Advisable to shim a Mauser bridge?

21 November 2012, 22:28

I had a Erfurt based Mauser bolt action re-worked. There is a bit of "slop" in the bolt at the rear causing some scarring on the handle root where it contacts the cam area a bit. Anyone out there ever epoxy in shims to tighten things up a bit back there? Lugs were seated. A fine Thanksgiving to all. CB

22 November 2012, 17:00

Bobster

Sounds to me that, when the action was re-worked, the bolt was welded or turned down or forged and not properly re-hardened. This is a common problem. The bolt root should be glass hard and not subject to galling. It is the primary extraction cam. Mausers were made loose and the slop is normal. Shimming is not a real option, but I have read a ball plunger arrangement was used in years past thru the rear bridge to tighten things up. I don't have a source or idea or knowledge of exactly how it was done.

22 November 2012, 22:13

dpcd

Mausers are sloppy by design. Yes, the cam and bolt should both be hard, but for sporting use, you probably won't work it enough to make any difference. Just polish the cams, keep them lubed with some moly grease, and don't worry about it. Shimming in that area won't work.

23 November 2012, 00:31

JBrown

quote:
Originally posted by dpcd:
Yes, the cam and bolt should both be hard, but for sporting use, you probably won't work it enough to make any difference.

I disagree. If the handle root is soft it can gall quickly. If it is already galling then it is safe to say that it is too soft.

I would have a good Mauser smith polish it and harden the bolt handle root. Have him take a look at the the cocking cam also. It shouldn't cost more than $25 IWT.

Jason

"You're not hard-core, unless you live hard-core."
_______________________

Hunting in Africa is an adventure. The number of variables involved preclude the possibility of a perfect hunt. Some problems will arise. How you decide to handle them will determine how much you enjoy your hunt.

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Selby's flat bed truck delayed the safari, Horn of the Hunter would have read like an indictment of Selby. But Ruark rolled with the punches, poured some gin, and enjoyed the adventure.

-Jason Brown

23 November 2012, 06:34

custombolt

I'll probably just dab some graphite lube there and let it go. Thanks guys.

23 November 2012, 16:14

p dog shooter

quote:
I would have a good Mauser smith polish it and harden the bolt handle root. Have him take a look at the the cocking cam also. It shouldn't cost more than $25 IWT

You must know a smith that works really cheap.

23 November 2012, 17:25

Allen Martin

Hey Ray
ARe you going to post pics of your new rifle ???

23 November 2012, 21:24

JBrown

quote:
Originally posted by p dog shooter:

You must know a smith that works really cheap.

Yes, I do. And he is darn good, BTW.

24 November 2012, 21:06

custombolt

quote:
Originally posted by Allen Martin:
Hey Ray
ARe you going to post pics of your new rifle ???

Good to hear from you Allen. I will try and post some soon. Email me sometime when you have a minute. I also did a 1936 Mexican in 7X57. Both were completed around the same time. Ray

24 November 2012, 21:37

custombolt

quote:
Originally posted by dpcd:
Mausers are sloppy by design. Yes, the cam and bolt should both be hard, but for sporting use, you probably won't work it enough to make any difference. Just polish the cams, keep them lubed with some moly grease, and don't worry about it. Shimming in that area won't work.

UPDATE: This certainly is a sloppy one. As I was cleaning it today, I noticed some sharp galling on the tang beside the rear screw. Most was on the right, some was on the left. At this point I may use the Mexican for deer on Monday. Last 2 deer only took one shot. But,.....best to have it and not need it than the opposite.

24 November 2012, 22:32

z1r

Sloppy bolt may not be the only cause. Check the shroud lock. Often the safety notch on the back of the bolt is too generous. This allows the shroud to rotate instead of keeping the cocking piece aligned straight up and down. When it rotates, it likes to scuff up the tang like yours.

Lots of folks say that trimming the tang down causes this when in reality if everything else is working properly it is not an issue.

25 November 2012, 01:06

custombolt

Hello Mike, There is definitely 2-3 degrees of rotational 'play' in the shroud. I appreciate the help and I'll send you a PD message later. Ray

25 November 2012, 09:51

Von Gruff

quote:
Originally posted by custombolt:
I noticed some sharp galling on the tang beside the rear screw. Most was on the right, some was on the left.

Possibly been exaserbated by the usual dressing down of the tang that removes the initial guidance of the cockingpiece at the rear of the tang. A hard and fast chambering atempt can result in a jammed action with the cocking piece trying to ride up on the edge of the tang. Many of us dress the tang down like this but it can lead to this problem.

25 November 2012, 11:15

JBrown

quote:
Originally posted by Von Gruff:
Possibly been exaserbated by the usual dressing down of the tang that removes the initial guidance of the cockingpiece at the rear of the tang. A hard and fast chambering atempt can result in a jammed action with the cocking piece trying to ride up on the edge of the tang.

The problem is 99% due to the tang being thinned. This is one of the reasons some custom smiths refuse to thin the tang(including Duane Weibe).

Widening the slot(creating a "funnel") after thinning solves the problem(usually).

