When I visited John here while back, I brought home with me his .338 Mauser Ackley Improved to work up loads for it. I haven't yet, but will be soon attaching the pressure measuring hardware. This preliminary report is just load/velocity/precision data.
 
John's goal was to produce a cartridge in .338 caliber that would get close to .338 Win Mag external ballistic performance while still fitting in a "standard" length action, specifically, a milsurp Mauser. He had the reamer done by Dave Manson so that the chamber would be optimally sized for the Combined Technology Silver Tip (CTST) at 200 grains. His Load From A Disk software suggested that a charge of 55.1 grains of Vihtavouri N-140 would yield a muzzle velocity of 2504 f/s with a chamber pressure of 53,333 PSIA. This charge represents a load density of approximately 90% and a charge-to-bullet ratio of .276.
 
Load From A Disk did not have data for N-150, but John thought that it might be a better choice as load density could be increased. He and I both like to have load densities as close to 100% as is reasonable. I fire-formed 20 cases and calculated what an appropriate N-150 charge range would be. Based on those calculations I loaded 5 each with charges of 52, 54, and 56 grains of N-150. I happen to like the Nosler 210 Partition in my .338 WM, so I loaded 5 of those bullets in front of 52 grains of N-150.
 
At the range I used 3 of the 52 grain charged 200-grain CTSTs to sight the 'scope in at 25 yds. The rest of the bullets were fired for precision and velocity at 100 yds. below is the velocity data.
 
200 grain CTST
52 grains of N-150
2749, 2725, 2740, 2702, 2722 - Mean=2728, St. Dev.=18.06
 
200 grain CTST
54 grains of N-150
2821, 2816, 2821, 2828, 2820 - Mean=2821, St. Dev.=4.32
 
200 grain CTST
56 grains of N-150
2907, 2917, Mean=2912 no St. Dev.
 
210 grain Nosler Partition
52 grains of N-150
2697, 2690, 2696, 2701, 2693 - Mean=2695 St. Dev.=4.19
 
I was doing a bunch of other stuff at the range that day as well, and the target with the groups for the 210 is at somebody else's house for the time being so I cannot present its precison information. As I said above, 3 of the 52-grained CTST-loaded cartridges were used to sight in the 'scope. That left only 2 for use at 100 yds. The first 56-grained load showed some signs of pressure. I fired one more round, and it showed the same pressure signs, so I stopped there. (Upon later inspection, the primer pockets were a little loose. Clearly too much pressure.) Therefore, the 56 grain group is also only a 2-shot group. Personally, 2-shot groups are not particularly interesting to me, especially when I'm working up loads. I include them here only for "completeness".
 
Finally, for comparison, I'll post the average velocity I get with some Hornady 225s in my .338 WM.
 
.338 Winchester Magnum
Hornady 225 SP
69.0 grains of H414
Mean=2839 St. Dev. 12.3
 
So... looks like John has met his goal of approaching .338 Win Mag velocities from a 57mm Mauser case. The 200 CTST at 2821 f/s in front of 54 grains of N-150, compares very favorably with the 225 grain's 2839 f/s out of the .338 WM.
 
Paul

whew. big power in a mid-size package. the 57mm based chamberings continue to amaze.
can you at least tell us if the accuracy potential looked hopeful?

never mind. i wrote the post before the graphs popped up. promising ...

Hi All,

          Verily I say to thee,
 
 
        Just what is it about the 57mm mauser case which seems to work so darned well ?????????????????? I mean to say that old 9.3x57 seems to be able to nearly match the 35 Wheelan although I do need to check the velocities with a chronograph, but according to the Vhit manual it about equals the 35 Wheelan with similar weight bullets. And then the ole 7.92mm or 8x57mm if you prefer equals the 30-06 with similar weight bullets. so just what is soooooooooo special about the 57mm case/ It sure beats me:rolleyes:
 
      Nice work Gitano, not really needed for Red Deer or Roe though;)

Once again I've been contemplating this issue of specific cases. Once again, I come back to some rather simple physics.
 
Bullets don't "know" from what cartridge they're being fired. Therefore, bbl lengths being equal, the only variable that matters with regard to muzzle velocity is how hard that bullet gets pushed from behind. In other words, pressure. So, if you've got a bullet of a specific diameter say .338", between cartridge cases, that diameter presents a constant area upon which the force of the expanding gases can work. Therfore, if you apply 55,000 pounds of pressure/square inch to the base of that bullet, it matters not what the shape of the container was that held the unburnt powder now generating the 55,000 pounds/square inch of pressure on the base of that .338 bullet.
 
