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Very nice bolt. Going to have to get one. Thanks for the details.
 

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I ordered 2 of these. They notified me yesterday that they would ship them. they should be here this week.
I think the release of these is going to have an impact on the price of used bolts. A NOS TRW bolt is still going to bring a premium, but who is going to pay $100 more for a used bolt. Not me!
 

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Hi, i´m searching a streeped bolt used, is someone interested ?
i dont care about the brand
 

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Discussion Starter · #46 ·
Is this what I'll get if I ordered a bolt with the LRB Group Buy?
Don't hold me to it, but I think so.

I finally got my bolt parts and I'm ready to go. I had to do some modifications to the Fulton Armory firing pin. The Fulton firing pin slipped right in for the most part, but the last 1/16" had to be knocked in and pryed out for the firing pin to protrude from the face of the bolt's cartridge seat, so I had to put my Sharpie Marker and files to work. LRB's bolt was built to USGI Specs so I think the Fulton firing pin was a bit out of dimensions. Most of the filing took place at the tail end and 1/4" at the front end of the firing pin. It took me about an hour of carefull filing to get the pin to "float" in the chamber like it's supposed to. The last thing I want is a out of battery discharge, or slam fire! Looks like I may have to order a USGI firing pin in the near future. Hopefully this pin will last me a few hundred rounds.

If all goes well I'll have a field report this weekend!
 

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I hope this works for you as this has been a long and pain ITA journey. Interesting that the FA firing pin was a problem. Seems like a lot of problems coming out of their business lately.
 

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Discussion Starter · #48 ·
I hope this works for you as this has been a long and pain ITA journey. Interesting that the FA firing pin was a problem. Seems like a lot of problems coming out of their business lately.
Thanks, this has been a great learning experience so far and I hope we all take something from this. It's a but frustrating but when I put my tools away, I don't mind as much. I don't think this would be as fun if there weren't any problems. Kinda like my Mac, it runs so well that I'm bored with it because there's never any problems with it.
 

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Don't hold me to it, but I think so.

I finally got my bolt parts and I'm ready to go. I had to do some modifications to the Fulton Armory firing pin. The Fulton firing pin slipped right in for the most part, but the last 1/16" had to be knocked in and pryed out for the firing pin to protrude from the face of the bolt's cartridge seat, so I had to put my Sharpie Marker and files to work. LRB's bolt was built to USGI Specs so I think the Fulton firing pin was a bit out of dimensions. Most of the filing took place at the tail end and 1/4" at the front end of the firing pin. It took me about an hour of carefull filing to get the pin to "float" in the chamber like it's supposed to. The last thing I want is a out of battery discharge, or slam fire! Looks like I may have to order a USGI firing pin in the near future. Hopefully this pin will last me a few hundred rounds.

If all goes well I'll have a field report this weekend!

Glad you are getting there and I know you said a write-up would be forthcoming soon, but how do you know it was the fulton firing pin that was out of spec ? It just seems like 1/4'' off the striker end of the pin is a bit much. Could you see inside the bolt to look for burrs or some obstruction, or was it the firing pin hole, bore diameter, that was tight ? As for the tail being tight with fultons pins, I have experienced that before. As you know, we live by spec around here, so I was curious about some measurements on the bolt, like lug lengths and the other measurements from the first thread I gave you to look for.....Oh, also targets with .30 cal. holes in them are required to be posted. DI2
 

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Discussion Starter · #51 ·
Glad you are getting there and I know you said a write-up would be forthcoming soon, but how do you know it was the fulton firing pin that was out of spec ? It just seems like 1/4'' off the striker end of the pin is a bit much. Could you see inside the bolt to look for burrs or some obstruction, or was it the firing pin hole, bore diameter, that was tight ? As for the tail being tight with fultons pins, I have experienced that before. As you know, we live by spec around here, so I was curious about some measurements on the bolt, like lug lengths and the other measurements from the first thread I gave you to look for.....Oh, also targets with .30 cal. holes in them are required to be posted. DI2
I didn't actually remove 1/4" of material if I understand you correctly, I had to trim the diameter down a bit off the first 1/4" of the firing end. I didn't have to touch the tapered striking surface at all. I forgot to mention that before I even touched the firing pin with a file, I gave the firing pin chamber a visual inspection and didn't notice any burrs or high spots. I only used my MK1 eyeball, because I don't have any gauges to check this with. I did some measurements with the LRB Bolt and found the dimensions to be be similar to the fulton but that's not saying much due to the fact that my Calipers were only accurate to 0.01 (I mentioned the same thing with the Fulton bolt thread) anything less had to be estimated with my MK1 eyeball again which is tough and inaccurate. I should probably invest in a good set of calipers, but that won't happen anytime in the near future unless I really need it.

I need to shoot this weekend, by trigger finger is twiching every time I think about it!
 

