Heavy boolet for 358 Win

[zooly]

Hello:

I need help designing a 245gr WW + 2% Sn boolet mold for my new 1: 14 twist 358 Win. I want to keep the lube groves inside the case without letting the GC hang down into the powder space ( 0.365 neck length), and shoot it it at least 2200 fps.

I have been working with the MM design program, but need to know more about ideal shank to BR nose legnth ratios.

Thanks

zooly

[Bass Ackward]

Zooly,

The only way you are going to be able to get everything you want is if you want to shoot that velocity rock hard.

The program is pretty easy to use. And from my experience, unsupported nose weight, is unsupported nose weight. By that I mean it does not contribute to the drive effort so it's simply along for the ride adding pressure to the base. You only need enough unsupported nose weight to establish a good BC.

So the softer the mix you want to run, the more drive area you need. Personally, I design everything for rifles to have 80% bearing area or slightly more dependent on meplat size. If the meplat is to be wider, I make the nose weight shorter. But you apparently don't have the throat length. (Ever consider renting a throat reamer for about $20. Can change your whole world.) But I never go over 60% on one of my designs because I shoot soft and don't need to.

And what is it with exposed lube grooves? You don't have to put lube in them just because they are there. If you don't want them, then you limit your choices. These will be that you have to have either a really wide band up front that means your center of gravity will be farther forward than it has to be and the bullet will be harder to stabilize, or less accurate if you can't, or two, you can go bore ride which contributes nothing for higher velocity use.

Have you ever read my opinion on bore rides? It's not pretty. :grin:

[zooly]

OK Bass:

So now I need some numbers to turn your advice into a MM mould of say 230 grns
from WW= 2% sn.

Here is what I've done so far :Tan style: 60% meplate: as cast .360: Front band .100; nose .365. So: .365 nose L + .547 inside case = .912 X 80% =.7296 or .73 = his bearing length of.732. OK so far? Now about his crinp grove numbers
.045 to .090: or no grove what"s up with this? Aslo ) 1: 2: or 3: lube groves?

I want to water quench them & soften the noses, and still get 2200 FPS.

I get that you don't like bore riders!


I'm on a fixed income and only get one shot at this so I need to get it right the first

time!

zooly

[Bass Ackward]

OK so far? Now about his crinp grove numbers
.045 to .090: or no grove what"s up with this? Aslo ) 1: 2: or 3: lube groves?

I want to water quench them & soften the noses, and still get 2200 FPS.

I get that you don't like bore riders!


I'm on a fixed income and only get one shot at this so I need to get it right the first

time!

zooly


Zooly,

Fine so far. I thought you wanted general information and now we are into specifics.

I don't use crimp grooves on bullets for bolt rifles. It limits your ability to adjust seating depth as your rifling moves out. But I assume from this that you have already slugged and know EXACTLY what your dimensions are that you need to work with. You may need to play with your meplat a little to get the olgive angle where it needs to be, etc.

On the number of grease grooves, you need to determine how that works out by using your case neck length since you don't want any exposed lube. Remember that you can widen your GC groove to hold a little more lube too. Is this a new gun? If so, then the angling of the rifling will change fairly rapidly in terms of the number of shots and I would go .050 deep into the case which is less than the height of the check. (No exposed lube) Then as the rifling changes you can seat out and this will maximise your bullet weight.

I would assume from this so far that you will be able to get 2200 fps from this bullet just out of ACWW. So if you want to harden it, 2400 to 2450 might be attainable and still hold MOA. Depends on your twist rate, barrel length, and bore condition of coarse. The longer your barrel is the wider selection of powders you can have to get to that level.

If you would like to use the PM feature we can discuss particulars much more closely as I need more information. This process should take a lot of time because you have a lot to consider. And your desires and opinions will change throughout this process. The way I do it is to design a bullet once every week so that I forget what I did last time using the same principals. At the end of that process I print out the specs. Then when I compare and get the same bullet design for three weeks in a row, I know I have what I really want.

But beside the number of grooves, you need to consider width, band width and a lot more. Mold material will affect my dimensions too. Some other designs can get you deeper grease grooves to hold more lube and then don't need to be as wide etc.

I would like to know more about your rifle setup and your climate too before we continue. I am going to fire off a PM so look for it in the upper right of the home page.

[PatMarlin]

Why not try the Saeco for the heavy boolit? It drives tacks in my 358 Winny.. :drinks:

[zooly]

Dear Mr. Marlin:

Since the price of a "store bought" mold is about the same as a semi custom from Moutain Molds, I think I'll play the ods & get a mold designed for my (very short throat) chamber. Besides I get to talk to, & learn from guys like you,Waksupi & Brother Bass Ackward! Free Fun. Thanks guys

zooly/ Brad Hall

[PatMarlin]

Well don't give em' your credit card number.

Specially the Bass Ackward guy... :mrgreen:

[waksupi]

Zooly, you could rent a throating reamer, and lengthen things out a bit....