I was looking over the loading data and found the 500 ASquare data. Obviously someone has managed to get 136 grains of IMR 4350 into their cases.

I can only manage to get 133 grains into my cases and this leaves them piled over the top of the case mouth. I cannot seat a bullet with the 133 grain charge let alone a 136 grain charge.

So all I want to know is HOW! How do you get more powder into the case than will fit? I really would like to get those kinda velocities with the 600 grain solids.

Nik

[QUOTE]Originally posted by Nik A:
Hi Nik,
I don't know what you use now to get your powder into the case or what the actual volume is with IMR 4350 but a long drop tube will help if your not using one already. If you are an archer or have a friend that is just get an old aluminum arrow shaft and use it. Somewhere around 28 to 30 inches will work well.

470 Mbogo

Nick, That is my loading data for the 500 A-Sq. I used a long drop tube, plus the cases were only neck sized so that by itself gave me a bit more case capacity. Those loads were worked up in my rifle that had an extra long throat (.800) at the time, the standard throat is only .375 if memory serves. I also used extra long seating depths something like 3.805 or 3.815 this allows you to attain more velocity safely by giving you more case capacity to work with. However if your rifle has a standard throat you may not be able to seat your bullets out as far as I did. Because you might not be able to chamber the round because the standard throat won't allow it.I would not attempt to achieve the velocitys I did using normal seating depths or a rifle with a standard lenth throat.

[ 05-26-2002, 16:40: Message edited by: Mitch ]

Thanks for the information Mitch. The cases I was loading were neck sized only. I will try a drop tube and see what happens. With regard to seating the bullets way out there I personally think that is an old wives tale. I have tried it both ways and as long as I did not place the bullet directly on the riflings the seemed to be no descernible pressure difference.

Nik

Nick, I have found just the opposite to be true, it depends on how far you seat the bullets out.If you only seat the bullet out a little say less than(.050) there won't be much of a difference. For example if the standard seating depth for a particular load is 3.700 and you seat the bullet out to 3.815 (if the throat allows) the velocity will be lower. Because with the bullet seated you will have more internal case capacity. So pressures will be lower provided your throat is long enough to allow the bullet to get a good running start before enaging the rifling. This practice works extremely in Weatherby rifles. Because their long throats allow you to seat the bullets way out and the bullet will still have a good long run before it engages the rifling.

[ 05-26-2002, 17:01: Message edited by: Mitch ]

Mitch I have found that the opposite of your statements seem to be true. There seems to be some logic that supports my claim. I believe that if you have alot of free bore you are better off from a pressure stand point seating your bullets in the SAAMI spec position. The reason is that when the bullet engages the rifling it will be travelling much faster than if you seated the bullet only 0.030" off the rifling. I believe you will agree with me that your maximum load will be reduced due to pressure if you seat your bullets so they are contacting the rifling.

I agree with you that seating the bullets out increases the case internal volume and that in and by itself would reduce the operating pressure. It is a relatively linear relationship so in reality you will have a small pressure drop associated with the small volume increase that the reduced seating depth allows. I just believe that this small pressure drop is negated by the increased pressure when the bullet contacts the rifling at a relatively low velocity as compared to SAAMI spec seating depth and long throat.

How long of a drop tube did you use? I have a 30 inch tube and I can only get about 134 grains in my cases. 134 grains fills the cases to overflowing by the way.

Thanks,
Nik

Nick, I have to disagree with you. In my 577 T.rex for example there is no way I can safely use 198.0 grains of VN560 with a 750 gr. bullet(see my loading data) unless I seated the bullets way out(I seated out to the lenth of my magazine(3.850). If I used normal seating depths(A-sq. manual says 3.710) the load would be much to hot for my rifle. It is true if you only have as little as .030 jump to the rifling pressures can go up. But I always try to have at least.100 jump to the rifling(in the case of my t.rex I had more than .200 jump to the rifling) if the throat and the profile of the bullet allows, that is probabily the difference. Another example would be in my 460 wby. If I seat a 500 gr. Barnes X Bullet to 3.810 with 118.0 grains of IMR 4350 the velocity averages 2611 fps. in my rifle. But if I seat that same Barnes X to 4.050 with 121.0 grs. of IMR 4350 the Velocity is 2597 fps. even though the powder charge is heavier (target only load). I can only speak from experiences with my rifles. But I have found what I have just said to be true in all of my rifles. BTW, my drop tube is 38 inches long.

[ 05-26-2002, 23:38: Message edited by: Mitch ]