MDI SLR receivers come loose.

[cr5]

I know this is pretty much the most basic way they could go at it, but I don't think they can readily drastically change the mounting system without involving the RCMP and FRT process... so we have to work with the currect design.

They aren't gonna change the system with a cross-pin because they would have to replace every receiver set made and sold and would instantly go bankrupt and end up on the street.

But the main problem with the currect design is that there isn't a mechanical fail-proof system to keep the main bolt from rotating by itself. A spring-loaded plunger locking into the bolt head would solve that issue and wouldn't alter the mounting system configuration.


Heck, I'm not affected by this SLR problem because I didn't buy into the design, but I still want to help those that did and have a problem to deal with.

Personally I don't care if they go bankrupt and end up on the street. They should have built it right to begin with then.

If they can't or are unwilling to change the design then people should stop buying them and those that already have them should be refunded 100% if they choose to opt out. The manufacturer screwed up and now the customers are left twirling in the wind and forced to come up with their own solution.
If they go out of business then so be it, I say that they should deliver a quality product that is well designed and makes their customers happy or they deserve to go out of business. Why support a company that doesn't support it's customers? They made a mistake, I can accept that but it's how they handle things once they know there is a flaw in the design that tells me whether they are worth supporting or not. What I've seen them do about it is nothing, just like when people were mad at how long past the "estimated" delivery date was, they just ignored their customers and acted like it was none of their business.

Have they offered anything to the guys having problems other than suggest they use threadlock? Which you say is a big no-no with a helicoil, so do they not know anything about helicoils and their product or are you wrong saying not to thread lock a helicoil?
They should be offering to exchange problem units and looking into a real fix rather than pumping out more and more receiver sets trying to maximize cash before people catch on and stop buying their stuff.

 

[Sqr]

No, not a metallurgist or a machinist but I still know this is a crap design that was simply the easiest way they could come up with to stop them from sliding apart. Works great on paper but not in the field.

The solution is not a better bolt, it's getting rid of the bolt altogether and changing the design to utilize a cross pin or some other type of plunger or something that can simply be depressed or slid out like a captured pin on an AR.

Really awesome how we stick together on this site isn't it? A few guys have problems but the guys that haven't had issues YET act like it's user error and stand behind the manufacturer defending the design which is obviously flawed. Everyone should be pressuring MDI to change the design to something more reliable instead of looking for a home fix to work around the crappy design.

To the guys that haven't had problems yet. If the bolt on your rifle starts working itself free are you still going to say there is nothing wrong with the design and you'll just go buy some fancy bolt? Or are you going to be pissed and want them to fix your rifle so it doesn't keep coming loose? I would bet that all of you will be pissed and want it repaired, so why is it a non issue just because it's happening to someone else? They bought the same product you did except they were not as lucky as you.
There's no way of knowing whether or not every single one of these will eventually start having the same issue but my bet would be that it's only a matter of time till every single owner of an SLR receiver set is having problems with it coming loose.

The take down pin design is not fool proof as an AR’s receiver set will become loose with usage and rattle like tin cans over time. Yes they don’t fall out but it becomes annoying enough that pistol grip tension screws and accuracy wedges are used. Secondly trigger and hammer pins are another bone of contention which has led to anti walking pin contraptions. This hardware is only used due to operator error and or out of mil-spec lowers. The reason I bring this up is I never read about people complaining about these real AR deficiencies and only deal with it. Just like some owners do with their SLR, Stags and ATRS offerings.

 

[Dietz]

I ordered a Nord Lock washer NL5ss. I think the OD is good but will have to drill out the ID by a mm to fit the current bolt. I’ll update here with results. I also think a lot of us our on the same wavelength. If a custom shoulder bolt could machined to sit high enough to be locked in place by the secondary bolt that would work great. Might need a secondary bolt with flat bottom. Not sure why it’s not a socket head cap screw too.

Yeah but still... the fit between the two can't be perfest so there's gonna be some back-and-fort between the two bolts and the retention screw would end up unscrewing itself off. That's why I think a spring-loaded plunger that sits under the bolt head is a good solution because the plunger can't screw off.

