Square lube groove vs rounded - pros and cons

[45 2.1]

I do know what happens when you get caught by the wind, it ends up a 9 or an 8, or it blows a really sweet group. OK Alan, since you asked in a decent form, I'll explain it to you. In your first sentence you say "it blows a really sweet group".... that really sweet group would be a core group, one that would be a group if you hadn't had one out. I also know people who claim fantastic results, to the point of being beyond the laws of probability. The CBA record groups have less than 0.2 MOA possible, just how is what I said beyond the laws of probability? A MOA rifle may be able to cut a one hole group, if you shoot it enough, but it's about impossible to shoot them on demand. I never said it was a MOA rifle, just a production Rem. 700. Jacketed match reloads have shot quite a bit under MOA in it. We have people here that can probably do much better than you state... on demand.

You never did explain your "core group". That really sweet group with a errant wind caused flyer.... as you noted above by you. What is the criteria that makes a shot outside the core? Usually a horizontal deflection due to wind, but if shot far enough away there are other documented problems also. How much of that determination is based on how badly you need an impressive number? There were two of us shooting. The rifles owner had two wind driven flyers.... I didn't. There's a lot left to the ethics of the shooter when you start a process that allows picking and choosing which shots count. We were not shooting a match nor competing... anywhere. I was introducing a loading technique for my friend to learn. I explained why he had flyers. It's that simple. The problem is some folks here get their shorts in a bind when I start talking about HV long range riflery that they can't do and find impossible.

Lacking any firm criteria I have to think that some of your claims are not so amazing when one considers the amount of smoke(screen) you have to overcome.

[badgeredd]

A person has to learn to seperate the oats from the chaff on these forums, and yes, recycled oats does have a certain smell to it.

Well put Scott. MEASURED velocities and true groups are the only accepted criteria to most shooters looking for perfection.

I haven't found any great difference in boolits of the same design but differing lube groove shapes. I know from a machinists perspective roughly square/rectangular/trapezoidal lube grooves are easier to cut or make cutters for. My experience, limited as it might be, seems to point out that our newer modern lubes are superior to some of the old lubes and require less volume of lube to be effective.

Edd

[Char-Gar]

I did indeed go to the CBA site and asked the purpose of bullet lubricant and here is my question followed by two answers which in my estimation are very credible.

First my question:

"Guys, does anybody here know, really know the purpose of cast bullet lubricant. Is the purpose of lubricate the passage of the bullet down the barrel or form a seal/gasket at the base to keep the fire off the sides of the bullet base? Perhaps there is another alternative or some kind of combination.

I have been reading opinions and theories for years, but it seems like this would be a known and proven fact after the passage of this many years. Is there a conclusion or just a variety of opinions? I would really like to know."

Please guys, don't state you opinion as if it were a fact. I don't need any more of that. I am seeking knowledge and not more opinions, theories and speculation. I really do want to know.

Next and answer from Ed Harris:

"Ken Mollohan nailed this years ago. Our bullets lubes form an ablative coating which coats the bore to prevent adhesionof "vaporous lead" abraded from the surface of the bullet, by action of powder gases. This is described as the "boundary layer" principle of lubrication, and in my experience is correct."

Last an additional response from John Alexander CBA President;

"Ed is right that the only person that I know of that has looked into this question in depth with a series of well designed experiments to back up his theory is Ken Mollohan.

Ken reported his work in the Fouling Shot quite a while ago and more recently referred to it. I am sorry that I don't know the location of those articles.

I can sympathize with Charger's lack of interest in hearing more opinions and unsupported theories. We have lots of then about cast bullets and a shortage of the kind of actual controlled experimentation that Ken Mollohan did."

[felix]

Perfect answer. ... felix

Accuracy is maintained when the boundary is maintained, giving a consistent shot-to-shot boolit acceleration curve. ... felix

[Char-Gar]

Perfect answer. ... felix

Accuracy is maintained when the boundary is maintained, giving a consistent shot-to-shot boolit acceleration curve. ... felix

Thanks Felix, you are a serious science guy and understand that stuff. While I have a good education (fine arts, law and theology), I am science deficient. I had to go an look that stuff, up but I think I have a good grasp on it now.

Until somebody comes up with a better answer, backed up with better science, I take this as the last word on the subject. I have grown very weary of opinions offered up as fact and it is good to have some facts based on experimentation. I am sad to say, that Ken passed away a few months back and we are without his vast body of knowledge any more. But he did leave much behind in his writings.

[DrCaveman]

Ok guys, this wisdom from harris/mollohan is much appreciated and seems to be more definitive than most statements on the subject.

What does this say about lube groove shape? It seems as though a consistent rate of delivery of lube to the bore is tantamount to maintaining the boundary...that is, unless the lube burns or boils off. So, the question is: which shape of lube groove will provide more uniform lube dispersion?

