I understand they are both made by necking up .375 H&H brass...what is the difference in dimensiions and performance, if any?

I think the Watts is a teeny tiny tad bit longer. Maybe Cartridges of the World has the dimensions. If I recall correctly, you can shoot Lott ammo in a Watts, but not vice versa. Could we think of a Watts as a Lott with a long throat?

It is my understanding that the 450 watts was designed around cylindrical belted brass, necked down slightly, with a case length of 2.850". The 458 lott was designed to use necked up 375 brass, and when you neck up 375 brass, it shortens, so the lott case is 2.800" long. The cases are both straight tapered, and have no shoulder, essentially elongated 458 win mags, though I believe the watts pre-dated the win mag, or was developed shortly after its debut. The lott was designed by Jack Lott after he had an incident where a win mag failed to decide matters with a buff and he ended up getting tossed by the buff.

There are probably a few minor differences in "neck" dimensions, as well as body taper, but, other then that, they are pretty close. I suppose the slightly longer watts would offer a few more fps, maybe 50, but asside from that, they are very similar cartridges. I'm personally biased towards the lott, as I had one, and really liked it. The other up side of the lott is properly headstamped brass is easily obtained.

Paul H. has stated my understanding of the difference, mainly it's the extra .050 case length. Curiously, the Clymer 458 Lott reamer will create chambers that handle cases up to 2.870 inches long, so the difference is moot if they made your reamer.

Don

Paul H.....where can you get Lott headstamped cases? I have a chance to but a Lott fairly cheaply and I may not be able to resist too much longer.

Midway lists them, I believe Huntington's also carries them, and may have a slightly better price. I just used necked up 416 rem mag brass when I had mine, but unfortunately it isn't as common as it was back then. I used RCBS 458 win mag dies with no problem, just spaced them .30" off the shell holder. I wrote up a little ditty for the guy I sold the gun to, if you are interested, I can e-mail it to you.

I ordered some from Huntington's - they looked like all the rejects that had been sorted over five times. Some were .020 short, they leaned a lot from the base, etc.

I sent all but 28 out of 100 back - and I wish I'd sent them back.

There is a new batch of Rem headstamped 416Rem brass on the street. You could get some here http://www.blue-star-inc.com/rbrass.htm last I knew.

Don

MAST sells 375 cylinders with no headstamp, and they might even have them stamped these days. I used them for my Lott and just engraved the "458 Lott" name on the heads with an electric engraving tool.

Both are not standards. As mentioned above, today a Lott also is 2.85 (Clymer). The problem were the cases. A .375 is good for 2.80, today the basic Barnes or even the .416 Rem are good for 2.85. An improved version now is to make the Lott or Watts with a ghost shoulder (parallel neck).

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That would make it virtually a 450 Ackley!

John S,
The Ackley and the .450 Barnes Supreme, I have the latter, actually have more than a ghost shoulder, a real shoulder though ever so slight and useless for headspacing, but allowing a little more powder space in the cartridge. Another case of fraternal twin cartridges, recreating the wheel. Though you say this in jest, for those that don't understand, like me until just recently, the ghost shoulder is different.

The ghost shoulder is merely a parallel sided neck gripping the bullet properly, and then the cartridge begins its slight tapering expansion from the base of the bullet, or somewhere along the shank, back to the maximum diameter at the cartridge base in front of the belt.

The Watts came first, both long and short versions, which Winchester copied with their short version. The Lott is really an identical twin of the Watts, if you accept the 2.85 inches for both, case OAL. I think Lott might have originally specified 2.80" to make it different from the Watts 2.85" original specification for the long version.

RAB-
Yes, you are correct about what a ghost shoulder is, which could be illustrated with a 470 Capstik casing.
BTW, what shoulder bruiser will you be packing along to Bots?

John S,
I am happy to say that I will be taking a corpulent Ruger 77 .416 Rigby and a flyweight Pre-64 Winchester 70 .375 H&H (custom). Either rifle could be used on anything with PH backup. Sort of like Saeed taking two .375/.404's. I will just have two types of ammo to keep up with.

I am also happy to say that Gerard's .416 FN's have arrived, and I likely will be reporting on how they did on buffalo.

I will save the .510 JAB for the next trip hopefully. I want to be sensible on this one. I am demonstrating gun control in limiting myself to .375 and .416.
Mitch has confirmed my desires to build a .585 someday. I just can't do it right now.

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Good huntin' and shootin',
Bwanawannabe, Daktari Ron

I have both a Lott and a Watts. At least in my rifles, the ONLY difference is .050 inches in length (the Watts is longer). I have measured the fired cases from both guns, and they differ by less than .001 inch in all dimensions except length. I use my Lott dies to reload both, and just set the dies accordingly.