Dr Big Bird PhD
New member
Wow $45 for a polymer? That makes it /almost/ tempting...
poly vs. steel ar build?
- Thread starter SpookBoy
- Start date
Is the ATI Omni any good http://palmettostatearmory.com/index.php/featured/ati-omni-stripped-lower-receiver.html
$40 sounds like a good price if it's a good lower
$40 sounds like a good price if it's a good lower
Metal god said:
I have not heard good things about the ATI Omni. I have a New Frontier lower I bought stripped and have liked it for its purpose. JoeBobs is out of stock on the stripped NFA lowers right now. They're $44.95 and you can use coupon code "slickguns" for 5% or $5 off, I can't remember. I think when I bought mine a few months ago it was $39.95 and coupon code took off $5. I will second the person that said JoeBobs ships quick. I've gotten good service from them.
viciouskitty
New member
I just bought an ATI omni complete lower I have only put 40 rounds thru it but it has been great so far, the fit is a bit tight but the gun is shooting accurately and it feels well made. Only time will tell how good it is but I feel at least as a casual plinking and range gun it seems to be great and the price is right. I bought it to make a lightweight build for the girlfriend
Actually, zukiphile, the test you linked explicity notes the direction of the impact on the sights:
"I attached three different types of BUIS... and dropped the rifle upside down from a height of 5 feet onto a concrete surface."
This means the impact struck the direct top of the sights. Do this to an MBUS, and it folds down (since it is not a "locked-open" design). Maybe they didn't fold all the way in to the locking position, but there is no doubt that the spring absorbed some of the blow.
You are correct in that it did not fail after one blow in this test. How it stands up to prolonged use/abuse is a different story. Again, I refer you to Sturmgewehr's excellent series of videos.
Please note that I own Magpul MBUS sights, and I own a set of the Troy Folding Battlesights. I personally have no problem with the polymer construction of the MBUS sights, and I think they are good back-up sights for the money.
But to insinuate that they are superior to the Troy sights (polymer contruction or not) is laugable. In addition to the question of long-term durability, the sight picture of the MBUS sights (with the chunky squarish rear aperature dictated by the requirements of the sight material) is pretty bad by comparision to the crisp, clear picture of the Troy sights.
Z said:
Fishbed77 said:
I think there is considerable doubt on that point. A straight drop onto a 90 degree deployed MBUS wouldn't fold it since it doesn't retract straight down but off to the rear.
The picture also shows the damage to the top of the MBUS.
I am not sugegsting that an MBUS is better than the Troy. (As an aside, I have a MBUS, but it has a round aperture. This may reflect a generational chnage in the design.) My point was that different materials react to different stresses differently. Concrete can withstand enormous compressive forces, but snaps where steel might bend. Hemp compresses easily, but has pretty good tensile strength. I wouldn't have much hope for a hemp or concrete lower.
Aluminium doesn't spring back well after deflection, whereas polymers are more likely to. Given the sorts of stresses an AR lower encounters, that could be useful. Polymers can do amazing things.
New Frontiers may be spoken about in future with the same kind of derision given Vulcan and Plum Crazy, and my purchase may turn out to be unfortunate. I find the concept interesting and couldn't find enough negative prior experience to keep me away from this modest outlay.
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zukiphile,
Note that I never questioned the use of polymer in the design of the MBUS (aside from the unfortunate design of the rear aperature) - I questioned the drop test you linked that is so often cited by Magpul fans (of which I am one), as well as the spring-loaded design of the MBUS sight, which - when it fails - fails spectacularly. I was also just correcting your quote that the other sights in the test were steel - they in fact are predominately aluminum.
The MBUS sights I have are the Gen2 variety. The rear aperature looks like this:
The sight picture is nowhere close to being as clean and crisp as the Troy sights (which are truly good enough to be used as primary sights). This is entirely because of the material. The chunky aperature piece is dictated by the polymer construction. It is also difficult to switch between aperature sizes - you have to literally pry them apart with your fingenails, as opposed to simply flicking them back and forth, as on Troy and other sights. I really hope that on Gen3, Magpul swaps these out for better metal pieces.
