First firing showing signs of over pressure?

[fatelvis]

I just bought 300 rnds Lapua 6BR brass, and after the first firing with normal loads, (30.0 grns Varget under 105 Hornadys), some of the rims refuse to slide into the shellholder, (about one in five) without turning it 90 or 120°, when sizing for the next firing. Would this be a sign that this load is overpressure?

 

[Bill Norris]

That does not seem like a hot load but I guess it would be rifle dependent. Any ejector marks on the headstamp ?

 

[Dub]

that is a sign of overpressure.

 

[joshb]

Yes. All 4 of my 6br’s see pressure signs as I approach 30 grains Varget with a 105. My loads are between 29 and 29.5. All my barrels were chambered by the same smith.

 

[JMayo]

Some shell holders are tighter than others. May have a edge/deform problem.

I have "worked" on a few.

 

[243Lapua]

Pretty sure it's not overpressure. Speedy and I just talked about this issue with Lapua brass and different rim thickness on Lapua brass. Your shellholder might be to tight or if your using a handheld primer the shellholder insert could be to tight also. I've dealt with this problem before so I just readjusted my Sinclair primer installer.

 

[dhagerty40]

I am going to pass on a problem I am having with a new box of Lapua 6BR brass (MFG: 2019). the problem I am having is the new brass is Piercing Primers with a very light load. I then loaded up 20 rounds with my old brass and did not pierce any primer.

My problem I think is that the brass is too soft since I am able to deform the necks with just my fingers. it is driving me crazy with this new brass. But since you are not showing any other signs, I would agree more that you have a tight shellholder.

 

[NorCalMikie]

Any chance that the case was loose in the chamber? When fired, the case just above the rim swelled? If sized, reloaded again and fired with the bullets jammed into the lands so the case couldn't move? No more case problem?

 

[fatelvis]

That does not seem like a hot load but I guess it would be rifle dependent. Any ejector marks on the headstamp ?

There were no noticeable ejector marks on the brass.

 

[fatelvis]

Any chance that the case was loose in the chamber? When fired, the case just above the rim swelled? If sized, reloaded again and fired with the bullets jammed into the lands so the case couldn't move? No more case problem?

The brass was a little looser than normal, being that the brass was virgin and tends to be smaller than normal right out of the box. I haven’t got to the second firing yet, so I can’t comment on seating the bullet out to be jammed. But I planned on seating with a .020” jump.

 

[Doom]

FWIW, I had a similar issue with a 223 Lee shell holder after first firing of Lapua brass. Changed to an RCBS shell holder and the issue went away.

 

[FNSafari]

I just bought 300 rnds Lapua 6BR brass, and after the first firing with normal loads, (30.0 grns Varget under 105 Hornadys), some of the rims refuse to slide into the shellholder, (about one in five) without turning it 90 or 120°, when sizing for the next firing. Would this be a sign that this load is overpressure?

Have you tried a different brand of shellholder? If you are feeling hard bolt lift, flat primers your rifle is telling you something. Back off.

I shoot short range BR and its not uncommon with a powder like H4198, to have to reduce or increase charge weight when changing lots. You may have a faster lot of varget?

 

[biggun2869]

One box of Lapua that I have formed to 22 BR is tight in a Sinclair holder. I really doubt you're over pressure. Some are just thicker-larger diameter. That is the only lot I have trouble with, and I have a couple more boxes formed to 22 BR. Gary

 

[LCazador]

The brass was a little looser than normal, being that the brass was virgin and tends to be smaller than normal right out of the box. I haven’t got to the second firing yet, so I can’t comment on seating the bullet out to be jammed. But I planned on seating with a .020” jump.

Measure a virgin case head with a .0001" micrometer and then measure head on a fireformed case. If you have more than .0008" case head expansion you have a very warm load and you may have damaged your brass.

 

[rwj]

I just bought 300 rnds Lapua 6BR brass, and after the first firing with normal loads, (30.0 grns Varget under 105 Hornadys), some of the rims refuse to slide into the shellholder, (about one in five) without turning it 90 or 120°, when sizing for the next firing. Would this be a sign that this load is overpressure?

One may want to consider setting aside a few virgin pieces from each brass lot to use in such instances. That said, I don’t see how excessive cartridge pressure would significantly change the dimensions of the relatively solid case head.

 

[butchlambert]

I am going to pass on a problem I am having with a new box of Lapua 6BR brass (MFG: 2019). the problem I am having is the new brass is Piercing Primers with a very light load. I then loaded up 20 rounds with my old brass and did not pierce any primer.

My problem I think is that the brass is too soft since I am able to deform the necks with just my fingers. it is driving me crazy with this new brass. But since you are not showing any other signs, I would agree more that you have a tight shellholder.

Sounds like you have a headspace problem.

 

[NorCalMikie]

Sounds like you have a headspace problem.

Me too but not so much a chamber head space barrel issue but more of the case moving in the chamber by not being fire formed? (virgin unfired brass)

 

[edwardware]

If you were sufficiently overpressure to enbiggen the rim, I think you'd notice other signs.

. . . like full case separations, leaking primers, gas cut bolt face, and the smell of fire and brimstone.

 

[dhagerty40]

Me too but not so much a chamber head space barrel issue but more of the case moving in the chamber by not being fire formed? (virgin unfired brass)

That is the same conclusion I came up with.

Now, I checked some of this brass and noticed mine has some excess brass around the rim that may be causing the Authors problem.

 

[AckleymanII]

I had the same problem a long time ago, I tried a different shell holder....problem solved!