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I’ve got about 8k rounds of 300blk on my original pin with no issues.

Could just be a part that fell in the standard deviation. It’s not a “common” issue if you ask me.

But it does point to the obvious in that spare parts should be kept around.

Specifically, firing pin, bolt, retaining pin, and any other bolt carrier part. My goal is to have 2 complete carrier assemblies as well as mag and bolt release spares by the end of next year.


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I’ve got about 8k rounds of 300blk on my original pin with no issues.

Could just be a part that fell in the standard deviation. It’s not a “common” issue if you ask me.

But it does point to the obvious in that spare parts should be kept around.

Specifically, firing pin, bolt, retaining pin, and any other bolt carrier part. My goal is to have 2 complete carrier assemblies as well as mag and bolt release spares by the end of next year.


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Same question to you then....is it the 'new' bulged firing pin design though?
 

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Same question to you then....is it the 'new' bulged firing pin design though?
I honestly have no idea off the top of my head. I’ll have to look when I get home. I’m also going to check for a crack on the op rod.


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I honestly have no idea off the top of my head. I’ll have to look when I get home. I’m also going to check for a crack on the op rod.


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Allegedly, if you have the relief cut in the 'foot'....you shouldn't have any crack issues, but I'd still check.
 

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My newer rifle has the choad firing pin(s)
Older rifles have the straight firing pin, no issues with either so far. 6k on 5.56, 8kish on 7.62 and 900ish 5.56/300blk on the choad
 

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My newer rifle has the choad firing pin(s)
Older rifles have the straight firing pin, no issues with either so far. 6k on 5.56, 8kish on 7.62 and 900ish 5.56/300blk on the choad
Well, that's good news. It would appear the OP just got a bad one then. Thanks for the feedback!
 

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So I’ve got the non relief cut piston and both styles of firing pins.

The straight pin has about 8k rounds on it.





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Do those appear to be cast?
Looking at the metal, there are some parts that do not look like they were lathe cut from round, and the surface texture is not smooth or showing the little parallel lines of a cutter slowly moving along a spinning piece of metal.

Shot peened?

I was talking with a machinist about an online debate over cast versus cnc in another forum, and the machinist pointed out that they can cnc for very close to the same cost, without the inherent flaws in the metal from casting. Flaws like the end of the pin breaking off in jagged diagonal. (Just a theory from someone guessing while looking at a picture.)
 

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It may be a metal injection molded part (sort of like cast)....MIM are quite common in gun manufacture....and are also known to break compared to a machined piece.

Hey OP,

Did they send you two or did you have to buy one as a spare?
 

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Discussion Starter · #31 ·
It may be a metal injection molded part (sort of like cast)....MIM are quite common in gun manufacture....and are also known to break compared to a machined piece.

Hey OP,

Did they send you two or did you have to buy one as a spare?
It may be a metal injection molded part (sort of like cast)....MIM are quite common in gun manufacture....and are also known to break compared to a machined piece.

Hey OP,

Did they send you two or did you have to buy one as a spare?
I order the second one just in case
 

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Cast? Maybe these
Selector levers, take down latch, stock folding mechanism, bolt catch lever/bolt catch. Those are the only pourus metals I noticed. Possibly the rear part of the oprod. Everything else is milled. I'm going to circle back to bad heat treat on that firing pin, or some sort of tolerance stacking that's putting it under more stress.
 

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They look so much better and solid, educated me a bit but why did they change the design of it?
I disagree...the newer iteration looks beefier.

Why'd they change it? Probably b/c RobArms thought the new bulged design was an improvement. Obviously, there's a lot more material on the new design. That said, the pins rarely broke as they were. If the factory ones were MIM, I'd wager buying the machined ones made from Stainless would probably solve the problem completely.....but that company (firing pins.com or whatever it's called) doesn't have the newest bulged style on their site. Not sure if the newest style bolt for this new, larger bulged firing pin will have too much slop if you tried to retrofit it with one of the original Type 2 pins out of Stainless. Might cause another set of issues. I guess I could bring the parts to work and use gauge pins to see if the ID in the bolts are different or markedly different.
 

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Discussion Starter · #37 ·
Probably b/c RobArms thought the new bulged design was an improvement. Obviously, there's a lot more material on the new design. That said, the pins rarely broke as they were. If the factory ones were MIM, I'd wager buying the machined ones made from Stainless would probably solve the problem completely.....but that company (firing pins.com or whatever it's called) doesn't have the newest bulged style on their site. Not sure if the newest style bolt for this new, larger bulged firing pin will have too much slop if you tried to retrofit it with one of the original Type 2 pins out of Stainless. Might cause another set of issues. I guess I could bring the parts to work and use gauge pins to see if the ID in the bolts are different or markedly different.
Ah I see, I had to also look at the design man I just hope it doesn't break on me again. I have high expectations on this Platform. If it does I'll just let them know and see what will they do in the future. The type 2 seem alot more durable too shoulda just stay with that design instead.
 

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With the thought now that these are MIM or some type of cast, I'm actually considering buying the Stainless ones for my Type 1s and Type 2 (non-bulged) set ups.
 

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Discussion Starter · #39 ·
With the thought now that these are MIM or some type of cast, I'm actually considering buying the Stainless ones for my Type 1s and Type 2 (non-bulged) set ups.
Same here I'll probably get a type 2 also it seem more solid and more trust worthy. It seem that's what they only offer now on the robinson xcr spare parts now.
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Yeah, but until you know the firing pin channel size is the same, you are gambling it will even work. EDIT To an extent, the firing pin spring may help index to keep the smaller pin centered in the cavity....assuming the spring size hasn't changed....but since it's at the rear of the firing pin, it probably very minimally would index anyway.
 
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