General mould/boolit design for rifle

[popper]

Ball seat, bore-rider, RD, Louverin style? What purpose/performance for each (primarily NOT plinker styles or FN vs SP)? Why the different designs work or not. Not interested in what works in yours type of comments. Got to wondering the 'why?' of all the rifle boolit designs in the Accurate catalog. Yes, some 'tinkering' there but lots of variations. I'm particularly interested in the nose designs. Drive bases are pretty standard. Yes, fit is king but fit where and why? Not taking slugging and chamber cast but boolit design.
I've only modified some 'standard' ones used whatever CG/CF ended up. Guess I'm really interested in dynamic fit or what happens when it's NOT a perfect fit - thoughts and ideas?

[ABJ]

I am watching with great interest. I used to think a lot of choice was a good thing, but Tom@Accurate has so many you start to wonder what the designer is thinking or does he know something that I should know. I just purchased from Tom a 30 cal flat nose 200 which is a 314299 clone. There were others I liked better, but knowing how well that design is, it's hard to pull the trigger on a $140 mold of unknown design. Bore riders where they meet the front driving are spread out all over the map, some are tapered, some are like a swc and some are a rounded band. I too would like to hear from shooters/designers as to the why of different features.
Tony

[ShooterAZ]

If there is such a thing as a "General Rifle" design, my opinion would be the Louverin mod style. The tapered design will fit most throats quite well, and therefore can be made to shoot accurately. Mine are all FN though. There's a "fat 30" version which can be sized at .314 or all the way down to .310 if needed. That covers a lot of ground. It's quite a versatile boolit style IMHO.

[waco]

If there is such a thing as a "General Rifle" design, my opinion would be the Louverin mod style. The tapered design will fit most throats quite well, and therefore can be made to shoot accurately. Mine are all FN though. There's a "fat 30" version which can be sized at .314 or all the way down to .310 if needed. That covers a lot of ground. It's quite a versatile boolit style IMHO.
Yep. The Saco 315 and the clones are another good all around fit for lots of rifles.
http://accuratemolds.com/bullet_detail.php?bullet=31-175B-D.png

[popper]

Ball seat - to fit '06/308/etc style chambers? Bore-rider to center the nose in the bore? Louverin (the one with grooves all along the body) to fit about any bore? I consider the RD style as just a WFN (specialty?) but it does well in all my rifles. Ed harris states full wadcutter is BEST for SD and I agree. He states the reason! I'm curious about the reasoning in the development of the different types, not the tweaks that some make. Any articles/ papers/etc on the logic?

[Rcmaveric]

I am not familiar with the term Ball Seat. By SD do you mean standard deviation or sectional density? When it applies to bullet nose design is all a compromise between internal ballistics, feeding, aerodynamics of flight, then terminal ballistics on impact. An hour of searching I can't provide any scientific articles, only hear say I have read over the years. A wiki article called Bullets was as close as I could get https://en.wikipedia.org/wiki/Bullet . According to the article in the design sections. Its all about physics for creating straight flight. Either its a hallow base with most of the weight forward or you have a large bearing surface with all the weight in the aft of the bullet. I know bullet nose designs and why, but I don't know bullet design styles for squat.

Lovern has all ready ready been described. Filling the throat increase accuracy by decreasing blow by when the bullet jumps the throat to lands. The blow by can miss align a bullet. The tapered bands can also act as a bore rider.

Bore riders work due to increased bearing surface. More bearing surface the more better. It also acts a guide to align the bullet during chambering and firing preventing the bullet from wobbling inside the barrel. Like a train going down train tracks.

https://www.montanabulletworks.com/bullet-information/ mentions WFN is for large wound channels inside 100yrds. Not very accurate past that due to aerodynamics.

I wish I could quote articles but I cannot. I am following along for curiosity. This post just got me inspire to get and now read "The Bullet's Flight From Powder to Target: Ballistics of Small Arms".

[popper]

Sorry, SD is self defense. Yea, throwing a lead filled beer can at target works well. Ball seat is the 'seat' or 'tapered' area between throat and bore. Bore rider and Louverin styles IMHO (so far) are to get as much boolit in the bore, 'ready' to get 'slumped' into the rifling and keep centered as much as possible. Just trying to get some historical design stuff,don't think any of 'us' designed them.

[ABJ]

The example that Waco is showing with the tapered bearing surface. Would that boolit not get sized out of round in a push through sizer like the star, That is unless you are real careful about holding it straight until the base enters the die? I have never shot that style so I have no experience. My most accurate designs have been the 314299 and the 311291 where the nose engraves just in front of the front driving band. The one I have trouble with is the 311041. That boolit gives me fits in accuracy dept.
Tony

[Outpost75]

I've gotten over a dozen rifle molds and an equal number of revolver molds in various calibers from Accurate. Every one was designed to fit a particular rifle or revolver as-cast, without sizing. I don't powder coat, but use Lee Liquid Alox for just about everything, except black powder, which I pan lube. For high velocity rifle loads over 2000 fps in the .30-30 and .30-'06 I seat GCs and fill the lube grooves with 50-50 Alox-beeswax and overcoat with diluted Lee Liquid Alox.