So... I think the 57mm case behaves so "well" because people have been lead to think that bigger cases mean faster velocities and more "power". Velocity comes from pressure, not case volume. A good case in point (no puns intended), is the .338 Whisper of JDJ origin. The case for this cartridge is a necked up 7mm BR. It can launch a 200 grain bullet at 2200 f/s. Very efficient, but again, its just a matter of pressure.
 
For me, the "beauty" of the 57mm case is the plethora of milsurp actions available for "toying" with.
 
Paul

well, you sure took the mystery out of that, didn't you paul? rats.

Sorry fish -

Paul

Paul,
 
Hmmmmm! As we discussed on the phone......Surprise! Surprise! I am simply amazed at the velocities.....a lot more than what I thought we were going to obtain! The SD (4.32) and the extreme spread (12fps) of the 54 grain load is most satisfactory and does show promise. Before we go any farther, the bolt release screw and the ejector I hope to get in the mail to you tomorrow or Friday at the latest. Send me an -e mail with your mailing address please. If you want I will send along 20 Remington pieces of brass that I will weight sort for uniformity. I would suggest loading the next batch of 18 with 6 each of 53.0, 53.5 and 54.0 grains of VV-150 and fire 2-3hot groups with each load. BTW what brand of brass and what primers are you using? I missed that info somewhere in our discussion.
 
Good work, amigo!
 
Ol' John...:D :D :D
 
BTW---Give us your thoughts on the Weaver KT-15 and the Burris Signature rings...good or bad as always!!!!...

Let's see... R-P nickle-plated brass - CCI 250 primers.
 

QuoteI would suggest loading the next batch of 18 with 6 each of 53.0, 53.5 and 54.0 grains of VV-150 and fire 2-3hot groups with each load.

Sounds fine to me John. In the end I'm gonna pool all of the shots within a specific loading anyway.
 
You can save the ejector if you want John, I took it apart and found it bent, not filed off. It looked filed because it wasn't coming out fully through the slot. I straightened it and there are no more ejection problems.
 

QuoteIf you want I will send along 20 Remington pieces of brass that I will weight sort for uniformity.

If that's what you'd like John, I'll take 'em and load accordingly.
 
The Weaver 'scope is a good quality 'scope. I'm just about the last person that should be asked to evaluate a 'scope. All my life I've made do with what I've had, and never felt 'deprived'. I just 'make it work'. That said, the 'scope won't be an 'issue' with regard to finding the best load for this rifle.
 
May get back to the range this weekend providing the weather doesn't get bad.
 
Paul

Looks real good. The 52gr showed real good accuracy for the 2 shots. The 54 had good speed but I personally would like a little smaller group. It will be interesting to see the next round.

HB,
 
What kind of MVs are you getting out of your .338 WM?
 
Paul

I'm getting 2919 with a 200gr Barnes X. So the speeds that you were getting with the 56gr load was comparable with a 338 Win Mag with less powder. If not for thoes darn pressure signs.............  It would be interesting to see what I could get out of the Combined Tech BTSP. Maby I'll have to play with it a bit this summer and see. But I have some other rifles to play with first.

Interesting cartridge and development.
 
HUNTERBUG, last .338 WinMag load I worked up using the 200 gr. Nosler BT's (twin of the BST less the Lubalox) averaged 3130 fps from a 24" barrel. Was for a friends rifle. Assuming you're also sporting a 24" barrel, I'd imagine your performance would be similar. R19 was used.

The 200gr BT which has considerable less bearing surface than a 200gr Barnes XFB so you're going to get a bit more speed . I could get a bit more speed out of my 338 with the 200gr Barnes and even more if I switched to a 200gr BT or the new 210gr Barnes Tripple Shock but fail to see the need. My rifle will shoot 5 rounds with this load into 1.5" with 3 going into .4" and has more than enough power to kill anything I plan to hunt at any range I will shoot. I use RL-15 in my rifle as it's considerably more effecient than the RL-19. I tried the RL-19 with a 225gr Nosler Accubond and my rifle was less than impressed or I should say I was not impressed with the accuracy. I will need to work up a new load next summer but I'll go with either the 210gr Partition or the 210gr TSX.

Morning HUNTERBUG  >>  Wasn't really making any comment on whether you needed the added BT velocity of not.  Just saw that you mentioned working up a load using the bullet and thought I'd mention what I found and what was used.  Whether you actually get to working up a load using this bullet     ...     not my concern.  Just sharing info based on what you said in a previous post.  Later.  >>  klallen