Winchester Model 70 - Dented Case Necks

[steinmaster]

I’m reloading a 223 for my brother-in-law. He said the gun never shot well with factory ammo from the time he bought it brand new. He only shot 150 rounds through it.

I loaded up some rounds with 53gr Hornady VMax and varied the powder loads (IMR 4320) to see which shot the best. The best I was getting was 1.25 inch MOA at 100 yards, which isn’t very good with reloads. I noticed the brass necks were dented in after I ejected the casing. I don’t think it is an over pressure problem since I’m only using 26.4 grains (mid-range) of IMR4320. This isn’t close to the maximum per Hornady reloading manual. I’m using brand new Lapua match brass, which I full-length resized.

Any ideas what could be causing the neck dents? I attached a picture. If it is the gun, I think it would be affecting its accuracy. The rifle is an older bolt action Winchester Model 70 Ranger.

 

[sandwarrior]

I'm thinking a lump of gunk in the neck? Can you shine a light in the bore to see if it is clean and rounded? I often see these kind of dents though, when I let my brass hit the ground.

FWIW, that rifle is a great candidate to have re-barreled with an excellent barrel instead of a third rate barrel.

 

[steinmaster]

Yeah - I inspected the bore and barrel with a bore light prior to shooting. I didn't see anything in there that would cause this. The gun is very clean and well maintained. Do you think this would affect accuracy? I did not let the brass hit the ground. I ejected the spent brass in my hand.

 

[sandwarrior]

I was told once that an under pressure load can cause this. If you are not near max, you might work up to the next node and see where that goes. Your primer certainly does not show any pressure signs coming on.

 

[Toomz]

Might be a long shot, but could it be the pressure of the ejector "slamming" the case into the receiver after it leaves the chamber and before the bolt is fully opening? Hard to tell from the pic, but do you see any signs of dragging or scraping where the dent is on the neck of the cases?

 

[korykhunter]

Dent from ejector.

 

[Quarter Horse]

Take a fired case and run it it to your sizing die just enough to straighten the neck. Chamber the case and extract slowly.

If no dent, chamber the case and extract with normal force. That should tell you if it's an ejector or ejection issue. I'd also fire a couple of factory loads to see if they indicate the same issue.