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View Full Version : BULLET SEATING DEPTH, HELP PLEASE!


rtc111
03-01-2012, 3:35 PM
I'm heading up to the coast this weekend to do some shooting, but before I go I wanted to reload some new ammo for my semi auto rifle (browning BAR safari .338 win mag). the problem I'm running into is that I can not get a clear reading for the bullet seating depth. I have tried using the RCBS precision mic but, but my Hornady SST bullets taper much more sharply than the tool used in the RCBS MIC so I can not get a comparative value between the two. I have also used Nosler's way, which is using a "dummy bullet" but when I jerk the bolt back it spits it out to hard and doesn't give me a clear reading! I think a may need to full length size it first to make it easier to remove. but what i finally came to conclusion with was that I would load it so it would fit the magazine with no room to spare (3.325 ") (SAMMI is 3.40) for 338 win mag, so I should be in the clear for pressure build up right? And than I would take 12 bullets going from 3.325 to 3.315 ex... and so on until i can find out which works best, does that sound like a reasonable idea?

Or if you have other suggestion that'd be great to hear. The hornday SSt bullets also have a cannelure should i crimp them or not?
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brando
03-01-2012, 9:03 PM
When in doubt seat to the COAL listed in the manual for your bullet. Finding the COAL to the lands can be done with a little trick of thinning the neck on a FL sized case. Run a bronze borebrush attached to a dremel or hand drill inside the neck of the case. The goal is to thin the inside enough that a bullet slides free with some decent pressure. Then you can seat the bullet to mag length and try loading it several times, each time noting the resulting COAL and any marks on the bullet. The thinned neck should have reduced tension and allow the bullet to slide back when chambered.

It's handy to know the max COAL to your rifle, but be careful shooting loads where the bullet is potentially jammed into the lands as it can lead to dangerous pressure spikes.