I make bullets fit the "ball seat" which for those unfamiliar is the portion of the chamber ahead of the case mouth before the rifling starts. My bullets do not have two parallel sections with a transitional angle separating them. The driving bands fit the diameter of the ball seat and the forepart of the bullet north of the crimp groove, if any, is tapered to match the angle of the origin of rifling. In revolvers the forepart diameter specified on the drawing is the same as the cylinder throat or ball seat, but I will specify "nose tolerance negative" on those designs so that the bullet will enter the chambers using speed loaders, without sizing, but that the bullet will be aligned during initial shot-start and exit the case straight.

I test my revolver loads at 50 and 100 yards in both single-action Rugers (mostly) and cowboy rifles. The bullet must feed in lever-actions, and have a meplat of about 0.6 of the bullet diameter to give good results on game.

Here are a selection of my designs:

21253721253821253921254021254121254221254321254421 2545212546

[popper]

The one I have trouble with is the 311041
One of the reasons I started this thread. Bama has done some good work in fitting bore rider, I found that just a slight portion of nose sizing the RD style helps. Nose sizing is a pain as is getting the exact mould needed for a tapered boolit design.

[Rcmaveric]

Is that not called the throat and leade? Throat is after the case mouth and the leade is the throats transition to the riffling. So would ball seating be matching a bullet design that complete fill the throat and match the angle of the leade? If I got that it sounds pretty similar to the bore rider approach. http://bisonballistics.com/articles/an-introduction-to-rifle-chambers

If I under stand correctly, then with ball seating the throat and leade would work as puzzle pieces to keep the bullet aligned and square for launch to ensure accuracy while maximizing meplate. Since fit is near perfect chances of hot gas blow by are nil and bullet misalignment while "jumping the throat" are almost impossible. Con side is finding that perfect bullet for a ball seat and it possibly only working in that gun. Another con is those noses are tapered, so as the bullet travels the bullet can "slump" or cock as it travels down the barrel. Would most beneficial for hand guns. Since nose profile is tailored as so, you would have maximum accuracy inside 100 yards and hunting affectedness but at a cost of bullet aerobatics at longer ranges.

I mostly shoot riffles and they are all of a bore rider styles bullets. The throats are all short with almost no leade. The bore rider sections all fit the bore with slight thumb pressure as cast. Then sizing to throat diameter makes the driving bands fill and plug the throat. I seat the driving band about .002 off the lands. Upon chambering the round the bore rider section would center and align the bullets. If I didn't size to throat diameter the bullet would still be centered during launch but hot gas could blow by and a chance of the bullet getting cocked is there. In my case the throat is filled and effectively sealed and also supports the bullet. The bore rider section also guides and aligns the bullet during chambering, ignition and travel down the barrel. Con is there is possibility to not filling the throat and causing inaccuracy and having to size a bullet for each throat. Another con is smaller meplate, can be used on game but wont be as effective so shot placement is more important. Plus side is its an inherently accurate design with increased aerodynamics so effective range is extended and an accurate shot is more possible. Smaller meplate disadvantage could be slightly compensated for with softer alloy and one bullet can be used for different guns. Bullet can not slump or cock while traveling down the barrel due to being fully supported during travel.

The Louvern style has lots of driving bands going down the body. Each band is .001 larger than the first. This allows it to fit multiple different throats merely by adjusting seating and possible even centering the bullet in the bore. The different diameter bands would center and support the bullet in the case mouth and throat and the short nose would act to align the bullet. Those bullets have a long bearing surface making them inherently accurate. Similar to bore riders. I can not help but wonder if all those driving bands create a turbulence buffer that helps keep the bullet stabilized as it transitions from sonic to sub sonic flight thus also keeping it accurate (like the seams of a base ball).

Looks like all those basic designs like Louvern, Keith, Whitworth ext is that that persons tweak on the basic design of # of lube grooves or driving bands then nose shape. There are your basic profiles and then everything is plug and play and tweek angles. Seams to me that after going over those designs. Accuracy is enhanced by filling the throat and lead, then supporting the bullet during launch and barrel travel. Doesn't matter with which bullet you do it with as long as it fits. After the bullet leaves the barrel then it needs to have the proper aerodynamics to maintain accurate flight. Louverin or Whitworth seam to fit the bill as basic accurate all around bullet. Hand guns would also benefit from a bore rider section if highpowered. Low power loads are not required much bearing surface, due to slumping not common on low powered because of lower pressures.

