458 Lott with 16.5 inch barrel

25 July 2005, 18:37

500grains

What kind of velocity do you guys think I would get from a 458 Lott with a 16.5 inch barrel? Assume that with a 24 inch barrel shooting 84.0 grains of IMR4320 behind a 500 grain Woodleigh I get 2300 fps.

This would be a brush gun, if I build it.

25 July 2005, 19:06

D Humbarger

After you build it I want to see a video of it being fired at night!

25 July 2005, 19:11

Customstox

Why would anyone want to shoot brush?

25 July 2005, 19:14

D Humbarger

quote:
Why would anyone want to shoot brush?

Chick he's not going to SHOOT brush, he's going to set it ablaze with the muzzle flash!

25 July 2005, 20:04

jens poulsen

He wants to go in orbit!.

25 July 2005, 22:27

Hog Killer

Sounds more like a long chambered 45-70 Guide gun to me.

Hog Killer

25 July 2005, 23:27

Tex21

Wear ear plugs in your ears under your ear muffs while shooting it.

26 July 2005, 00:39

GonHuntin

I'd guess somewhere close to 2150 fps.......

26 July 2005, 09:24

Hog Killer

I would be surprized if he got over 2000fps.

Hog Killer

26 July 2005, 18:04

zimbabwe

As I responded on the other forum, Remington gives 10fps loss for every inch under 24 for velocities from 2000/2500fps. I have an 03 Spfld that has been cut to 16" with mil stock shortened to match,beautiful winchester style safety,lowered bolt handle, new front sight blade,Lyman Alaskan in G&H side mount. Built by Les Womack for a prominent gunwriter to use in Alaska as a trail rifle. Both my 416Rigby and 375 Brno's have 21" bbls for use in the thick stuff in Zim. Very handy and I NEVER notice the muzzle blast when shooting game. All guns shoot less than an inch with good loads so have no disadvantages at distance either. 75fps is not significient velocity loss. I have found the Remington data to be accurate for big bores.

26 July 2005, 19:36

GonHuntin

Hog Killer

I believe you would be surprised.......having a background in big bore single shot handguns has proven to me that relatively straight walled cartridges, shooting heavy bullets from short barrels, don't lose nearly as much velocity as most people think.........

Here is some barrel velocity loss test data for you to ponder......it's from Charlie Sisk of Sisk rifles:

quote:
For a long time I have wondered about how barrel length
affected velocity. I had always been told you need a certain
length barrel for certain calibers. I have read when folks
compared one gun to another with different lengths but I
always thought that was not an apples to apples comparision.
So I did a few test myself.
All these were Shilen barrels. I used the same brass through
out the whole test. All weighed to with 1 grain. Bullets
were tested on the Juenke machine. Powder charges were
weighed to .1 grain. The same rest, chronograph, Redding
press, primers all from the same lot, bullets for the same
box, same lathe, same crowning tool, same cutoff tool, and
each rifle done from start to finish on the same day.
Ambient temperature was the same because I shoot from inside
the shop. I held the rifle the same way on the rest every
time. I shot ten rounds first to break in the barrel. Then
cleaned with Sweets and fired one fouling shot. Then shot
five rounds and took the average. I used a midrange load
fron the Nosler book, not too hot but certainly not a
reduced load. Here is what I got.

22-250 Hodgdon 380 34 grains Federal GM210M Remington brass
55 grain Ballistic Tip
27 inches 3469 fps
26 3451
25 3425
24 3407
56 fps from highest to lowest

270 Winchester Hodgdon 4350 54 grains Federal GM210M
Winchester brass 130 grain Sierra
27 inches 3115 fps
26 3093
25 3071
24 3054
23 3035
22 3027
21 3001
114 fps from highest to lowest

300 Winchester mag Federal GM215M Winchester brass 74 grains
of Reloder 22 180 grain Partition
27 inches 3055 fps
26 3031
25 3024
24 3003
23 2984
22 2960
95 fps from highest to lowest

340 Weatherby Federal GM215M 250 grain Sierra
81 grains Reloder 22 Wby brass
27 inches 2837 fps
26 2817
25 2809
24 2791
23 2777
22 2755
21 2731
106 fps from highest to lowest

I think I will do a little more thinking before I recommend
a barrel length in the future. What do you folks think ?
Charlie

Here is the info about the 338 Win and the 257 Roberts.
338 Win mag
Winchester brass
Federal GM215M primers
Reloder 19....73 grains
250 grain Partitions
27 inches.....2806 fps
26 inches.....2787 fps
25 inches.....2761 fps
24 inches.....2743 fps
23 inches.....2716 fps
22 inches.....2697 fps
21 inches.....2676 fps
20 inches.....2656 fps
150 fps from 27 inches to 21 inches

