I have a Remington 700 that has custom barrel/trued. it's a factory bolt. with 340 rounds on it. After my last match i took it apart to clean it and found my lug with groves on it. And the other side looked good. I did have 3 or 4 times hard to re open the bolt. Which never happenedd before. And iam shooting light loads. .243 with h4350 40 gr 107 smk. So I don't think it's from that. Just hoping I don't need a new bolt any advice and thought thanks
Gunsmithing Bolt lug help!!!
- Thread starter Wrong hander .243
- Start date
To me it looks like galling/spalling.
https://en.wikipedia.org/wiki/Galling
I've usually seen it with bolts screwed in cast iron dry. A little oil or greese goes a long way to prevent it. Usually the damage is about the same on both sides in this case the action and bolt. I'm not a gunsmith, but I don't think it is going to be worth fixing. Of course if you always lubed your bolt lugs then it must be something else.
https://en.wikipedia.org/wiki/Galling
I've usually seen it with bolts screwed in cast iron dry. A little oil or greese goes a long way to prevent it. Usually the damage is about the same on both sides in this case the action and bolt. I'm not a gunsmith, but I don't think it is going to be worth fixing. Of course if you always lubed your bolt lugs then it must be something else.
OK, what was the rest of the "custom" gunsmithing that was performed ? By chance, was the factory extractor replaced with an aftermarket one ?
I've never seen galling as bad as that. It looks like someone may have taken a torch to the bolt to solder in a new sleeve and managed to take all of the hardness out of the bolt.
I've never seen galling as bad as that. It looks like someone may have taken a torch to the bolt to solder in a new sleeve and managed to take all of the hardness out of the bolt.
Its supost to be all stock except truing the action , grinding the recoil lug , and a rock creek barell
You may not need a new bolt but if you get that cleaned up by a gunsmith the barrel will need to be set back to keep the headspace in the GO range, now if the lug abutment looks like that too then more work will be need. If you leave it as is it could get worse.
Montrose
Montrose
Thanks it's just weird that it would happen to one side and still have good contact on the other. It's like one lugv is supper soft. Is this common with factory bolts?
On a 2 lug bolt when the bolt is in the locked position the lug on the bottom takes the most wear, there is a lot of play in the factory bolt to action fit so when you cock the bolt the back of the bolt moves up putting the bolt at a very slight angle and unloading the top lug a little and putting more of the load on the bottom lug. you can test this your self with a unloaded rifle cock the bolt and pull the trigger watch the back of the bolt brop down it's not going to be a lot but you will see it.
Montrose
Montrose
Full story, please...
Was this your action that you had "trued" and re-barreled, or was it sold to you as a newly built rifle? What did it look like when you took possession?
Looks like still a factory finish on the lug faces (where it's not been affected by whatever's been going on there). Meaning, IMHO, the lugs were never faced or even lapped. What's the boltface look like? Was that faced/trued?
I'm no metallurgist- but I don't buy galling causing that on an otherwise clean action with only a few hundred rounds even if run bone dry.. If that was indeed a new action, or at least newly "trued", something else is going on...my vote is sand or grit in the action.
You need to see what's going on with the lug abutments in the receiver, and it's best to pull the barrel or get a borescope all the way down the tube to see what their condition is.
Was this your action that you had "trued" and re-barreled, or was it sold to you as a newly built rifle? What did it look like when you took possession?
Looks like still a factory finish on the lug faces (where it's not been affected by whatever's been going on there). Meaning, IMHO, the lugs were never faced or even lapped. What's the boltface look like? Was that faced/trued?
I'm no metallurgist- but I don't buy galling causing that on an otherwise clean action with only a few hundred rounds even if run bone dry.. If that was indeed a new action, or at least newly "trued", something else is going on...my vote is sand or grit in the action.
You need to see what's going on with the lug abutments in the receiver, and it's best to pull the barrel or get a borescope all the way down the tube to see what their condition is.
This is easily explained: (No, it wasn't my shop who did this initially)
You have/had a small inclusion on the lug abutment of the bolt and/or the receiver. That little "bug" then got the snot rubbed out of it over and over again by running the action. This work hardens the material. -Take a coat hanger once and bend it back and forth. It'll get hot. If you stop and allow it to cool it'll bend right next to the original once you start up again. That is work hardening in a nut shell.
So this process continues until that little ball of hard steel starts to break loose. From there it's a "crunch-a-thon" on its journey to self destruction. It boils down to surface finish on the parts post machining... A tight case in the chamber or forcing something can create this problem out of thin air. The damage can happen very, very quickly. On most parts like bolts/actions it's generally thought to be best if the two have a hardness differential of at least 5 points if you are playing in the low 40's for the Rockwell C scale. On parts in the 50's it tends to matter less. Remington actions are usually in the low 40's and bolt heads aren't much different. Being chromoly helps as its a fairly lubrice material by nature.
