New Lapua 6br brass so tight bullet won't seat even after expander

[urbanrifleman]

A 243 expander is not big enough for Lapua virgin brass in my experience.

 

[rwj]

The rifle is chambered for a 6 Dasher. I had Kelbly's ream 2 barrels. The existing barrel for a dedicated fireform barrel and a new Krieger 28" #15 Contour (should have gone a little heavier) 1:8 twist, .237 4 groove, .030 Freebore, .2705 Neck. Both barrels reamed with the same new reamer I purchased (JGS "6 Dasher BB"). While I'll try several loads/bullets, my intent is to shoot Berger VLDs Hunting in 105 grain. Hopefully, this will work well from 600 to 1000 on a calm day.)

A .030” long freebore may be a little short for the 105 Berger Hunting VLDs...

 

[jjhall91]

You can measure case neck ID using the ID jaws on your Mitutoyo caliper. Subtract this value from the case neck OD value then divide by 2 for wall thickness...

Thanks, I'll give that a try.

 

[jjhall91]

A 243 expander is not big enough for Lapua virgin brass in my experience.

Your right! I just found that out as it only measures .241. Thanks.

 

[jjhall91]

A .030” long freebore may be a little short for the 105 Berger Hunting VLDs...

RWI, You're "dead on". I wish I'd have ordered a .150 or so. Right now I'm right at the neck/shoulder junction (the boatail, itself, is just below the junction) and just about touching the lands.

The only good news is that I can "chase" the lands a little.

 

[Sheldon N]

In answer to your questions:
1) .266/.267
2) .268 (loaded with Berger 105 VLDs)
3) .265 (Obviously when I use that bushing. I've tried .266 but felt it to light for neck tension.)
My fired casings measure .270/271.

Okay, that's making more sense.

If you are loaded round at .268 with Berger VLD's you've got normal Lapua brass. The necks are not too thick and you are running an appropriate no-turn chamber.

Your original problem of it being really hard to seat the bullets in virgin brass is common, it's a friction issue more than a dimension problem. Clean brass neck and clean bullet just grip each other really well. You can expand further to make seating easier or use some sort of lube/graphite to help reduce the friction.

Personally I don't expand the neck or lube when fire forming Dasher because I'm going to jam the bullets in the lands (in addition to false shoulder) and I want all that friction to help keep the bullet in place and the case head against the bolt face. I don't use an arbor press for seating so I've got a lot more mechanical advantage in the press and it's no problem to seat the bullet into virgin brass.

 

[jjhall91]

Where does the .224 number fit into all of this?

What is the measurement of #3... a case you have prepped and processed BEFORE you put a bullet in it?

It does. I removed the larger

Okay, that's making more sense.

If you are loaded round at .268 with Berger VLD's you've got normal Lapua brass. The necks are not too thick and you are running an appropriate no-turn chamber.

Your original problem of it being really hard to seat the bullets in virgin brass is common, it's a friction issue more than a dimension problem. Clean brass neck and clean bullet just grip each other really well. You can expand further to make seating easier or use some sort of lube/graphite to help reduce the friction.

Personally I don't expand the neck or lube when fire forming Dasher because I'm going to jam the bullets in the lands (in addition to false shoulder) and I want all that friction to help keep the bullet in place and the case head against the bolt face. I don't use an arbor press for seating so I've got a lot more mechanical advantage in the press and it's no problem to seat the bullet into virgin brass.

Sheldon, I just sent you a PM seconds before I got this post. Please disregard.

Thanks for the confirmation. I feel you're right in that the neck tension, itself, is the problem. Thankfully, the expander mandrel/die will fix this. The necks were so tight when I forced the bullet into the case neck it actually peeled a little of the brass from some of the bullets.

One good thing came of it. When I jammed (about .035 to .040) I didn't have to worry about the lead being pushed back into the case. The shoulders looked very sharp and I only had 1 cracked neck out of 100.

 

[KMart]

how about a wrong bushing taking it down to .224 for the expander to work also

They're to tight right out of the box. When I used the expander I didn't have a bushing in the die and only had the expander clear the neck, not the body.

This is the OP's statement in post #5

 

[DJSBRS]

All the 6 Br Lapua brass that I have dealt with this year is running between .012 to .0125 neck thickness.

DJ

DJ's Brass Service
205-461-4680

 

[urbanrifleman]

Your right! I just found that out as it only measures .241. Thanks.

No I'm saying that simply running a .243 neck turning expander mandrel through them is still not enough from my experience. They spring right back

 

[jjhall91]

All the 6 Br Lapua brass that I have dealt with this year is running between .012 to .0125 neck thickness.

DJ

DJ's Brass Service
205-461-4680

Between your measurements and mine (.013), actually my friends, it seems to clarify the problem is not uncommonly thick neck walls, but simply very tight necks.

Thanks for the information!

 

[Link]

I didn't read all this however my guess is wrong die. Try putting a bullet in without sizing first.

 

[jjhall91]

No I'm saying that simply running a .243 neck turning expander mandrel through them is still not enough from my experience. They spring right back

I get it, now. That's not good. Could you suggest an alternative? Could I could get the .243 mandrel along with a .257 (if there not out of that,too). Then I could neck the .257 back down with the correct bushing.

How do you deal with it?

 

[urbanrifleman]

I get it, now. That's not good. Could you suggest an alternative? Could I could get the .243 mandrel along with a .257 (if there not out of that,too). Then I could neck the .257 back down with the correct bushing.

How do you deal with it?

That is exactly what I do. I do the first 1/8 inch with a 257 mandrel. Then I shoot it.

 

[jjhall91]

That is exactly what I do. I do the first 1/8 inch with a 257 mandrel. Then I shoot it.

Great! I'll get both the .243 and .257. In this manner I'll get a version of a false shoulder using the .257 and my bullets will seat for sure. I'll Jam them about .020 and see what happens.

Thanks for the great tip? It is much appreciated.

 

[jjhall91]

It seems I'll have to wait a little as I just checked the order and the expander die is available, but the 4 mandrels are on back order.

 

[JMayo]

I've loaded 400 new 6mm lapua with 105 & 108 bergers ....none needed expanding so I'm confused with all this ....

 

[Dusty Stevens]

Couple a false shoulder dasher cases ready to form. Using 68gr bullets (no bullet jam for me). They headspace off the new shoulder expanded with a .257 mandrel

 

[urbanrifleman]

View attachment 1131820

Couple a false shoulder dasher cases ready to form. Using 68gr bullets (no bullet jam for me). They headspace off the new shoulder expanded with a .257 mandrel

Very cool.

 

[jjhall91]

I've loaded 400 new 6mm lapua with 105 & 108 bergers ....none needed expanding so I'm confused with all this ....

I don't doubt that at all. Over the years I had very good luck with Lapua brass being consistent.

Unfortunately, and in this case, if you had this lot you'd understand. Over 50 years I've loaded all manners of calibers/brass and never had ones like this, either.