Question on brass. 300 prc box ammo

[Decker]

Question on my brass, shooting eldm 225 box ammo

Shooting some more today and I’m struggling to shoot better than 1.5moa at 100. Started to look at my brass and I notice the black carbon around my necks, further investigating I notice this ring along bottom.
Went back and looked at first box of ammo I shot. Have the ring and carbon build on them too. 60 rnds down barrel so far.
Thoughts? Pressure issues, chamber issues?

 

[Mojave]

What is the rifle?

 

[Decker]

What is the rifle?

300 prc custom build I had done.

 

[Decker]

Here is the primer side. There could be nothing wrong and I’m over thinking this.

 

[dieselchessy]

Nothing looks off to me. Ring at bottom in brass is normal, case web.
Carbon around necks looks normal to me. Sooty powder, softer load maybe.
Primers look fine.

 

[IrkedCitizen]

Shoot a 10 or 20 shot group and see how large it is.

How are you supporting the rifle? More specifically the buttstock while shooting? A 300prc shooting 225gr bullets is substantial recoil.

 

[waspocrew]

Looks totally normal to me. I’d try different factory ammo - your rifle may not care for the 225 ELDM.

 

[Decker]

Shoot a 10 or 20 shot group and see how large it is.

How are you supporting the rifle? More specifically the buttstock while shooting? A 300prc shooting 225gr bullets is substantial recoil.

Was shooting 5 rd groups
Using a a bag to support the rear and bipod to support the front. I have the Xlr carbon butt stock on Xlr mg chassis.
I dont feel recoil is to bad. But rifle does jump on the shot.

 

[Decker]

Looks totally normal to me. I’d try different factory ammo - your rifle may not care for the 225 ELDM.

That’s my next step, just wanted to double check and make sure there wasn’t other issues before spending bunch of money on other ammo.

 

[Decker]

Why does the case web show on my 300 prc but not my other rifles?

 

[dieselchessy]

Why does the case web show on my 300 prc but not my other rifles?

Looks like your chamber walls put a bit of texture on the brass making the transition from shiny brass to chamber wall textured brass easily visible.
Also likely related to original brass size vs chamber size.
Higher pressure loadings, ect…,

I see it enough I don't pay much attention to it.

 

[Decker]

Took some Measurements when I got home today. Pulled the sammi specs as well. Chamber specs for 300 prc are .533 +.002
Measure my fired brass and the expansion at the web is exactly .535 and my unfired Hornady and Peterson brass is .529.
So it’s expanding .006.

I realize everyone is saying this brass looks normal. Just seems like a lot to me.

 

[IrkedCitizen]

Most custom 6.5prc/7prc/300prc chambers are the AW2 reamer which makes the .200 line larger to aid in not getting clickers.

I know you don't want to admit it since you spent all this money on a custom gun but it could simply be that this barrel is only capable of that size group. Shoot a 20 shot group and measure the cone.

 

[Decker]

Most custom 6.5prc/7prc/300prc chambers are the AW2 reamer which makes the .200 line larger to aid in not getting clickers.

I know you don't want to admit it since you spent all this money on a custom gun but it could simply be that this barrel is only capable of that size group. Shoot a 20 shot group and measure the cone.

Definitely possibly could be. Just trying to cover if anything could possibly be wrong before I settle on that.

 

[dieselchessy]

Custom doesn't always equal highly accurate.
Also some barrels just dont like some loadings, factory or hand rolled.

It may be the gun, might just be it dont like that ammo, or might be the jerk on the trigger.

Try other ammo, lighter slugs, ect..

 

[JMundy84]

What's you scope and mount setup? Is everything torqued properly?

 

[Decker]

What's you scope and mount setup? Is everything torqued properly?

Scope is a nx8 on UM premier rings

 

[Decker]

Most custom 6.5prc/7prc/300prc chambers are the AW2 reamer which makes the .200 line larger to aid in not getting clickers.

I know you don't want to admit it since you spent all this money on a custom gun but it could simply be that this barrel is only capable of that size group. Shoot a 20 shot group and measure the cone.

I believe this is what I’m seeing. Looking at the specs of the aw2 reamer. This is exactly the size of my fired brass

 

[TaperPin]

What brand of barrel?

 

[Decker]

What brand of barrel?

OMR barrel