Re: Is the 7mm-08AI too big a hassle overall?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ArmchairElite</div><div class="ubbcode-body">When I first decided to change calibers I wanted to go to a 284. I found out that the 284 wasn't an ideal caliber for short action so the plan changed to 7-08. Can anyone tell me if their is ample room to seat the bullet out of the case in 7-08 in a short action?
I intend to shoot the 162 amax with H4350. I thought that maybe the extra power of an AI would allow me to shoot 180 gr or the new 171 gr Barnes Match Burner with adequate speed or just shoot the 162 amax another 50fps faster. Sounds like I might be looking at pressure issues if I go that route though. I'm only going to be using it at the range, but maybe I should just stick with the standard 7-08 and keep it simple anyway. </div></div>
My buddy and I just finished his (old 4.27" action) Savage 10FCP with Mcmillan A3. We put a 26" CBI 708 barrel on it. After a little generic-load shooting, I ran a (double) ladder with 162amax and H4350. The rifle is a "BDL" type, and because it needs to be a repeater, the cartriges were loaded to magazine length, which ended up being ~2.850. I stopped the ladders when I had 3 consecutive caseheads with ANY ejector mark. That was 48.5gr. I loaded an OCW from 45.5-47.5 H4350, again at 2.850" COAL. 46.5gr showed best promise.
Then I discovered the brass I was using (FC 308 necked down) didn't provide adequate neck clearance, so I neck-turned about 15 cases to continue work with. I ended up loading/reloading those 15 cases 6 or 7 times, and the primers were still going in tight. Velocity, as measured by an Oehler 35 was 2776fps, with an ES of 15 and SD of 6.
The ballistics of a 162amax @ 2775fps are superb.
At 2.850" COAL, and a CASE length of 2.015" (which is shorter than spec for 708), I've got about .050" from casemouth to the ogive. So, that means the 162 is seated quite deeply. The 162 does have a rather long ogive and I believe the Berger 180's have an ogive about .030" longer, meaning it will "fit" in the 708 and be magazine compliant. The Berger 175XLD however will not fit, because the ogive will begin inside the casemouth.
Does the 708 have the horsepower to properly launch a 180 class bullet? I'm GUESSING you could get 2650ish with a 708, and probably close to 2700 with an AI. A .67 BC bullet @ 2650-2700fps is going to fly very, very nicely. Not quite as awesome as 3000fps, but superb nonetheless.
All that said, you should ask yourself what you want/need the rifle to do, because all of this is pretty academic, and the gains from 100-1000 yards are going to be SMALL. However, if you really need/want that last bit of performance to score the hits out past 1000, the improved case and/or bigger bullets will help a bit.
I know it's hard to nail down exactly what you want and need - especially when there is so much overlap from one cartridge to the next.... But, don't lose sight of the fact that a 162amax @ 2750 (TOTALLY reasonable with a 26" 708) is going to perform beautifully. It will drop just a shade more than a 140-class bullet at 2850 from a .260, and drift a decent bit less.
Final word: Now that you've decided on a 7mm, you really can't go wrong. If you'll be spending time (and be asked to score first or second round hits) past 1000 yards, the AI is probably worth the effort.
Good luck.
