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So, I am a big fan of JRA for multiple reasons.
1. Great customer service
2. Awesome sale prices
3. Stand behind their product, even as a home builder
4. Hitting the market strong and improving all at the same time.

Here are the pics of my two JRA receivers. 308 was a almost terrible stamping on the serial and there was a small hump from machining on the inside near the heel.
In 325, machining has cleaned up dramatically. Stampings are awesome and they even thickened the heel markings.

The second generation as I like to call them/ recent run of receivers started at serial 313.
 

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I'd be interested to know if you placed a bolt in the receiver and retracted it fully to the rear would the bolt make uniform/flush contact with the receiver heel? With a few receivers I've observed the receiver heel cut with large radii that impede bolt travel. Specifically on the side closest to the FP relief cut.

For example:



A properly clearanced receiver would look like this:
 

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my two JRA receivers. 308 was a almost terrible stamping on the serial....In 325, machining has cleaned up dramatically. Stampings are awesome and they even thickened the heel markings.
+1, I'd agree, the newer one looks great. I like attention to detail like that.
m14brian
 

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I'd be interested to know if you placed a bolt in the receiver and retracted it fully to the rear would the bolt make uniform/flush contact with the receiver heel? With a few receivers I've observed the receiver heel cut with large radii that impede bolt travel. Specifically on the side closest to the FP relief cut.

For example:



A properly clearanced receiver would look like this:

It's those little things that get ya. What is your cure for this? Dremel? Send back? Fixing this "right" isn't gonna be cheap and with CNC being what it is there probably is a whole run of these that are identical. What's a run? 500? 5000?
My first thought would be to Dremel some clearance in there and repair the finish. Immediate concern is cutting through the hardness, but will it matter? I guess time will tell. This should be discounted as a second. IMHO
To fix it right you would have to anneal the whole receiver in a heat treat oven with a vacuum, (to remove carburizing)then recut that area, and finally heat treat again and refinish. The cost to do one this way would approach the cost of a new receiver. I suspect even to do 500 the cost (per unit) would be significant. I think "we" learned from other manufacturers that multiple heat treat is not a good thing.
 

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I'd be interested to know if you placed a bolt in the receiver and retracted it fully to the rear would the bolt make uniform/flush contact with the receiver heel? With a few receivers I've observed the receiver heel cut with large radii that impede bolt travel. Specifically on the side closest to the FP relief cut.

For example:



A properly clearanced receiver would look like this:
Blue Oval Fan, what serial number range is your JRA heel? I knew you were doing some research on this and wondering if you have a serial number range of those that need modified.
 

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It's those little things that get ya. What is your cure for this? Dremel? Send back? Fixing this "right" isn't gonna be cheap and with CNC being what it is there probably is a whole run of these that are identical. What's a run? 500? 5000?
My first thought would be to Dremel some clearance in there and repair the finish. Immediate concern is cutting through the hardness, but will it matter? I guess time will tell. This should be discounted as a second. IMHO
To fix it right you would have to anneal the whole receiver in a heat treat oven with a vacuum, (to remove carburizing)then recut that area, and finally heat treat again and refinish. The cost to do one this way would approach the cost of a new receiver. I suspect even to do 500 the cost (per unit) would be significant. I think "we" learned from other manufacturers that multiple heat treat is not a good thing.
The difference in the two pics is obvious, but what does the GI drawing look like? Would hesitate rejecting one over the other unless compliance, or lack of to the print was established. Know you have backround in this so figured you would be the best to answer.
 

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The difference in the two pics is obvious, but what does the GI drawing look like? Would hesitate rejecting one over the other unless compliance, or lack of to the print was established. Know you have backround in this so figured you would be the best to answer.
Neither of the two pictured are cut to the G.I. print exactly. I assume the second is an SEI, right Blue Oval Fan ? Of the two shown the second is the closest. The problem is the tooling required to get in this spot and cut the compounded angles. It requires specific tools be made and a five axis machine, or a multi-purpose lathe and table with additional trunnion arm and rotating head. 40,000 rpm's minimum. That is what we are finding out the hard way. Thank you for posting the pics BOF.
 

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Blunderdog,

Educate me here, if that particular item of discussion is not to GI spec, what is the real issue? Safety? Functionality? Or is it something that falls in the it-does-not-matter category?

