Don,

I wonder if you would run 3 combinations through your modeling software sometime when you are free.

They are as follow:

1. 470 Capstick (case length 2.850, cartridge length 3.650) using 600 grain Barnes original RN (bullet length 1.435")

2. 470 Capstick using 400 grain Speer Flat Nose (0.900" bullet length)

3. 500 A-Square (case length 2.900, cartridge length 3.740) using 700 grain Barnes Original (1.475" bullet length)

Thanks!

500grains,

I need a case capacity on the Capstick (and preferably the 500 A-Square, but I have a default value for that in my data base), barrel lengths and desired working pressures in all cases.

Case capacity is measured in grains of water at overflow in a fired, unsized case. It can be measured as follows: Weigh the empty case. Hold the case under the thinnest stream of water you can get out of the faucet until it bulges over the top. Dry off the outside of the case with a paper towel. Weigh the case plus water and subtract off the case.

If you have the known velocity for any loads in your rifles, give them to me so I can try to tweak the model to match. Again, these big almost straight-wall cases are not what QuickLoad is best at.

Don

500grains,

You do know how to get people's expectations up!

I thought you were asking our friend Don to actually "model" for you. Like we got old Walter to do in Africa to intice an old cantankarous hippo out of the water.

By the way, it diod not work, the hippo even refused to show his eyes out of the water, just the tips of his nose to breath.

------------------
saeed@ emirates.net.ae

www.accuratereloading.com

At least Walter had the decency to wear a fright mask. No self respecting man would show his own face in an outfit like that!

Don

Saeed,
I must confess that I thought the same thing when I read the topic. The corrupting influences of the thread from hell must be spilling over onto other forums. I think there is one sick puppy out there, and even this mention pays to much attention to the nameless one.

Walter is not a really ugly fellow, but it makes me nauseous to look at him in a skirt and bra. Got to go vomit now.

------------------
Good huntin' and shootin',
RAB

Saeed,
Kindly shoot Walter!!

------------------
Ray Atkinson

ray@atkinsonhunting.com
atkinsonhunting.com

Ray,

We came very close to shooting Walter one day. And I can tell you, he was NOT amused at all at our attempt.

A mutual friend turned up here with a bullet proof vest. It is one of those you put on with velcro.

We were trying to see how the parts fit together, and of course Walter, our local genius, said he would show us how.

He assembled everything, and put the vest on. I told my friend in Arabic - which Walter does not understand - that he should get behind Walter and hold his hands behind his back, and I will attempt to shoot a pistol at his vest.

My friend got behind Walter and grabbed him, I got a Browning P35 9mm pistol, and was in the process of loading it.

Walter went berserk! He was swearing and threatning us both with all sorts of nasty things. I was laughing so much I don't think I would have been able to hit him.

We told him to quiten down, as we were worried I might miss the parts of his body which was coverd by the vest.

He went into overdrive!

Eventually we told him it was all a joke. He said he did not much care for our kind of jokes!

------------------
saeed@ emirates.net.ae

www.accuratereloading.com

Don,

I will check case capacity tonight and let you know.

Don G.,

Here is the data I have:

1. 470 capstick
case capacity: 115.2 grains of water.
sample load: 600 grain bullet ahead of 80.0 grains of Reloader 7 gives 1990 fps.

My barrel is 25 inches with muzzle brake, 23 inches without.

The Max Avg CUP for the 470 is 53,701, and Max Ind CUP is 61,756.

The Max Avg PSI for the 470 is 62,409 and Max Ind PSI is 71,770.

2. 500 A-Square
case capacity: 166.5 grains of water
sample load: 600 grain bullet ahead of 117.0 grains of IMR4064 yields 2503 fps at 61,300 psi in a 26 inch barrel.

I want to shoot a 700 grain bullet from a barrel that is 27 inches including muzzle brake, or 25 inches without muzzle brake.

Thanks!

Saeed,
Thats a riot, actually a one man riot!!!

