bullet seating variation

[TackDriv3r]

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.

 

[timeout]

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 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.

There are a number of things that can cause this such as variation in the bullets themselves, uneven neck tension, seater stem not compatible with the bullet. I measure each cartridge as I seat them. That way you won't get the big surprise after you have finished the entire batch. Also, you will never be able to feel differences in neck tension until you switch to an arbor press and Wilson seater dies.

 

[mikecr]

How deeply are you seating bullet bearing?
How much neck sizing (amount & length)?
Are the necks cleaned in some way, affecting seating friction?

 

[TackDriv3r]

Powder is only 42.9 grains, just up to the bottom of the neck. Neck sized 80% of the neck, and cleaned with a 30 cal bronze brush on my RCBS case prep machine. Bullets are seated to 2.840 COAL. I don't feel any powder crush either.

 

[243winxb]

Redding website <>If your loading press is worn, the ram may not stop in exactly the same spot each time you raise it. Obviously, this will cause variations in bullet seating depth. Although our instructions warn against it, raise the shellholder and adjust the outer, threaded die body to make light contact with the shellholder. (Make sure you keep the contact light, so you don't damage the die.) This creates a "dead length" seating chamber that is unaffected by where the shellholder stops. The only disadvantage to using the die adjusted this way, is that it may be awkward to read the micrometer if it ends up on the back side of the die. http://www.redding-reloading.com/tech-line-a-tips-faqs/143-seating-depth-variation

 

[243winxb]

Lee makes a Lee dead length seating die, but maybe not for Lapua??

 

[timeout]

IMHO, if you are striving for accuracy/consistent seating depths, invest in an arbor press and Wilson seating die. Not that many $$. My way may not be the best, but I would not use a bronze brush inside the necks. I do not tumble or sonic clean my brass. Some 0000 steel wool outside the necks and shoulder and one pass with a nylon brush inside the necks. I anneal every firing. That may or may not be overkill.

 

[RonAKA]

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 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.

Could the tip of the bullets be contacting the seating stem cup, instead of further down on the body of the bullet?

 

[TackDriv3r]

Could the tip of the bullets be contacting the seating stem cup, instead of further down on the body of the bullet?

I already checked the seating stem cup, the bullet seats right inside the cup perfectly, not on the tip.

 

[Tim Singleton]

Wilson inline with arbor press

 

[500Stroker]

Wilson inline with arbor press

I am with Tim, it's time to upgrade your equipment.

 

[dkhunt14]

The biggest advantage to a Wilson die and arbor press, besides straight ammo is the ability to feel differences in seating tension. Matt

 

[mikecr]

Seating friction

 

[TackDriv3r]

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.

 

['Freak]

There’s a slight ogive shape variance going on where the bullet comparator contacts an OD on the ogive nearer to where the ogive contacts the skinny of the lands, and the cup on the seater stem contacts an OD on the ogive further up nearer the bullet’s tip.

 

[Shynloco]

There are a number of things that can cause this such as variation in the bullets themselves,......

Just ran into that myself yesterday while seating .308 Sierra 168 gr HPBT's into Lapua brass all evenly trimmed to 2.005. The bullets came from two different lots and varied up to as much as .0005. Thank goodness I have the adjustable heads on my Wilson Dies which made them less aggravating while seating them using my Arbor Press. But still, Sierra needs to do a better job than that and have their QC people get their heads out of their tailpipes.

Alex