.338-08 (Federal) and .338 Win Mag (Sauer 90) Load Workup

Started by gitano, February 18, 2016, 12:16:42 PM

Previous topic - Next topic

0 Members and 1 Guest are viewing this topic.

gitano

You'll notice from the following trajectory and energy table that the 225 Accubond (hereafter AB) doing only 2716 f/s, carries over 2100 ft-lbs out to 300 yd and is ~9" low with a 200-yd zero. (Scope' center-line above the bore center-line has been measured and is correct for these calculations.)

That velocity is achieved with only 51,300 PSI of max chamber pressure. That leaves approximately 11,000 PSI headroom to use to find the 'sweet spot'. That velocity with that powder (Reloder-17) is at a timing node, BUT it produces about 3700 ft-lbs of muzzle energy. The muzzle energy I try to achieve is about 3400 ft-lbs because I can shoot my Ruger "all day" at that ME without adverse effects like a headache. However, I could "easily" run this bullet up to 2800 f/s at the muzzle and only be at 56,565 PSI max pressure. (The max pressure for a standard Mauser '98.) However, at 2800 f/s, the muzzle energy is over 3900 ft-lbs. My butt starts squirmin' at those MEs, and I flat out don't like MEs above 4000 ft-lbs. I can also move it "down" too because I have the trajectory headroom (about 1.2") as well as energy headroom (about 660 ft-lbs).

Turns out, the 1.2" of trajectory headroom isn't enough to get the ME down to the "shoot all day long" goal of 3400 ft-lbs unless I raise the above-the-LoS figure to 3". But even at 2" above Los, it gets close: Total vertical = 12.1".

If I raise the max above-LoS height to 3", the total vertical distance is only 10.5".

Even though the trajectory has more curve to it, the 225 AB still produces the best paper ballistics even in the .338-08. However, I need to put the max pressure at 56,565 PSI AND set the max height to 3" above the LoS to get even 13" of total vertical movement out to 300 yd.

If I drop the 300 impact energy to 1500 ft-lbs in an effort to lower the max pressure, the trajectory gets 'problematic'. Ain't no free lunches. Still, 13 inches of total vertical trajectory and 1700+ ft-lbs out to 300 yards makes the .338-08 a VERY good cartridge for most of North American big game.

Paul
Be nicer than necessary.

gitano

Are you talking about the 250 AB, RJ? If so, I did. What do you want to know?

The recoil isn't an issue as general rule. It becomes an issue when the trajectory tends toward a rainbow because you have to up the MV to flatten the trajectory which in turn ups the ME, BUT as a general rule does NOT up the impact energy very much. So you get kicked harder and the trajectory gets a little better, but the delivered energy doesn't improve a whole lot.

More important to me in this case is the need for the extra 25 grains of mass of the 250. I've shot several big game animals with the 225 Hornady and they were either pass-throughs or under the skin on the far side after breaking shoulder blades and on LONG. The 210 Partition does exactly the same. (I do NOT like the Partition in ANY cartridge of mine except the .338 WM, in which it shoots 'like a laser'. That mitigates the pass-throughs which I don't like.) From my perspective, there just isn't a need for that extra 25 grains of weight.

Paul
Be nicer than necessary.

gitano

There are only 4 calibers that have Accubond "Long Range" bullets - 6.5, 270, 7mm, and .30 caliber.

Paul
Be nicer than necessary.

recoil junky

Yeah,

a. I was refering to the AB LR

and b. I went to the Nosler website and found that out.

and c. I don't see the reasoning behind the .270

and d. why don't they build one in .243

I think it would be onehelluva bullet for the 338WM. I've got the 180 grain AccuBonds working so well in the 300RUM that I'm not going to switch now. (as seen in this 500 yard 2.364" three shot group, the bullet to the lower right is from the .243 :p)



RJ
When you go afield, take the kids and please......................................wear your seatbelts.
Northwest Colorado.............Where the wapiti roam and deer and antelope run amuck. :undecided:  
Proud father of a soldier medic in The 82nd Airborne 325th AIR White Falcons :army:

gitano

I'm surprised they didn't make one in .338 on the 'first pass', but I suspect they will get to it.

Paul
Be nicer than necessary.

recoil junky

It would make me want to get a rifle chambered in 338 Lapua.  

