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Topic: Polymer Cartridges (Read 297 times) previous topic - next topic

Re: Polymer Cartridges

Reply #16
Yes, in this manufactures formate. My post was intended to discuss technological advances that could be applied to this idea for advancements in reloading. Unfortunately my statements got construed into a personal recommendation of a product that has had reports of being unsafe. Kind of a sad and unfortunate twist in the thread. Make’s me hesitant to share other thoughts and ideas regarding the science of shooting. Guess I will need to be more careful in the future to make sure I am not so misunderstood. It is disappointing to me after posting to this form as the most senior member (2013 registration) that my history of statements and information shared could be so callously tossed to the wayside with trout even a question of where I was coming from with the thread. Something like: “Jerry are you recommending this product? My information suggests it’s unsafe. “

Re: Polymer Cartridges

Reply #17
In an effort to get the original discussion back on track here is an article from 2020

It mentions the problems from around 2015 and later mentions advancements made by true velocity and other companies since then.

Also mentions it's likely not intended to replace brass cartridges for the rest of us.

https://www.military.com/daily-news/2020/04/05/after-50-years-army-and-marine-corps-are-closing-dumping-brass-cased-ammo.html
Dave

Re: Polymer Cartridges

Reply #18
Good article! Thanks for sharing.

Re: Polymer Cartridges

Reply #19
The more current article mentions being able to reshape the interior of the case regardless of the exterior dimensions by changing wall thickness and I'd assume interior shoulder angles. That would in theory allow a case to be Ackley Improved and or increase neck length internally to improve ballistics but keep a 20° - 30° shoulder on the exterior to keep the chambering and feeding reliability at it's best if I'm reading it correctly.

That of itself would create untold tuning and or wildcatting options where the cost of reamers, barrel rechambers or swaps,brass etc would not have to be footed on a piece by piece or gun by gun basis.
Old chambers could benefit from the new internally shaped brass with no modifications.

Lots of possibilities here to save money at some point if they get the kinks ironed out.
Dave

Re: Polymer Cartridges

Reply #20
Man this thread got all sorts of turned around.. i just want to say that when i suggested digging into them a little it was merely on a safety standpoint.. thats all..i never once said anyone was recommending them.. my apologies to anyone who took my words as that.. was for sure not my intention.. and jerry i apologize to you if you feel i have compromised your integrity.. i would never do that.. period.. my apologies to the forum as well for my part in this thread..
Grant

Re: Polymer Cartridges

Reply #21
Grant we all get turned around on occasion. I sure have been guilty of multiple infractions in that category.
There is one thing about this thread that I am so happy to see. We are a group of men who can exchange the ideas, toss out a little testosterone to defend them and still be mature enough to come back together and let our ruffled feathers settle for more productive discourse. Do you know how special and rare that is in a public forum? I’m proud to be a part of this group and hope I can always give more than I take.

Re: Polymer Cartridges

Reply #22
If these were "perfect" cases, albeit single use, that'd free up a lot of equipment. Probably easiest to imagine what to keep; primer seater and bullet seater and, dare I say, Forc..., nah :)

Cost would have to be considered too; I figure about $100 for 100 count Lapua brass but I get about 10x uses so 10 cents per case.
Chris

Re: Polymer Cartridges

Reply #23
Man this thread got all sorts of turned around.. i just want to say that when i suggested digging into them a little it was merely on a safety standpoint.. thats all..i never once said anyone was recommending them.. my apologies to anyone who took my words as that.. was for sure not my intention.. and jerry i apologize to you if you feel i have compromised your integrity.. i would never do that.. period.. my apologies to the forum as well for my part in this thread..

Very big of you Grant, probably unnecessary and unwarranted but a huge gesture no less.

I've IMO wasted the better part of the day doing some research and finally caving in and watching full video. My opinion of those guys has not changed one bit but after reading the article I posted from 2020 but I now have no doubt there were problems from as far back as 40 - 50 years ago including the 2014 - 2015 era when the incident happened and the video was made.