Trying to learn....
 

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"Or is it something that falls in the it-does-not-matter category?
Trying to learn...."


Same here, if both are not to GI print, then what is the qualifier that makes them "Good to go"?
 

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" At this point , what difference does it make"?
Are we getting picky picky picky, or is there really something out of line?
As has been asked, does this make either a safety or functionality problem?
 

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Neither of the two pictured are cut to the G.I. print exactly. I assume the second is an SEI, right Blue Oval Fan ? Of the two shown the second is the closest. The problem is the tooling required to get in this spot and cut the compounded angles. It requires specific tools be made and a five axis machine, or a multi-purpose lathe and table with additional trunnion arm and rotating head. 40,000 rpm's minimum. That is what we are finding out the hard way. Thank you for posting the pics BOF.
Since I would assume 40K spindles and 5 Axis CNC was all Buck Rogers back in the 1950's would there be some kind of tooling or machining process sheets beyond just the part drawings lurking in some archive somewhere on how is was done back in the day?
 

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Clearance it with a die grinder and run it. As long as the clearance is done with a smooth radius and no deep gouges to cause stress risers, it's not an issue and should not need re-heat treating. I'm pretty sure the entire receiver is heat treated and through hardened, not just surface hardened.
 

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neither of the two pictured are cut to the g.i. Print exactly. I assume the second is an sei, right blue oval fan ? Of the two shown the second is the closest. the problem is the tooling required to get in this spot and cut the compounded angles. It requires specific tools be made and a five axis machine, or a multi-purpose lathe and table with additional trunnion arm and rotating head. 40,000 rpm's minimum. that is what we are finding out the hard way. Thank you for posting the pics bof.
OK, the eyes wide open in amazement emoticon doesn't seem to be working, but say what????
 

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I may not be seeing the picture correctly, but it looks to me like the bolt is going to hit on the firing pin side rather than square across the rear face. This is not a minor mistake and "we" have gripped about how some manufacturers make this cut for quite some time. Many of them look like they sent a small rodent in thar. I think a lot of folks get too caught up in the surface finish, "rough tooling" as it is called a lot. Wait till we see some beat up bolts and then we will see how important this is.

I agree, I would fix it with a die grinder, but to say I wouldn't worry about it would be a stretch. Most of us have used a die grinder/dremel on receivers to build them. Yes the whole thing is heat treated with a hard skin, mainly for wear. Does it add to the overall strength? Don't know. This spot is vulnerable. It takes all the force of the bolt coming back and it's a corner.

I am not very familiar with USGI prints and heat treating is not my expertise by a long shot. I just know a little about "fits". No body is using '50's technology to manufacture today so yes it is going to be different. I enjoy looking at how people approach the same problems with different solutions. I have enough SAI receivers thru different years that I can see they have continually changed. Pretty interesting really.

The only machinery I know of with spindle speeds of 40,000 rpm are turbines. I can't imagine there would be any need for high rpm's to make a cut here or any where on these things, but I am a dinosaur when it comes to machining. One thousand RPM is fast for me. Let me get a calculator and try to figure surface feet per minute at 40,000 rpm. Put a fork in me I'm done. Glad I got a five axis elbow! GI3
 

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To the OP, I'd like to apologize for contributing in the derailing of your thread. My intent was honest with an earnest interest in understanding if the machining had improved in the area in question. I believe the inquiry is still valid. If you could assist with adding to the discussion by posting pictures it would be greatly appreciated.

"...what is the real issue? Safety? Functionality? Or is it something that falls in the it-does-not-matter category?"
" At this point , what difference does it make"? Are we getting picky picky picky, or is there really something out of line? As has been asked, does this make either a safety or functionality problem?
At this juncture it is somewhat subjective if the machining in this area will cause long term issues with safety and function. The end user, should he possess a receiver in this state will have to determine if this meets their standards for quality and workmanship. Let alone entertain ramifications to function and safety.

I for one have reservations regarding fielding a firearm where a high-speed component will adversely impact another area of operation. The fact remains the impact of the bolt will deliver it's full force on a concentrated area of the receiver not intended for this condition.

Can one simply whip out a dremel and grind the interference away--I suppose so. But I do share the same sentiment as MM that breaking through the case hardening may not be a desirable "fix" in this particular area due to load transfers.