------------------
Ray Atkinson

ray@atkinsonhunting.com
atkinsonhunting.com

Oh yeah Don, I forgot to say that I am hoping to get 2100 fps out of a 600 grainer in the 470 capstick, and 2150 or 2200 fps out of the 700 grainer in the 500 A-Square. Let's see what the model says.

____

Saeed and Ray,

I would be sorry to have inadvertently started a cross dressing thread, but you guys are having too much fun!

500grains,

The subject of this post is the 470 Capstick, 600 gr Barnes, 24 inch barrel. QL recommends 54608 PSI max load design pressure for your 62409 avg peak pressure, so that's what I used. It is the only note of conservatism in this discussion!

I have to twist the model so badly to get a match to your RL-7 data that I am afraid it is even more of a fairy tale than normal.

I used 24 inches as the effective barrel length, that's not much of a stretch.

I assume that you must have quite a bit of freebore in your rifle. Usually this means the primer can squirt the bullet and powder out of the case at very low pressure and the "effective case volume" is somewhere out past where the lands start (because the bullet had such a long jump and is so heavy the engraving force is not important.)

Do you have data off another powder? It might help me get over my fear factor.

I ran into the same thing in the Lott case working with Paul H. It really makes me want to not publish the data at all for fear of being so far off reality that starting 10% down is not enough and starting 20% down might be too much for safety.

Here's what I find: QL's stated method to handle the straightwall cases is to bump up the case capacity to fictitious levels. "usually 5-7%". To match your sample data I had to increase the functional case capacity to 157 grains (that's 37% above your measured 115!!). The problem is that this fictional case capacity is so twisted that I'm afraid we're out in left field somewhere.

[It seems that any appreciable shoulder is enough to make the 5-7% rule work OK in QL, my .416Rem being a good example.]

FWIW, this twisted model says that a 5% compressed caseful of H322 (93 grains)should get you 2080 fps with the 600 grain Barnes. The predicted pressure is only 48000 PSI using the twisted case size. I have no confidence in this answer, but I observe that if you started at 75 grains of this powder and worked up in 5 grain increments to 85, then two grain steps after that, the case would never be less than 85% full, and the starting pressure even using the 115 grain case capacity is only 55,000 PSI.

IMHO, this case is 'way too small for this bullet, so all these fiddly games are necessary, and if, for some reason, the bullet stuck in the case neck the peak pressure for 93 gr. H335 would hit 112,000 PSI!

(Note that's about the same as for your load of 80 grains RL-7 if the bullet stuck in the case neck. According to the model you are within 1.5 grains of the recommended max load of RL-7 for the fictional case size.)

My recommendation would be to be VERY careful when working up the loads. After you've worked one up, do not suddenly decide to crimp the case (or even stop crimping), change primer or powder lot or vendor, or add or remove moly, etc. Start over for every different bullet style. All the usual precautions are redoubled because you are building a bomb! If someone used your load (that expects a long freebore?) in a rifle with no freebore he could exceed the design pressure of both action and barrel.

I'm tired and scared right now, so I'm going to go have a beer!

Don

Don,

I will check the data for the 470 again tonight. I have not shot 600 grain loads yet. The data I have is from the Harvey manual and a Handloader 1991 article.

Don,

This is the data I confirmed for the 470 capstick:

1. case capacity: 113.2 - 115.2 grains of water
2. 600 Barnes original bullet: 1.435" length
3. case length after trim: 2.825"
4. ctg. OAL: 3.650

Sample Data:

a. 80.0 grains IMR 4230 behind 600 grain Ballard Built RNSP bullet gives 1985 fps (3.58" OAL). This load is from a G. Sitton article in Handloader magazine from Mar-Apr. 1992
b. 80.0 grains Re7 behind a 600 grain bullet (brand not mentioned) gives 1990 fps. Nick Harvey loading manual.
c. 76.0 IMR 4320 behind 600 grain bullet gives 1880 fps. Nick Harvey loading manual.

I have not yet shot a 600 grain bullet in my particular rifle. I do not know if I have a long throat or not. The rifle was deep chambered by Pac-Nor and headspaced by my gunsmith.

Sounds like a job for the 470 Mbogo after all.