Anyway.... we have gone pretty far off topic, and this has become a bit of a measurement contest. Getting back to the polymer vs. aluminum AR lower receivers, in most cases, forged aluminum is the way to go. They don't cost much more, and they are stonger. You note that:
Well... yes and no. This is dependant entirely on the formulation of the polymer. This is testified to by the photos floating around of polymer AR lowers broken at the rear takedown pin hole. Forged aluminum is much more resistant to this - the strength of forged aluminum is so much higher that it doesn't need to rely on its elasticity to stay in one piece.
That said - I am totally open to using a polymer lower receiver (but not a polymer fire control group - that is just silly) on something like a lightweight hunting rifle. I think it could be pretty cool. To that extent, I'm curious about the Omni lower receivers (which supposedly take standard AR fire control groups) that I see for sale on Palmetto State Armory's website occasionally, and am curious about any owner feedback on them.
Note that I never questioned the use of polymer in the design of the MBUS (aside from the unfortunate design of the rear aperature) - I questioned the drop test you linked that is so often cited by Magpul fans (of which I am one), as well as the spring-loaded design of the MBUS sight, which - when it fails - fails spectacularly. I was also just correcting your quote that the other sights in the test were steel - they in fact are predominately aluminum.
The MBUS sights I have are the Gen2 variety. The rear aperature looks like this:
The sight picture is nowhere close to being as clean and crisp as the Troy sights (which are truly good enough to be used as primary sights). This is entirely because of the material. The chunky aperature piece is dictated by the polymer construction. It is also difficult to switch between aperature sizes - you have to literally pry them apart with your fingenails, as opposed to simply flicking them back and forth, as on Troy and other sights. I really hope that on Gen3, Magpul swaps these out for better metal pieces.
Anyway.... we have gone pretty far off topic, and this has become a bit of a measurement contest. Getting back to the polymer vs. aluminum AR lower receivers, in most cases, forged aluminum is the way to go. They don't cost much more, and they are stonger. You note that:
Well... yes and no. This is dependant entirely on the formulation of the polymer. This is testified to by the photos floating around of polymer AR lowers broken at the rear takedown pin hole. Forged aluminum is much more resistant to this - the strength of forged aluminum is so much higher that it doesn't need to rely on its elasticity to stay in one piece.
That said - I am totally open to using a polymer lower receiver (but not a polymer fire control group - that is just silly) on something like a lightweight hunting rifle. I think it could be pretty cool. To that extent, I'm curious about the Omni lower receivers (which supposedly take standard AR fire control groups) that I see for sale on Palmetto State Armory's website occasionally, and am curious about any owner feedback on them.
While I have no experience with the Omni lowers, I can confirm that my Plum Crazy lower took all standard AR parts with no issue. We were surprised to find that it even took a full auto fire control group with no internal modification needed beyond drilling a hole for an auto sear. New Frontier lowers are reportedly made from a similar or possibly even the same molds, so that the OP shouldn't have any issues swapping standard AR parts into the NFA lower that he's considering.
Apologies for my error on that.
I don't mean this to be a contest. I looked for negative information on polymer lowers, found some cracked Plum Crazy pictures and a video of a Omni that was giving the fellow problems in dropping a magazine. (FWIW, those searches also bring up cracked aluminium lowers, but since those are so much more numerous one can't draw any valid comparison based on those reports.)
I also agree that polymer performance will depend on the formulation. That is one reason that Plum Crazy experiences may not apply to New Fontier, who claim to have a different formula.
I can remember older guys, the ones old enough to have been trained on the M!4, telling me that ARs are garbage that shatter if you hit someone with them. (This did raise the question in my tender you mind "If you have a rifle in your hands, why are you hitting someone?") I don't think ARs are garbage even if they aren't ideal clubs, crowbars and shovels.
I look forward to evaluating polymers based on their fitness for the intended purpose, and hope this new generation will be sufficient. If they aren't, my loss and disappointment will be mild.
