Chamber problem or ammo problem?

[Topshot]

I have been hand loading some ammo for a new Remington SPS in 7mm Remington Magnum. I also bought some Remington Factory ammo to use for comparison. Now this ammo is standard Remington 175 grain Cor-Lokt stuff nothing special but should be OK.
The first group I shot with it went just under 4 inches at 100 yards while my first few attempts at hand loads went into about 1 1/2 inches. I also found the factory ammo hard to extract.

I have since replaced the plastic stock with a new Laminate stock and have worked on the trigger. The rifle now easily groups under 1 inch with my hand loads.
Today, I went back and tried another group with the Remington Factory ammo to see what improvement this may have had.

Well it grouped right on 5 inches at 100 yards. Also with two of the shots I had to belt the bolt open with a block of wood. I am not game to fire any more of this ammo in my rifle.

Now is this just poor factory ammo or is there something wrong with my chamber?

 

[Mikecr]

That ammo would probably work fine in somebody's gun, but why assume that gun should be yours?
And why do you wonder about a problem with your chamber?
Because some abstract factory ammo doesn't do well in it?
Or is it because of something with your measured brass(what matters)?

Every barrel is unique.
With this, you clearly see THE benefit in reloading(it's purpose).

 

[Topshot]

Mike there is marks on the brass, like teeth marks or chatter marks from the chambering reamer.
I only see them on the Factory ammo and on my loads that I assumed were too hot, although primer look OK and primer pockets are holding up nice and tight.

Don't see them on the milder loads and they extract easy.

On the stuck cases, the bolt lifts easy but it won't come back.

 

[elkaholic]

I worked on a friends Ruger a while back and it shoots moa with handloads and 3 moa with Factory core lokt. Have you chronoed the factory rounds vs yours? The reamer marks could account for the difficult extraction but it is odd they don't show at all on your loads? A little chamber polishing with some crocus cloth might help.....Rich

 

[Johnboy]

I'd bet the remmy ammo is alot hotter than yours.all remmy ammo that I have shoot have had flatter primers than any of my hand loads.even sound hotter/feel hotter.and all primers are flatter than a pancake.just something about a remmy loaded bullet.I guess thats why they came up with managed recoil loads LOL.

and thats one of the reasons I reload.factory ammo just does not cut it anymore.but have and still load up the 150gn corelokts for hunt'n.

 

[J E Custom]

If you can post a couple of pictures of the fired brass that has the marks on them.

If a chamber is done right the brass should not have any marks of any kind on it
even if the load is hot (Only on the case head).

I said this on a earlier post but if you will spend 30 to 40 dollars on some Cerrosafe
from brownells you can make a cast of the chamber and then measure and inspect
it to verify that there is nothing wrong with it.

J E CUSTOM