Re: Which 7mm
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Jedi</div><div class="ubbcode-body">Nope
my thinking is based on this
http://www.6mmbr.com/gunweek095.html
25" barrel, short action, OAL 2.90
re17 3045fps
i have to run some QL sims but looking @ 24" maybe 22" barrel
OAL 2.975 so i have a lil more boiler room, still feed from Alpha mag max is 2.985
Based on article i should be able to run 2900fps from a 22"
thats kinda what i,m looking at.
plain jane 284 hmmm
Melonite barrel, run RE17 162amax
barrel should go 5k maybe more
do able very do able </div></div>
I studied the rifle build you linked to prior to building my 284.
My build:
http://www.snipershide.com/forum/ubbthre...046#Post3147046
Couple notes:
You're not going to be able to load at 2.985", or even 2.975" with the Alpha mags. The maximum COAL that will feed correctly, and not cock/bind in the mag is 2.950" (+/- a couple thousandths).
I'm getting 2950fps with 162amax with 52.5gr Re17. I don't think it's going to go alot faster with ok pressure. Perhaps my barrel will work in and speed up a little, but I'm not counting on it.
Also, the jury is still out on RE17. Many folks claim they get speed, but poor accuracy. I've read very conflicting information about its temp stability. As far as I'm concerned, if it's not temp stable, it's garbage. It is the only powder out there like it, and the only powder that's going to get a 162amax going ~3000fps from a SA 284. Otherwise, you're looking at H4350 or H4831, and a 100fps+ drop in velocity.
There is no provision for "chasing" the lands when you throat a rifle to seat a bullet on the lands - right at your max magazine length.
284 brass is not real easy to come by. The winchester branded brass is only made once a year, and is of iffy quality, and Lapua sure is proud of their 6.5-284 brass. If you shoot tactically, and lose brass, it sucks leaving $1.25/each brass on the deck when you move to your next position.
The 284 sits in a nice "niche" place between the low and high capacity 7s. It has a definite horsepower advantage over 7-08, but a distinct disadvantage to the 7RSAUM, 7WSM and 7-300WSM. That all said, when forced to load a max COAL of 2.950, the 284 has about an 8gr of powder advantage over 7-08.... With new dies, new brass, new inventory of powder etc etc etc (tooling up for a new cartridge), consider wisely if you REALLY don't want the extra steam the higher capacity 7s offer... I only have 50 rounds downrange with my 284, and I'm already thinking my next 7 will be the 7RSAUM or 7-300WSM.
Lastly, the 162amax and 162hpbt bullets are extremely well designed bullets, and have great BC. Anything over 2700fps is going to be quite flat, and drift little.
I'm not trying to talk you out of 284, just suggesting you think long and hard about it - particularly because we're talking about a COAL-limited 284...