Author Topic: 358 Win AR-10 Reporting for Testing  (Read 3360 times)

sqlbullet

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Re: 358 Win AR-10 Reporting for Testing
« Reply #15 on: May 09, 2016, 12:04:01 PM »
Well, the easy road degraded.

First issue was the barrel had very, very little freebore.  The long 298 grain cast bullets would not chamber unless they were seated with only about 1/4" protruding.  Here you can see the rifling engraved on a dummy round crimped at depth and then "assisted" into the chamber:



I thought I would just shoot jacketed bullets until the throat eroded a bit, but the 225 grain Sierra BTSP also would not chamber.  Same issue.  Bullet seated to min COAL for the load would not chamber.

So, I ordered a 358 leade reamer from Pacific tool and opened it up a bit.  My cast loads now just touch the rifling, and the 225 are about .050" off the lands.

Loaded up some starting loads of WC846 under some 225 grain bullets.  I was at the range this weekend for the semi-annual Utah Mosin Nagant Challenge.  After the competition was over we still had the range for an hour, so I decided to try a couple. First shot, huge bang, huge hit to an already sore shoulder.  The brass was missing the primer and the action was tied up.  I later determined the primer was the source of the tie up.

So, pulling those down.  And re-thinking my cast bullet loads too. The military brass is about 3 grains less volume, so I will drop the starting load 10% and try again, for both 225 and 298 grain loads.

Hopefully this will turn a corner soon and I can get some fun back in the project.

The_Shadow

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Re: 358 Win AR-10 Reporting for Testing
« Reply #16 on: May 09, 2016, 02:03:15 PM »
You are getting the things dialed in...looking good, carry on!
The "10mm" I'm Packin', Has The Bullets Wackin', Smakin' & The Slide is Rackin' & Jackin'!
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blaster

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Re: 358 Win AR-10 Reporting for Testing
« Reply #17 on: May 09, 2016, 04:14:52 PM »
cool rifle in a cool caliber. 8) good luck with it!