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View Full Version : Mossberg 100 ATR 7mm-08 rebuild



lar45
09-12-2021, 09:49 PM
Several years back my youngest son and I went to a church trap shoot and won a new Mossberg 100 ATR 7mm-08. It was the Bantam model with 20" barrel. A couple months later we had a shop fire and the plastic stock melted all over it.
http://www.lsstuff.com/pics/guns/mossberg100atr/100atr-01.jpg

Being a hoarder, I couldn't just throw it away, so I set it in the corner and forgot about it. A couple of months ago I was needing a new project to work on, so I pulled it out. The stock was melted to the action and the action bolts were not visible at all. So I took a hammer and chisel to the stock and cut it off in chunks. Once the stock was out of the way I started scrubbing with steel wool and Ed's Red. The bore took quite some time to get all of the fire fumes scrubbed out.
I contacted Mossberg, but they didn't have any 100 ATR stocks. Boyds on the other hand will build pretty much anything you want. I ordered their Classic in Forest Camo Laminate.

http://www.lsstuff.com/pics/guns/mossberg100atr/100atr-02.jpg

The stock was an almost perfect fit. The barrel rubbed a little on the left side and caused some horizontal stringing. I took a half round file to the barrel channel and relieved it some until a dollar bill would slide freely.

http://www.lsstuff.com/pics/guns/mossberg100atr/100atr-05.jpg

http://www.lsstuff.com/pics/guns/mossberg100atr/100atr-03.jpg

The only 7mm bullets I could find were some Hornady 154gn SSTs at Gander Mtn. I found Lee dies at Midway.
I took some LC 7.62 brass and ran into the sizer die, trimmed, deburred and I was about ready to load.
Hodgdon's site showed some wonderful velocities with Win StaBALL 6.5. I reduced the charge by 15% and worked up to 1 gn below max with no pressure signs. I seated the bullets .010" off the lands to start with and got a .775" group. I tried .005" and it opened way up to 2.28", so I went back to .010". The previous group resulted in one leaking primer, so I backed off .5gn and shot the following target which gave .418"

http://www.lsstuff.com/pics/guns/mossberg100atr/100atr-04.jpg

I think I'll hunt with it this year and then pass it down to a grand child.

358429
09-12-2021, 10:39 PM
Very cool choice for the wood rifle stock.

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