NOE Clone of NEI 358 282 GC, 300gr Flat Nose?

Ian

Ian

Notorious member
Ben, thanks for the kind words, maybe one day I'll come up with some satisfactory sketches to illustrate some of the things I'm trying to explain, but the several times I've tried it's hard to capture the nuances of dynamic fit on paper it just hasn't work out. Please realize that I'm putting out the facts as I see them, and my preference isn't the only way nor is it the way everyone should follow because it isn't always the best approach to meet a certain need. I mostly shoot pretty speedy, gas-checked bullets running the ragged edge of flying off into space, and that can take a couple of different approaches to the norm to work well. I also shoot plain-base powder-puff loads sometimes, but even then I tend to do things a little differently than most
 
JWFilips

JWFilips

Well-Known Member
Ian,
Very good info & I'm understanding it fully.
While I'm sure you are correct about the slower acceleration of the boolit into the throat, that would rather negate the shooting of fast powders with high (fast) pressure curves that I know shoot very accurately for me using plain base bullets. In fact my testing recently has proven to me that light loads of Red Dot powder shoot more accurately then any other powder I have tried ( Of course this is for light & slow plain base boolit loads) From what you describe as the "ultimate transition into the throat" this should not work in the Red Dot loads but they do. Not questioning, just curious as to why.
Jim
 
Ian

Ian

Notorious member
Lots of things work at low velocity, JW. Balance and launch damage isn't nearly so critical as it is at jacketed velocities. The other "philosophies" of bullet fit as I was attempting to outline for Ben a couple of posts ago all work just fine within certain windows. The "self-aligning" concept won't give good accuracy at any velocity if the bullet is too hard, too soft, too gummy, or the powder is bumping it too lightly or too hard. To my way of thinking, one should probably take the intended use of the gun and load as the starting point, have a bullet weight, shape, and velocity range in mind, and engineer everything specifically to those ends.
 
JWFilips

JWFilips

Well-Known Member
Ian,
I'm understanding the multi tapered, Convex nose concept, and would think a bullet nose describing a parabola as ideal, however I'm not grasping or envisioning the concave bullet nose. Is there an example of this you can share so I can better understand your thoughts on this type of nose?
 
Brad

Brad

Benevolent Overlord and site owner
Staff member
Don't just think of the nose as the forward most part of the bullet. The nose stops when you get to full bore diameter. How that transition occurs is important.
Think of a gentle curve from the tapered nose to the full diameter. Many bullets have a sharp edge on the forward most drive band. Which centers the bullet better?
 
Ian

Ian

Notorious member
JWFilips said:
Ian,
I'm understanding the multi tapered, Convex nose concept, and would think a bullet nose describing a parabola as ideal, however I'm not grasping or envisioning the concave bullet nose. Is there an example of this you can share so I can better understand your thoughts on this type of nose?
Click to expand...

Maybe this will help?



Here's a detail of the AM 31-157G in the middle:
31-157G-D.png
 
Brad

Brad

Benevolent Overlord and site owner
Staff member
Look at the area where the diameter goes from .302 to .311. That is a critical area too. It is what I was speaking of.
 
JWFilips

JWFilips

Well-Known Member
Perfect! Now i understand what you are talking about! Thank You
Now I just need to find something like that in a .326" mould
This is becoming a very exciting thread
 
yodogsandman

yodogsandman

Well-Known Member
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I'm second guessing the nose diameter, wondering if it should be larger. SAAMI specs call for a .350" bore so, if the nose only tapers up to .350" will it wobble? Would a taper up to .351", reaching the .350" dimension in the middle be a better choice to help align the boolit in the bore?
 
Ben

Ben

Moderator
Staff member
I can only say that cast bullets with a .301 or .302 nose in .30 cal. barrels ( bore .300 ) certainly shoot well for me. If we take the same " mindset " and apply this to a .35 cal barrel, I can't see why the same .001 or .002 ( depending on the individual barrel ) larger than the bore wouldn't work VERY WELL.

Your bullet design reminds me somewhat of the Lyman / Ideal 311290, one of my favorite all time classic cast bullets for a .30 cal. barrel. If you can get the fit right and your twist is correct, I predict that you'll have a very accurate cast bullet.

Ben
 
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yodogsandman

yodogsandman

Well-Known Member
Just did one pound cast. Too hot and humid for more tonight. Preliminary measurement of the bore/land diameter is just a tudge under .350" using an RCBS steel dial caliper (.000).
 
Ben

Ben

Moderator
Staff member
A nose of .351 for about .100" in length ( forward of your 1st drive band ) then taper things to .347 " like your current drawing is what I'd do.

Ben
 
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Brad

Brad

Benevolent Overlord and site owner
Staff member
I would taper from .345 to .354 with no parallel section then taper from .354 to .360 over .15 inches or so, no sharp edge on forward driving band.
Look at the 157-G Ian posted the print of, look at nose taper then the sharper taper from nose to body.
 
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