I think that if someone came up with a polymer AR lower that had a molded-in steel reinforcement around the more critical and wear-prone areas (take-down, hammer, and trigger pin holes, and buffer tube connection), they'd really be onto something! That would probably silence most critics (except those who just like to complain about everything polymer).
I have about 500 rounds through the AR I put together on a New Frontier lower this year, and I couldn't be happier.
I had already built one AR...a retro A1 clone. I had a second shorty upper and BCG already that I had been shooting on the one lower.
When I saw the New Frontier complete with FCG for a cheap price, I tried it.
Picked it up at my rifle club FFL and went directly to the range, where I slapped on my upper and tried it out. Worked perfectly....and has ever since.
The poly FCG seems very nice. The trigger pull is light and crisp. After 500 rounds, I see no evidence of wear. The lower is compatible with metal LPK's if you want.
I had already built one AR...a retro A1 clone. I had a second shorty upper and BCG already that I had been shooting on the one lower.
When I saw the New Frontier complete with FCG for a cheap price, I tried it.
Picked it up at my rifle club FFL and went directly to the range, where I slapped on my upper and tried it out. Worked perfectly....and has ever since.
The poly FCG seems very nice. The trigger pull is light and crisp. After 500 rounds, I see no evidence of wear. The lower is compatible with metal LPK's if you want.
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fishbed77 said:
I think the front take-down/pivot pin is an acknowledged weak area, and NFA discourages letting the upper slam itself open when the rear pin is removed.
I could see the utility of a threaded steel insert for adjustible stocks; that arrangement with the castle nut looks like it stresses the threads a lot more than a fixed stock rifle extension.
The area I find interesting is around the rear takedown hole. That area is small but take some bending stress under recoil. What I found interesting in high speed film is the direction of the bending force. I would have expected the receiver/stock junction to flex upward relative the to rest of the rifle, but it doesn't. It flexes downward.
If the failures of Plum Crazy lowers through the rear takedown hole occured under recoil, this suggests to me that the pictures of failure through the rear takedown hole are failures relating to insufficient tensile strength rather than insufficient rigidity. (That isn't to suggest that PC lowers were very rigid, just that the lack of rigidity wasn't the clue to the reason they failed.)
Technosavant
New member
That area is critical for another couple reasons. That's where there's holes drilled through the lower for the rear takedown detent/spring and the detent/spring for the safety selector.
If they are not beefed up, the right side of the lower is potentially much weaker thanks to those two holes. Easy enough to add reinforcement (IIRC, NFA does exactly this), but the maker does need to remember to do it.
I have read most of these post . what i'd like to know is what makes a good or bad polymer lower . Yes I know the basics . If it's made with weaker meterials it would not be as good . What spesificlly makes one bad and another one good ? I see some post saying this type is garbage or another is so so . What should we all be looking for .
I don't know the answer to your question, but for the last 25 years I have known the patent counsel who was widely regarded as a leading figure in polymer intellectual property. He talks about bonds, links, strands and molecular structure as if I have any idea what he is talking about, and complains that patent courts don't understand the technical issues in his cases.
Currently, there is a spanish outfit that has the rights to a polymer that can be formed into a reliable functional 5.56 case -- the whole case, not a plastic sleeve attached to a brass base as was done 15 or 20 years ago. (It was looking for a western hemisphere distributor, and being caught up in the middle, yes, I was hoping for a test sample.)
That's my long way of suggesting that polymer formulas go beyond good and bad and can be engineered for specific traits according to intended use.
If I were building an AR, I'd prefer to use a stainless steel lower, and stainless upper, if available. Very hard to find, and I don't know if any stainless uppers were ever made. Why use aluminum or plastic when you can use stainless steel? Weight??? Seriously??? I lug a Savage all steel and wood scoped 30-06 around and up trees when I am hunting, I'm not going to cry over a few extra ounces on an AR.
The bottom line - I just don't like having what everyone else has.
The bottom line - I just don't like having what everyone else has.