My fiest thought when I heard about this was "hey #### that, let's lockwire that stuff up" but then you don't have a field-expediant way to open the gun. The bolts backing out would be solved permanently, but if your gun pukes it's gonna take a little while before you can get into it.

Hence the plunger. You could even design a tool comparable to a front sight post tool to make disassembly less of a pain in the ass.

 

[cr5]

The take down pin design is not fool proof as an AR’s receiver set will become loose with usage and rattle like tin cans over time. Yes they don’t fall out but it becomes annoying enough that pistol grip tension screws and accuracy wedges are used. Secondly trigger and hammer pins are another bone of contention which has led to anti walking pin contraptions. This hardware is only used due to operator error and or out of mil-spec lowers. The reason I bring this up is I never read about people complaining about these real AR deficiencies and only deal with it. Just like some owners do with their SLR, Stags and ATRS offerings.

A little rattle is not a problem with a traditional AR. It may annoy some people but there is no need to try to tighten it up with an accuwedge or tensioner screw. People do it because they read the internet too much and make a big problem out of a nothing.
As you said the anti trigger pin walk stuff is junk designed to make money off guys that read too much on the internet forums and a complete waste of money, if you assemble your trigger group correctly the pins don't and can't walk.

The biggest problem with you using the example you did with pins wearing and stuff is that you're talking about a rifle with 10's of thousands of rounds wearing out and becoming loose, what we're dealing with here is a problem with brand new rifles with 100 rounds through them. If this happened after a few thousand rounds I could support finding a home fix but I'd still expect the manufacturer to listen to it's customers and try to make it better to increase it's service life.

In my opinion. They either take responsibility for the problem and make it right with every customer affected and also start working on a fix that can be retro-fit into existing units or they deserve to be out of business by the end of 2019 and I hope when they go under they're flat broke and not skip out as millionaires after taking people's money and delivering a half-ass product that has been nothing but headaches for customers.

Like I said earlier, just because your rifle isn't affected doesn't mean that it won't develop the same issues within a few hundred rounds. Some guys may never see it but I think the chances are good that eventually this is going to be an issue for every owner of an SLR receiver set.

This quote is exactly why I think it's very likely that this will eventually be a problem for every owner

Yeah but still... the fit between the two can't be perfect so there's gonna be some back-and-fort between the two bolts and the retention screw would end up unscrewing itself off.

 

[Dietz]

The take down pin design is not fool proof as an AR’s receiver set will become loose with usage and rattle like tin cans over time. Yes they don’t fall out but it becomes annoying enough that pistol grip tension screws and accuracy wedges are used. Secondly trigger and hammer pins are another bone of contention which has led to anti walking pin contraptions. This hardware is only used due to operator error and or out of mil-spec lowers. The reason I bring this up is I never read about people complaining about these real AR deficiencies and only deal with it. Just like some owners do with their SLR, Stags and ATRS offerings.

Those are not deficiencies.

Receivers rattling is a non-issue. Not until you get into the exteremely worn-out old beat-up 60's era M16A1's that don't pass the takedown/pivot pin no-go gauges.

Secondly, pins walking out is another non-issue. The design of the trigger and hammer pin slots with the hammer J spring and hammer spring legs sitting in the slot makes this a problem that can't occur. Unless you installed your springs incorrectly or bought some cheap noname chinese crap out of spec LPK.

 

[ThatM305Guy]

A little rattle is not a problem with a traditional AR. It may annoy some people but there is no need to try to tighten it up with an accuwedge or tensioner screw. People do it because they read the internet too much and make a big problem out of a nothing.
As you said the anti trigger pin walk stuff is junk designed to make money off guys that read too much on the internet forums and a complete waste of money, if you assemble your trigger group correctly the pins don't and can't walk.

Wait a minute....

 

[Armedsask]

Wait a minute....

Ha ha ha. Zing!

