Bolt Slop
- Thread starter Goose25
- Start date
Mystic Precision
CGN Ultra frequent flyer
- Location
- Summerland, BC
That is pretty common in hunting rifles as that 'slop' allows the bolt to cycle even when it gets dirty.
Not ideal for accuracy but that is why many will shim the bolt body or replace the bolt body to get rid of this slop.
Can it have an adverse effect on accuracy? For the average gun owner, not that much but it can lead to wonky shaped brass and early pressure signs/hard bolt opening.
For a match shooter or anyone trying for best performance, yes.
Look up Borden Bumps, or PTG bolt body or accurizing a Rem 700 for more info on shimming the bolt body. Eccentric shims are likely the best compromise between accuracy and function. Similar to the Borden Bumps.
The goal is for the bolt to stay true with the chamber and bore, AND not move when the sear is dropped. Benchrest shooters believe that any bolt movement can change the ignition 'force' or harmonics and is bad for accuracy.
For the average shooter, the movement in bolt typical means the lugs are no longer square to the receiver face (likely loose contact with the receiver too) and this can lead to brass being forming crocked in the chamber because the case head is no longer supported.
If trying to run higher pressures, this misalignment and possible looseness can cause issues like bent or oval brass, and heavy bolt lift.
It would surprise me that a bolt could be lapped to the receiver if it was wobbling around that much. Hopefully, the back of the lugs are not now curved.
I believe that unless the bolt body is supported and locked in place when a rd is chambered, best accuracy is rarely achieved.
This is one of the reasons that I have moved away from Rems into Savages. Savages simply do not have to worry about this issue.
Jerry
Not ideal for accuracy but that is why many will shim the bolt body or replace the bolt body to get rid of this slop.
Can it have an adverse effect on accuracy? For the average gun owner, not that much but it can lead to wonky shaped brass and early pressure signs/hard bolt opening.
For a match shooter or anyone trying for best performance, yes.
Look up Borden Bumps, or PTG bolt body or accurizing a Rem 700 for more info on shimming the bolt body. Eccentric shims are likely the best compromise between accuracy and function. Similar to the Borden Bumps.
The goal is for the bolt to stay true with the chamber and bore, AND not move when the sear is dropped. Benchrest shooters believe that any bolt movement can change the ignition 'force' or harmonics and is bad for accuracy.
For the average shooter, the movement in bolt typical means the lugs are no longer square to the receiver face (likely loose contact with the receiver too) and this can lead to brass being forming crocked in the chamber because the case head is no longer supported.
If trying to run higher pressures, this misalignment and possible looseness can cause issues like bent or oval brass, and heavy bolt lift.
It would surprise me that a bolt could be lapped to the receiver if it was wobbling around that much. Hopefully, the back of the lugs are not now curved.
I believe that unless the bolt body is supported and locked in place when a rd is chambered, best accuracy is rarely achieved.
This is one of the reasons that I have moved away from Rems into Savages. Savages simply do not have to worry about this issue.
Jerry
What you are seeing is the slop of the cocking piece in the trigger opening in the receiver and it is meaningless. The trigger housing acts as a guide for the cocking piece. Even with the trigger housing in place, there will be a certain amount of movement before the nose of the cocking piece contacts the cocking cam surface.
A "mushy" feel when the bolt is closed is pretty hard to quantify. My sense of touch is severely hampered on the internet.
Nothing in the barrel fitting and chambering would have any effect whatsoever on rotational bolt movement such as is shown here. It is, of course, impossible for me to comment on any other aspect of the work because I cannot handle it. Regards, Bill.
A "mushy" feel when the bolt is closed is pretty hard to quantify. My sense of touch is severely hampered on the internet.
Nothing in the barrel fitting and chambering would have any effect whatsoever on rotational bolt movement such as is shown here. It is, of course, impossible for me to comment on any other aspect of the work because I cannot handle it. Regards, Bill.
Glock4ever
CGN Ultra frequent flyer
- Location
- Edmonton, AB
It is hard to tell without actually holding the rifle but the first two pics don't look like the bolt shroud is screwed all the way in. The mushy feeling could be coming from how the firing pin is being cocked (i.e. too loose) the rattling could be something to do with the firing pin (pretty unlikely). Unless something is significantly wrong with the chamber you shouldn't hear a rattling noise with a chambered round. I would take it to the gunsmith and see if the barrel was threaded all the way in or if something was improperly installed on the bolt.
I am not an advocate of lapping the lugs. I have seen locking lugs and locking lug recesses end up quite tapered and this can lead to a mushy feeling on 'locking up' and does nothing for accuracy. It is much better to machine the lugs and recesses and bolt face true to the bolt raceway. That makes the lock up much more positive.
Truing a 700 action is a one time procedure which I highly recommend before installing an after market barrel. It doesn't cost that much and you end up with the strongest, safest two lug action made with the most after market accessories available.
Truing a 700 action is a one time procedure which I highly recommend before installing an after market barrel. It doesn't cost that much and you end up with the strongest, safest two lug action made with the most after market accessories available.
With no trigger in place, the rifle is not cocked and it is going to rattle.
Lapping lugs is just like lapping anything else; done properly, it can improve surface finish and enable one to achieve proper dimensions. Done improperly it can perpetuate flaws or even introduce flaws into what would have been a good piece.
It is possible but not probable that lug lapping has anything to do with any problems which may or may not exist with this rifle.
The problem with having a supposed deficiency diagnosed on the internet is that you not only have skilled, knowledgeable 'smiths trying to diagnose a problem without valid information, you also have people who don't have a clue trying to do the same.
Pull the barrel off and measure the tenon length, counterbore depth, and the amount a "GO" gauge protrudes from the chamber. Then measure the distance from the receiver face to the bolt face and add recoil lug thickness. Measure the distance from the receiver face to the bolt nose. When you can do this, you can ask the question and have a reasonable expectation of getting a valid answer. If you can't do this, you probably can't ask the right question and either can't, or won't, understand the answer.
Right now, a condition is being described which probably has nothing whatsoever to do with chamber depth or barrel clearances. Regards, Bill.
Lapping lugs is just like lapping anything else; done properly, it can improve surface finish and enable one to achieve proper dimensions. Done improperly it can perpetuate flaws or even introduce flaws into what would have been a good piece.
It is possible but not probable that lug lapping has anything to do with any problems which may or may not exist with this rifle.
The problem with having a supposed deficiency diagnosed on the internet is that you not only have skilled, knowledgeable 'smiths trying to diagnose a problem without valid information, you also have people who don't have a clue trying to do the same.
Pull the barrel off and measure the tenon length, counterbore depth, and the amount a "GO" gauge protrudes from the chamber. Then measure the distance from the receiver face to the bolt face and add recoil lug thickness. Measure the distance from the receiver face to the bolt nose. When you can do this, you can ask the question and have a reasonable expectation of getting a valid answer. If you can't do this, you probably can't ask the right question and either can't, or won't, understand the answer.
Right now, a condition is being described which probably has nothing whatsoever to do with chamber depth or barrel clearances. Regards, Bill.
As Leeper said in his opening sentence,
This is what you are showing in your pics. This is normal and perfectly acceptable because it allows for easier function and does not in any way negatively effect accuracy nor durability. You may have other concerns but this is not one.
This is what you are showing in your pics. This is normal and perfectly acceptable because it allows for easier function and does not in any way negatively effect accuracy nor durability. You may have other concerns but this is not one.