This happends in every JRA thread some "expert" points out a blemish in an area that doesnt matter. Single and double digit receivers have been built by the pros on this board with glowing reviews. If and when an error or flaw comes up, AND JRA is advised it is fixed with out a question.
I supposed my curiosity in JRA's latest offerings and inquiring on a particular area in their manufacturing process could be misconstrued as pointing out a blemish, but I believe you're truly dismissing the concern without rational, justification and perhaps credentials to backup your statement.

I would venture a guess that an engineering degree, 18 years in the industry, coupled with a professional licenses provides me enough of a background to possess an "educated" opinion on application of forces, stress-strain relationships and ramifications from substandard manufacturing processes when all three of these elements are working against each other in concert.

Its been my observation that you're certainly an advocate for JRA, and that's fine. You're entitled to your opinions as well as another other on this forum. However, it would be refreshing for once if folks would avoid a combative engagement in the free exchange of opinions. I for one could care less who manufactures the receivers I purchase, from a consumers point of view JRA leaves some room on the table for improvement. I'd like to know if they've indeed heeded our advise on this topic.

However, your proclamation that the "pros" on this board have provided glowing reviews of JRAs receivers and this condition should be trivialized is a misnomer. In fact I sought out the professional opinion of a lead and well-know M14 armorer regarding this concern. His reply wasn't favorable and he advised against dremeling this way--I believe "send it back" was his final reply. This just solidified my apprehension.

If you need more validation than I'll offer for your consideration a pictorial illustrating what 200-rounds through a firearm will result in--receiver galling and bolt peening. This is just one of three offering provided to me by others. Will this become worse with continued use to effect function and safety--my "educated" opinion is yes.

In addition it doesn't sit well with me that a $300 bolt and $800 receiver may experience premature wear, less I forget a perceived notion that this could adversely effect the resell value of my rifle. If this was any other receiver in question I could venture a guess that the popular opinion would be send it back--this aint right!

Here you go, the results of the interference.






Here's a up close view of the area in question and where clearancing is required.
 

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I have personally built on 2 of these receivers. The clearance issue in the heel is an issue that the owner has admitted and has discussed with me.

Last I spoke with them( It has been probably 4-5 months since I spoke with them) they were trying to figure out a solution for it but it was going to require an expensive tooling fixture is what he was thinking. Basically they have been going in there by hand to relieve the heel for the bolt.


The problem with the heel is as follows:

1. The bolt will move rearward and stop on the areas of the heel that have not been properly relieved.

2. The bolt is stopping prematurely which causes the oprod to stop prematurely.

3. The oprod is not stopping on the front of the receiver where the oprod guide connector lock assembly sits like it should.

4. When the oprod is NOT stopping its rearward travel due to the front of the receiver, the oprod is then being stopped by the BOLT ROLLER/camming surface of the oprod.

5. I would then speculate that the bolt roller will endure unnecessary impact which could cause the roller to fail.




What I did on both of my builds is relieve the heel area until the oprod could be pulled back FULLY and still have the bolt move back and forward inside the camming section of the oprod. Basically the bolt should be loose while the oprod is fully retracted.

Not a hard fix but would be nice for them to correct them.
 

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To the OP, I'd like to apologize for contributing in the derailing of your thread. My intent was honest with an earnest interest in understanding if the machining had improved in the area in question. I believe the inquiry is still valid. If you could assist with adding to the discussion by posting pictures it would be greatly appreciated.



At this juncture it is somewhat subjective if the machining in this area will cause long term issues with safety and function. The end user, should he possess a receiver in this state will have to determine if this meets their standards for quality and workmanship. Let alone entertain ramifications to function and safety.

I for one have reservations regarding fielding a firearm where a high-speed component will adversely impact another area of operation. The fact remains the impact of the bolt will deliver it's full force on a concentrated area of the receiver not intended for this condition.

Can one simply whip out a dremel and grind the interference away--I suppose so. But I do share the same sentiment as MM that breaking through the case hardening may not be a desirable "fix" in this particular area due to load transfers.
I'm curious as to what load transfers you're referring to? I also want to know if you're sure these receivers are case hardened, or if they are through hardened? If the entire receiver is heat treated in an oven, I believe it's going to be the latter.

