy comes from how much a barrel loves the bullet n powder combo and whether it matches a vibration node....the rest is farting in the wind....lol!

 

[TackDriver284]

Years ago my buddy bought two boxes of 308 federal match grade 168 mk ammo. We sorted them over my rcbs run out checker and were shocked to find 1/3 had over. 006 run out...some as much as. 011!
We sorted them into 3 groups.....003 and under.....004 to. 006.... and the rest over. 006. When he shot them at 330yds there was no difference in groups....all hovered around 2.5". Sometimes I think 98% of accuracy comes from how much a barrel loves the bullet n powder combo and whether it matches a vibration node....the rest is farting in the wind....lol!

Same here, I measured 55 bullets of 168 SMK, from base to ogive on a Hornady comparator and 50 of them measured .001 - .002" " over or under in variation, its reasonable, except that 5 other bullets measured .028 to .031" over and tossed those 5 in the bin.

Found the newer 168 grain Nosler Ballistic Tips for the .308 at Bass Pro Shop yesterday, grabbed 3 boxes. It has a better BC than the older 165 Nosler BT. Had that old 165 from 20 years ago, and loaded the last of them for deer season. Finally the empty old box is in the bin.