257 Roberts
Federal GM210M primers
Remington brass
H-4350....45 grains
120 grain Partitions
27 inches.....2860 fps
26 inches.....2834 fps
26 inches.....2815 fps
25 inches.....2815 fps
24 inches.....2798 fps
23 inches.....2775 fps
22 inches.....2760 fps
21 inches.....2739 fps
20 inches.....2717 fps
143 fps from 27 inches to 20 inches
I want to test this on the next 450 Marlin I build and on a
222 Remington. If I get the same results with those, in my
mind the test is over. I think this will be enough data to
support the findings. Are there any folks out there who have
a degree in this sort of thing ? Maybe explain how many data
points would be needed to be able to say this would work
with the majority of calibers ? Someone with experience in
statistical(spell check) quality control ?
Charlie

A few weeks ago I done some testing with shortening barrels
with various calibers. I just finished this test with a 300
Ultra.
These loads were EXTREMELY HOT !!!!!!!!!
I will not post the grains here because on the third loading
the primer would fall out of the case . I never load this
hot , only this time for the test. I used Remington brass,
Federal GM215M primers, 220 grain round nose bullets. I used
the same procedures as the last test.
length.... H-4895 .....H-870
.....27 .....2740 .....3107 FPS
.....26 .....2709 .....3088
.....25 .....2685 .....3062
.....24 .....2663 .....3046
.....23 .....2636 .....3018
.....22 .....2612 .....2997
H-4895 lost 128 fps
H-870 lost 110 fps
Charlie

26 July 2005, 23:27

500grains

Guys, thanks for the responses. It looks like dropping down to 20 inches will not hurt velocity very much. But I wonder about the drop from 20 to 16 inches.

26 July 2005, 23:51

GonHuntin

Check out the Hodgdon website and compare rifle loads with single shot pistol loads........ unfortunately, they don't have loads for a Lott in a handgun, but I think you will get the idea........a nearly straight walled case with heavy bullets in a short barrel will surprise you!!

27 July 2005, 00:24

Geronomo

I really don't understand the need for this venture? There is a significant loss in muzzle energy when losing 100-150 fps. pushing a 500 gr. bullet. There is also a significant increase in muzzle whip and blast in such a gun. Not to mention the likelihood of a poorly balance gun to boot. Why do you think no one makes guns in this caliber to these dimensions? If you want a short large caliber rifle, why not start with one which will give the above balistics in a shorter barrel without the extra recoil, muzzle whip, blast, and muzzle flash. IMHO a 16-18 in. barrel in a 458 Lott is impractical if not rediculous.

Geronimo

27 July 2005, 00:24

bill439

I doubt if anything on the receiving end of a 16.5" lott will notice any difference, God forbid would you now have a .458 win? Isn't that is what the lott was to replace because of lack of power?

27 July 2005, 03:54

Art S.

I don't know if any of the ballistics programs do this calc. I used to use the old Powley Computer, purchased from Bob Forker (in my mind the best and most technical wildcatter ever). You used the case capacity in grains and the volume of the barrel based on length and diameter. It calculated the expansion ratio for the cartridge/barrel/load and gave surprisingly go answers. One thing you noticed when using this was that straight walled cartridges were relatively insensitive to barrel length, since the expansion coefficient was fairly high for any barrel length. Huge cases with small bores are the worst. It is only a big problem when you cross into the zone where significant amounts of powder are burning outside the barrel.

30 July 2005, 00:20

CRUSHER

I load a 338 in a 223 case and get 2400 from a 16 in bbl and they said that was imposible you just never know but 20 would be a better balance but hey try it its only money

30 July 2005, 01:35

Paul H

2050 fps +/- 50 fps based on 30 fps/in velocity loss, though I don't know if the Lott really looses that much.

My first 458 Lott had a 21 1/2" barrel, but the last 1 1/2" was back bored with 10 1/4" holes drilled in it. With 87 gr RL 15 it would push a 500 gr hornady soft 2280 fps 15' from the muzzle.

I can't see cutting a lott tube shorter than 20".

30 July 2005, 09:00

Tumbleweed

That thing is gonna look like the north end of a southbound bazooka!...

...I wanna watch!

30 July 2005, 11:13

500grains

Paul,

What is your concern about going shorter than 20" on a Lott? Muzzle blast/muzzle rise, or velocity loss?

I fired on the the Blaser Scout rifle which is a 5.5 pound 16 1/2" .375 H&H. The recoil is a very minor jab. So I got to thinking about a 7 pound 16 inch 458 Lott. Perhaps I should be thinking of a 7.5 pound 20 inch 458 Lott.

If I do go with the 16 inch tube, do you think the U.S. Forest Service will make me install a spark arrestor in it?

31 July 2005, 06:45

invader66

Sounds like fun. I think, from what I have read, you could stay over 2000fps. I think a Fire Extinguisher may be best.

31 July 2005, 06:50

Paul H

500,

Muzzle blast and velocity loss. The whole purpose of a 458 Lott is having a bit more speed than a 458 win mag, and cutting down a lott so that it is slower than a win mag seems counter productive.

My previous Lott when re-stocked by the friend I sold it to was 8 1/2 #'s and braked, it was brisk on the shoulder. A 7# lott would be a sadistic practical joke, hey bubba, shoot this!