Excessive bullet seating variance

[stanley52]

I am having excessive variance in my seating depth with my new Whidden seater. I'm am seeing .015-.020 variance every few bullets. I am using new Lapua brass, sized with .0015 neck tension. I am loading 190gr ABLR. I used only bullets with the same OAL to find these measurements. I don't have a tool to measure ogive but I used the seater stem to verify the bullet lengths were consistent to ogive length the best I could and for all intents and purposes, the bullets were extremely consistent. I did the same with some 168gr SMKs to see if it was just those bullets, but no. The seater still does the same thing. I am using a Redding T7, and a consistent throw each time. Caliber is 30-06...

 

[dok7mm]

The first thing you can do is get comparators for checking base to ogive consistency. Your CBTO is the important measurement. OAL measurements will vary quite a bit with secant ogive bullets, but it is consistent base to ogive ammo that shrinks group size, if all other aspects of your loads are good. The hornady comparators are the cheapest way to go with digital calipers. A sorting stand w/comparators & digital dial is far faster, if you shoot a lot of bullets.

 

[RockyMtnMT]

Is your load compressed?

Steve

 

[stanley52]

Is your load compressed?

Steve

So here's the deal on that, the load is not compressed, however, I believe the boatail is pushing on some powder with there being space to the sides of the tail. I've tried everything from 53.8-56-5gr of H4350 in it. With less powder the spread does tighten some but by no means is it acceptable. I took the seater stem out and it pushes down very close to the plastic tip and I wonder if the seating stem just isn't made for VLDs. I wonder if the bullet is slipping to different depths in the nylon plastic insert in the stem causing inconsistencies/or compressing the nose since these ABLR are weak/hollow up there

 

[awesymoto]

I had to get the redding VLD seating stem from Brownells to help with variance issues. Long story short the nose is so long it bottoms out on the seating stem adjustment.

 

[AZShooter]

awesymoto,

You beat me to it. I have encountered this issue with seater cups on several occasions. If the OP has access to a lathe the center of the seater can be drilled out and polished to allow tip clearance.

OP if you have a drill you can make your own comparator from a nut. Choose a drill that is a few thousandths smaller than bullet diameter, drill hole in side of nut and then chamfer to remove burr.

looks like this:

SINCLAIR HEX STYLE BULLET COMPARATORS | Sinclair Intl

 

[stanley52]

awesymoto,

You beat me to it. I have encountered this issue with seater cups on several occasions. If the OP has access to a lathe the center of the seater can be drilled out and polished to allow tip clearance.

OP if you have a drill you can make your own comparator from a nut. Choose a drill that is a few thousandths smaller than bullet diameter, drill hole in side of nut and then chamfer to remove burr.

looks like this:

SINCLAIR HEX STYLE BULLET COMPARATORS | Sinclair Intl

That's a great idea for a comparator. Thanks! So the tip of the bullet is not touching any part of the stem. It seems to be drilled hollow. I checked some .308 dies I have from him and they came with a stem that had no plastic/nylon insert that seats the bullet and the stem was a wider diameter at the opening. I put that in instead and it seems to seat just fine now.... So in summary, all I can deduce is that if a seater stem tries to seat the bullet too closely to the meplate/tip then it may not seat a VLD properly even if the tip is clearing. Alternatively the plastic/nylon may give a little and cause the bullet to slip in the stem slightly and cause variations