------------------
Good huntin' and shootin',
RAB

500grains,

I will run the examples against the model tonight.

Did you mean IMR4320 for both loads? I never heard of IMR4230.

Don

500grains,

The IMR4320 loads (I assumed both were IMR4320) agree very closely if I twist the case capacity to 128.5 grains. I then predict (using the Barnes RN) 1891 and 1975 fps for 76 nd 80 grains respectively.

An important characteristic of this load is that even if I drop back to the 115 gr. capacity (i.e high bullet retention forces), the max pressure hits 61113 PSI -- it does not exceed the max design pressure.

I think the IMR4320 is about 100 times safer than the RL-7 load (or the H322 load) for this situation.

Don

Don,

Thanks. It is weird that the case capacity does not match up.

What do you think about 700 grains in a 500 A2? I wonder if I am going to run into the same case capacity problem.

A word of warning about Nick Harvey's manual
the load data for the 416 Weatherby seems to be wrong for the ADI powders. So I would want to cross check any load data in his manual with another manual before using it.

500grains,

The case capacity issue is really with QuickLoad's model only. The cartridge "is what is, and does what it does". I suspect that there is a different "effective case size" for every different powder and bullet. This drastically limits the value of QuickLoad for these straight-wall cases. It can predict pressures only after the effective volume is found by actual testing. Thus somebody sometime has to buy the powders and do the testing to get started. In the bottleneck cases QL does a very good job of prediction -that's because the pressures and velocities are largely determined by the case rather than by bullet retention and engraving forces.

What I'm pointing out with the IMR4320 is that it has a much safer failure mode than the RL-7 load in the Capstick.

On the A-Square case, my data base says that the actual case capacity is 143 grains of water. Can you double check your number? I've never had a need to check it before.

I match your example load of 117 gr of IMR4064 in a 26 inch barrelled 500 A-Square if I use and effective volume of 151 grains - well within QL guidelines. The pressure required in the model to get the bullet to 2503 fps in a 26 inch barrel is 70,000 PSI. That is about where good modern brass starts to show ejector marks, and is 7000 PSI above design pressure. A-Square had a reputation for publishing loads like that. Barnes in COW (not known for conservative loading practices) shows 104 gr of IMR4064 yielding 2280 fps for a 600 soft. My model predicts 2270 fps at a safe and sane 50,000 PSI using that load, so I'm fairly sure I have the model right.

I match COW's 500 A-Square load of 114.5 grains of IMR4895 at 2460 fps with a 156 grain effective volume and 60,000 PSI for the 600 grain RN.

I match COW's 500 A-Square load of 116.5 grains of IMR4320 at 2475 fps with a 150 grain effective volume and 64,000 PSI for the 600 grain RN.

I match COW's 500 A-Square load of 124 grains of IMR4350 at 2450 fps with a 150 grain effective volume and 57,000 PSI for the 600 grain RN.

It sure looks to me like the IMR4350 is a better bet for the 600 grain bullet in the 500 A-Square.

I get a 500 A-Square load of 102 grains of IMR4064 at 2170 fps with a 151 grain effective volume and 57,000 PSI for the 700 gr. RN.

I get a 500 A-Square load of 105 grains of IMR4895 at 2224 fps with a 156 grain effective volume and 57,000 PSI for the 700 gr. RN.

I get a 500 A-Square load of 104 grains of IMR4320 at 2184 fps with a 150 grain effective volume and 57,000 PSI for the 700 gr. RN.

I get 500 A-Square load of 115 grains of IMR4350 at 2250 fps with a 150 grain effective volume and 57,000 PSI for the 700 gr. RN.

It sure looks to me like the IMR4350 is a better bet for the 700 grain load in the 500 A-Square, because you get the best velocity and the lowest pressure in the event of high retention forces.

Note that QL does a much better job of modeling the 500 A-Square than the 470 Capstick. That shoulder isn't much, but it shows why shoulders were invented in the first place - performance is much more consistent in the face of varying throats and loading practices.

