Help with .458 loading

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  • Last Post 09 January 2014
GBertolet posted this 21 October 2013

I recently aquired a Ruger 77 in 458 in a trade. I have had good results with my light load, consisting of a RCBS 300 gr GC bullet, sized to .459, which actually weighs 325 gr, lubed w/gas check, alox lube, with 35 gr 4759, acheiving 1640 fps. 3 shot groups under an inch are common at 100 yards. Recoil is of 45-70 level. This is intended to be my main load.

I deceided to move up to a Big Boy load, to see if I could get it to shoot. I wanted a factory duplication load in my data book if I ever needed one. I purchased a Lee 500 gr RNFP mold. Alloy used was 50% linotype and 50% WW. Final weight lubed w/gas check was 487 gr. Also lubed with alox and sized to .459.

For my first loading, I got the starting load from the Lyman manual for their 500 gr jacketed bullet. 60 gr Reloader 7 was what I selected. I shot at 50 yards, 2051 fps for a 5 shot average. According to the Lyman manual the velocity was not supposed to be that fast, more like 1700 fps. Quite a velocity difference between cast and jacketed with the same powder charge. Any how, all shots keyholed, giving a 15 inch group at 50 yards.

My theory on this event is, that Reloader 7 was too fast, creating too high of pressure. Even though the loading was safe, pressure wise, and within limits for the firearm, it still caused the alloy to fail. The bullet alloy was quite hard and should have easily withstood the 2051 fps, but obviously it didn't. A slower burning powder might give better results. Does anyone have any experience with full power loads with cast bullets in this caliber?

I must add also, that firing this rifle with these loads from the bench really gets your attention. I used a PAST magnum shoulder pad, which really made things tolerable. One time at the range, I met a fellow who had a .416 that he was zeroing for a trip to Africa. He was using a portable table, with screw on pipe legs 5 feet high, that he made. He could then shoot standing up, which was much more tolerable than sitting. Seems like a good idea.

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bushranch posted this 21 October 2013

I have a Ruger Number 1 Tropical in .458 & like most I had to try the 500 grain full cast load ONCE off the bench. Cast bullet enjoyment came when I began to consider it a 45-90 belted and I now use 45-90 loads with bullets around 400 grains. 13 grains of Unique has been a good starter.

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Brodie posted this 21 October 2013

GBertolet, I agree with you about powder speed, but I would slug the barrel if you have not already done so; .460 is a much more common diameter in my experience.  I used to use IMR3031 and had good success with it 4198 just kicked too fast for my taste, and I think that 4895 would probably be even better the burning rate being somewhat slower.  Brodie

B.E.Brickey

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Little Debbie posted this 21 October 2013

I'm not sure that pressure made your alloy fail; half WW/Linotype is plenty hard, maybe too hard. 100% key holing makes me believe your bullets may be too small /hard to seal the bore. I shoot the RCBS 500 grain FP gas checked bullet at right around 2,000 fps using 4198. My alloy is pretty soft, it's is the reclaimed lead from my bullet trap. A little Linotype, a lot of wheel weight, and a fair amount of .22 RF. It's fairly easy to scratch the bullets with a finger nail. I size my bullets to .459 using Ben's Red lube. I get 1 inch groups at 50 yards, but from the bench it's rough! My rifle is a M70 and I've never slugged the bore because the .459 bullets work great. You might need to slug yours, a friend had a Ruger 77 .458 years ago that never shot my cast bullets well, (nothing like 100%keyholing) but we never determined why. Remington 405 gr bullets were so cheap back then he just stuck with them. I'd try slugging or a softer bullet and see what happens, are you getting leading?

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onondaga posted this 22 October 2013

http://www.castbulletassoc.org/view_user.php?id=1738>GBertolet

Tumbling bullets at any load level has specific reasons.  Your alloy may be so hard that it makes obduration impossible and the bullets won't seal. I sized my bullets .460” for a while but honed the Lee bullet sizing to .461 and I'm shooting better with my .458 Win Mag Colt Sauer Grand African. My RD bullet mold drops at .462” with #2 alloy.

Have you checked your “as cast"bullet diameter"? If they are under the bullet sizing die diameter you have accentuated a gas jetting situation with the gas check sized diameter being larger than your bullets causing an instability down the bore that promotes gas jetting.

How loose are your .459” bullets in the chamber throat? Do a chamber casting and match your bullet size to that with bullets that have a slide fit when chambering loaded rounds. These little things if unaccounted for magnify problems with higher load levels and cause gas jetting and tumbling bullets.

If these bullets are for game, even Polar Bears. The harder alloy you are using destroys any expansion compared to Lyman #2 alloy that expands well will handle the load level with gas checked bullets that really fit the chamber throat.

