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Rethinking My .338 MAI
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Old 09-05-2007, 02:40 PM
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Default Rethinking My .338 MAI

Since I've had such terrible luck getting my .338 MAI to shoot even modest groups, and since Ol' John's same rifle shot well, and since I'm beginnig to clutch at straws, I decided to step back a bit and consider other initial constraints from those I have been working under.

Just a brief recap of where things are to date:

Ol' John (AKA LLANO JOHN) built two .338 MAI rifles - one for himself, and one for me.

His has an Adams & Bennet 26" barrel, mine a Lothar Walther 24" barrel.

They were chambered with the 200-grain Combined Technology Ballistic SilverTip bullet in mind as the primary projectile.

I took his rifle in hand, installed a pressure sensor, and started working up loads. His rifle shot well from the start, and I was able to come up with some loads that shot no worse than MOA.

When I got my rifle I commenced to work up loads, starting with the loads I had developed for John's rifle. As the chambers were cut with the same reamer, by the same person, I assumed this starting point was reasonable. I also wanted to try 180-grain Accubonds.

I had trouble right from the start, but it was 'scope (actually base) trouble. I fixed that. The next range session, the 'scope I was using shot apart. The next range session was inconclusive - too many "things" going on. The next "range session" was at Recoil Junky's in prep for the elk hunt. That was only a couple of shots just to make sure it was "on the paper" after transport. THEN it was a powder issue (at least that's what I think the problem was) and blowing primers (during the hunt) with loads that had been fine in John's rifle and mine. After completely re-doing loads, AND replacing that 'scope, the best I have been able to shoot is 5 MOAs. The current 'scope is a 50-year-old, fixed-power 4X Leitz, with a German-style reticle - two horizontal posts and one vertical, that do not meet in the center. I don't particularly care for this kind of sight picture, but I thought the 'scope was a good one. I'm now having my doubts.

As I discussed this matter with Nels and others (here http://thehunterslife.com/forums/sho...6165#post66165 ), I was focused on the 180 and 200 grain bullets. In that discussion, I noted that the bullets that shot best for me in my .338 Win Mag were the Nosler 210-grain Partition, and the Hornady 225 SP - both flat-based bullets. All my rifles shoot flat-based bullet better than boat-tails - no exceptions. (A couple of rifles wil shoot boat-tails almost as good as FBs, but certainly not better.) However, I wasn't particulary interested in even trying the Nosler and Hornady, because given their weight and the smaller case capacity of the x57 case, I didn't think I could wring enough velocity out of them to satisfy my terminal performance benchmarks. Those benchmarks being: Muzzle energy of 3500 ft-lbs or less; carry 2000 ft-lbs out to 300 yds; and be less than 9" low at 300 yds when sighted in for a 6" target.

Because I am at the point of clutching at straws, I decided to have a look at what QuickLoad predicts for the Hornady 225 SP. Well, well, well. Keeping the pressures to very reasonable levels, I should be able to get the 225 to deliver 2100 ft-lbs out ot 300 yds and only be 7.5" low. Muzzle energy is a tolerable 3400 ft-lbs, and predicted chamber pressure is 53,789 PSI. If the QL predictions turn out to be close, I'll have "room to move" both directions to find the precision sweet-spot.

So...

At this point, I am going to buy a new 'scope specifically for this rifle, and
load up a variety charges for the .225 Hornady bullet. I'm considering fire-lapping the barrel, but I will wait 'til after I scrub the barrel with Wipeout, AND the next range session with the new 'scope and loads.

By the way... the load I mentioned above for the 225 yields an estimated muzzle velocity of 2608 f/s. I can drop that back to 2555 f/s at a chamber pressure of only 50,200 PSI, and still have 2000 ft-lbs at 300 yds, a ME of 3261 ft-lbs, and a drop at 300 of 8.4".

If my problem getting the MAI to 'shoot' is bullet-related, maybe this will be the solution.

Paul

Last edited by gitano; 10-06-2007 at 12:13 PM.. Reason: spelling
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Tags
.338 caliber, .338 mai, bore polishing, load work-up


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