7 PRC factory loads are too hot!

[6.5 forever]

My grandson has a 7 PRC from Christensen Arms.

We got everything set and tested the 175 and 180 gr factory loads. Both were +50 fps faster than speed listed on the box. And they are hot. Ejector hole marks on most cases. I'm pulling down the rest of the loaded rounds and will start working with some Berger 175. The loads are very accurate, sub half moa.

Anyone else have any experience with this new cartridge?

 

[6.5 forever]

Want to attach a picture of the powder from one of these rounds. Ball powder. Nothing in Hornadys load data listing a ball powder.

 

[6.5 forever]

The powder is very consistent 72.5 grains.

 

[FURMAN]

The 175s and 180s I got prior to launch were RL26.

 

[6.5 forever]

I believe this is Magpro.

 

[antunRC]

Check here:

National Center for Forensic Science

 

[nakneker]

Any idea what primers they are using. I have 10 boxes of factory loads, I may just pull the bullets and reassemble using powder I plan on using anyways.

 

[FURMAN]

Mine were cci 250s.

 

[6.5 forever]

We pulled the remaining rounds down tonight.
The 175 had 2.5 grains LESS powder than the 180. They have a problem. No way factory loads should run this over pressure. Half the fired cases barely held a primer.

 

[lawman29]

Contact Hornady

 

[CJ6]

It could also be the chamber/reamer ....

 

[Orr89rocz]

It could also be the chamber/reamer ....

Which if you read about the reviews of christensen arms, this could likely be true

 

[Ray123]

Christensen Arms is the only rifle I've ever seen with so many issues...and returned to Sportsman's because of them, a lot of angry guys...really bad accuracy with premium factory ammo, chamber problems, and the last 300 RUM would not feed any rounds out of the magazine...
That said Hornady had issues with the 6mm ARC factory ammo being too long for ARC chambers, causing pressure issues and bullet stuck in chamber and powder dumped into the action...took quite awhile to resolve, such a simple problem...again angery customers.

 

[Hudge76]

Honestly, I’d contact Hornady and Christensen Arms. I kind of think the rifle maybe the issue, but again it may not be.

 

[6.5 forever]

Got a update.

I pulled the rest of 180 and 175 Hornady loaded rounds apart. Dumped the powder.
Run the cases thru the sizer, put 65 grains of H4831sc in the cases and put the bullets back on top and my grandson shot these four shot groups. Easy extraction and absolutely no pressure signs.

The problem is not the Christensen rifle.

Also he put 24 more rounds into steel out to 600 yards. All groups were 1/2 MOA

 

[antunRC]

Got a update.

I pulled the rest of 180 and 175 Hornady loaded rounds apart. Dumped the powder.
Run the cases thru the sizer, put 65 grains of H4831sc in the cases and put the bullets back on top and my grandson shot these four shot groups. Easy extraction and absolutely no pressure signs.

The problem is not the Christensen rifle.

Also he put 24 more rounds into steel out to 600 yards. All groups were 1/2 MOA

What was your velocity with H4831SC [65gr]

 

[6.5 forever]

What was your velocity with H4831SC [65gr]

2954 with 175 Berger elite and 180 Eldm. Both the same!

 

[Hudge76]

Glad it’s not the rifle, but did you contact Hornady?

 

[6.5 forever]

No. I've been down that path before with disappearing 147 ELDM'S.

ALL the rounds have been pulled and we are successfully using H4831sc. These Hornady cases are pretty useless also. Waiting for Petersen and ADG to get this 7PRC where it belongs. Hornady ballistician/engineers are above their production teams quality in my opinion.

 

[6.5 forever]

Anybody else out there working with this cartridge yet?