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POF Roller Cam Pin

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Replied by OleCowboy on topic POF Roller Cam Pin

Fun, I have the same questions and have to roll with you on this. Hoping I can talk with them and get some further insight.

As for balancing...lets go back to the engine metaphor again. Balancing is called 'invisible horsepower'. Hard to detect on a dyno, but today its common in any engine producing about 1 Hp/cu in and on any engine spinning the crank above about 5 k rpm. Thus results on race day and in the longevity and lifecycle.

This then begs the question, would balancing the BCG provide any observable results?

At what point on the linear length of the BCG would one place CoG.

Is there a +/- to having it balanced, front heavy, rear heavy?


There may be an advantage to having a balanced BCG, good question. I think I can make a case for it: Balancing the BCG would insure less wear on the BCG and its touch points. That said is that a factor????? or just a solution in search of a problem.
9 years 4 months ago #43853

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Replied by funfred on topic POF Roller Cam Pin

Whenever thoughts have to do with balancing acts, I refer to my old stand-by, the baseball bat. I think it's appropriate for this situation.

The only thing you're trying to do is balance the bat, on end, in the palm of your hand.
- With the heavy end down, it's really difficult for any length of time and invariably gets out of control.
- With the light end down, it's quite doable for a lengthy amount of time.

Now lets add a pin perpendicular to the side of the bat about a quarter of the bat's length from your hand. We'll imagine the bat is a bolt carrier with an attached gas key.

Again, do the balancing act. This time, however, apply an upward force to the pin with your other hand, mimicking pressure exerted on a gas key during the bolt cycling.
- With the heavy end of the bat down, the force you exerted on the pin quickly destabilizes the bat before any appreciable lift is transmitted to the bat itself.
- With the heavy end away, and the pin on the light end, the bat is cleanly lifted from your palm.

What this demonstrates to me is that the rear of a bolt carrier needs to be heavily weight-biased to address any concerns of balance.
It's about controlling the pitch or levering off axis, is it not?
At that rate, and considering the design of the carrier, I don't think they can put enough weight on the rear of the carrier.

........


The baseball bat analogy, if you will, originally came about when discussing motorcycle dynamics. Some were saying you had to put weight low, others said it was better to have it high. The baseball bat immediately demonstrates the fallacy of putting weight low on a motorcycle if you understand the principles that keep it upright.
Extrapolating from the errant motorcycle designer's mistakes and applying them to a bolt carrier, perhaps they thought lighter was better.
"Sure, we can improve cyclic rates, wear-n-tear, etc."
Did they take into account side loads when they considered reducing longitudinal loads? I think they've only served to relocate the wear-n-tear, and increased side loads is not something I want running down my rails, if that's the result of weight reduction.

I consider myself a smart guy, albeit, uneducated. Regardless, the original designers of such great platforms as the AR, 1911 and M2 had to have made compromises in the designs. What is acceptable wear? What can be done to mitigate it? Does that adversely affect other components?
These original thinkers, I'm sure, asked themselves way more esoteric questions than I can even begin to imagine. To think that new technology somehow makes things better is arrogant without going back to the drawing board of the original design and understanding why the compromises were made. Yeah, making a trigger slicker makes sense, to a point.
Making a bolt carrier lighter and slicker seems to make sense too, but what have you done in consideration of the rest of the action and its new affect on the platform?

I think you could have a serious conversation with these guys. Popping a new idea, or another way to think, into people's heads is not unheard of even if the recipients are "industry experts".
Last edit: 9 years 4 months ago by funfred.
9 years 4 months ago #43855

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Replied by OleCowboy on topic POF Roller Cam Pin

Fun, you have said nothing I can take a negative view on. Improvements on any platform must overcome any negative side effects that improvement causes.

Lets look at the state of our Federal govt. The worlds shortest book would be titled "Things the Federal Govt does that works". WHY?

What has happened over the years is that law makers, Congress and the POTUS have drifted from laws and regulations that outline results to laws and regulations that specify process. Thus we have failure and a lack of progress, which is where the US is at this time.

Going back to the roller bearing on the cam bolt it appears someone did not have their eye on the results. When we fail to focus on the results of our efforts and instead focus on the process that gets us there we often do not have success that is measurable and worth the effort.

Some years ago the EPA came out with the process and results for sewage water purification. All sewage water was to be purified to 99.999%. The city of Dallas sued stating 1 it was just not necessary. 2 the cost to purify to 99% was $X, yet to get to the 99.999 was $XXXXXXXXXXX, just simply not cost effective and failed to yield any measurable improvement. They won, lucky for us taxpayers.

Point being the AR platform is a well tested unit and has a long life of use in high volumes. While it was not perfect on day 1, it has seen few mods and at this stage of its life and that scream volumes.

Some things take a LOT of well thought out engineering to be worthy of an improvement. As the platform matures it becomes hard and more difficult along with cost to find improvements that significantly increase performance.
9 years 4 months ago #43861

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Replied by funfred on topic POF Roller Cam Pin

Winding my participation in this discussion down, I hope no one took the view that I was pissin' on them for linking the discussed products...I don't shoot messengers in peace time. :D

I'm happy enough to let someone else design something else while a workable something else exists. I, however, am not about to reinvent the wheel. For those that are, or think they can improve on the tread pattern, more power to 'em.

In the case of firearms products, I think it's commendable that SRC had their products tortured by people that actually used the product thus being able to provide real world feedback, unlike Joe Tacticool who has every mod on his AR platform and only puts 100 rds a year through it...he'll never know what works and what doesn't.

It seems nothing is ever as simple as it looks.
So, if things are gonna be complicated in design or function, it better damn well be worth it. I imagine a Kriss Vector fits that bill, as does the P7. I think the jury is still out on Piston Impingement.

As to our government and its current state of operation and function?
The box I'm checking says, "Not fitting the criteria that keeps me satisfied in the performance of a product."
It's time to go back to the drawing board and revisit the original plan. Too many chefs makin' stew.
9 years 4 months ago #43866

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