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Discussion Starter · #1 · (Edited)
Alright, as promised and for anyone interested here are the pics of my LRB bolt after 500 rounds of Portuguese NATO ammo.
EDIT: bolt is installed in an LRB M25 receiver



Right and left Lugs




Rear view



I can say that nothing has changed since the first 40 rounds I've shot (with the exception of of parkerizing wearing off at some spots) and that it works flawlessly. It matches the LRB receiver perfectly, and it works like a charm. I don't know what else to say, besides get one!

EDIT: I also wanted everyone to know that I have not done any modifications to the receiver of any kind (ie: grinding particular spots) other than the initial lapping of the bolt to the receiver. The receiver was left as is.

Just two questions:
How many rounds does it take to say that a new rifle is "broken in"?
Is there any such thing as shooting too much in a short period of time to prevent overheating?
 

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There's some debate over whether a rifle requires "breaking in" but after 500 rounds I think you're there. As for your second question, I'm not sure what you're asking but as long as you follow the guidlines for the different rates of fire, you should be fine.
 

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The wear patterns look normal but, I think that you should have a bit better bolt lug contact to the receiver's lugs. The wear pattern on the left lug looks especially uneven.

Looks like you have about 55-60% contact on the lugs by the wear marks. On a service grade rifle you should have about 80-85%. Ideal is 90-95% contact.

Was the bolt lapped to the receiver?
 

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Glad you have Gotten past your Previous Bolt issue and Moved on
The LRB bolt seems to be the "Cats Meow"
Please keep us updated as you increase your round count
 
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Discussion Starter · #10 ·
The wear patterns look normal but, I think that you should have a bit better bolt lug contact to the receiver's lugs. The wear pattern on the left lug looks especially uneven.

Looks like you have about 55-60% contact on the lugs by the wear marks. On a service grade rifle you should have about 80-85%. Ideal is 90-95% contact.

Was the bolt lapped to the receiver?
It sure was, I didn't want to go too crazy with the lapping this time just because I went pretty far with the previous bolt and I didn't want to open up the headspace too much. I do plan to do some more careful lapping in the near future to get the appropriate lug contact. Head space is currently at 1.633 right now. I could go up to 1.634 but I don't want to go much more than that. It also had something to do with my lack of patience because I wanted to shoot the darn thing

GI2
 

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Nice job. I was hoping the bolt issue would work out for you. That is the great thing about this forum. Folks are willing to advise upon request as in your case. I have a couple of barreled actions with their bolts coming from the last group buy. That will complete the LRB section of my herd. Enjoy the hobby.

Semper Fi
SGT USMC 66-72 RVN 67-68
Art
 

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Whatever receiver that bolt is in, needs the right lug recess, rear radius cut, smoothed out and extended a tad. Grind the small mushroom off the bolts right lug also. I just finished an LRB build for Andy, and the right lug recess on the receiver was the same way. It also required grinding the area that the right bolt lug contacts, flat, because it would not rotate completely down into battery. It is common for the tool to get trash or slag filings under the knife when machining, causing humps....no big deal, but you need to smooth your radius cut in the receiver out...Other than that, it looks good to go, cheers for Lou !
 

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Scrub, scrub, scrub....

Hey Yellow I say you are broken in once you are able to get the op-rod out without wanting to smash your head into a brick wall. lol!!
Know the feeling!

Very Nice bolt, BTW! Nice to know!

As for how fast to shoot, by fast repetitive shooting, and the resultant very hot barrel, you do force some excessive deposition of bullet gilding metal (i.e.: the jacketing) onto and into the rifling especially near the chamber, by too fast a rate of fire. This also increases the rate of fatal throat erosion. Ouch!

BTW, I can only imagine what the bores look like on one of those GE .223 Gatlings! Ouch!... but then, they probably have to do a complete bbl-set replacement service after every use of those guns where it was used for more than a few moments! Anyone familiar with these guns?

Back to reality: if you shoot faster than, oh... a round every few seconds, for a total of 15 - 20 rounds, you'd start to see a fairly hot (to the touch) barrel. Remember; Weatherby ammo makers (and other such high-pressure hot stuff) warn about shooting too fast & too often, with no cooling between shots. The benchrest boyz all give their bbls as long a cool-off between shots as is possible given the shoot rules.

Otherwise get used to Sweet's 7.62 copper remover. The inevitable buildup of gilding materials on and in the rifling will seriously decrease the accuracy of your rifle over time, but also know that proper and complete cleaning-out of that gulding material will usually assist in retuning your bbls' initial accuracy. Cleaning like this also helps with overall barrel smoothness over time: see "Barrel Break-in" in any of the long-range shooter's journals.f

Otherwise, for complete details, you can DM me. Please do!
 

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Looks good. Normal wear patterns on the contact surfaces. I might consider one of these in a future build.
 

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It sure was, I didn't want to go too crazy with the lapping this time just because I went pretty far with the previous bolt and I didn't want to open up the headspace too much. I do plan to do some more careful lapping in the near future to get the appropriate lug contact. Head space is currently at 1.633 right now. I could go up to 1.634 but I don't want to go much more than that. It also had something to do with my lack of patience because I wanted to shoot the darn thing

GI2
First you lap then you headspace.
 

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Discussion Starter · #20 ·
Hey Warren!
This was written a while ago and I plan to start a new thread for the "1000th round count & my first M1A build with first production LRB bolt" in the near future. So far my rifle has 700 round put through her and I'm still waiting for my JAE stock.

My camera is a simple "Canon Powershot A720 IS". It's got a Macro setting and it's a decent little camera! Not sure if they still make them anymore though. Don't know when I'm coming back to NYC but I do know that I will be deploying to Kuwait early next year so we'll have to see! I hope things have been good for you lately.

USNA
 
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