 

[no-one special]

My set was not anodized but looking at how poorly the helicoil was installed and the lack of back up by the manufacturer I took the lower to another shop and had them open up the holeenough to properly thread the pocket then make a bushing that was threded inside and outside. This bushing was then red loktited into the lower. I chose to go with 1/4x20 TPI which if it does get lost can be found at any hardward store. I believe it would have solved the problem of the helicoil failing (yes it was that badly installed) but it would not have solved the possible problem of the screw holding the upper and lower together. I say possible as the more I thought about that along with the other issues opted to cut my loses and sell it while I still could.

I believe the bushing would have been a better way to go than a Helicoil but can offer no proof. What I DO know is that it looked a whole lot better after the improvement than before.

 

[cr5]

Wait a minute....

Lol, so you don't think that people get stupid ideas in their heads from reading crap on the internet? It's why the world is as f'd up as it is these days.
Never heard of anyone replacing every part on a rifle that they haven't even fired yet based solely on what they read on this site?
Hmmm, does the 102 ring any bells? Not saying that a BCL has a single good part in it but you'd think that guys would at least shoot it first then replace parts if they have problems.
Go to car forums and you'll find the same thing, guys changing out parts on their cars because one or two guys had a problem and all of a sudden it's a well known issue that everyone should replace even though no one else has had a problem yet. Same happens on motorcycle forums and pretty much anything you go look for.

Or are you saying that a little upper/lower slop on an AR actually is a big problem that needs to be addressed?
Or that trigger pins walking out the side is a real problem and everyone should "upgrade" to a KNS anti-walk pin set?

 

[r34skyline]

Lol, so you don't think that people get stupid ideas in their heads from reading crap on the internet? It's why the world is as f'd up as it is these days.
Never heard of anyone replacing every part on a rifle that they haven't even fired yet based solely on what they read on this site?
Hmmm, does the 102 ring any bells? Not saying that a BCL has a single good part in it but you'd think that guys would at least shoot it first then replace parts if they have problems.
Go to car forums and you'll find the same thing, guys changing out parts on their cars because one or two guys had a problem and all of a sudden it's a well known issue that everyone should replace even though no one else has had a problem yet. Same happens on motorcycle forums and pretty much anything you go look for.

Or are you saying that a little upper/lower slop on an AR actually is a big problem that needs to be addressed?
Or that trigger pins walking out the side is a real problem and everyone should "upgrade" to a KNS anti-walk pin set?

Or maybe people could put on a lock washer or oring on their slr and move on...

 

[Daver_II]

I have personally seen an AR-10 that was accurized and fitting the upper and lower so there was zero-play had a massive effect down range.

For practical application it doesn't really matter but when precision matters... well..

 

[Sqr]

Lol, so you don't think that people get stupid ideas in their heads from reading crap on the internet? It's why the world is as f'd up as it is these days.
Never heard of anyone replacing every part on a rifle that they haven't even fired yet based solely on what they read on this site?
Hmmm, does the 102 ring any bells? Not saying that a BCL has a single good part in it but you'd think that guys would at least shoot it first then replace parts if they have problems.
Go to car forums and you'll find the same thing, guys changing out parts on their cars because one or two guys had a problem and all of a sudden it's a well known issue that everyone should replace even though no one else has had a problem yet. Same happens on motorcycle forums and pretty much anything you go look for.

Or are you saying that a little upper/lower slop on an AR actually is a big problem that needs to be addressed?
Or that trigger pins walking out the side is a real problem and everyone should "upgrade" to a KNS anti-walk pin set?

I can not argue with this post, but I personally HATE sloppy receivers. But that is just me.

 

[r34skyline]

I have personally seen an AR-10 that was accurized and fitting the upper and lower so there was zero-play had a massive effect down range.

For practical application it doesn't really matter but when precision matters... well..

Explain this to me please. Go with the before and after of the "accurizing" process and how removing the play from the upper and lower.

What was the groups before. And what were they after with zero change in any other componentry but the tightening of receivers.

 

[Daver_II]

Explain this to me please. Go with the before and after of the "accurizing" process and how removing the play from the upper and lower.

What was the groups before. And what were they after with zero change in any other componentry but the tightening of receivers.

I didn't do the work, but was a witness to the results. Many hours of machining and some very nice groups.

The gun was reported to shoot over an inch, and after the work of a talented machinist, was significantly under.

