Reduced loads for .458 Lott

[jamesicus]

I have a surfeit of Hornady .458 DGS 500 GR Bullets. I intend to use a charge of 38 grains of Accurate 5744 powder with Hornady .458 Lott cases and Remington 9 1/2M primers.

Will I still need to crimp the cases in the bullet cannelure with this reduced load?

Intended usage is paper target shooting at 50yds.

Thank you for all responses.

James

[Unclenick]

That's only about 50% full in the case. Its a fast rifle powder, but I'd still have some concern for the powder lying flat in that long case and that the primer might ignite that whole exposed surface area rather than starting at one end. With rifle powders that can produce serious pressure spikes. It's less likely as the burn rate goes up, and is no problem with Unique or other relatively fast pistol powders. 5744 is sort of inbetween, so I don't know the risk?

A couple of things commonly done are to charge the case then put a tuft of polyester cotton pillow stuffing over it to keep the powder back against the flash hole. Another is to use IMR SR4759 powder, which is very bulky and is commonly employed in reduced rifle loads for that reason.

[jamesicus]

Thank you, Unclenick.

[80viking]

One thing to keep in mind with a straight wall rifle cartridge is it need a considerable amount of pressure to properly. The only resistance to build pressure with is from the weight of the bullet and friction in the bore. Thats why it can be difficult to get good results with reduced loads in the big rifle cases.

For 50yd plinking I would think that Unique would be a top choice.
My load for my Trapdoor Springfield is 12gr Unique with a 500gr plain base bullet. It flies at just over 1000fps. It groups around 2" @ 100yds.

This load would be worth trying in your .458 Lott. Its my silhouette load for my .458 Win Mag. Its 50gr of 3031 with a 500gr gas check bullet, 1600fps and it groups just over an inch @ 100yds. Its the lightest load I could get to group well.

Yes you should stick with the crimp. Those heavy bullets like to stay were they are when the gun recoils.

[jamesicus]

Thank you, 80viking.

[hickstick_10]

give IMR trail boss powder a try, youl have a good laugh at how quiet it is.

[jamesicus]

hickstick_10 wrote:

give IMR trail boss powder a try, youl have a good laugh at how quiet it is.

Thanks, I will.

James

[jamesicus]

It was off to the range today:

Rifle: CZ 550, American Safari, .458 Lott (/.458 Win. Mag.), Open iron sights, weight: 10lbs.
Ammunition: reloads using Hornady New Dimension dies, RCBS Rock-Chucker press
Brass: Hornady
Powder: Accurate 5744 - 38 grains (no fillers)
Primers: Remington 9 1/2M Magnum rifle
Bullets: Hornady 500 grain DGS - .458 dia.

Full length resized without crimping.

I shot twenty rounds in four five shot groups from the bench at 25 yds. This was mainly a function/performance test although the groups were nice and tight (3 inches high) given the handicap of iron sights and my diminished eyesight. The recoil was quite mild and the shooting experience pleasurable - I could have comfortably shot many more rounds during this range session. I single loaded cartridges directly into the chamber, over-riding two dummy rounds that I kept in the magazine in order to check uncrimped bullet set-back resulting from recoil. After the first five round string I removed and checked the dummy rounds -- they had both set-back in the cases approx 1/8". I think I will crimp future loadings in the bullet cannelure. The powder performed flawlessly -- extraction of fired cases was easy and they were in excellent condition. I fired three factory loaded cartridges offhand before I departed the range -- just to remind myself how brutal the .458 Lott recoil can be!

An aside:

I was already a fervant fan of Western Powders after using their "Blackhorn" powder for my inline muzzleloading (Thompson Center .50 caliber "Bone Collector") -- it revolutionized the sport for me -- no bore fouling (you can shoot numerous rounds without cleaning between shots), easy breech plug extraction, easy cleaning of the bore upon completion of shooting using regular cleaner such as Hoppes #9. After the performance of "Accurate 5744" I am an even greater fan of Western Powders.

