300 BLK AR Optimized Subsonic Boolit

[Jupiter7]

It'd be nice to get both cut in the same mold.

[Dr.Phil]

It'd be nice to get both cut in the same mold.

Since they are both the same shape, I would think that would be possible.

"Artful's" idea of using an endmill to finish up the profile on the mould sounds feasible, but that is out of my lane.

One of the added benefits of the subsonic design is that it will tumble much easier on impact than the 247 NOE FN.
My biggest concern is whether or not the nose would get damaged by the feed ramps while loading.

[Greg5278]

I would check and see if a Machine Shop with a Ram type EDM machine could help you. maybe get the Mold with a slightly shorter nose that Accurate or MM can produce. The EDM then can make the final Profile Changes. It sort of Dissolves the Metal with an Electric Discharge and water as the conductive Fluid. The nice thing is it will cut any conductive material regardless of Hardness. Carbide no problem, Titanium the same.
Good Luck
Greg

[wlc]

Dr Phil if you go forward with this I'd definitely be interested.

[Artful]

Another dumb thought - what if you order it as a hollowpoint and insert a nylon tip into it to get the shape you want?

[wlc]

Dumb question..... I assume you mean nylon tip as in similar to the tips in a Nosler ballistic tip? Where would one get a supply of these???? Interesting concept. Bet it would help negate nose damage in an AR. I like it.

[Artful]

There are several threads here by guys who use the ballistic tips on cast and swaged - I'd have to ask them some pointed questions as this tip would have to be a specific shape to get what he wants.

[kawasakifreak77]

A place called cutting edge makes jwords you can put plastic tips in. They sell extra tips on Midway.com

It would increase the b.c. & maybe it's likelyhood to tumble in flesh?

[wlc]

Or possibly, if the alloy was soft enough cause some degree of mushrooming......????? This has really piqued my interest. Like I need another "project" on my plate.

[StratsMan]

I'm no boolit engineer, but I have noticed a pattern in accurate cast boolits: high percentage boolit to barrel contact = best accuracy... That's the length of contact (driving bands + bore ride) / total boolit length... The design shown above as SuperSonic is a very low percentage contact area... looks like 40%, maybe less... Short contact boolit designs like 311414 were notorious for their lack of accuracy and are no longer favored.

On the other hand, high percentage contact boolits like the Loverin (sp?) designs have great reputations for accuracy, though they aren't nearly as pretty... Lead boolits just don't behave like a jacketed bullet, and long skinny points are much more likely to deform during acceleration and set up a wobble in the boolit (as I understand it)..

Personally, I shoot the Accurate 31-235B in my 300AAC because I like the longer ogive better than a shorter design. I've never had a feeding problem in my CMMG barrel. I haven't compared the feed ramps to other 300AAC rifles; it just works, and I think the barrel/ramp has as much (or more) to do with that success than the boolit design.

[Artful]

Ah, midway
http://www.midwayusa.com/find?sortby...ensionid=20614

I know the NOE makes pointy boolit molds

and
JTknives aka HM² has made some sharp round nose


I don't know about
Mp Molds / Mihec molds

[Sweetpea]

Is this what you're looking for?

http://noebulletmolds.com/NV/product...roducts_id=207

[leadman]

The Lee design 230-5R-TL is similar in shape to what Dr Phil is posting but with a boat-tail. I tried many approaches to get this to shoot in my 300 Whisper Contender including putting a gas check on the boat tail. The boolit usually leaves oblong holes in the target. My Savage 110 30-06 did the best with these loaded to about 1,900 fps.
I did drill out the base of one of the cavities so am going to try this out hopefully tomorrow.
The most accurate heavy boolit in my 300 whisper is the Lyman 314299 sized to .310". Don't know how it feeds in an AR. I have given out many samples of these to AR owners and requested feedback but so far have not had any. Only been about 2 years now.

[Dr.Phil]

Is this what you're looking for?

http://noebulletmolds.com/NV/product...roducts_id=207

That is the exact same mould (-the GC) that I currently own and can't get to feed properly.

Another dumb thought - what if you order it as a hollowpoint and insert a nylon tip into it to get the shape you want?

Adding polymer tips is a cool idea.
That is exactly what Barnes did with their wildly popular 110 grain TAC-TX "Black Tip" that was designed for the 300 BLK.
My concern with that is adding cost and the potential for the tips to no longer be available for individual purchase.
(One of the primary objectives is to get an inexpensive cast subsonic boolit that runs as reliably as a 300 BLK specific bullet.)