Don

500grains,

After reviewing this data, I would limit the 470 Capstick to 480 grain Woodleigh bullets or lighter. These would not have the desirable very high SDs for buffalo at odd angles - but it is a respectable .304 -and velocity would be enough to get good soft point performance on heavy but thin-skinned game. IMHO the case size is below marginal for the caliber. I'd like to get 2400 fps with a SD above .33 for buffalo. I suspect this is a very "real" brown or polar bear stopping rifle, but I'd much rather have a Lott (with better SD at 2400 fps) on buffalo.

The A-Square is a "real" buffalo and elephant stopper by all the criteria commonly used on this board. SD .334 and velocity 2450 is potent medicine. Too potent for me to shoot though, at 600 grains! I'm about at my recoil limit with the 416. Unless I improve with use (and I'm over 700 rounds now), I wouldn't be able to handle the Lott day in and day out, much less this monster!

I do think you'll be better served by the 600 grain bullet at 2450 in the 500 A-Square, than by the 700, but that's based solely on advice absorbed on this board - no personal experience above 500 grains at 2400 fps.

Don

Don G,
Your analysis is excellent. The 500 A-Square is the ultimate in my mind, and on my shoulder. Maybe I don't need that 585 Nyati after all?

The 470 Mbogo is my alternate new pick. It is the biggest thing you can do with the Rigby case, and it can do at low pressure what the Capstick strains to do. Other cartridges may be more versatile, but if you want a stopping rifle that is more easily controlled in recoil and may be built a little lighter than the 500 A-Square for ease of carry, then it is the 470 Mbogo, a .475/.416 Rigby Improved.

If GS Custom could come up with the proper HV and FN combo for a 14 twist barrel, the 470 Mbogo might give the versatility bit a good go too. A 380 grain HV at 2700 fps (hypothetical) and a 500 grain FN at 2500 fps at low pressures?

Then one could also do something with the 600 grain .475 lead core bullets.

Plenty of whack, whomp, and whump is predicted.

------------------
Good huntin' and shootin',
RAB

Don,

Many thanks!!!

When I was a university student, I wrote some econometric modeling software. The model worked for numbers within the 'normal' range, but for radical or fringe numbers, the model gave weird and unpredictable results. I wonder if the Capstick with heavy bullets is a fringe case.

I am also surprised that the Capstick appears to have difficulty reaching Lott velocity levels even though the Capstick has greater case capacity and shorter bullets. Perhaps the slight taper of the Lott case is useful. If a shoulder is useful, then a 500 Ackley would be the best .458 belted caliber.

I think the Lott is a marginal case. (But not below marginal.)

The Lott struggles to get 2400 fps with 500 grains, just as the 470 does.

The advantage of the Lott over the 470 Capstick is that the SD is better when bullet weight is 500 grains.

Don

RAB,
you don't need a 585? Someone who shoots Mitches' 577 that well is born to own a 585

Don G,
Thanks for your data on the other thread. Actually it appears my case is about 200 gs on average.
Don't suppose you could tell me which powder will get the most out of it and what speed for the 750gn woodleighs in this case from 25" barrel?

Karl.

P.S
Will get to the range this weekend hopefully and test some medium loads of AR2209 for starters until I can get some of the powders Mitch recommended-vihtavuori(difficult to get here)

regards,
Karl.

Dang it Karl! Didn't you see the question mark after that line. Of course I will have a 585 Nyati. The 470 Mbogo and 450 Vincent Long will have to wait. I am going to quit playing the politician and kissing up to other people's ideas. I am just going to follow my heart.

585 Nyati or bust!!!

As soon as Kevin Jenkins gets through with the 470 Capstick he is starting on the Nyati.

PS: I am supposed to meet Mitch at the range tomorrow for my third session of shock therapy with the T. rex. This should surely straighten out my noggin. I am so excited I won't be able to sleep tonight! Like a kid on X-mas eve!
------------------
Good huntin' and shootin',
RAB

[This message has been edited by R. A. Berry (edited 06-30-2001).]

Karl,

I answered your question on the original thread. Good luck this weekend.

Don