Since the dispersion of lube into the bore is related to the boolit spinning while hot gases are bringing the lube to liquid state, it makes sense that the process is more radial than linear. Therefore it makes sense that a radial (rounded) lube groove would fit into this paradigm somehow.

Remember, while lube function is part of the discussion, i was asking about mold design, so lets try to tie back to lube groove shape. Maybe the CBA guys have insight about that, too. Itd be nice to track down and republish those mollohan articles. Bet a bunch of threads on the forum would be assisted

[Oreo]

I haven't seen a link to this guy Mollohan's work yet so forgive me that I haven't read it before posting this.

That we know more about what the lube does and how is imo entirely separate from what the groove does and how. Whatever Mollohan had to say about lube doesn't change the real-world practical aspect of what works and what doesn't. What we as a group know from experience is that good results can be had from a wide range of groove profiles. We know that trying to scientifically calculate a precisely optimal groove profile for a specific application is a canyon of permutations as wide as it is deep. Imo, trial and error starting with the most likely candidates based on prior experience is likely to be the quickest path to success.

In a nut-shell: the only way to really know is to try and see and even then, someone else is likely to get different results.

[badgeredd]

I haven't seen a link to this guy Mollohan's work yet so forgive me that I haven't read it before posting this.

Whatever Mollohan had to say about lube doesn't change the real-world practical aspect of what works and what doesn't. What we as a group know from experience is that good results can be had from a wide range of groove profiles.

In a nut-shell: the only way to really know is to try and see and even then, someone else is likely to get different results.

Mollohan is/was our own Molly. His observations have been based on real world applications. For that reason, anything I find written by him has my attention. We are poorer for his passing to the shooting fields beyond.

Edd

[Char-Gar]

Gentlemen. The Fouling Shot is the journal/magazine published by the Cast Bullet Association and a source of very good information that pre-dates the internet and places such as this. Back issues are available either on disc or paper and Molly's work, as well as that of Ed Harris and others are there to be read.

The CBA also puts on regular matches in several different classes with cast bullets. This is the practical application of cast bullet shooting. The shooter who shoots the smallest group, in a given class, at a given range wins. This is not theory, or opinion, it is holes in paper.

The CBA also has Postal Matches for those unable to travel to the matches. Putting your rifle, your load and your skills up against another's can be intimidating, but it does weed out the blow hards and posers.

Match results are published in The Fouling Shot, and this includes the rifle, bullet, alloy, sizing diameter, powder, powder charge and bullet lubricant. Time spent analyzing this information will yield a huge benefit in cast bullet learning, for this is not Internet gas, but real holes in real paper. A membership in the Cast Bullet Association that includes a subscription to The Fouling Shot is a very good expenditure of a few bucks each year for those interested in cast bullet shooting.

I suppose one could do a study of the bullets used to win these matches and gain some information about lube grooves, their size, configuration, depths and so forth. However, I truly doubt if that is worth the time to do. It is my opinion, that other factors are far more important that flat bottom vs. round bottom lube grooves. To expend time on that would be "majoring on the minor". However some of us have an inquisitive nature and that just might be an itch that somebody needs to scratch. It is just something that does not interest me. It have enough problem putting what I do know into practice to concern myself with what I don't know, but that is just me.

Shooting competition (small bore, high power, bench rest, skeet, Bullseye Pistol and handgun falling plates has been a part of my life for a half century. It keep me involved and honest. I have never been the champion at anything, but that is not what it is all about. It is about discipline, riflecraft, accountability and the fellowship of shooters.

In this day of the Internet, we have become a group of posters and in the process much of has been lost. Some kind of organized competitive shooting even, keeps our skills honed and we have great fellowship with like minded people. There are always a few tightly wound folks to whom winning is everything, but 95% are just there to have fun and hang out with others shooters at the range. I compete on a weekly basis and would find life and shooting much less rewarding without that.

[Oreo]

Mollohan is/was our own Molly. His observations have been based on real world applications. For that reason, anything I find written by him has my attention. We are poorer for his passing to the shooting fields beyond.

Edd

I mean the man no disrespect and if you guys say he pioneered an area of knowledge then I believe it. I don't see how that diminishes what I posted, but maybe it would be more clear to me if I read his work. As the scope of his work has been presented here, I stand by my own words.

Did the man have a lube groove preference of his own? Keith is the only name that ever comes up about lube grooves. If Mollohan had similar or differing thoughts that would be welcome info.

[Char-Gar]

I mean the man no disrespect and if you guys say he pioneered an area of knowledge then I believe it. I don't see how that diminishes what I posted, but maybe it would be more clear to me if I read his work. As the scope of his work has been presented here, I stand by my own words.

Did the man have a lube groove preference of his own? Keith is the only name that ever comes up about lube grooves. If Mollohan had similar or differing thoughts that would be welcome info.

I don't think anybody took what you said as disrespectful, nor diminished your post. I don't have any answers to your questions and I try and keep my mouth shut when faced with my own ignorance.