50% Linotype and 50% pure lead gets BHN 15 like #2 alloy, if your wheel-weight is stick-on WW alloy, that is very close to pure lead,  but if your WW is clip-on alloy it's likely muck harder and adding to your problem with .459” bullets that are small for your caliber already.

The velocity difference when using jacketed bullet data with cast bullets you have gotten in normal. Cast bullets shoot faster than jacketed bullets with the same charge due to cast bullets having much lower friction in the bore and your situation with undersize cast bullets magnifies the result of increased velocity even more.

I'd also recommend  4895 over Rel7 it has a smoother pressure curve that cast bullets like better for a softer start instead of the punch from Rel7. Also, 4895 loading will match much better to your bullet strength than Rel7 for the same velocity due to characteristics of 4895.

My 350 gr FNGC and 57.7 gr H4895 clocks 1700 fps , That is the load I use for New York Black Bear in .458 WM. It has over 1500 foot pounds left at 200 yards.  That is clean kill energy for bear at 200 yards, I don't need any more and my shots are always shorter than 120 yards.

I don't crank it up higher even when I go to Alaska as the load is for close range bear protection when bow hunting and will flatten anything on the planet at close range.

Gary

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onondaga posted this 22 October 2013

http://www.castbulletassoc.org/view_user.php?id=1738>GBertolet

Look at this rifle position for bench shooting. This is not my .458 but this is the same setup I use with the .458.

Note that the rifle is high and far back on the bench. I can sit up straight on the chair, not leaning into the rifle and my body goes back with recoil as well as standing offhand shooting. This significantly reduces felt recoil with rifles that thump hard.

I use the Past magnum vest also and can easily sit up straight and shoot 50 rounds full power .458 WM rounds with this setup.

Gary http://s30.photobucket.com/user/rhymeswithwhat/media/AtBench.jpg.html>

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GBertolet posted this 22 October 2013

Onondaga, my Lee mold drops at .4595 to .460., which I was pleasantly suprised about, It is the new style mold design, and my wheel weights are of the clip on type. I will try to slug the barrel, but I don't think the diameter is the issue, as my RCBS mold bullets, cast from the same alloy and sized to the same diameter work just fine. I originally used this alloy to insure a large as cast diameter. I think my next step will be trying some loads with 3031, H4895 and 748 and see what happens then, and take it from there. Thank you all for your responses.

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grouch posted this 22 October 2013

I hesitate to offer advise on .458, but based on 45-70 experience, it could well be worth your time to try working up a load with 18 or 20:1 alloy. It shoots better in several of my rifles, and I can approach 2000fps in a 1:12 twist 30 30 with that alloy. Grouch

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GBertolet posted this 22 October 2013

I tested a few more loads this morning before the rain came. 68 gr H4895 with the 500 gr Lee = 2070 fps. Accuracy was wild, but no keyholing though. My next load was 68 gr of 748 = 1850 fps. I got a 2 inch group at 50 yards. Some promise here, so I am upping the load to 70 gr, and see what the result is. I picked this powder to try as according to Winchester data, the pressures are much lower at full power levels. I took onondaga's advise and raised my rest higher, and it was much more comfortable to shoot these loads. Still have 3031, Varget, and 4320 on hand to try.

I finally slugged my barrel, and was astounded that my bore is .4595. My .459 sizer does .4592 on my bullets. I think there is no problem with obturation, as I have no signs of any leading whatsoever. It has been suggested to soften my alloy, and I will have to see how much smaller the bullets will drop from the mold. Lapping the mold and the sizer die are also possibilities if ultimately necessiary.

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onondaga posted this 22 October 2013

http://www.castbulletassoc.org/view_user.php?id=1738>GBertolet

The bore of my .458 slugs at .4570” as checked 4 times. Yours slugs very much bigger at .4595” and you are using smaller bullets. Add this up... with your accuracy and occasional keyholing of bullets. Your bullets are way too small.

If you can get a larger bullet sizing die or hone yours out to drop bullets at .461” your accuracy will climb significantly. You should likely have to back out your FL sizing die about 1/4 inch to accommodate for seating of the larger diameter bullets as I have to do to avoid bulging brass or shaving bullets when seating them.

My pure lead round ball slug from testing my .458 WM Colt Sauer Grand African:

http://s30.photobucket.com/user/rhymeswithwhat/media/slug.jpg.html>

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onondaga posted this 23 October 2013

http://www.castbulletassoc.org/view_user.php?id=1738>GBertolet

For your Lee mold that drops .460", I'd just hone your bullet sizing die so bullets size at .460” then size, seat the checks, lube, load and shoot. If you are going to hone the casting mold larger then you can hone the bullet sizing die even larger to .461". I doubt you will have to go past that size.

Here is my very unsophisticated setup for honing out the Lee Lube and Size  push through bullet sizing dies. This is my .457” die that I honed out to .461” using a slotted wooden dowel, a 300 grit strip of emery cloth and some light oil with my variable speed electric hand drill.