:MOGRIN:

RJ
When you go afield, take the kids and please......................................wear your seatbelts.
Northwest Colorado.............Where the wapiti roam and deer and antelope run amuck. :undecided:  
Proud father of a soldier medic in The 82nd Airborne 325th AIR White Falcons :army:

gitano

The only time in my life I have ever felt 'under-gunned' was when I shot that big brown bear with the 7x300 Weatherby. And that wasn't until AFTER the bear was dead. Once, I actually WAS under-gunned on a Sitka black-tail deer hunt in Southeast Alaska. Some numbskull in my hunting party broke the scope on my 7x300 IN HALF. Fortunately, I had brought the .17 Remington along for some 'varmint' shooting. I killed three deer with it, but one that I shot at a range pushing 300 yd I had to track a VERY long way and shoot again. The other two dropped in their tracks. Literally. One of them wasn't even laying on its side when I came up on it. It had collapsed in the 3" deep snow. Its belly and legs were under it. On a sheep hunt once the guy I was with that was shooting an '06 felt under-gunned and asked to borrow my 7mm RM.

I've always had both all the range I felt I needed and all the 'oomph' I felt I needed. But then I have only rarely shot at much over 300 yd at big game. I think my all-time longest shot on a animal of any sort was a jack-rabbit out in the Mojave desert at something like 400-and-some-odd paces. I used a 7mm Rem Mag with probably Hornady 154s, as that is what I shot in those days.

Paul
Be nicer than necessary.

gitano

For a while, one could buy .50 caliber sabots with .30 caliber pockets for use in the .50 BMG using .30 cal bullets. There were some impressive MVs generated with that combination.

Paul
Be nicer than necessary.

gitano

The 225 Accubonds came in today. :D

I had an "Old Mother Hubbard" moment. (Old mother Hubbard went to the cupboard to get her doggy a bone. When she got there, the cupboard was bare and so the poor doggy had none.) I calculated loads to give the correct timing for 7 different powders, 6 of which I "have". The two I was most interested in were H4831 and Accurate 4064. I had exactly ONE charge-worth of powder left in each canister. :( But I had plenty of the other ones. I loaded 6 rounds each of I3031, Accurate 2495, and Reloder 17. All were spec'd to give exactly the same exit time of the bullet.

Once I had the .225 ABs in hand, I had to make a few adjustments. First was the ACTUAL bullet length vs QuickLOAD's nominal length. Second was the fact that I wasn't going to unload the cartridges that were loaded with 225 Hornadys because those are good loads. Therefore, I had to use some new brass. The new brass was all federal. The "old" brass was all Remington-Peters. The REALLY good news was that the case capacities were essentially identical once I trimmed the new brass to the same length as the old brass.

After adjusting OverAll Length for the extra length of the AB, I was a little concerned that the relationship of the the bullets to the bore - the "jump" - was going to be different. In fact, I was a little concerned that they might be too long to chamber properly. So the FIRST thing I did was chamber the first AB-bulleted cartridge that I made. It was NOT too long. Next, I got out my Stony Point (Now Hornady Lock-N-Load) cartridge/bullet measuring device. Measuring the OAL from the bore diameter of the bullet to the base of the 225 Hornady-loaded cartridges (the 'old' good load) and the same for the 225 Accubond-loaded cartridges, yielded a difference of only 0.001". No joke! I didn't think I could make the measurements on an ogive to a consistency of 0.001". In fact, I would have had "squinty eyes" if I had read where someone else did that. Skepticism aside, the point is that the ogival length of the "good, old, 225 Hornady" load was essentially identical to the ogival cartridge length of the new Accubond loads.

So... I have done just about everything I can to make the new loads as "identical" to the old, good, loads. I have six cartridge of each charge in each powder. I will shoot two three-shot groups allowing the barrel to cool completely between groups. God willin' and the creek don't rise, one of these three powders will produce good groups. I still need to get some H4831 and Accurate 4064 so I can try those powders as well.

Just thinking about it, I MAY load three more cases in each load in each powder to use to get muzzle velocities. While all the shots in the groups shot in this thread http://thehunterslife.com/forums/showthread.php?t=18941 had the MagnetoSpeed attached, I don't feel comfortable shooting "for precision" with the MagnetoSpeed attached. By the same token, getting good MV figures is imperative for load workup.

I'm going to try to get to the range tomorrow.

Paul
Be nicer than necessary.

Tags: