Buffer Made of Brass

[Armed Eye Doc]

36 minutes ago, MinnMD66 said:

Updated lock back issue.

Well guys, I ordered the 7 position Vltor A5 buffer tube, EA1095 armalite buffer spring, a 5.0oz H3 buffer and everything finally works great. It's just amazing how the simplest of all component can be such a pain in the ass. Thanks to all that commented.   

 

That's great!  Enjoy shooting it.

[98Z5V]

Very good news. 

[survivalshop]

I dont believe the Buffer retainer is spec'ed to be at a slight angle , its the easiest way to bore the hole , with out having to bore through the Receiver Extension Threaded area in the Lower Receiver , see drawing . Boring through the Extension & making it a straight hole & not angled , would not change the orientation of the Buffer retainer .

 The 10 1/2" Buffer Spring length that was described seems a little short , nor was a coil count described . Mix components from retailers or manufacturers , who have no idea what an AR 10 or a DPMS LR 308 are or their differences , is what is getting a lot of builders in trouble , not the individual systems . 

Good to see the Rifle running well , enjoy !

 

[Matt.Cross]

12 minutes ago, survivalshop said:

I dont believe the Buffer retainer is spec'ed to be at a slight angle , 

Looking at the blue print, bottom row, 2nd from left part view. Look directly above and to the right of the rear receiver threads and you'll see the 6° specification for the buffer retainer hole offset.

[survivalshop]

6 minutes ago, Matt.Cross said:

Looking at the blue print, bottom row, 2nd from left part view. Look directly to the right of the rear receiver threads and you'll see the 6° specification for the buffer retainer hole offset.

Ok & whats your point , where is that going to change its location , if bored straight  from the top & not at an angle to miss the Receiver ring ?  Spec will be the same , only there will be a notch or hole cut into the Receiver Ring to bore it . 

[98Z5V]

If it's bored pure vertical, it sets the buffer further back in the receiver extension - and increases the chance that the BCG won't make contact with the buffer, and push it off the retainer when you close/pin the receivers together.

[Matt.Cross]

8 minutes ago, survivalshop said:

where is that going to change its location , if bored straight  from the top & not at an angle to miss the Receiver ring ? 

That would place the tip of the retainer further towards the rear of the receiver, requiring a longer BCG tail to make contact with the buffer. It would also make the area at the top of the receiver extension threads weaker by virtue of less metal there.

[survivalshop]

You guys miss the whole point , if bored directly straight from the top , it would be in the exact same place , the difference would be that you would have a hole in the Receiver Ring . its bored at an angle for purely manufacturing ease & cosmetic's , because it not only would look funny with a hole in the Top of the Receiver ring , but also in may weaken the Narrow area of the Receiver ring . 

 Also the Bore is somewhat of a loose fitment for the Retaining Pin & when the Receiver Extension is screwed in , the Retaining Pin levels with the bottom of the Extension , until the Buffer contacts it & it then will canter slightly forward ,because of fitment & Spring Pressure . Thats all the Pin is for is to hold the Buffer in the Extension while the Upper receiver is separated from the Lower . & I know you'all know that ?

 Probably will not find any photo's now ( but I will look , just because its you guys ?) , but some real early after market prototype Lower Receivers were actually made with a notch at the top to the Receiver Ring for boring the Retaining pin hole & I believe they were doing so because of Patent right infringement at the time or thought it was a better way then Armalite's manufacturing technique & of course they are history & never went any where.

[98Z5V]

Hey, brother, we didn't design it. Eugene Stoner did.  He designed it that way for a reason.  I think the examples that you could show where there's a notch in the lower receiver ring at the top, would be a shortcut that you'd have to make to bore it true vertical, and not go through the machine setup to bore it on a 6-degree angle. 

Don't blame us - that's the reason it's bored at an angle, and not true vertical, by the designer.  That man knows alot more about the system than I do.  I'm just here to bastardize his creation, and help people that buy parts that others make (you know the ones...  those manufacturers that can't understand his creation)...  

[Matt.Cross]

57 minutes ago, survivalshop said:

directly straight from the top , it would be in the exact same place , the difference would be that you would have a hole in the Receiver Ring

What do you mean by "in the exact same place"? The top of the hole is in one place, and the bottom is in another. Where between those two locations is the "same place" a vertical hole should be? 

If you mean that the straight vertical buffer retainer would hypothetically terminate at the same location, that's not a good idea or practice in terms of manufacturing and good engineering/quality control.

[98Z5V]

2 hours ago, Matt.Cross said:

What do you mean by "in the exact same place"? The top of the hole is in one place, and the bottom is in another. Where between those two locations is the "same place" a vertical hole should be?

If bored true vertical, it would have to be forward of it's current location on order to accomplish the same placement of the buffer retainer pin (end), and still accomplish the same dimensional placement of the buffer - to be kicked off that retainer pin when you close the receivers.  There's not alot of room there to be placing it any further forward, and still retain the lower receiver's strength in that area...

That's just my non-machinist, non-engineer point of view, but what do I know...  

[Matt.Cross]

26 minutes ago, 98Z5V said:

If bored true vertical, it would have to be forward of it's current location on order to accomplish the same placement of the buffer retainer pin (end), and still accomplish the same dimensional placement of the buffer - to be kicked off that retainer pin when you close the receivers.  There's not alot of room there to be placing it any further forward, and still retain the lower receiver's strength in that area...

That's just my non-machinist, non-engineer point of view, but what do I know...  

That's pretty much where I was going, but I don't know Jack....

 

[98Z5V]

10 hours ago, Matt.Cross said:

That's pretty much where I was going, but I don't know Jack....

 

Nah, I'm just trying to keep up...  

[survivalshop]

22 hours ago, 98Z5V said:

Hey, brother, we didn't design it. Eugene Stoner did.  He designed it that way for a reason.  I think the examples that you could show where there's a notch in the lower receiver ring at the top, would be a shortcut that you'd have to make to bore it true vertical, and not go through the machine setup to bore it on a 6-degree angle. 

Don't blame us - that's the reason it's bored at an angle, and not true vertical, by the designer.  That man knows alot more about the system than I do.  I'm just here to bastardize his creation, and help people that buy parts that others make (you know the ones...  those manufacturers that can't understand his creation)...  

It was mentioned that it was possible that the Buffer system might not be working because of no angle in the Bore of the Retaining Pin , thats not true , if it had the same placement , but true vertical , it work the same as if it was bored at an angle , thats the only reason I mentioned this whole thing . its not bored at an angle for any function of the Buffer system or its retainer , its Bored at an angle for pure manufacturing ease , thats what i said . For someone to say its not working because of it not being at an angle is baloney , as long as it is in the correct position to achieve its purpose .

If anyone believes its bored at an angle for an operational purpose , please show me the documentation .?

Edited August 4, 2018 by survivalshop

[98Z5V]

12 minutes ago, survivalshop said:

It was mentioned that it was possible that the Buffer system might not be working because of no angle in the Bore of the Retaining Pin , thats not true , if it had the same placement , but true vertical , it work the same as if it was bored at an angle , thats the only reason I mentioned this whole thing . its not bored at an angle for any function of the Buffer system or its retainer , its Bored at an angle for pure manufacturing ease , thats what i said . For someone to say its not working because of it not being at an angle is baloney , as long as it is in the correct position to achieve its purpose .

If anyone believes its bored at an angle for an operational purpose , please show me the documentation .?

Boring it at a 6* angle will place the buffer further forward, when installed.  Boring it straight vertical will place it more rearward, when installed.  When not installed as far forward as it's supposed to be, the BCG might not/will not kick it off the buffer retainer when you close those receivers.

It's an 80% receiver, not a fully-machined lower.  He chewed up his buffer face.  That's the only reason I brought that up, in the very beginning.

Who bored that buffer retainer hole - the owner (OP here), or was it part of the 80% that was already done when he got it?  If it was already done when he got it, is it at the proper angle?

My questions, and line of reasoning for asking.

Here's his buffer face, all chewed to shiit.

^^^  That's his picture, from page 1 in this thread.

There's only ONE thing that will cause a buffer face to get chewed up - the BCG didn't push it off the buffer retainer when the receivers close/pin together.  That's the only thing.  There is no other cause.  Typically, that's because of uppers or lowers that are not machined correctly.  His upper is AP. His lower is 80%.  You check what you can, first, and inspect in the most logical manner...  

Edited August 4, 2018 by 98Z5V

[308kiwi]

I'll pitch my 2c in here as well, with all due respect and not wanting to be argumentative.

Yes it is bored on an angle, probably to ease in manufacture, BUT, the fact is is bored at an angle DOES shift the tip of the pin further forward than if it was bored vertical WITH the top of the bore in the same place, it's logic, the more you tilt it forward the further forward the tip of pin will be, sure the top end of the hole may be in the same place but the retainer protrudes further than that and will keep moving forward the more it is tilted. Think of the top of the bore as being a pivot point, the top of the pin moves forward and the bottom of the pin moves rearward proportionally as the angle of the hole increases.

There is another thing that will cause the buffer to hit the retainer when all is assembled and that is if the barrel extension is too far forward in the upper,  how many posts have there been about 'steps' from the front inside face of the upper receiver and the rear face of the barrel extension locking lugs? plenty, there was one here just a week or two ago from the SAME member on the SAME rifle.

 

 

 

[98Z5V]

33 minutes ago, 308kiwi said:

There is another thing that will cause the buffer to hit the retainer when all is assembled and that is if the barrel extension is too far forward in the upper, 

Matt and I talked about this very thing tonight.  This very thing.

If your buffer face is getting chewed up, there's only ONE thing that going on with that - and in the past,with so many "billet, custom receivers" from so many companies that don't know what they're doing... it still comes down to this.. 

If your buffer face is chewed, your "receivers are out of spec."  Period.  There's only TWO things that can make that happen.  ONLY TWO.  If your receivers PIN together, and "mate" then nothing else, in this free world can cause a chewed buffer face.  Nothing...  Look at these two things, right here:

#1.  Your lower receiver is out of spec, and your buffer retainer hole is out of spec.  It's either drilled NOT on a 6* angle, or it's drilled too far back in the lower receiver.  Period.

#2. Your upper is out of spec, and the THREADED area of your upper receiver is too long.  Somebody jacked that up, and it's the LESS likely of the two. If your UPPER THREADED AREA is too long, it places your barrel too far forward, which locates your BCG too far forward (when assembled), and your BCG is too far forward in the upper, to...

PUSH YOUR BUFFER OFF THE BUFFER RETAINER PIN, IN THE LOWER.

It's REALLY that simple.  It can  - really - be only those two things.

If you chew up a buffer face like that, your lower buffer retainer pin hole is jacked in it's spec, or your upper threaded end wasn't to spec, and it's too long.

Yeah, short BCG, whatever - that shiit is a standard. Both platforms, big and small. RRA doesn't have this issue, and their BCG is another 1/4" longer, and their buffer is another 1/4" shorter - they don't chew buffer faces.

Those two things are the problem. Nothing else.  More often than not, it's the buffer retainer hole.

I bought a Spike's Tactical Billet Receiver set before they were announced.  Got one of the first ones made. It's either serial # 31 or #34 - I'd have to dig the bastard out to tell you for certain.  No matter, one of the first ones out.  That thing chewed the SHIIT out of my buffer face within 100 rounds.  I didn't bitch, complain,demand a refund... I fixed it - with a Tubbs Carrier Weight System - which added 0.080" tothe length of the BCG.  THAT pushed the buffer off it's retaining pin, in the lower.

I never talked about that here by manufacturer-name, and I've even refused to state the manufacturer, when I discussed the issue I had, but what my Tubb CWS fixed.

Well, it was a Spike's Tactical Billet 5.56 upper and lower set, and it was a pretty penny, back then.  Something in the upper, or the lower was out of spec.  It's a low-run serial number, and they didn't have it right.  I fixed it.

There really is only those two things, right there, that will cause you to chew up a buffer face. Only those two.  Your upper threaded portion on the upper receiver is too long, or your lower receiver buffer retainer pin hole is jacked, and not to spec.

Nothing else will chew a buffer face.  Nothing.

@308kiwi - thanks for posting what you did, brother.  I've needed to vent on this subject for awhile.  Years...  

( I built that Spike's billet 5.56 gun in 2010....)

Edited August 5, 2018 by 98Z5V

[survivalshop]

  So you are saying that if the hole was bored straight down with out an angle & placing the Pin in the exact same position  , it wouldn't work ?  You do know the Hole diameter is quit a bit larger in diameter then the Pins Out side diameter & it floats in its Bore , so no matter what angle you make ( 6 degree's is not very much ) it will move forward with Buffer /Spring pressure & it will do it no matter what its Bored at .

 The Receiver Extension actually keeps it in a somewhat straight up angle , with the over bore being as it is , when pressure is on it from the Buffer/Spring it does tilt a little forward , & its not because its bored at that 6 degree angle , its because the Bore is larger then the Pin & it tilts all by its self with out any angle , the only thing that keeps it with in a certain limit is the Length of the Pin its self . 

You'all have you thoughts on it & I have mine , lets just say that & you'all go about your repairing & figuring out all this Gunsmithing stuff .

[Snow_N_Surf]

On 8/3/2018 at 3:07 PM, survivalshop said:

I dont believe the Buffer retainer is spec'ed to be at a slight angle , its the easiest way to bore the hole , with out having to bore through the Receiver Extension Threaded area in the Lower Receiver , see drawing . Boring through the Extension & making it a straight hole & not angled , would not change the orientation of the Buffer retainer .

 The 10 1/2" Buffer Spring length that was described seems a little short , nor was a coil count described . Mix components from retailers or manufacturers , who have no idea what an AR 10 or a DPMS LR 308 are or their differences , is what is getting a lot of builders in trouble , not the individual systems . 

Good to see the Rifle running well , enjoy !

 

I'm with Survival on this one.  The stopping point is the closest point to the buffer head, which is the same regardless if the hole is vertical or off 6 degrees.  The difference is at the 6 degree angle the top of the pin would slope outward away from the face of the buffer instead of parallel to it.  This is all in theory though, in a perfect world without tolerance variances.  Account for the play in the hole & pin, between the buffer & tube, shape and angle of the buffer head, ect and there's a lot of play in the system.  Even so, you're probably talking tens or thousandths of an inch in difference, in other words, not enough to make an operational difference.  It's most likely drilled at an angle purely due to ease of manufacturing.

[Matt.Cross]

19 minutes ago, Snow_N_Surf said:

I'm with Survival on this one.  The stopping point is the closest point to the buffer head, which is the same regardless if the hole is vertical or off 6 degrees.  The difference is at the 6 degree angle the top of the pin would slope outward away from the face of the buffer instead of parallel to it.  This is all in theory though, in a perfect world without tolerance variances.  Account for the play in the hole & pin, between the buffer & tube, shape and angle of the buffer head, ect and there's a lot of play in the system.  Even so, you're probably talking tens or thousandths of an inch in difference, in other words, not enough to make an operational difference.  It's most likely drilled at an angle purely due to ease of manufacturing.

 

It's not the same, and grade school trig proves it. Not only that, but survivalshop was incorrect in that the blueprint he posted does in fact specify a 6° angle at the top of the centerline datum for that feature. Let me assure you as a machinist that's it's not easier from a manufacturing standpoint to drill an angled hole as opposed to perpendicular.

[Snow_N_Surf]

25 minutes ago, Matt.Cross said:

 

It's not the same, and grade school trig proves it. Not only that, but survivalshop was incorrect in that the blueprint he posted does in fact specify a 6° angle at the top of the centerline datum for that feature. Let me assure you as a machinist that's it's not easier from a manufacturing standpoint to drill an angled hole as opposed to perpendicular.

You're right, not easier to drill a 6* hole, just necessary to clear the top of the receiver.  As a machinist you'd know that finding a right angle tool and bit that would fit in that space may prove impossible.

Let me explain it another way.  Say you've got a wall and you slide your shoe along the floor until it meets the wall.  Regardless if that wall is plum or at an angle sloping away, your foot is going to stop at the same location.  In this example the wall represents the pin and the shoe represents the head of the buffer.  Unless that shoe rides up the wall, which is possible depending upon tolerances, it's going to stop at the exact same location.  We could do the math of worst case scenario, given that some how due to slop the first point of contact on the face of that buffer tube was the very end of the pin.  Unfortunately, I'm not good enough with a computer to draw it up and post it here but all you'd have to do is measure how far the pin extends, draw a right angle triangle with a 6* corner and solve the lengths of the other sides.  We're talking a few mm at most.  Not enough to make a difference.

This is pure speculation on everyone's part but one logical reason to drill the hole at an angle has been provided.  To backup your position you'd need to provide a different, functional need.

[Matt.Cross]

27 minutes ago, Snow_N_Surf said:

You're right, not easier to drill a 6* hole, just necessary to clear the top of the receiver.  As a machinist you'd know that finding a right angle tool and bit that would fit in that space may prove impossible.

Let me explain it another way.  Say you've got a wall and you slide your shoe along the floor until it meets the wall.  Regardless if that wall is plum or at an angle sloping away, your foot is going to stop at the same location.  In this example the wall represents the pin and the shoe represents the head of the buffer.  Unless that shoe rides up the wall, which is possible depending upon tolerances, it's going to stop at the exact same location.  We could do the math of worst case scenario, given that some how due to slop the first point of contact on the face of that buffer tube was the very end of the pin.  Unfortunately, I'm not good enough with a computer to draw it up and post it here but all you'd have to do is measure how far the pin extends, draw a right angle triangle with a 6* corner and solve the lengths of the other sides.  We're talking a few mm at most.  Not enough to make a difference.

This is pure speculation on everyone's part but one logical reason to drill the hole at an angle has been provided.  To backup your position you'd need to provide a different, functional need.

Where is your theoretical and perpendicularly drilled hole located as opposed to the drawing shown?

[Snow_N_Surf]

4 minutes ago, Matt.Cross said:

Where is your theoretical and perpendicularly drilled hole located as opposed to the drawing shown?

If I understand what you're asking, it's in my head, lol.

If you're asking where the hole is drilled, I'm assuming the hole (aka the base of the wall) is drilled in the same location regardless if it were perpendicular or at an angle.  The edge of the hole closest to the buffer is the stopping point (the shortest distance).

[Matt.Cross]

1 hour ago, Snow_N_Surf said:

The edge of the hole closest to the buffer is the stopping point (the shortest distance).

That's also incorrect. The end of the buffer tube overlaps the nearest side and the central pin on the end of the buffer retainer blocks the buffer travel.

What I'm looking for is the specific position of your theoretical perpendicular hole, as opposed to what's shown on the drawing. As a machinist, the drawing shows the location and specifics of the angled hole with so much specificity as to remove any doubt about how to machine that feature. What I want to know is where your hole would be located with equal specificity. If you give that some thought, you might understand some of the necessity of both the angle of the hole and it's specific location in the bigger picture of when the assembly comes together.

 

[jtallen83]

6 hours ago, Matt.Cross said:

If you give that some thought, you might understand some of the necessity of both the angle of the hole and it's specific location in the bigger picture of when the assembly comes together.

Thank you, I was starting to think I didn't understand what I thought I understood 

Now if I was smart enough to explain what I think I understand..............