20 VT Pressure Issue

[Fyrchief]

I have used 18.0 - 19.0 gr. H-4198 under Berger 35 gr. FB bullet with Lapua brass and CCI BR-4 primer with no issues; however, when I switched to Nosler brass and 17.8 gr. powder, it blew out the primer on the third round with resultant very hard bolt lift. This was virgin brass, sized and trimmed before loading, and all three rounds chambered without issue. The first two rounds were normal at 3,480 fps. I weigh each load to the kernel with an Fx-120i and Dandy trickler, and visually check each load prior to bullet seating. Primers are seated with an RCBS APS hand seater.

Anyone else have issues with Nosler .221 FB brass, or thoughts as to why the overpressure with this load? Thanks in advance!

 

[Gabe22BR]

Id say you’re reaching max pressure early with the less case capacity & weak pockets from the Nosler 221 brass..

low capacity 221 Nosler brass?

I'm just getting started on a 20 vartarg and I'm using Nosler brass to save some forming steps. After 2 firings I still can't fit more than 18.5 gr of H4198 and it is compressed even with a 32 gr pill. I have just a tiny bit of radius on the shoulder-body junction but I can't imagine that I'll...

forum.accurateshooter.com

I know nothing about Nosler brass- they bought-Silver State Armory ..

It has less capacity than any other- Lapua, Rem 221 brass.

 

[Gabe22BR]

I’ve went to Starline 222 brass & Hornady 223 brass reformed.. ( I like the thicker rim on this brass-) no primer pocket lose yet- EXCEPT 1 case..intended..
Sorry couldn’t be of more help- just my experience so far…

 

[snert]

Case change will do that. I have Rem and LC 20 VT brass. I changed bullets to 40gr Vmax and went with a load (down 10 percent) of LT32 I thought would be fine given my previous experience with Lapua brass. It was too hot. I attribite that to the brass change, because everything else was the same .

Develop a load from lower charge in the Nosler brass and see what velocity you get, work from there.

 

[Fyrchief]

I’ve went to Starline 222 brass & Hornady 223 brass reformed.. ( I like the thicker rim on this brass-) no primer pocket lose yet- EXCEPT 1 case..intended..
Sorry couldn’t be of more help- just my experience so far…

Thanks Gabe. I appreciate your experience with this cartridge!

 

[Fyrchief]

Case change will do that. I have Rem and LC 20 VT brass. I changed bullets to 40gr Vmax and went with a load (down 10 percent) of LT32 I thought would be fine given my previous experience with Lapua brass. It was too hot. I attribite that to the brass change, because everything else was the same .

Develop a load from lower charge in the Nosler brass and see what velocity you get, work from there.

Thanks Snert. That will be my next step!

 

[drewh]

Check the diameter of leaded rounds also to make sure you have neck clearance for you chamber diameter
Drew

 

[7315br]

I would say it's a case capacity problem more than anything else. My experience has been Nosler brass has less capacity. I've made 20VT brass from Rem .221 Fireball (has the most capacity), LC brass, and even .204 Winchester brass (picture included). I still use H-4198 when I can find it and 32gr V-Max bullets, Rem 7 1/2 primers. I average 3725 fps with the Rem .221 Fireball brass and it last a long time. Best of luck.

 

[TAJ45]

As has been said, case capacity. Pressure related could also be neck tension from brass composition, springyness and or nk thickness. Just a swag.

 

[snert]

@drewh hit on a good point. Also check case length vs your chamber. If you are into the leade or too tight in the neck, it will drastically increase pressure.

 

[L.Sherm]

You say it was with virgin brass, it could also be a head space issue. What is a virgin case datum line measurement with a comparator compared to a 3 times fired case?
Measure a virgin Nosler case compared to a 3 times fired Lapua case.
Nosler brass is soft you will not be able to run it like Lapua brass.

 

[20VarTarg]

There are a couple different reamer prints out there. I've seen chambers that can use Virgin Lapua Brass and others that wouldn't. Was your Lapua brass turned or not? I have no knowledge of the neck thickness of Nosler stuff. All answers above can lead you in the right direction. Case Capacity difference will always lead to higher pressure. Personally I quit using H4198 and exclusively use CFE BLK in all my VarTargs. It works incredibly well.

 

[Fyrchief]

Thanks to all. Appreciate your responses!