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My LRB Bolts came in Friday, one of them has the exact same issue with the firing pin. Mine are complete not stripped. I have several USGI firing pins and they all did this, some are worse than others. Even the pin that was in it was sticking pretty bad. I'm not sure how I'm gonna fix it but I don't think it is the pin. I would rather open the hole up a little so I can grab a pin from any where for it if needed. I see this as a minor problem.


Don't hold me to it, but I think so.

I finally got my bolt parts and I'm ready to go. I had to do some modifications to the Fulton Armory firing pin. The Fulton firing pin slipped right in for the most part, but the last 1/16" had to be knocked in and pryed out for the firing pin to protrude from the face of the bolt's cartridge seat, so I had to put my Sharpie Marker and files to work. LRB's bolt was built to USGI Specs so I think the Fulton firing pin was a bit out of dimensions. Most of the filing took place at the tail end and 1/4" at the front end of the firing pin. It took me about an hour of carefull filing to get the pin to "float" in the chamber like it's supposed to. The last thing I want is a out of battery discharge, or slam fire! Looks like I may have to order a USGI firing pin in the near future. Hopefully this pin will last me a few hundred rounds.

If all goes well I'll have a field report this weekend!
 

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I ran the same hardness test on one of those LRB bolts as I did on the Fulton a few weeks ago. The test results show almost the same number on the hardness scale as the TRW. Even though the test is not 100% conclusive it is interesting.
I think the way to solve the tight hole problem is to use a 1/4" dowel pin and some lapping compound. I will spin the dowel pin with a hand drill.
Edit: Hole is not 1/4, but I found a pin the right size and cleaned it out with rubbing compound
 

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Discussion Starter · #54 ·
My LRB Bolt range report and comparison

M25 LRB Reciever (80 Rounds)
LRB Bolt (Lapped to reciever) (40 Rounds)
Krieger Heavy Profile Barrel (80 Rounds)
USGI Stock used
USGI Trigger Assembly

So I took my rifle out to the range at the first opportunity I had this weekend and the bolt performed great! The LRB Bolt cycled with no issues, extraction worked just fine and there were no issues with firing. there was some markings on the bolt but no where near as bad as the Fulton bolt.





I had contacted LRB about the marks on the bolt and the marks on the back of the bolt are due to the reciever heel and will need some work with a dremel, I can clearly see now where the two was making contact (couldn't with the Fulton). The minor peening on the bolt's hammer camming surface is from the hammer's camming finger and there is almost always contact here until bolt becomes form fitted. The right lug's slight deformation is normal caused by inside top corner at forward end of rail.

As far as the marks on the rear of the bolt they are minor, I don't even know why I labeled them as "Peened" and other spots that were noted are minor. I'd be very interested to see how other bolts such as USGI and other commercial bolts compare.

I think this LRB Bolt is working out just fine and look forward to the breaking in process!



Here's a shot of my best group at 100 yds. How's this for a begginer? Yes I cheated I used my scope but that chin weld I was using feels like someone socked me in the jaw. Maybe it's time for a stock pad?
 

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Nice group size !

I would have to be suspect of the right lug peening, it is not normal. Have Lou look at the receiver. Something is going on in my opinion. As for G.I. bolt comparisons, I have many of them in a bunch of different manufacturer's receivers, and none show the right lug peening. The heel needing dremel work also to stop rear lug peening, or the upper area of the receiver shroud that caps the bolt off, should be done by a professional. A little too much off for thickness, and you will be through the surface hardness. Of course I know you know this already, just posting for the benefit of newer members.
 

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Discussion Starter · #56 ·
Update after 100 more rounds

Just a little update, I've put another 100 rounds through my rifle over the weekend and nothing has really changed. Which is a good thing! the pics on the left is after the first 40 rounds and the pics on the right is after 140 rounds. I've also verified the headspace which has not changed.







I've been shooting Surplus Portuguese NATO ammo without any hiccups and having lots of fun! If anyone is wondering about the marks on the back of the bolt, it is from the heel of the receiver and no, I haven't done anything to grind down the wear spots because I honestly see no reason to unless the marks get worse. The wear spots have not changed one bit but I will keep my eyes on them after every range session. After looking at these pics, you can hardly tell the difference. I'm going to stop posting updates till I reach the 1000 round count.


This was the best group I had out of all 100 rounds. I'm starting to think groups like this is purely luck lol. After 100 rounds, my jaw was starting hurting over the weekend, I think I need a cheek pad.
 

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Did LRB offer to fix the receiver heel for you? Personally, I'd be a little upset if they suggested I take a Dremel to my brand new $900+ receiver. For that kind of money, I'd expect it to be perfect. Good to hear the new bolt is working out though. Keep us updated.
 

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nice group size !

I would have to be suspect of the right lug peening, it is not normal. Have lou look at the receiver. Something is going on in my opinion. As for g.i. Bolt comparisons, i have many of them in a bunch of different manufacturer's receivers, and none show the right lug peening.
+1
 
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