450 Ackley Magnum/458 Lott

26 November 2014, 07:53

+Templar+

Been doing a bit of reading on the 450 Ackley Mag. From what I understand, the case is a bit longer than the 458 Lott and it has a slight shoulder. So basically an improved 375 H&H case necked up to 458. Does anyone have a typical reamer print for the 450 Ackley? I'm curious about the case taper per inch(easy extraction?). Can a 458 Lott cartridge be fired in a rifle with a 450 Ackley chamber? I'm not necessarily interested in an increase in performance, if any, but I don't like looking at a 458 Lott case that is buldging towards the case mouth from the seated bullet. Like this:

Just looks ugly...

And while I'm at it, I might have a reamer made for the case length of the 458 Lott instead of the H&H case length and call it the 458 Lott improved(sorta). Probably not worth the effort, but it sounds fun to me...

26 November 2014, 08:13

Colt Commander

The .450 Ackley can fire the Watts, Lott and Win.Mag.

26 November 2014, 11:10

waterrat

Win Mag ??

27 November 2014, 23:37

butchlambert

This is a cartridge on the left that was fireformed in my Enfield that is marked 450-500 Express. The brass on the right is a 458 Lott brass. The Lott looks shorter, but it isn't. I've always thought of it as a 450 Ackley Magnum. I can't find info on the 450-500 Express.

29 November 2014, 09:21

+Templar+

Butch, that's an interesting cartridge. Id like to know its origin and specifics. Have you ever done a chamber cast on that Enfield?

I got ahold of JGS and they were kind enough to send me a reamer print for the 450 Ack Mag. The first thing that catches my eye is the body taper. It's only 0.0041" per inch. That seems very "straight". It seems that one would experience sticky extraction with a taper like that. Especially when you consider how hot Ackley liked to load his cartridges. I figured that .0065-.007 is as low as one would want to go. I did notice that the 470 Capstick had had a taper of .006" per inch. Maybe I should make a post on the Big Bore section to see if any 470 Capstick shooters experience troublesome extraction. The 450 Ackley chamber also had a neck diameter of .490" at the front where the 458 Lott is spec'd at .483". Is be curious to know what the taper is on a loaded 458 Lott case from the case mouth to the base of the bullet. SAAMI shows the chamber having .012 per inch of taper from the case mouth to the belt. Surely the "neck" of a loaded 458 Lott case doesn't possess that much taper. Any thoughts?

30 November 2014, 00:10

butchlambert

Here is the best measurements from the fired brass and the cerrosafe cast. The OAL is 2.880, the neck is approx .400 long, the shoulder is .508, the base just above measures .512.
I hope that this helps. Like I say, the barrel is marked 450-500 Express. I wish I knew more about it.

03 December 2014, 00:41

Whitworth

This is a photo of a loaded .458 Lott (left) next to a loaded .450 Ackley.

03 December 2014, 00:58

butchlambert

quote:
Originally posted by Whitworth:
This is a photo of a loaded .458 Lott (left) next to a loaded .450 Ackley.

Could you check your measurements and compare them to mine? My picture of a fireformed case came out with a shorter neck than my cerrosafe cast. Indicates the 458 Lott basic brass is too short.

03 December 2014, 09:59

+Templar+

For reference:

03 February 2015, 23:59

tiggertate

quote:
Originally posted by +Templar+:
Butch, that's an interesting cartridge. Id like to know its origin and specifics. Have you ever done a chamber cast on that Enfield?

I got ahold of JGS and they were kind enough to send me a reamer print for the 450 Ack Mag. The first thing that catches my eye is the body taper. It's only 0.0041" per inch. That seems very "straight". It seems that one would experience sticky extraction with a taper like that. Especially when you consider how hot Ackley liked to load his cartridges. I figured that .0065-.007 is as low as one would want to go. I did notice that the 470 Capstick had had a taper of .006" per inch. Maybe I should make a post on the Big Bore section to see if any 470 Capstick shooters experience troublesome extraction. The 450 Ackley chamber also had a neck diameter of .490" at the front where the 458 Lott is spec'd at .483". Is be curious to know what the taper is on a loaded 458 Lott case from the case mouth to the base of the bullet. SAAMI shows the chamber having .012 per inch of taper from the case mouth to the belt. Surely the "neck" of a loaded 458 Lott case doesn't possess that much taper. Any thoughts?

I owned one for a while and extraction was never a problem. It was a re-chambered Brno 602. I still have the reamer if your interested and a few boxes of properly stamped A-Square once-fired brass plus a few leftover Lion Loads.

04 February 2015, 04:28

PWS

Lott in Lott, Win in Lott, Win in Ack, Lott in Ack, Ack in Ack.

All fed and fired normally and developed pretty much full velocity. I personally prefer the slightly smaller and "sloppier fit" of the Lott over the Ackley in standard H&H length mag boxes.

10 February 2015, 23:28

AFRICAN LEADWOOD

I zeroed the 450 Ackley of a ph once and fired both 450 Ackley, Lott and Win Mag in it as part of the process. He had to 450 Ackleys both M70 pushfeeds and mentioned that he had experienced sticky extraction from time to time, but who knows the loads, how clean the chamber was, how hot it was in the Zambesi Valley at the time etc. It is by far the best looking cartridge in that performance range in my opinion. I think a Lott is close and cheaper and easier.

11 February 2015, 00:08

butchlambert

quote:
Originally posted by PWS:
Lott in Lott, Win in Lott, Win in Ack, Lott in Ack, Ack in Ack.

All fed and fired normally and developed pretty much full velocity. I personally prefer the slightly smaller and "sloppier fit" of the Lott over the Ackley in standard H&H length mag boxes.

Your 458 Lott brass fired in the 450 Ackley look just like mine.

11 February 2015, 01:00

Biebs

Butch, is that the Enfield you got from me 5-6 years ago?

11 February 2015, 01:06

butchlambert

Yes it is.

11 February 2015, 03:10

Biebs

I had a 450 Ackley once in a Griffin & Howe Model 70. As I understand, it uses the 375 case, but full-length. I never loaded for it, as I had plenty of Superior Ammunition for it when I got it. It's a pretty powerful 45, for sure.

12 February 2015, 06:32

jeffeosso

can fire a lott in an ackley, but not the other way .. I've seen lott/watts fired in a ackley chamber. didn't seem to be bad results

28 February 2015, 09:23

CMcDermott

Ackley and Watt did their development in the late 50's when a H&H Belted "Basic" full cylinder case was available so they could form their brass, trim it lightly to square the mouth and still have the full 2.85" case length of the 375 H&H magnum. Lott did his work in the late 70's using 375 H&H brass, which by the time he expanded the neck and trimmed the mouth, weren't quite long enough to match the 375 length, so he settled for a case length of 2.80". Ackley 450 Magnum shouldn't fit in a Watt or Lott chamber, You might be able to jam a Watt into a Lott chamber but you shouldn't as the case is too long and the neck will have a hard time releasing the bullet causing raised pressures and possible blow-ups.

24 March 2015, 12:43

Idaho Sharpshooter

I still have several new boxes of the NORMA cylindrical brass out in the shop somewhere.. It measures pretty close to the 470 Capstick.

I keep thinking I need another Lott or the Ackley, but it doesn't make much sense with an OM 70 Jim Kobe fitted a 450/375 RUM barrel to for me last year.

On the other hand, who says common sense figures into the equation?

Rich