I use the slowest speed on my drill and pass the snug fitting abrasive through slowly about one pass every 5 seconds. After 20 passes I check by cleaning the die then  sizing a bullet and measuring it till I get what I want.

Finish up with a couple passes at highest speed to polish up the inside die surface.

It ain't that hard to do! Gary http://s30.photobucket.com/user/rhymeswithwhat/media/PA230041_zps049d7528.jpg.html>

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GBertolet posted this 23 October 2013

Thanks onondaga, I just honed out my Lyman .459 sizer to .460 today. I used a similar system to do it. I put the die in the headstock of my lathe and had the slotted stick with 320 grit emery held in a pair of vicegrips. Turned out good. I slugged my Ruger again today, verified again @ .4595, so I am on the right track to success.

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Ken Campbell Iowa posted this 24 October 2013

up to a couple years ago. my model of achieving better accuracy was ” everything happens in the first 2 inches ” ... this mostly from shooting benchrest rimfire ... in general any of the top names in match barrels shot about the same ( 1/2 moa with top ammo ) ... but there was a noticeable difference from chambering configuration .. my best results came from chambering so tight that i had to shoot the cartridge or i might not be able to extract same. ( rem.40x action ) . i used a seperate 1/2 degree throater and the front of the case was tight in the throat. i thought safe because 22 rf is a heeled bullet.

so now my model is ” everything happens in less than an inch ” ...

so, in way ( long way ? ( g ) ) of collecting data points, i would like to know the diameter of your bullet seat ...chamber throat ... . this is being more and more suggested here as a big factor in acceptable accuracy; i am hopeful that we can make a list of top ten things shooters can check off to achieve acceptable accuracy.

in fact, it could be that if the bullet fits the throat well, the list may only be 3 or 4 other things !!

just some thoughts .. ken

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RDUPRAZ posted this 24 October 2013

Ken:

Interesting, Need to hear more. Sounds like a good topic for a separate thread.

RD

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onondaga posted this 24 October 2013

http://www.castbulletassoc.org/view_user.php?id=7735>RDUPRAZ and http://www.castbulletassoc.org/view_user.php?id=40>Ken Campbell, Iowa

"everything happens in less than an inch"

My effort at bullet fit is the sliding fit of  the bullet that can be felt when the round is being chambered. When I get that with bullet fit, any reasonable load groups less than 1 inch at 50 yards in all of my rifles. I believe many cast bullet shooters and experimenters miss the mark when they assign an amount of thousandths of an inch related to bore diameter or groove to groove  bore diameter. Sliding fit of the bullet in the chamber throat and contact with the taper of the lead to the rifling (ball seat) does the accuracy thing for my rifles.

The .461” bullet does that in my .458 WM.

Gary

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argie1891 posted this 09 January 2014

If you are using lee alox tumbling the bullets why size at all??? try shooting as cast and you might be surprised how well your rifle shoots. I have for many years sized my 30 caliber bullets through a .314 die I am actually not sizing but using the die to lube the bullets. I am convinced that in any rifle that the bolt can be closed easily on an unsized bullet shoots better without sizing. argie1891

if you think you have it figured out then you just dont understand

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onondaga posted this 09 January 2014

http://www.castbulletassoc.org/view_user.php?id=896>argie1891

I can shoot them unsized and just lubed too. That will cause some of my bullets to be pulled a little upon unchambering rounds in some of my calibers too. Most of my bullets are gas checked too and the checks are installed with the Lee push through dies..

Additionally a couple of molds of mine are big enough for 7.62X39 but are really too difficult to chamber for .308 unless sized.

Universaally not sizing tumble lube bullets doesn't work for me. I don't use soft lead either. I use either certified Lyman #2 or a clone I mix that is also BHN15. These are not soft at all and will be a lot harder to load/ unload than Wheelweight alloy.

Bullet roundness is important to me too. I have over 50 bullet molds. Zero of them cast as round as sized bullets are round and roundness does improve accuracy when the bullets fit. Roundness also keeps neck tension even when seating bullets. That aids in accuracy too.

Sizing for me is definitely an accuracy thing for me. It does show on my groups reliably, time and again.

I have tried sizing with my .3125” die that I use for 7.62X39 for my .308 Win bullets, sort of like you do with your .314. This causes an annoying problem for me. The gas checks expand the case necks seating bullets and leave the bullets loose in the neck. That poor fit then causes gas checks to separate from bullets when firing and the bullets fly fine but the gas checks hit my chronograph and dent it. I don't do that anymore. That will give me the same failure repeatedly with my rifles.

Gary

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argie1891 posted this 09 January 2014

I forgot to mention that if the gas check is bigger than the bullet seating below the neck just wont work. the bullet will drop into the case as there will be no neck tension.

if you think you have it figured out then you just dont understand

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