I recieved some sample cases from Quality Cartridge and Pete sent some Headstamped 500 A square along. I was alittle surprised at the difference.





RNS

Neal--As I say, the straight and belted is the absolute best use of Weatherby 460 based brass. And the basic case
after the draw and before trimming, in the manufacturing process, is probably
longer yet if say a 3.2 in case was wanted.Ed.

It would be great if one of the gunmakers could be convinced to offer the 550 mag as a standard production offering. It is truly a fine cartridge design, along with the 600 OK, but not needing a 0.750" bolt.

RNS - what are the anticipated velocities of various bullets in the 550? Is it to be called the 550 magnum (I kinda liked the name "550 Ivory Express") - what is the expected total rifle weight? Good shooting - KMule

Kmule-Yes it is called 550 Magnum, Headstamped on
brass Neal has got them delivering. As for power 600 gr 2550 plus fps.
700 gr 2400 plus fps.Ed.

Ed,



Those velocities look a bit optimistic to me. I would believe that these are more realistic:



700 grain bullet - 2260 fps (63000+ psi)

600 grain bullet - 2530 fps (63000+ psi)



Thinking IMR 3031 would be best, followed by IMR4895.

Regardless, it should be a VERY effective hunting cartridge.



Scott

I figured with dense ball powders and my formula.I personally don't use either of those as the faster pressure spike would stretch cases.It is easy to run higher velocities with ball and cases last 3 times as long.Ed.

Ed,
I am going to have to look at this in a shorter case... this is an awesome round, man

as usual, i would expect that matching or beating a NE round would be sufficent.. since there's not one, the 577 ne would be the closest.. and it's 750 at 2150.... if you have that, you'll have a higher SD .. and more velocity is just gravy

but, then again, remember that a certain "member" can get 78kpsi in a lever gun

jeffe

500grains
I have been talking to Karl At Rifle Actions and they are interested in offering the 550 MAgnum in their line of rifles. I think that would be great

Jeffeosso

458 lott,458 win mag 500gr, 550 Mag 2.5" 800gr, 550 Mag 2.920" case
Here is a shorter case 2.5" lemght same as the win mag. The bullet is a 800gr alittle heavy I will post another pic with a lighter bullet.

RNS

Ed I would agree velocities would be 2400fps plus with the 700grainer, since the 500A2 can go over 2300fps with same bullet weight.



Jeffe, staying near a nitro round always is always a strong argument.And the 550 is closest to 577 as you said.



I see it more as a large 50 gibbs/jeffery myself(higher speeds) for some reason...that's just pure preference of course.





Karl.

It was mentioned somewhere that the 550mag was listed as a sporting cartrige. Where could I go to find that published list to see what is on it?

TIA

hmmm,
a 650gr would be sd of .307 ish...
a 700 .. .331ish
a 750 .. .354..

a 577 750
.313

so, a 675 grain at 2200 would be just about perfect...

call it the 550 hippo
jeffe

Karl,

Have you ever owned a 500 A Square? Obviously not since there is NO WAY you would get a 700 gr bullet over 2300 fps out of one! Do you have any idea what the powder energy levels would have to be in the available powder space of the 500 A Square to achieve such ballistics? No, that is just as I thought. Would love to see your 585 rifle, not just the dummy cartridge, but the actual rifle. I have posted pics of many of my rifles, not seen yours though, only your incessant BS. Oh yeah, have a nice day.

Ed,

I base my calculations off of actual data gathered over the years from actual load development and data acquisition. I could be wrong but I doubt I am off by 150 fps. Now if you were publishing a reload manual, or ammunition catelog, then I would agree with your velocities.

Ball powders aren't any better either. In fact, they seem to be a little less stable, prone to compacting, and provide lower energy per unit mass than most extruded powders in any particular ball powder's burn class. The compaction/instability issue, is particularly true when heavily compressed. Of course they are the cat's meow when it comes to metering. Thus they are very production line friendly. Just my own opinions based upon my actual experience.

Scott

Scotts

http://www.accuratereloading.com/500as.html

The following data was developed by my friend Mitch Carter, in a custom rifle built on a Weatherby Mk V action. It originally was a 460 Weatherby. This rifle had a 26" McGowan barrel, with a 1 in 12 twist, and a muzzle brake was also installed by McGowan. Mitch noted that this rifle is more accurate with the 700 grain bullets than the 600, which might be due to the fast twist barrel. The 500 A-Square is a necked up and improved 460 Weatherby. 460 Weatherby brass was used, and the Federal 215 primers.



POWDER VELOCITY BULLET
124.5 REL 19 2314 BARNES 700 SP
125.5 2338
126.5 2378
128.5 2409

124.0 IMR 4350 2350 BARNES 600 SP
127.0 2448
128.0 2473
130.0 2507
132.0 2539
134.0 2571
136.0 2604

115.0 REL 15 2416
116.0 2437

126.0 VVN 560 2317 BARNES 700 SP

A-SQUARE FACTORY LOAD
2346 600 LION LOAD

My point here is it can be done or ScottS needs to tell Mitch he does not know what he is doing. If the 500A2 can get these figures the 550 can and at a lower pressure.

RNS

Scott, it sounds like the little unanswered posts I have been making to you have been taking their toll.



Jolly good! (I was afraid you were ignoring me)



You may return to your trolling until I require you again.



RNS,

I said on another thread to Mike375 I think this calibre will see higher power use (OVER 9000ftlbs) than the 585's and 600's in average use. Due to the usual brass choices and most importatly bullet weights of the latter two.



Karl.

RNS,
PM sent

jeffe

RNS,

Lets just say that data is unique, and leave it at that shall we.

Scott