Same shooter, conditions, and ammo.

 

[ThatM305Guy]

Lol, so you don't think that people get stupid ideas in their heads from reading crap on the internet? It's why the world is as f'd up as it is these days.
Never heard of anyone replacing every part on a rifle that they haven't even fired yet based solely on what they read on this site?
Hmmm, does the 102 ring any bells? Not saying that a BCL has a single good part in it but you'd think that guys would at least shoot it first then replace parts if they have problems.
Go to car forums and you'll find the same thing, guys changing out parts on their cars because one or two guys had a problem and all of a sudden it's a well known issue that everyone should replace even though no one else has had a problem yet. Same happens on motorcycle forums and pretty much anything you go look for.

Or are you saying that a little upper/lower slop on an AR actually is a big problem that needs to be addressed?
Or that trigger pins walking out the side is a real problem and everyone should "upgrade" to a KNS anti-walk pin set?

Nothing personal CR, but I find your comments to be extremely obnoxious.....openly advocating for the bankruptcy of a company because they.....used a threaded fastener to retain two mating peices? Come on man. People have used these to hold things together for well over a hundred years now (including guns).
Maccabee has made mistakes, but in MY OPINNION they were mistakes. Any claims of their actions being malicious or vindictive, is simply projection of personal frustration onto them.

I dont own an SLR, and I dont really plan on getting one. Simple fact is that I couldn't afford one when they dropped, and in retrospect I just dont like the magwell profile.....

I'm going through the leg work to hopefully shut up all the people #####ing. Also because I'm a nice guy and I want to help out maccabee by finding a good source for these nylock screws, instead of flaming on the internet with the stated goal of advocating for their bankruptcy.

Give your head a shake man...

 

[Sqr]

 

[walterklassen]

Nothing personal CR, but I find your comments to be extremely obnoxious.....openly advocating for the bankruptcy of a company because they.....used a threaded fastener to retain two mating peices? Come on man. People have used these to hold things together for well over a hundred years now (including guns).
Maccabee has made mistakes, but in MY OPINNION they were mistakes. Any claims of their actions being malicious or vindictive, is simply projection of personal frustration onto them.

I dont own an SLR, and I dont really plan on getting one. Simple fact is that I couldn't afford one when they dropped, and in retrospect I just dont like the magwell profile.....

I'm going through the leg work to hopefully shut up all the people #####ing. Also because I'm a nice guy and I want to help out maccabee by finding a good source for these nylock screws, instead of flaming on the internet with the stated goal of advocating for their bankruptcy.

Give your head a shake man...

If you want to see an example of how a non-restricted ar should function, buy yourself a modern varminter.

 

[Gatehouse]

That's far too complex an operation for anyone but a trained gunsmith or engineer to undertake.

 

[ThatM305Guy]

If you want to see an example of how a non-restricted ar should function, buy yourself a modern varminter.

Modern Sporter*

 

[Gatehouse]

The more I look at it, the more I like the bolt design. I know "they" say that a loose fit between an upper and lower on an AR15 has nothing to do with accuracy, but I am starting to wonder if the tight fit with the SLR is contributing to the excellent accuracy that many of us are experiencing with this rifle. A pin system may allow for more movement than a tight bolt, which may result in less accuracy.

And keep in mind what applies to an AR15 (loose fit not a factor in accuracy) may not apply to an SLR, which really is quite a different design.

My bolt isn't coming loose, but if it does, it looks like the problem can be solved with one of the Nord Loc or similar fixes. MDI might want to start supplying the recievers with one of these washers or one of the nylon bolts or something. There is an awful lot of machinery that is subject to heavy stresses that is being held together with bolts, so I'm confident that a rifle can also be held together with one.

Actually, I have an ATRS lower that is held together with a bolt, in a very similar fashion to the SLR. Not exactly the same of course, but close enough. It's a 50 BMG and works fine.

The other argument about using pins- that take down should be able to be performed without tools- is pretty subjective. Including a hex key with your gear is simple enough, and as you saw in the video, it's a very short process to perform.

Perhaps the most important question is "why would someone buy a receiver set with a bolt if they didn't want a bolt?"