Rem 700 bolt timing issue?

358Rooster

358Rooster

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I had a .284 built on a Sendero magnum action a few years ago and traded my mag bolt with a guy who had a LA standard bolt. At the time it was built, the smith showed me that after truing everything, the timing was only okay (location of the handle on the bolt body) but very close to its effective limit. It ran well this way up to about 1100 rounds.

What I've been experiencing now is hang up on extraction. The bolt rotates all but the last tiny little bit to fully disengage the lugs to allow retraction of the bolt. A mildly firm thump with the base of my hand opens it the rest of the way every time. This only happens after firing a round - functions normally with an empty chamber, while extracting an unfired loaded round, and extracting an empty case (previously fired, unresized, firing pin having been let down prior to extraction).

Would I be correct in assuming that there is now enough wear on the lugs or area where the bolt handle assy. contacts the receiver (secondary camming, right?) is such that it has put me past the "okay" timing (if you can decipher what I'm saying:redface:)

If so, my options would be to have it re-timed or get a new bolt, correct? There seems to be a bit of a shortage of smiths who feel confident with silver soldering to relocate the handle - at least that I have spoken with. I've considered ordering a PTG replacement and seeing as they require fitting as well, am I really any better off than finding a smith who can fix my existing bolt confidently?

Do my assumptions sounds plausible to those of you who have experience with this? And if it is wear on the lugs........is it normal to expect measurable wear or is there something else going on here?

My loads are near top end but not what I consider hot. 168 VLD's at 2860 & 171 Barnes Burners at 2820 from a 26-3/4" barrel. To possibly give you a bit more insight in this regard (maybe), my throat has eroded .022" in over 1300 rounds.

All experienced thoughts /advice appreciated.
Rooster
 
Correction; I just went to mess with this rifle again (haven't used it in a couple months) & in fact I do have a rotation issue in all scenarios mentioned in paragraph 2 above.

I'll post a few pictures in a bit.
 
Sounds like you need to bump the shoulders on your brass each time for reliable function. Because unfired rounds function normally there appears to be your issue. Does the brass need to be annealed to allow for spring back to happen again. How many shots on the brass may be telling. If the brass is too hard and the loads are at top end you will get harder extraction regardless. I would explore this first before looking at some other issue.
My 2c.
 
Thanks Elkhuntr. I've always shot for a .002 to .003" bump for this rifle. I just measured some cases with my Sinclair comparator and I get a consistent 1.792" from fired cases and 1.789" to 1.791" with the last batch of sized cases. Guessing maybe I need to look at annealing, as you suggest - if the cases were malleable enough, the 2-3 thou would probably be okay? I will get my cases annealed & see what that does for me.

In the pictures below (apologies for the quality - left my good camera at work), you can see that there is only a very small point of contact between the handle & action camming points, at which, there is now a small burr on the action. Am I wrong to assume that there should be more contact between these two angled cuts?




 
Remove your firing pin assembly from the bolt. Then put the bolt back into the action and with the bolt handle at 3:00 measure the gap between the rear of the action and the bolt handle root with feeler gauges. That will give you a real number to work with.
 
As small as will still permit proper function - I've seen them with more gap, but you could definitely have your handle moved forward. Also remove all the raised burrs on the action and bolt handle.
 
358 Rooster

You are basically correct and you are on the right path. The action looks like it has been filed; apparently for esthetics because, IMO, not much has been removed.

The 700 is a good action. Very good for a factory action. 700 timing is great for what it is but not "great" for perfection. When we ask for perfection, we need to understand the 700 can be easily modified to be pretty darn good. In you're case the bolt timing "wants" to be better because of what you are doing.

Are you prepared for moving the bolt handle or do you want a new bolt with handle?
 
Just looked at your primary extraction surface. What tool was used? Nice job actually. Certainly not desired but interesting.
 
Just hone off the edge of the bolt handle where it comes up against the receiver in you pics. If you don't want to hone the bolt, hone the angled edge in the receiver to allow your bolt handle a bit more travel. It should have been done by the gunsmith when he fitted the replacement bolt.

This sort of situation is why it is so difficult to get replacement bolts from the manufacturer.

This condition is nothing new although it is a condition that will very likely never occur with a factory assembled rifle. I have had to work on a few that had replacement or donor bolts installed. Not a tough fix. Just be careful to use a stone instead of a file or grinder. It may take a bit longer with a stone but at least you won't slip off and make an unsightly mark.
 
So it is only stiff after firing ? Sounds like you may have a rough chamber making it rough to open.
 
Thanks for the responses, fellas.