That does NOT however make those two guys any more credible because of their delivery, lack of proof and venue which it was delivered. They proved nothing and just pointed blame when the blame may well have been their own negligence. I don't know and they didn't it prove either way.

So you owe me no apology Grant and I wouldn't worry about them selling much of it for the prices they're asking and they only have .308 in stock so no Creedmoor shooters will be hurt. Someone needs to warn Glen though 😁


https://tvammostore.com/




Dave

Re: Polymer Cartridges

Reply #24
OK, time to move on.

As Chris stated, do you think they could produce them at a cheap enough cost (10 cents or less)
that a one shot and throw away would be cheaper than multiple uses on brass?
Or do you think that they could be used over and over?

Re: Polymer Cartridges

Reply #25
I’m guessing the current format is directed at one shot and you are done. But advancing technology in plastics is mind boggling. I’m thinking of products coming out of aerospace R&D. I see no way for the current polymer cases to be adaptable to what I had in mind. But I’m speculating the materials that could be applied are already there our on the design table now. Maybe just a pipe dream on my part. To rehash - my thoughts are directed at producing case clones since I believe case variabilities in volume and expansion characteristics is one of the critical variables in internal ballistics - where the whole process of accuracy and precision begins.

Re: Polymer Cartridges

Reply #26
One other thing I wonder about is how it would have to defy the role virgin brass plays in the precision reloading game. I may be wrong about this but, I figure the first time brass is fired denies the reloader the chance to make them all the same. It takes fireforming to get us closer to making them all the same; shooting virgin brass is perfunctory for all intents. Of course, if polymer cases really are all the same, that could be a game-changer, if being the same is more important than being formed to a particular chamber.

So much to ponder; if it's single-use I'll no longer be a reloader, just a loader; if they give it away, I'll be a freeloader  :D
Chris

Re: Polymer Cartridges

Reply #27
I am just catching the tail end of this.  That is what I get for spending my Sunday morning sorting bullets.  This reminds me when Carbon Fibre first came out.  It was one of the Aerospace technologies that made it into the commercial market.  I was road racing about 40 years ago with a very competitive team.   There were companies that were taking Carbon Fibre and making engine internals...things like Rods and Connecting PINs.  We saw reducing the reciprocating weight as a big advantage so we decided to play with this bleeding edge technology...the promise was very compelling.   We put together a new motor in preparation for the next season.  We the motor lasted barely thru the 20 minute break-in session on the dyno.  Made great power while it lasted but then it came apart.  This cost us most of the season since we needed to spend a lot more money and time to rebuild it.  It wasn't that the technology was bad.  It was still in need of some maturing which eventually happened.  Also, how you do what you do, needed to change.  Like you don't machine Carbon Fibre like you do steel.  Tolerances are different, etc.  So Polymer cases will probably happen since there are distinct benefits.  But, unless you are willing to bleed a little along the way, it is wise to wait for the technology to be proven and the methods/processes for working with it to get figured out.  
Bob
If everything seems under control......you're just not going fast enough

Re: Polymer Cartridges

Reply #28
Excellent point. This is fun to exercise your mind and imagination with but don’t go hog wild with expectations.

Re: Polymer Cartridges

Reply #29
Along the automotive line Bob mentioned; I had an almost-new pickup powered by a very nice Cummins turbo diesel. This thing hauled real good, until it didn't. One day she just flat out lost power. Back at the dealer, the problem was diagnosed as a blown intercooler, which was the subject of a recall. Turns out someone decided making an intercooler out of plastic was a great idea. I don't want to overstate the case, maybe it was just the intercooler's frame, or other components made of plastic, I don't know, I don't work on car motors. Anyway, the intercooler was replaced by one made of metal, it didn't fail for the ensuing years I owned the truck.

I wouldn't be surprised to learn they finally figured out a way to make intercoolers out of plastic, and that they are in fact superior. No animus for the manufacturer, they tried, failed, and took care of me, the customer. Glad I took the first arrows for those enjoying their new plastic intercoolers :) 
Chris