ATRS 260AI First Load(s)

Redhouse

Redhouse

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Been sitting on the rifle a while, other than fireforming, as Rick is having a little trouble with Redding getting the neck/bump dies. I finally got tired of waiting and bought a Lee collett .260 neck die today and it works fine for the AI cartridge, doesn't touch the shoulder at all.

Trued Rem 700 action, Rock 5R barrel 27", Badger knob, Jewell trigger @ 2.5lb, McMillan A5, Nightforce 8x32x56 in Nightforce rings on Nightforce base.

Loaded up 30 with 140 Berger VLD's and H4831SC, 15 @ 47.5gr and 15 @ 48.5gr. They are off the lands somewhat, and I will be trying them jammed also - I had been deep jamming for fireforming the Nosler brass.

Didn't take my chrony with me so not sure speed, but est 2900 to 2950 based on other shooters' data. The 47.5gr shot quite a bit better and further fine tuning around this is forthcoming.

.775 - .260 = .515 5 shot group, I can live with that for just starting. To the lower right is just 4, (I ran out), top left is foulers, top center is 3 for group. Edited to add, 100M @ Genessee, with front rest and rear bag.

5-30-09260AI140H4831-475.jpg
 
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btw, it was fun asking people "what is wrong with my gun???" and showing them pre- and post- fireformed brass. The "OMG THAT CAN'T BE SAFE" reactions were indeed worth the price of admission. After explaining, I had to be quick on my feet to avoid :kickInTheNuts:
 
Looks great, I like the build. Some more trigger time and load tuning should work out the groups to snug them up.

Most people don't understand how much brass can safely stretch. I remember hearing of a guy who's smith totally screwed up the head space on his 308 and the brass was coming out looking like a 3006 and it still shot really well. He had it fixed of course, but he shot off a 100 rounds not knowing what was wrong.

BTW, how well does the AI brass load out of the mag, have you tried it yet?
 
Nice looking rig and you are well on your way to a great shooter.

Do consider the 120 and 130gr Berger, and 123gr Lapua. The 139 and 140's are very long and the odds of them fitting in the mag without taking up alot of room is slim. I have my 139's seated to 2.95", 10 thou off the lands. They feed and fit fine in a Savage Det mag but will not fit in a standard 308 length mag.

Should have no problem making the lighter bullets or an Amax fit.

They are now special order, but the 7-08 AI body dies works great if you have a 40deg shoulder. Looks like the chamber is a close fit to your brass. That is a good thing to reduce any wear on the case head during fireforming.

If you want to save some barrel life, you can neck up then back down forming a false shoulder that is a snug fit to your chamber. you can then fireform using a light load of pistol powder and cornmeal/cream of wheat.

Look forward to your progress reports.

Jerry
 
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MagnumPeanut said:
BTW, how well does the AI brass load out of the mag, have you tried it yet?
Click to expand...

Tried today, definitely not. Loaded up some 123 Sierras to factory OAL or very close, easily into the mag. They all jammed up, even dropping the floor plate didn't clear them, I was digging them out with my multitool :runaway:

The 123's shoot real nice, I shot 30 rds at 300m with 6 different loads (5 of ea in 1 gr increments of H4831SC 45-50gr). 26 of them went into about 3" so I didn't learn much lol Chronied them, 49gr puts me just under and 50gr puts me just over 3000 fps. Forgot my rest tho, wasn't quite as scientific shooting off a bipod and no rear bag, well, an improvised one.
 
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