I supposed my curiosity in JRA's latest offerings and inquiring on a particular area in their manufacturing process could be misconstrued as pointing out a blemish, but I believe you're truly dismissing the concern without rational, justification and perhaps credentials to backup your statement.

I would venture a guess that an engineering degree, 18 years in the industry, coupled with a professional licenses provides me enough of a background to possess an "educated" opinion on application of forces, stress-strain relationships and ramifications from substandard manufacturing processes when all three of these elements are working against each other in concert.
Lets look at the manufacturing of these receivers. IN the JRA receiver, you have more material in the corner causing the early contact with the bolt. In a properly machined receiver, you have less material in the corner allowing for clearance for the bolt. In a properly repaired JRA receiver, you now have less material in the corner to allow clearance for the bolt; ironically now just like a properly machined receiver. If the receiver is through hardened, removing the .010-.020" in the corners, especially with a nice radius and finish, is inconsequential to the structural integrity of the part. If the receiver is case hardened, then it's just for wear and not for structural integrity and again, removing .010-.020" form the corner is inconsequential to the structural integrity of the part.

Its been my observation that you're certainly an advocate for JRA, and that's fine. You're entitled to your opinions as well as another other on this forum. However, it would be refreshing for once if folks would avoid a combative engagement in the free exchange of opinions. I for one could care less who manufactures the receivers I purchase, from a consumers point of view JRA leaves some room on the table for improvement. I'd like to know if they've indeed heeded our advise on this topic.

However, your proclamation that the "pros" on this board have provided glowing reviews of JRAs receivers and this condition should be trivialized is a misnomer. In fact I sought out the professional opinion of a lead and well-know M14 armorer regarding this concern. His reply wasn't favorable and he advised against dremeling this way--I believe "send it back" was his final reply. This just solidified my apprehension.
An armorer is not necessarily qualified to asses and advise on something like this, no matter how many M14's he's worked on. This is not a "gunsmith" issue, it's not even a firearm-specific issue. It's a very simple minimal clearance issue that really doesn't need books written about to cure.
If you need more validation than I'll offer for your consideration a pictorial illustrating what 200-rounds through a firearm will result in--receiver galling and bolt peening. This is just one of three offering provided to me by others. Will this become worse with continued use to effect function and safety--my "educated" opinion is yes.
I disagree. Once the small areas of contact in the corners have deformed enough, the bolt will contact the heel of the receiver as designed and that's as far as everything will go. I am not recommending things are left this way and just letting it take it's course, I just disagree that the condition will continue to get worse. In my "educated opinion" it will reach a state of normalcy.

In addition it doesn't sit well with me that a $300 bolt and $800 receiver may experience premature wear, less I forget a perceived notion that this could adversely effect the resell value of my rifle. If this was any other receiver in question I could venture a guess that the popular opinion would be send it back--this aint right!

Here you go, the results of the interference.






Here's a up close view of the area in question and where clearancing is required.
Just my opinions.
 

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I have personally built on 2 of these receivers. The clearance issue in the heel is an issue that the owner has admitted and has discussed with me.

Last I spoke with them( It has been probably 4-5 months since I spoke with them) they were trying to figure out a solution for it but it was going to require an expensive tooling fixture is what he was thinking. Basically they have been going in there by hand to relieve the heel for the bolt.


The problem with the heel is as follows:

1. The bolt will move rearward and stop on the areas of the heel that have not been properly relieved.

2. The bolt is stopping prematurely which causes the oprod to stop prematurely.

3. The oprod is not stopping on the front of the receiver where the oprod guide connector lock assembly sits like it should.

4. When the oprod is NOT stopping its rearward travel due to the front of the receiver, the oprod is then being stopped by the BOLT ROLLER/camming surface of the oprod.

5. I would then speculate that the bolt roller will endure unnecessary impact which could cause the roller to fail.




What I did on both of my builds is relieve the heel area until the oprod could be pulled back FULLY and still have the bolt move back and forward inside the camming section of the oprod. Basically the bolt should be loose while the oprod is fully retracted.

Not a hard fix but would be nice for them to correct them.
Good explanation and thank you. Bu tlike I said they will and do fix the problems if there are any. I love these guys and they will continue to get my money!
 
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