Wadcutters as self defense makes perfect sense due to a full wadcutter being one giant meplate on a fully supported bearing surface. Out of a revolver at high power it would be inherently accurate due to bullet design and highly devastating on impact with maximum energy transfer. I also read where they were good for small game loads some where. I don't think it is that important to perfectly match the leade angels ext or "Ball seat" as it is discribed. I think fully filling the throat is key and a little bore riding for extra bearing surface and alignment helps.

http://www.corbins.com/design.htm
http://www.mountainmolds.com/helpDesign.htm
http://www.lasc.us/Fryxell_Book_Chapter_9_MouldsMouldDesign.htm
http://castboolits.gunloads.com/showthread.php?134480-Names-of-Cast-Bullet-Shapes (was short and dead)

[popper]

Rcmaveric - you are getting my drift.
Con side is finding that perfect bullet for a ball seat and it possibly only working in that gun IMHO, the Louverin is an attempt to get good alignment and fill throat/leade as best possible in any rifle. Band are small and weak enough to force fit and lube between the bands can accept displaced alloy. Tapered designs (XCB project) are to create the best fit for spec rifles. Bama's bore rider tests verify that the nose slumps into the rifling. His test verifies also that this slump is very concentric (IIRC a one R nose). Unfortunately he has fancy tooling to accomplish this - that most can't afford. Got me to thinking (dangerous) that a slightly smaller bore rider design (especially for us PCrs) with a single larger dia. drive/centering band (sort of a reverse rounded LG) on the nose. A ball seat/taper type transition from body to nose would allow centering at the throat end.
Bama got me to thinking when he asked why I couldn't shoot bore riders in my AR10. Don't like getting jams. However if I can get the funds I might work up something like I describe for an experiment.
Sorry i didn't get this written last nite, got interrupted by an 8th grade BB game. Took district last year, not lost this year but it was a closer game last nite - still won by 18 pts.

later.

[popper]

Somebody has the same idea as me. 31-210NR. Anyone here claim it? How does it perform?
212872
Wondering how well this would work (lighter) in Marlin 30/30?212887

[Rcmaveric]

Isn't the NOE Grendel bullet mold a bore rider design for 6.5 Grendel in the AR? That bullet feeds fine in my AR and is highly accurate. The 6.5 Grendel bullet looks like a shortened 266-140-SIL RCBS design. The 31-210 NR looks a wider version of both bullets. LOL your getting out of my league in your thinking. I wouldn't mind trying those 31-165C bullets though in my Mossberg 30-30.

[Good Cheer]

Bought one bore rider from Accurate. Very nice mold.
212947

[Rcmaveric]

I tried looking at the Accurate mold catalogue. It hurts my mind, I don't do well with so many choices. Then it saddens me because I cant find any .277 bullets.

[popper]

31-165C is for my AR10 308W. Dwg I made used the 165C base and 183 nose (RD) with a ring added. I've heard the 30/30 levergun doesn't like bore riders. This thought is a ball seat at the bore start and undersized bore rider with alignment ring.

[Rcmaveric]

I use the Lee C09-150-F seated longer. With the first driving band .002 off the lands I use the first lube groove as a crimp groove. I have been able to tighten the groups to about 2.5 inches at 100 yards. Not impressive but minute of a deer so I am finnaly getting happy with it. I am still speramintin and some tests loaded. Wish I can find a SIL style .277 bullet...

With today industry standards of throat and lead dimensions I don't think its important to ball seat. I think its important you use some method or ideology to create concentric ammo that fires a bullet straight down the pipe without deforming. If you had a worn out throat ball seating makes peferfect sense for guns with worn throats and leades and need to be matched to support the bullet. I bet those Louverin bullets would really shine there. I can visualize a gentle 45* leade of 1/8 to 1/16 th in length of a new gun to accurately shoot most properly sized projectiles, but get sloppy worn military riffle or great great granddads six shooter its gonna take som special fit ment to keep the bullet centered during chambering and firing. Ball seating on new riffle may end up being like flash hole deburring, might do some good, but I m not good enough shot to tell the difference.

[popper]

IMHO the ball seat is to make a good transition between the throat and bore, steeper angle than a normal ogive transition. Allows a reasonable close fit (fill) for throat and bore (leade). So 3 areas of the chamber to fit.

[John Boy]

popper - books have been written and bullet designs tested extensively in different twist ratios. To consolidate all this information, there are calculators and based on inputs, the bullet with the highest SG or SF for Stability Factor is the bullet of choice. Don Miller's & Powley's are a couple. Here's Miller's
accurateshooter.net/Blog/millerformula.xls

[Rcmaveric]

popper - books have been written and bullet designs tested extensively in different twist ratios. To consolidate all this information, there are calculators and based on inputs, the bullet with the highest SG or SF for Stability Factor is the bullet of choice. Don Miller's & Powley's are a couple. Here's Miller's
accurateshooter.net/Blog/millerformula.xls

From my understanding those excel file (I have it) and Powley's pocket computer were designed around copper jacket bullets. True, bullet stabilization is equally as important, but with cast bullets so is fit. Now the question is how much fit is necessary? Would love to read a good research article about bullet designs, seating methods and bullet "fit" methods.

