I have asked Dave Manson about the dimensions of reamers for the caliber 458 Lott. The standard SAAMI dimension is for 2.8" lenght of brass and a 0.150" lenght of throut. $110

Their original dimensions for Lott is for 2.85" lenght of brass and a 0.450" lenght of throut. $160

I think most factory maded rifles in caliber 458 Lott is with the short throut, so if you like to get a 458 Lott you have to build it as a custom or rechamber.

Anyone who would choose 450 Ackley instead of 458 Lott?

Kalle,

This is good information. It explains why the ammo manufacturers have been downloading the Lott.

I guess it would be simple enough to re-chamber the "SAAMI" Lott to the "Wildcat" Lott to make it safer when shooting the hot wildcat handloads, but it sucks that the factory loaded stuff will probably be a downloaded proposition. Why the heck did they do that?

This may turn into having reload manuals w/ a category for max loads for the original Lott and max loads for the SAAMI Lott. If this was a blunder, can the SAAMI standards be changed to the original Lott dimensions? If it was not a blunder, then why did they make it short?

Gary

quote:

Originally posted by Kalle:

Anyone who would choose 450 Ackley instead of 458 Lott?

"NO!" Though the AIs are fine wildcats, and I have owned many rifles, and TC contenders chambered for AI chamberings, they are still, at the end of the day, WILDCATS! In this case the 450 Ackley has to be made up, while the LOTT is simply a factory round. The 450 Ackley is not an IMPROVED round, in the sense of a chamber you can simply fire a factory round in to make the brass, as all Ackley Improved rounds are. With the LOTT, one still has the option of shooting 458 Win Mag in the rifle if ammo is lost, in the same vane the Ackley improved were designed to be.

The ballistics are vertually identical for the 450 AM to the 458 LOTT, for all practical purposes, and in fact I would even down load the either of them to the balistics of the old 450NE 3 1/4", simply because nothing more is needed for the shooting the LOTT, and Ackley were made for!

The LOTT is what the 458 Win Mag should have been in the first place!

I had my Lott custom built with the long chamber and longer throat and it is definitely the way to go.

I have been told by more than one powder co. rep. that the reason they do not list any reloading data for the Lott is, there is no SAAMI standards for this round. And they do not want to pony up the $$ to get the testing done for SAAMI standards.

Hog Killer

I don´t know why they choosen the short throut, but i don´t want it anyway. It´s not fun if buying a new 458 Lott from factory you then have to rechamber it to get a real 458 Lott.

I understand that it´s no deal to get a 458 Lott if the difference between 458 Lott and 458 WM is 50 fp/s (Hornady Data), but reloading data tested of Belgium Proofhouse list that they get 2402 fp/s with 500 grains Hornady bullet and use of Vihtavouri 540 Powder at 52.200 PSI with the original Lott dimensions.

With 500 grains Swift they get 2300 fp/s at 52.400 PSI and it´s 200 fp/s more than they get out of a 458 WM. I get 2150 fp/s out of my 458 WM, but it´s diffently maxload, and it´s not in hot climat. I prefer a original 458 Lott loaded to 2200 fp/s.

My ruger 77 pushes 500's out at an average of 2360, with no hard extraction,loose primer pockets or any such pressure signs..OK by me. Some brass is 6 times used. Now having said that,I only neck with a 458 wm die

Let's be perfectly clear

the 458 lott is a saami round. Again, it is a SAAMI round, and has a standard. There is NO commerical ammunition sold in the US that is not loaded to a recognized standard, due to the litigous nature of the US.

the saami throat is .450, not .150

Dave is a great guy, and I am certain he has the saami drawing, but I am also certain he misread the drawing, as throat of .150 would result in a MAXIMUM length 2.8 (case) +olgive +.150 and taper., or about exactly the same oal as a 458 winmag

(wadcutter) lott
2.8 + .150 (throat) is 2.950

as the winmag is
2.5 +.450 or 2.950 (max length to olgive)

Kalle,
in this case, I believe you have posted with good intent, but the data source just read a drawing wrong. As I am dyslexic, i can fully understand how tha can happen. I've ordered a couple reamers, and have had to have some ground. I have yet to approve the first faxed drawing, as these types of things happen all the time.

This is contra-indicated with rounds like the 257 roberts and the 8 mauser, which are loaded to the total minimum strength of any of the actions that those might have been loaded in, or, inthe 8 mauser, it's an anemic .323 load "just in case" it's fired in a .318 barrel

Jeffe

Thank´s Jeffe!

I looked at Cymer and their 458 Lott have 0.46" throut. Do you have any experience about the quality of reamers bought from Midway (PTG)?

Jeffe,

I have a magnum action chambered 458WM. This combo never quite felt right to me and I'm thinking of having it rechambered to Lott.

I'm getting mixed info:

Some are saying that the SAAMI Lott was standardized w/ a shorter chamber than the original wildcat, therefore it may not be safe to use the upper end of the original Lott wildcat handloads and as a result factory ammo has been backed down a bit. I thought this info started with testing done by D'arcy Echols but am unsure. It has been suggested to use the longer original Lott wildcat reamer to alter the SAAMI chamber to the original length.

Others are saying that the SAAMI Lot chamber dimensions are identical to the original wildcat Lott chamber and that the reamers are one and the same.

Which is correct?