I'm no boolit engineer, but I have noticed a pattern in accurate cast boolits: high percentage boolit to barrel contact = best accuracy... That's the length of contact (driving bands + bore ride) / total boolit length... The design shown above as SuperSonic is a very low percentage contact area... looks like 40%, maybe less... Short contact boolit designs like 311414 were notorious for their lack of accuracy and are no longer favored.

On the other hand, high percentage contact boolits like the Loverin (sp?) designs have great reputations for accuracy, though they aren't nearly as pretty... Lead boolits just don't behave like a jacketed bullet, and long skinny points are much more likely to deform during acceleration and set up a wobble in the boolit (as I understand it)..

Personally, I shoot the Accurate 31-235B in my 300AAC because I like the longer ogive better than a shorter design. I've never had a feeding problem in my CMMG barrel. I haven't compared the feed ramps to other 300AAC rifles; it just works, and I think the barrel/ramp has as much (or more) to do with that success than the boolit design.

While I would prefer the most accurate boolit possible, I understand that this design would likely not be as stable,
but I would rather have the reliability of a better shape.
If the gun doesn't run reliably, the accuracy of that boolit doesn't matter.
Unfortunately, without actual test data, it is impossible to know what the performance might be.
If you look at the performance of the NOE 247 FN in this video, I would go so far as to say this boolit is too stable for my taste.
http://www.youtube.com/watch?v=6ag-dtVjHz4
Much like a fighter jet, I believe that a projectile that is operating just on the edge of stability will perform best terminally.

[Artful]

Well - there is a thread on here about making your own tips with a hot glue gun.

[Dr.Phil]

Well - there is a thread on here about making your own tips with a hot glue gun.

I'm going to find that hard to resist.
It will not likely be a practical solution, but I will have to tinker with it.
A mould for hot glue ballistic tips would be killer.

Hopefully I can find the thread you mentioned.
The curiosity is killing me...

[wlc]

Since they are both the same shape, I would think that would be possible.

"Artful's" idea of using an endmill to finish up the profile on the mould sounds feasible, but that is out of my lane.

One of the added benefits of the subsonic design is that it will tumble much easier on impact than the 247 NOE FN.
My biggest concern is whether or not the nose would get damaged by the feed ramps while loading.

I saw a video that "twang n bang" posted on his youtube channel where he shot the NOE 247 grainer into ballistic gel. That thing traveled through 30 some odd inches of gel without tumbling. I do think your design would tumble much better and IF it could be hollow pointed and/or have the nylon tip added you would get actual expansion and not have to rely on the tumbling. Alloy would have to be played with to balance out shootability with softness, but (I'm guessing here as I'm not any kind of eggspurt.. ) I would think that with the slow velocities we shoot the BLK softer alloy wouldn't pose a huge problem.

As far as the custom mold.... I really hesitate to say this, but LEE could also do it. IIRC they are doing custom stuff again. Don't know what the turn around time would be. They wouldn't be my first choice in this but is one avenue to explore if other vendors can't/won't do it or aren't interested in a one of thing.

[Frozone]

well for myself I'd rather see one larger lube groove on your design but it is yours so what ever floats your boat.

2 reason for feed problems with the NOE offerings.
I have both the 247 and the 165 grain molds. Neither feed well.

First is the fat ogive at the nose, it likes to hang up on feed ramps. That is is easily fixed with a little ramp re-profiling/polishing.

Second is the bore rider design itself. The sides of the boolit rub on the ribs in the magazine, and the darn thing is nose heavy to start with.
It is impossible to load more than ~10 into a 30 round mag and get the cartridges to pop up in time to catch the bolt.
Fixed that by getting a bunch of cheap plastic mags and taking the ribs out. I found that Tapco are easiest to mod.
However, that rather defeats the idea of the 300 blk.

So here is my idea: (You can't draw it with Mountain Mold's software however)

A semi boreride design out to where the rib in a standard GI mag would be, ~ 5mm. Then a rounded section (think reverse ogive or a lube groove with only the back wall) to get around that.
Then the taper to as sharp a point as practical.

Example: Look at the of the Lyman 311644, now imagine a taper from the 'wasp waist' to the nose.

I cut down a NOE 247gr to show what I have in mind. but I for some reason I can't upload a pix
ftp://206.174.53.227/Images/300blkWW.jpg

[wlc]

Frozone, that's interesting. Correct me if I'm wrong, but the "groove"/wasp waist is where the boolit meets the rib in the mag? I bet that would work well and feed as long as the nose doesn't hit the feed ramps.

[Frozone]

.... the "groove"/wasp waist is where the boolit meets the rib in the mag?.....

Correct.

I need to pull the boolit and see what it weighs but I bet it's still around 220gr.

< edit I pulled that one - almost exactly 220gr /edit >


Depending on a few things, I think it will tumble easier than the original as well.
Or maybe break in 2. not sure.