Lapping a bolt is literally a process to try and fix fundamental machining errors. To drive this home a little better think of it this way: If we spend more than a week on this very site we'll likely see a post/thread about someone dialing in a barrel to the gillionth of an inch. -yes, a little sarcasm. Does one expect to see the chamber get lapped too? I would venture to say no.
I would propose the same argument here. If the machine work had been well executed to start with, then the problem would have been avoided. Most custom actions made today serve as an example. The vast majority are not lapped. They've taken the time to figure out the correct tool package and machining strategy so that they don't have to. It adds to cost as its all labor. Plus its a kick in the nuts to try and clean out afterwards. Do that a few hundred times a month and you'll be compelled to find another way.
Happy to help. It'll take the whole barreled action and will likely involve some fairly intensive machine work to resolve. A time/tig service on the bolt is likely also.
C.
You have/had a small inclusion on the lug abutment of the bolt and/or the receiver. That little "bug" then got the snot rubbed out of it over and over again by running the action. This work hardens the material. -Take a coat hanger once and bend it back and forth. It'll get hot. If you stop and allow it to cool it'll bend right next to the original once you start up again. That is work hardening in a nut shell.
So this process continues until that little ball of hard steel starts to break loose. From there it's a "crunch-a-thon" on its journey to self destruction. It boils down to surface finish on the parts post machining... A tight case in the chamber or forcing something can create this problem out of thin air. The damage can happen very, very quickly. On most parts like bolts/actions it's generally thought to be best if the two have a hardness differential of at least 5 points if you are playing in the low 40's for the Rockwell C scale. On parts in the 50's it tends to matter less. Remington actions are usually in the low 40's and bolt heads aren't much different. Being chromoly helps as its a fairly lubrice material by nature.
Lapping a bolt is literally a process to try and fix fundamental machining errors. To drive this home a little better think of it this way: If we spend more than a week on this very site we'll likely see a post/thread about someone dialing in a barrel to the gillionth of an inch. -yes, a little sarcasm. Does one expect to see the chamber get lapped too? I would venture to say no.
I would propose the same argument here. If the machine work had been well executed to start with, then the problem would have been avoided. Most custom actions made today serve as an example. The vast majority are not lapped. They've taken the time to figure out the correct tool package and machining strategy so that they don't have to. It adds to cost as its all labor. Plus its a kick in the nuts to try and clean out afterwards. Do that a few hundred times a month and you'll be compelled to find another way.
Happy to help. It'll take the whole barreled action and will likely involve some fairly intensive machine work to resolve. A time/tig service on the bolt is likely also.
C.
So I'm still trying to figure out...
Like I said, doesn't look to me like any work was done on the lugs- judging by the areas I can see that look like they were not affected by the "inclusion" on the bolt lug. Chad, I'm unclear what you mean by this- leftover from original production (meaning the lugs were not turned/trued or lapped as the OP supposedly paid for) ? I just don't see how there could be any imperfections left on the lug faces if they were lightly faced on the lathe- or even lapped if that was all that was required for even/ adequate contact.
Like I said, doesn't look to me like any work was done on the lugs- judging by the areas I can see that look like they were not affected by the "inclusion" on the bolt lug. Chad, I'm unclear what you mean by this- leftover from original production (meaning the lugs were not turned/trued or lapped as the OP supposedly paid for) ? I just don't see how there could be any imperfections left on the lug faces if they were lightly faced on the lathe- or even lapped if that was all that was required for even/ adequate contact.
When we chatted offline (text) I was under the impression the shop that did the original work whittled on the receiver as well. That's where I'm coming from on this.
Assuming I am correct:
Typical tool is a boring bar correct? Reach down the hole and squeal the lug abutments to qualify the faces. My issue has always been the single point tool on an interrupted cut. In the lug, raceway, back in the lug, raceway, etc. . . On the trailing edge it will almost always leave an inclusion in the form of a roll over on the edge.
It's one of the principle reasons I went to a mill where I can climb cut in a circular pattern. Get the helix right on the cutter and the edge break all but goes away. The rub is you gotta spend cash and lots of it.
Assuming I am correct:
Typical tool is a boring bar correct? Reach down the hole and squeal the lug abutments to qualify the faces. My issue has always been the single point tool on an interrupted cut. In the lug, raceway, back in the lug, raceway, etc. . . On the trailing edge it will almost always leave an inclusion in the form of a roll over on the edge.
It's one of the principle reasons I went to a mill where I can climb cut in a circular pattern. Get the helix right on the cutter and the edge break all but goes away. The rub is you gotta spend cash and lots of it.
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Thank for the replies, it was a new action. I know it was lapped for sure. I had a new barrel put on. The bolt didn't look like this before my last match. Then with in 86 rnds. I brought it home ran a patch threw it pulled the bolt cleand the face and found that. At the match after 30 rnds I had 2 hard bolt lift in a row then I did it 2 more times randomly.
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