Thanks,
Gary

Gary,
lets back into this
1: if you JAM a bullet into the grooves, you raise pressure
2: other than the rem 405, all .458 bullets have only ONE chrimping groove
3: the 458win has a .450 throat, which means the olgive must be at a place shorter than this
4: if one took ANY .458 bullet, we'll say the olgive is .350 above the chrimp, and then put it in a ".150" throated lott, you would push the bullet back into the case or not be able to close the bolt.

this is a simple 10# in a 5# sack

jeffe

Jeffe,
Sounds like you guys in Porter,tx wake up on the wrong side of the bed. I didn't think the bullet ogive had to engage the rifleing to cause a high pressure spike.

I phoned Dave Manson, but his shop is closed for the weekend.

I called his former boss, Clymer. He currently produces the SAAMI spec reamer. Off hand, he did not know the dimensional differences between the old wildcat reamer and the SAAMI one. He said he would have to research his archives by hand for that and he was just too busy. As for why there would be a difference. He said its not unusual for SAAMI to alter dimensions in the throat area of the chamber from a submitted application to ensure that a different cartridge would not fit such as one of the other .450 wildcats. That makes sense to me.

As for my conversion (from my notes), I've been told that most of the current reamers will work for a case up to 2.85" long w/ any differences being in the freebore/throat dimensions. That the original Lott had a long freebore/throat to lower pressure on his loads. That the SAAMI chamber has a different dimention in the freebore or throat chamber and therefore may cause a pressure issue. I don't know if this is alleged to occur because of pinching around the crimp or reduced distance between the ogive and rifling or what.

I'm just trying to prove or disprove this difference (if there is any) and trying to determine if it would be wiser to use the old wildcat reamer if there is a difference.

I'll try contacting Echols or Sisk, maybe they can share some light on this.

Thanks,
Gary

Gary,
sorry if that came over grummpy.. was just trying to answer your question but i was in a rush.

Here's what I meant to say.. "if" a .150 throat was saami, there's no was you could safely load conventional .458 bullets at the crimp and NOT drive them into the grooves.

If there was a "safe" load, at a "safe" length, and suddenly removed the throat, the pressure would spike.


So, if you took a hornady 500gr, set it to the crimp, used a good hard crimp, AND the throat was .150, you could NOT close the bolt without a large effort, as you would be driving the grooves into the bullet (assuming crimp holds) or defecting the crimp, for at least .200 travel.

as most people agree that somewhere between -.03" to 0" is a good distance off the rifling, we would then have, at least, +.200 (closer to .30) bullet into the rifling....

it just don't make sense that the saami throat is .150, and I think where it comes over that I am grumpy is that a typo or misread is being present as fact, and real world function demonstrates that just aint the case.

for a little humor, it's like an engineering saying a bumblebee can't fly... as it lands on him and stings him

jeffe

Jeffe,

I think Dave Manson calls the dimension in front of the case mouth "freebore" on his reamers. Up where it tapers down to the bore he call the "throat" and that is usually something like 2degrees. So as far as the freebore is concerned, I don't think he was saying that measurement is .150"

Putting all of this aside. I prefer the Lott in a magnum action and for shooting monolithic solids. Someone had pointed out that the dimensions in the freebore or throat area was different. I thought this was Echols (but am unsure) and thought as a result it was decided to to back down from 2300fps. This may be all bogus. If this is valid, then I wanted to verify that I could use an original reamer or if that would be wise.

I think it would be a good idea to prove this true or untrue.

Gary

Gary,
what Kalle said is that the saami lott is .150 throat, and the wildcat is .450.

I have bought reamers from and designed them to be made by Dave, including providing the case drawings and approving the reamer drawings.

Throat and freebore are sometimes used interchangably. Almost all rounds have a fairly decent throat, except saami on the 45/70 and 405 win, which are notoriously short.


Case length...
number 1, DO NOT go by reamer length to determine trim-to (also called nominal) case length
number 2 ALL rifle cartridge reamers (even bench rest, but to a lesser extent) are larger than the nominal case drawing, as this allow extraction
number 3 most rifles have .050 allowable case OVER length built into them. this is so you can trim your brass every once in awhile, rather than after every shot.

So, there's a couple items here
1: the lott CASE drawing is 2.80" long.. eos
2: the nominal reamer allows for a 2.85" length brass... YES, by design, eos
3: if kalle's stipulation is correct, you could not chamber a 500gr bullet, crimped at the crimping groove, in a lott, as the throat would be .150 Kalle's statement is a misread of a print.

Please do verify.

As for using the wildcat reamer vs the lott reamer, it would have a higher cost/benefit to buy a standard reamer, and a throater and work your throat out.

over Long throats, as proven in weatherby rounds, only "matter" in "at the edge" critical loadings OR if you are going to use over sized bullets.

The Lott (saami) will hit 2300 with a 500 gr bullet, box stock fatory. If you had a longer throat, you COULD load a couple FPS faster, agreed.

but, the least of them (assuming the saami is the lesser) hits the published velocity, in the short throat (.450) so a longer throat would not be a "standard" improvement, but your gun MIGHT go faster, with a longer throat.

That all being said, my 500 jeffe is .365 longer than standard, to allow me to single load 50bmg bullets, if i wanted to, and I still get factory ballistics out of it.

Is that a wildcat? Nope, just long throated factory.

jeffe

quote:

Originally posted by Kalle:
but reloading data tested of Belgium Proofhouse list that they get 2402 fp/s with 500 grains Hornady bullet and use of Vihtavouri 540 Powder at 52.200 PSI with the original Lott dimensions.

The Belgium Proofhouse measured for my loads the same (may be they are referring to it), but the Lott dimensions were for 2.85 case lenght.