As far as I'm aware and recounting the discussion I had with the smithy, there was no filing of any sort done (this perception could well come from the crappy pictures) and there was no actual bolt 'fitting'. He trued the lug mating surfaces and the bolt face but that's as far as he went. He brought the engagement to my attention when he had everything done. We had already had the discussion about this possibility prior to his starting work on the rifle & I was fully aware that this could present an issue. He felt at the time of completion (and after his test firing) that it would continue to function, though the engagement was not as much as he would like to have seen. He seemed hesitant to address timing (removal & re-soldering) and I never really pushed it.

Aside from this mildly aggravating issue, I've been so happy with the way this rifle shoots and behaves, I couldn't care less if the bolt was a railroad spike. I really don't have any desire for a 'better' bolt, I just want to make sure I understand what is actually going on here. Unfortunately, I tend to be the guy who thinks worst case scenario when things happen :rolleyes:

Earlier this afternoon, I worked on the action portion a bit with a stone and it did make a small but noticeable difference. Just a bit cautious though, as I worry that if primary extraction relies solely on those two very small points of contact & I whittle them away, I'll really be in trouble.:redface: I'm starting to believe that this burr definitely contributes to my condition, although my case sizing and annealing may play a bigger role is this instance (at least I'm hoping). I spent some time going through a bunch of brass today and have noticed some inconsistencies that very well could be attributable to case hardness. I'll get this remedied shortly and try again.

As for the rough chamber comment, I'm not so sure that if it were an issue, it would not wait until I put 1100 rounds through it to pop up. It would cause trouble from the start, wouldn't it?

Any recommendation for a competent bolt timing wizard? Thanks for all the help so far guys!
Rooster
 
The bolt handle needs to be moved forward by about .030" or a little more. Alternatively, the handle can be moved counter-clockwise but there are some caveats.
The theoretical ideal has the extraction cam contacting exactly when the locking lugs clear. In practice, there must, of course, be some clearance but with most 700's, especily the newer models, there is much more than necessary. When I am doing one, I first check to see if the locking lugs are vertical when the bolt is closed (barrel off, of course) If not, the handle can be moved counter-clockwise on the body. When this is done, it is necessary to shorten the tail on the handle base; other wise the base of the handle won't clear the raceway.
If the lugs are vertical, then the handle will be relocated forward. When everthing is right, the first contact when the bolt is pushed forward will be the camming surface and not the trigger sear. It will be possible to #### the rifle by simply raising and lowering the handle without withdrawing the bolt at all.
A common problem with a simple, if not easy, fix. Before anyone asks, I am retired but surely there is someone doing this sort of work.
 
Is that a CrMo bolt in a stainless receiver? Any galling happening? Using a good high pressure lube on the locking and camming surfaces?
"Truing up" the locking lugs removes metal, allowing the bolt to move rearward slightly. This will reduce primary extraction, how much being determined by how much metal was removed from the locking surfaces of the lugs.
A 700 bolt handle can be moved. They are induction brazed at the factory. Red heat is required to remove one. After the contact surfaces are cleaned and prepped, the handle can be reattached by silver soldering. This also requires red heat. Proper clamping jigs are essential.
 
Let me know when you've got time this weekend or next week to run your brass.

IMO I think your bolt handle needs to be moved forward. My new model 700 (308) could also use some love in this department.
 
358Rooster said:
Thanks Elkhuntr. I've always shot for a .002 to .003" bump for this rifle. I just measured some cases with my Sinclair comparator and I get a consistent 1.792" from fired cases and 1.789" to 1.791" with the last batch of sized cases. Guessing maybe I need to look at annealing, as you suggest - if the cases were malleable enough, the 2-3 thou would probably be okay? I will get my cases annealed & see what that does for me.

In the pictures below (apologies for the quality - left my good camera at work), you can see that there is only a very small point of contact between the handle & action camming points, at which, there is now a small burr on the action. Am I wrong to assume that there should be more contact between these two angled cuts?




Click to expand...

From these pics it looks like there is enough camming action happening so extraction shouldn't be an issue. You have already done some stoning and it helps. Before you do more you may want to check the faces on your lug ways. Make sure they aren't set back. By this I mean hot loads have pounded the lug ways and left a ridge on each side. This happens more often than many realize. I can see the extraction being difficult right from the first round but not just starting up after a thousand rounds.

When I first looked I thought the bolt may not have been turning a full 90 degrees.

If it really is that little camming surface in the corner, there is another way to fix this. I used to have access to the proper torches equipped with a small hopper that you fill with the appropriate metal powder. It doesn't require nearly as much heat. What it does is heat up the face of the material you need to build up and turn the metal powder to a molten form that will readily adhere to the steel you want built up. It still needs to be cleaned up of course but it blues well and if stainless, polishes or bead blasts well and is very tough/permanent.

I would think your local welding shop should be able to do this for you at a reasonable price.
 
