Accurate molds has a large inventory of pre made designs of cast molds you can choose from. I am wanting to challenge us in our own community to design our own slug . The biggest limitation with the accurate molds is a maximum bullet length of 1.375. I currently am using there 51-625S mold with great success in my .510 texan.With a b.c of around .5 .510 Cal that max 1.375 in length is going to limit any higher bc without going longer. So what is the highest b.c bullet that we could design with the limitations of there requirements of length and angles. In my mind would think somewhere between 7mm 200grain plus or375 cal or 40 cal. On accurate molds website they have a program to design your own cast design. Thanks for any suggestions.
Lets make perfect big bore ballistic slug with accurate mold custom design!!
- Thread starter RM.510bigbore
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Sounds interesting! Accurate makes great molds. I have an Airforce Texan in .457, and have tried at least 15 different bullets, 10 of which I cast myself. Here are some parameters I think are important:
- Pins to have the ability to do a deep hollowpoint, a shallow hollowpoint, or a wide metplat flat nose
- A hollow base, similar to a Webley, that will allow for improved sealing to the barrel
- Alternatively, a boattail base to improve BC
i would prefer a 4-cavity bronze mold, in .459. As to diameter, maybe we can basically design the slug without diameter, then use the attributes to have the same bullet design in any caliber?
- Pins to have the ability to do a deep hollowpoint, a shallow hollowpoint, or a wide metplat flat nose
- A hollow base, similar to a Webley, that will allow for improved sealing to the barrel
- Alternatively, a boattail base to improve BC
i would prefer a 4-cavity bronze mold, in .459. As to diameter, maybe we can basically design the slug without diameter, then use the attributes to have the same bullet design in any caliber?
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Yes accurate do make great molds. But not any HP/HB molds nor boat tail... And not under 7mm if I recall correct. So even if one could design a good model which company can produce that mold?
NOE has hands full to keep up with inventory. I think Arsenal has same thing... I don't know any other mold maker than Tom on Accurate who do custom molds or you can change diameter etc from catalog. One possibility is do a mold without pins and send it to Erik on hollowpoint molds.... That raises expenses
I might be wrong so... Hope You get someone to do it.
NOE has hands full to keep up with inventory. I think Arsenal has same thing... I don't know any other mold maker than Tom on Accurate who do custom molds or you can change diameter etc from catalog. One possibility is do a mold without pins and send it to Erik on hollowpoint molds.... That raises expenses
I might be wrong so... Hope You get someone to do it.
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I like my noe molds but what is in the catalog is what you get. No hollow points from accurate molds but he will cater to custom designs. There are not many spire point boat tails in the cast mold game. Lee s design on there 230 grain 30 cal is great with a b.c of .688 something. I'm sure the equipment lee has access too is real good. I'm real happy with my 625s boat tail mold with a b.c of .5. I'm sure accurate could make that same design in .457 with a 1.375 length an .b.c should be better dnt know what the weight would be. I'm real happy my stupid air gun slings 650 grain .5 b.c slugs put if lee can make a cast mold with a b.c of above .6 for under $50. 
As air gunners are choices of custom molds I hope continues to improve.
As air gunners are choices of custom molds I hope continues to improve. Upvote 0
NOE has more than few Spire point designs on .30 but not with BT. Lyman has also at least one Spire point but not with BT. Is boat tail mandatory? Haven't noticed any huge advantage on BT models. Plain base and GC base bullets are worked just fine for me. Shooting 100-300m on my .30 Corsair
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Tom's "problem" is that he bores all his moulds on a lathe and thus needs a meplat of at least .18"
That limits a true aerodynamic design.
That limits a true aerodynamic design.
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Seems like that 30 cal 230gr is going to be hard to beat as far as BC. I wonder how much drag it'll have in the barrel though because that could hinder velocity substantially.
Custom mold - 7mm 190gr ??? Might be able to drive it faster. In centerfires the 30 cal 230gr and the 7mm 190 gr copper jacketed bullets are similar in BC.
Custom mold - 7mm 190gr ??? Might be able to drive it faster. In centerfires the 30 cal 230gr and the 7mm 190 gr copper jacketed bullets are similar in BC.
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I don't think lees design can be beat. Its a modern bullet like a hornady eld-x. To bad lee wouldn't make more subsonic cast extremely low drag bullets in other cals. That lee 30 230 is made to be a subsonic bullet for 300 blackout. Maybe if the 8.6 blackout or 338-creedmore catches on lee will make a 338 subsonic cast 300 grain. I'm going to try to shoot some local 100 yard 300 yard 500 yard ground hog bench rest matches this year. It will be all powder burner s and custom guns shooting 2 inch groups at 500 yards. I think I going to take my Texan and shoot with it no rules against airguns. I won't win any prizes put im sure happy to go and spend a day shooting with like minded friends. I quit shooting competition years ago the price and components are out of hand. Shooting air guns may be the only affordable option for our shooting sports sadly to say. If I shoot my 50 cal it will be easy to Ser bullet holes the paper at 500 yards lol
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I like Accurate molds and have several designs in Tom’s catalog. I’ve had great luck with Arsenal as well.
