View attachment 90742 FYI I posted this in the reloading forum as I wasn't sure where it belonged. So I'm having a bit of an issue and hopefully you guys can provide some help. I have a new Christenson Arms in 7mm rem mag. I am using nosler brass and 162gr hornady ELD-X's. I had trouble finding my distance to lands using the hornady oal gauge as I was getting a number well below saami max (2.619" w/ comparator). So I used Jim Wheelers stripped bolt method and a fired case with light neck tension to "jam" the bullet into the lands and both methods were very close to each other and gave me a distance to lands of 2.737" using a comparator. During my fireforming process I had the bullets seated to a depth of 2.685" using a bullet comparator and everything worked well. I even stripped the bolt and ran the unfired rounds through the chamber and they fit with no resistance. After fireforming I neck sized my brass and seated the bullets to the same depth and went shooting. I also cleaned the gun very well. The problem is that when running the bolt forward I can feel resistance as the bullet enters the throat and the bolt is stiff to lock down. When I would try to unchamber the unfired round the bolt would lift with some resistance but I had to bang on it to get it to move rearward and there is scuffing on one side of my bullet near the case mouth (see picture). The rounds shot well and showed no pressure signs and the fired cases ejected like normal. I got home and took the firing pin and ejectors out of my bolt and ran one of the now twice fired cases into the chamber and the bolt closed with little to no resistance so I think my cases are sized properly. I saved one of the problem unfired rounds and started incrementally seating the bullet deeper but was still getting scuff marks even down to a length with comparator of 2.610". It didn't matter how the case was oriented, the scuff mark was always in the same place. I bumped the shoulder back using a Redding body die and same issue. I tried seating the bullet with a rcbs gold metal match die to a depth of 2.685"...same issue. I'm really scratching my head on this one. The rounds worked well on their first firing but not on the second but the cases chamber easily.
The scuffing is only on one side. I can rotate the case 180 degrees and rechamber the round and the scuffing will stack up on top of the old scuff mark. Fired neck diameter is .314 and loaded is .3125-.313Is the scuffing all the way around or on one side ?
Also measure the fired case neck diameter and compare it to the loaded round neck diameter.
J E CUSTOM
So what your saying is you think the chamber is too tight in the neck region?
I have the same thing going on with a custom 300 win mag. Same mark on one side of the bullet. What else I find strange is 3.59 is max length but I can still see rifling marks on the bullet even when I seat them down the 3.45-3.48 range. I’ve had a hard time finding a max oal. Ive had to bang out several bullets from the barrel that have gotten hung up while experimenting with seating depth. I have never had these issues with anything before. The gun shoots 2-3 moa average no matter what I try. Sorry for a hijack of your thread but my current battle as well.