If one wants to weld up the surface or build it up using a spray weld technique, that can be done, I suppose. However, if you are going to do any welding, you might as well remove the darn handle, locate it where it should be, and have it TIG welded in place. I actually think this is the BEST way to do it but since I never have had a TIG welder, I have never done it and have relied on silver brazing. I believe Guntech has had some done this way and can probably tell us more about the results.
 
Again, thanks for replies. I'll try to address as best I can (just try to remember, I'm a good kid but not all that bright;)

1) The bolt handle can not be moved forward .030", as I only have .026" between handle and action as it is, unless some of the non-critical portion of the handle is removed to attain that dimension. Prior to cleaning everything, I noticed a small 'smudge' in the grease where the handle made near contact with the angled cut in the receiver. Not hard enough contact to put a shine on the area but close enough to leave evidence that it's almost there. Maybe it doesn't need major surgery just yet... I've been thinking that if I took more material off the bottom corner of that cut, it should allow more purchase between the handle and the face of the receiver cut. This might be a bit of a gamble. However, if I'm looking at surgery anyway, there's not a lot to lose, is there?

2) That is a carbon bolt. And yes, regrettably, there is a small bit of galling on one lug. This pisses me off because I was going to argue that it is far more likely to have galling between stainless parts than SS/CS parts (which it is). But I guess I'll have to eat crow on this one :redface: Yes, I do use good grease but maybe some unintentional neglect has come into play here. I'm often faced with, "hey, I actually have a very rare bit of time here! Grab a rifle & let's go!" From my way of thinking, if it were the amount of material removed from the lugs in the first place that sets the bolt assembly too far back and causes my issue, it would have been an issue from the start, correct?

3) As far as I can tell, there doesn't appear to be set back. Now, this is tough to quantify without chucking up & dragging a finger dial over it but visually, I can see a bit of burnishing but no defined ridges / steps, etc. Just that damn bit of galling at the minor diameter of the right lug. As far as hot loads go, I have to say no. During testing, the 32nd round since build completion created a stiff bolt lift. Nothing requiring hammering or anything. I soon after settled on a load 2.5 grains under that load and have been using it ever since.

I really need to get some brass annealed and try that approach to at least eliminate it as a variable. What do you all think of knocking that bottom edge down on the receiver cut to get more contact between bolt & receiver cam face? The only hard contact is at that bottom corner.

Guys, I know it's very difficult to diagnose things like this in this manner but I really appreciate the effort!

Rooster
 
358Rooster said:
Again, thanks for replies. I'll try to address as best I can (just try to remember, I'm a good kid but not all that bright;)

1) The bolt handle can not be moved forward .030", as I only have .026" between handle and action as it is, unless some of the non-critical portion of the handle is removed to attain that dimension. Prior to cleaning everything, I noticed a small 'smudge' in the grease where the handle made near contact with the angled cut in the receiver. Not hard enough contact to put a shine on the area but close enough to leave evidence that it's almost there. Maybe it doesn't need major surgery just yet... I've been thinking that if I took more material off the bottom corner of that cut, it should allow more purchase between the handle and the face of the receiver cut. This might be a bit of a gamble. However, if I'm looking at surgery anyway, there's not a lot to lose, is there?

2) That is a carbon bolt. And yes, regrettably, there is a small bit of galling on one lug. This pisses me off because I was going to argue that it is far more likely to have galling between stainless parts than SS/CS parts (which it is). But I guess I'll have to eat crow on this one :redface: Yes, I do use good grease but maybe some unintentional neglect has come into play here. I'm often faced with, "hey, I actually have a very rare bit of time here! Grab a rifle & let's go!" From my way of thinking, if it were the amount of material removed from the lugs in the first place that sets the bolt assembly too far back and causes my issue, it would have been an issue from the start, correct?

3) As far as I can tell, there doesn't appear to be set back. Now, this is tough to quantify without chucking up & dragging a finger dial over it but visually, I can see a bit of burnishing but no defined ridges / steps, etc. Just that damn bit of galling at the minor diameter of the right lug. As far as hot loads go, I have to say no. During testing, the 32nd round since build completion created a stiff bolt lift. Nothing requiring hammering or anything. I soon after settled on a load 2.5 grains under that load and have been using it ever since.

I really need to get some brass annealed and try that approach to at least eliminate it as a variable. What do you all think of knocking that bottom edge down on the receiver cut to get more contact between bolt & receiver cam face? The only hard contact is at that bottom corner.

Guys, I know it's very difficult to diagnose things like this in this manner but I really appreciate the effort!

Rooster
Click to expand...

If you had set back that is bad enough to cause extraction issues it would be pretty obvious without needing a dial indicator on a tip arm.
 
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