I wish Erik at hollowpoint molds wasn’t so busy so I can send several of my designs to him to get his sliding bar hollowpoints system.
I wish Erik at hollowpoint molds wasn’t so busy so I can send several of my designs to him to get his sliding bar hollowpoints system.
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I’m a moldmaker by trade. Never built a bullet mold but I’ve built some extremely complex $200,000+ injection molds. I would be doing this when I had a chance but my machine is a Dmu75 monoblock by DMG-Mori. 5 axis bad mama jamma. Built plenty of tools with interchangeable inserts, hand loads, or core pins that would be exactly what you’re describing.
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"So what is the highest b.c bullet that we could design with the limitations of there requirements of length and angles. "
Evidently Mr Reedmosser you do not under stand BC .
BC will change if a cloud covers up the sun and drops the temp a few degrees. And you have to take in altitude and barometric pressure also . True target shooters are always checking the speed of bullet and the outside temperature through out a match and correcting for the change in BC of the bullet. This way they can correct the scope setting they are shooting at that time of day.
So if joe blow of NY has a 600 BC cast bullet at his place in NY it will not be the same 600 BC if he went to the western desert states and fired the same bullet with the same fill pressure just simple physics .
All I am saying is don't get hung up on BC it is not what you are thinking it is.
For the boat tail people out their the flat base bullet will out shoot a boat tail bullet as long as the range is kept under 600 yards, this has ben a fact for over 100 years in the target shooting world .
Evidently Mr Reedmosser you do not under stand BC .
BC will change if a cloud covers up the sun and drops the temp a few degrees. And you have to take in altitude and barometric pressure also . True target shooters are always checking the speed of bullet and the outside temperature through out a match and correcting for the change in BC of the bullet. This way they can correct the scope setting they are shooting at that time of day.
So if joe blow of NY has a 600 BC cast bullet at his place in NY it will not be the same 600 BC if he went to the western desert states and fired the same bullet with the same fill pressure just simple physics .
All I am saying is don't get hung up on BC it is not what you are thinking it is.
For the boat tail people out their the flat base bullet will out shoot a boat tail bullet as long as the range is kept under 600 yards, this has ben a fact for over 100 years in the target shooting world .
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In a perfect world, that's not true.
A true BC won't change. We sometimes change BC to compensate for an imperfect match with the drag model.
For those atmospheric changes, the amount of drag changes for a given velocity. So we do need to take those things into account when calculating a trajectory. But that does not change the BC.
For a correct drag model, the BC remains constant across projectile velocity and air density.
Because the drag models that we use are rarely a perfect match for the projectile shape, we might compensate by making BC adjustments based on velocity or even air density.
When atmospheric conditions change, I enter those atmospheric changes into the trajectory calculation, but I leave the BC alone.
I might agree with you that for supersonic projectiles, forget the boat tail out to 600yds. However, when shooting long range subsonic, I'll go with the boat tail.
Back to the OP topic - I'd ask what is a "perfect big bore ballistic slug"? The highest BC might not be the "perfect" slug. Big bore slugs with high BC usually have a high sectional density. Sure, higher BC slugs typically fly straighter for longer distances, but we still need to launch them straight. We pay the price when shooting long, heavy slugs at high velocity. It's best to balance BC, fpe, velocity, distance. At this point, I'm looking for the best accuracy with at least 200fpe, and probably never farther than 400m. A BC of 0.20 to 0.30 is probably the best compromise for me. I might try 500m. How high of a BC do we really need?
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Assuming the molds are intended for PB bullets in rifles then you will not find one with a boat tail. Anything driven at standard rifle velocities usually requires a gas check to avoid severe leading. For a gas check to fit the bullet, the heel must be square.
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This is the NOE boat tail mold that I'm currently using for my 1:14 twist 7mm. It is designed specifically for airguns:
284-106-FN-BX6 4 Cavity RG4 BT | NOE Bullet Moulds
noebulletmolds.com About 0.26 BC(G1) tested at 980fps down to 650fps
For subsonic, a spire point won't buy you much. Even a 50% meplat is OK, and it makes the projectile shorter.
The highest BC in an airgun specific boat tail slug is their 112gr .257 or the 176gr .308:
257-112-FN-BF5 5 Cavity BT | NOE Bullet Moulds
noebulletmolds.com 308-176-FN-BF3 4 Cavity BT | NOE Bullet Moulds
noebulletmolds.com Those last two would likely be for a very specific purpose. Both are over 1" long.
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OK, fair enough. WOW
on the 30 cal! That BC is like a Sierra MatchKing. Definitely a multi-100 yard projectile. Too bad that the only limitation would be the lower airgun MV, otherwise that's a 600+ yard proposition..Upvote 0
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