[popper]

Would love to read a good research article about bullet designs, seating methods and bullet "fit" methods. Me too. This is what I'm trying to learn but not finding much. I know about powley/miller stuff.

[Rcmaveric]

The nerd in me and my tendency to ponder cant help but wonder if those groves up a pope bullet disrupts airflow like the dimples on the golf ball and also lead to its increased accuracy. If you size that bullet you just uniformed its sizing bands taking away from its stepped bands.

I did just get Dr. Manns book to read though.

[Rcmaveric]

https://castbulletassoc.org/blog/article/2017/11/123/adequate-accuracy-is-attainable-with-simple-techniques Para graphs 13-15 talk about fitting the throat.

https://castbulletassoc.org/blog/article/2017/8/107/some-additional-remarks-regarding-accuracy Only mentions slugging the barely.

https://castbulletassoc.org/blog/article/2017/7/92/loading-cast-bullets-in-the-9mm-luger First article I have found where it talks about leade seating. I need to read the article a few more times when not half asleep.

https://castbulletassoc.org/blog/article/2018/1/134/a-radical-bullet-design Food for thought.

Off topic but https://castbulletassoc.org/blog/article/2017/5/74/observations-on-gas-checks This article makes actually ponder what makes an accurate bullet.

Various articles from most cast bullet manuals and books and articles, they always talk over .002 over groove or throat diameter. I have read other opinions about sizing to bore diameter but that was just passing. I haven't found an article yet that talk about it from a reputable source. Seating depth is matter of choice from seated into the lands to .002 off the lands, to even adjusting bullet seating depth to fine tune a load. I would have to fish up the article were it talks about where a small jump is more accurate than set into the lands. It has to do with the high pressure spike on the base where a jumping the throat is more gentle and less upsetting to the bullet base. Which goes back to Dr. Manns theory. With that thought in mind, would ball seating then be short changing your accuracy potential. Even in my 9MM Luger I seat .002 off the lands and produce respectable/repeatable accuracy.

All in the search of the golden most accurate bullet. I found various articles that talk of bearing surface. I cant help but to think design from the driving band forward is purpose driven. Do you want it to kill something, do you want to punch paper or do you want to hit long range targets or do you want a happy medium of knock down verses medium range. Ojive down is what makes it accurate. Bearing surface and the bullet base. I think we may be over thinking this bullet design. Any design that will offer adequate bearing surface with a sharp driving band and sharp base will produce accuracy. Next step of accuracy is loading techniques, what methodology/(or mythology) are you using to minimize the damage to the bullet when it jumps the throat and travels down the barrel. Use a slower powder, longer barrel, and slower twist. Maybe accuracy is a puzzle that needs to be solved for a particular bullet and barrel then mix and match till you get an accurate fit and load.

[popper]

Maybe accuracy is a puzzle that needs to be solved for a particular bullet and barrel then mix and match till you get an accurate fit and load.
Exactly what I'm trying to avoid. Consider alloy as really heavy modelling clay. When fired, it squishes into the space between the mouth and throat, fills the throat, and (if a bore-rider) into the grooves and bore. If a pointy boolit the nose can slump anywhere. Bama shows a concentric boolit helps. The question is how much does the aloy get 'torn up' or mangled when firing and can we design a boolit that reduces any problems. And doesn't have to be 'fitted' to the rifle. I'm proposing an 'almost' bore rider with an alignment ring on the nose. Tapered seat between drive band and nose ogive. Sized to the smaller part of the throat to prevent jams.

[Rcmaveric]

Sounds very plausible. I am curious. Or several thin bands to act as gas seals and a guidance system. My only comcern is an ease of chambering in a variety of rifles. Several thin rings that are tapered would ingrave easier on chambering.

Sent from my SM-G925T using Tapatalk

[Yodogsandman]

NEI used the DD rings on their noses. It was a band aid for poor fit.

[popper]

It was a band aid for poor fit Poor fit or 'general' fit? Any links to NEI moulds and results? Choices seem to be - chamber cast and get a 'special' mould to fit a single rifle or guess and hope for the best? So far I guess I've been lucky in choices but wondering if there is an approach that will give general good results. I'm kinda thinking the 30xcb with reduced nose dia. ( I coat vs lube) and a 'guide' ring that fits into the lands. I size the drive bands to fit the throat. I shoot ARs and avoid seating touching the bore, I'm thinking longer to increase BC but mag length eliminates a long bore rider. I could size a small nose ring with little trouble. Bama's approach is great but I don't have that capability.