James

[jamesicus]

I hand loaded some cartridges using the following prescription: Hodgdon IMR "Trail Boss" powder - 18.2 grains minimum load (70% of carefully measured 26 grains of case capacity using once fired factory brass and new factory bullet) - based on this Hodgdon (PDF) page

I shot the following groups from the bench at 50 yds this morning under very breezy conditions .....



..... bottom five shot group using 500 grain Hornady DGS bullets - top three shot group using 500 grain Hornady DGX bullets. This was a test of recoil effect (very light indeed) and grouping capability (no sight adjustment). CZ 550 American Safari Magnum rifle - .458 Lott caliber. Nikon "Buckmaster" 1x20 scope sight in Talley QD mounts.

James

[kraigwy]

Another vote for trail boss.

I have a 416 Rigby that kind of hurts with full loads. I tried reduse loads but ended up with inconsistant ignition because to too much empty space in the case,

Not so with Trail Boss, consistant ignition, extremely mild to shoot. And accurate at resonable ranges for a 400 grn slug going about 1360 FPS.

Also works in my 375 H&H.

[Hedning]

Its mentioned above aswell, but be carefull loading that thing with to little powder. That goes for all "long" cased calibers....You could mess your self up a bit... Iv seen a broken Brno 602, belive it or not. I have a Brno 602 375H&H myself. So I know that the lock is rock solid. The poor guy that cracked his gun got what we call a double ignition. Some of the powder was ignited by the primer. Then the rest of the powder ignited way to fast because of the initial powder blast. Dynamite....Doesent happen too often, but it happens.

[jamesicus]

Its mentioned above aswell, but be carefull loading that thing with to little powder. That goes for all "long" cased calibers....You could mess your self up a bit... Iv seen a broken Brno 602, belive it or not. I have a Brno 602 375H&H myself. So I know that the lock is rock solid. The poor guy that cracked his gun got what we call a double ignition. Some of the powder was ignited by the primer. Then the rest of the powder ignited way to fast because of the initial powder blast. Dynamite....Doesent happen too often, but it happens.

\
I called Hodgdon Powders (technical) this afternoon and queried them about this. They intimated that this phenomenon had not ucurred during their labratory testing of IMR "Trail Boss" utilized as reduced loads in large capacity rifle cartridge cases as prescribed on this Hodgdon (PDF) page

[Hedning]

What I mean by to little powder is when you go below starting loads for a specific powder. Some people think that going under the starting load is safe. Its NOT......

[jamesicus]

Short afternoon session at the range. Hand loads using 18.5 grains of Hodgdon IMR "Trail Boss" powder (minimum load plus .3 grains), Hornady twice fired brass, Hornady 500 grain DGS bullets, Remington 9 1/2M magnum rifle primers. CZ 550 American Safari Magnum rifle - .458 Lott caliber. Nikon "Buckmaster" 1x20 scope sight in Talley QD mounts/rings.

Shooting from the bench under calm conditions - 70 F temperature - bright sunshine - Caldwell rifle rest.


Three shot group at 50 yards (after two sighting-in shots).



Five shot group at 50 yards (sight adjustment verification).



Three shot group at 100 yards (3" POI drop from 50 yards).


I don't think the groups are too bad - considering my diminished eighty year old eyesight and accompanying trigger finger tremor.

I will shoot strings using this loading (and components) through the Chronograph this coming weekend

Caveat: My handloads work in my rifle. You may not achieve the same results in your rifle using the same load and components.
Always refer to the data published by Hodgdon relating to their IMR Trail Boss Reduced Loads For Rifle and Pistol

James

[jamesicus]

.......... Hand loads using 18.5 grains of Hodgdon IMR "Trail Boss" powder (minimum load plus .3 grains), Hornady twice fired brass, Hornady 500 grain DGS bullets, Remington 9 1/2M magnum rifle primers. CZ 550 American Safari Magnum rifle - .458 Lott caliber. Nikon "Buckmaster" 1x20 scope sight in Talley QD mounts/rings .......... I will shoot strings using this loading (and components) through the Chronograph this coming weekend.

