Playing with seating depth

[bluesteel]

I'm shooting a Remington 700 AAC-SD in .308, with an AICS chassis. I've been loading to a 2.860" OAL to make sure they fit the magazine and will feed properly. With the stock Remington, the throat's pretty long so the only way I can get anywhere near the lands would be to single-feed.

I tried shooting a few groups today with the bullets seated .02" off the lands to see if it'd make a difference. I saw 1.4" MOA groups go to .7" MOA. I didn't think I'd be taking that much of a hit loading to mag length, and I'm curious if others have seen similar results.

 

[Rprecision]

There is a point of diminishing returns.

Some rifles, some bullets, some loads shoot best at or near the lands. Some

I understand adjusting the COAL for accuracy purposes, but for feeding purposes its usually a waste of time on factory guns with long throats. A lot of SMK I have loaded both for my guns and friends have all shot more then acceptable at magazine length

 

[sib1948]

I never found significant changes in accuracy on my rifles-2 DTA A1s and AI AXMC 308. Agree near max mag length usually works. Might make a difference with some of the wildcat cartridges.

 

[Pinecone]

I did seating depth testing when developing my load for my Rem 700.

The longer I went, the smaller the group. I stopped at mag depth. This is with a 175 SMK.

 

[Steel head]

In my 260 berger 140 VLD don't shoot very well loaded to fit the AI mag but the Hornady 140 bthp loaded well within mag confines shoot just as good as the berger's loaded near the throat.

The 140bthp also was a lot less sensitive in my barrel.
You just have to decide what's important to you and find a combo that fits your needs.


Long throats make things difficult.
Every bullet/barrel seem to have a happy zone and some times that zone won't work how you want.

 

[kansas]

There is at least one other reason to seat bullets out longer other than getting close to the lands. One being case capacity. I was using RL17 and 190 SMKs and I had to seat out farther to get enough powder in the case without compressing it too much. You can use different mags. I bought several Alpha II mags and have been able to shoot heavier bullets and seat them out farther. Not sure if they work in a AICS but I'm going to find out as soon as I get my .260 put together.