Twenty shot string from the bench using a Caldwell rifle rest through a "Pro-Chrono" digital chronograph positioned 15ft in front of 25" barrel muzzle -- High velocity: 729fps, Low velocity: 691fps, Average velocity: 710fps.

Calm weather conditions, 75 F temperature - bright sunshine.

Clean, complete powder burn.

The components:


Hornady thrice fired brass (cleaned) - Hornady 500 grain DGS bullet -
18.5 grains of Hodgdon IMR "Trail Boss" powder (minimum load plus .3 grains) - completed cartridge

Note the bulky, "fluffy", "cheerio shaped", powder.

Caveat: My handloads work in my rifle. You may not achieve the same results in your rifle using the same load and components.
Always refer to the data published by Hodgdon relating to their IMR Trail Boss Reduced Loads For Rifle and Pistol prior to formulating your own handloads.

James

[jamesicus]

My own goal is to produce safe hand loads that are comfortable to shoot from the bench for prolonged periods; will produce consistent, reasonably accurate, target groups; serve as suitable close range light game hunting loads. The near minimum (Hodgdon data) loads I am presently using in my CZ 550 American Magnum Safari .458 Lott rifle fall short of the "light game hunting suitability" criterion. I want to achieve approximately 1000 fps muzzle velocity with 500 grain bullets which will produce 1100 foot lbs of muzzle energy. I will work slowly to that end.

Early morning Range session -- very light breezes -- ideal for chronograph usage.

Hand loads using Hodgdon IMR "Trail Boss" powder; Hornady five times fired brass; HSM 405 grain lubricated, cast bullets (.458 diameter); Remington 9 1/2M magnum rifle primers; CZ 550 American Safari Magnum rifle - .458 Lott caliber.

Shooting from the bench under calm conditions - 70 F temperature - bright sunshine - Caldwell rifle rest. Bullet velocity measured using a ProChrono chronograph positioned 12 feet from the rifle barrel muzzle.

I opted for 405 grain bullets for better ballistic balance and cost savings. I loaded four groups of five cartridges (using Hodgdon IMR Trail Boss powder data) in 2 grain increments from a near minimum of 19 grains to a near maximum of 25 grains (I never use maximum loads as a matter of principle). Bullets were seated to the crimping groove but were not crimped -- I believed the very light recoil produced by these loadings would not result in bullet set-back in the box magazine -- this proved to be the case as rounds were chambered via the magazine (flawlessly), two and three, without any set-back.

Below:

HSM 405 grain lubricated cast lead bullet (top)
Fired Hornady cartridge case (middle)
Hornady 500 grain DGS factory jacketed bullet (bottom)

Showing relative OL lengths of bullets, seating position in case and location of crimping grooves (seated to this index)



I used magnum rifle primers to insure optimum powder burn -- fired cases were clean with no evidence of unburnt powder granules. The 19 grain (near minimum) loading produced the best target groupings and the most consistent velocities:

1165 fps
1157 fps
1160 fps
1169 fps
1169 fps

1164 fps average - 1157 low/1169 high

This average velocity with 405 grain bullets equates to 1219 ft/lbs energy (at 12 feet from the rifle muzzle). The oft quoted minimum striking energy for taking white tail deer and other thin-skinned animals is 1000 ft/lbs -- therefor I believe this loading meets my requirement for a suitable close range light game hunting load.

Caveat: My handloads work in my rifle. You may not achieve the same results in your rifle using the same load and components.
Always refer to the data published by Hodgdon relating to their IMR Trail Boss Reduced Loads For Rifle and Pistol prior to formulating your own handloads.

James