25 November 2012, 21:54

Don Markey

I would weld up and recut the notch in the bolt. Recut the notch with a few degrees draft in it. One of the little things I do to aid in creating a smooth bolt throw.
Don

25 November 2012, 23:48

custombolt

quote:
Originally posted by JBrown:
quote:
Originally posted by Von Gruff:
Possibly been exaserbated by the usual dressing down of the tang that removes the initial guidance of the cockingpiece at the rear of the tang. A hard and fast chambering atempt can result in a jammed action with the cocking piece trying to ride up on the edge of the tang.

The problem is 99% due to the tang being thinned. This is one of the reasons some custom smiths refuse to thin the tang(including Duane Weibe).

Widening the slot(creating a "funnel") after thinning solves the problem(usually).

Interesting. I had thought of doing just that to the tang and/or adding a fine radius to the corner of the cocking piece sear face. I don't know if I'm skilled enough to do either. I can't express how much gratitude I have for all who post here. I am lucky to have found this site and appreciate the "caliber" of those who responded to this and my other posts. Eventhough I haven't mentioned your name, I am grateful. I don't recall who told me about it. If they are reading this, would like to thank them. Ray

25 November 2012, 23:58

custombolt

quote:
Originally posted by Don Markey:
I would weld up and recut the notch in the bolt. Recut the notch with a few degrees draft in it. One of the little things I do to aid in creating a smooth bolt throw.
Don

Thanks for chiming in Don. At this point the best solution is to rebuild the tang and then machine the trough and radius the entry. But, first I'm going to replace the mag follower spring which is weak. I don't know if enough upward pressure is exerted to lower the rear of the bolt or not. But, it wouldn't hurt to rule it out. Better get to the range one more time so I can decide which gun to take for deer tomorrow. Thanks.

26 November 2012, 01:06

custombolt

Well. I ran out of time to get to th range. Both this Erfurt and my seocnd choice a newly customized 1936 Mexican won't feed and rounds won't slip under the ejector properly every time. Both are on the back burner until January.

26 November 2012, 01:18

custombolt

quote:
Originally posted by Don Markey:
I would weld up and recut the notch in the bolt. Recut the notch with a few degrees draft in it. One of the little things I do to aid in creating a smooth bolt throw.
Don

Doesn't the draft create a shroud that rotates causing my tang marring issue to start with? Please define draft. New magazine spring did nothing. I've got other feed issues. Case binds on the turn of the bolt, jumps the ejector etc. 1 step forward , 2 steps back.I need a break. Til January.

26 November 2012, 07:45

Don Markey

The draft is to guide the lock in. It should lock up tight with zero shroud rotation in the lock position.
Don

26 November 2012, 18:02

Jim Kobe

A common problem when altering the tang!!

There are two different issues here. The first, the three position aftermarket (I hope not a Gentry or Dakota as this is the timing problem most have mentioned here) may be causing a rotational problem due to the timing of the shroud to bolt. This usually occurs wehn the safety lever is in the middle postion and the bolt is cycled allowing the cocking piece to misalign.

When the safety lever is in the forward position allowing the bolt to cock on the opening stroke, the sear area of the cocking piece rests against the bolt body in the wrong position and causes the problem duscussed. The cure to this is to grind a slight notch in the back of the bolt in the correct location to allow the cocking piece to orient correctly. This problem happens before the bolt lock takes over and releases itself from the bolt.

I reduce/cut down the tang area in most of the Mausers I work on. But, like Duane has pointed out previously, you need to taper the rear of the action slot to allow the cocking piece to center itself in the action slot. That is where you could eliminate the problem depeicted in the original pictures.

Confused now?

Jim

26 November 2012, 23:24

custombolt

quote:
Originally posted by Don Markey:
The draft is to guide the lock in. It should lock up tight with zero shroud rotation in the lock position.
Don

Ah...thanks Don.

27 November 2012, 00:00

custombolt

quote:
Originally posted by Jim Kobe:
A common problem when altering the tang!!

There are two different issues here. The first, the three position aftermarket (I hope not a Gentry or Dakota as this is the timing problem most have mentioned here) may be causing a rotational problem due to the timing of the shroud to bolt. This usually occurs wehn the safety lever is in the middle postion and the bolt is cycled allowing the cocking piece to misalign.

When the safety lever is in the forward position allowing the bolt to cock on the opening stroke, the sear area of the cocking piece rests against the bolt body in the wrong position and causes the problem duscussed. The cure to this is to grind a slight notch in the back of the bolt in the correct location to allow the cocking piece to orient correctly. This problem happens before the bolt lock takes over and releases itself from the bolt.

I reduce/cut down the tang area in most of the Mausers I work on. But, like Duane has pointed out previously, you need to taper the rear of the action slot to allow the cocking piece to center itself in the action slot. That is where you could eliminate the problem depeicted in the original pictures.

Confused now?
Jim

Yes. But only on Paragraph 2. I'm wondering how the sear area can rest on the bolt body when it is in the cocked (retracted) position? All tests were done with the Wisner 3 postion safety lever forward or on Fire. There are other feeding issues. For now, I'm putting it on the back burner until January. I have another action with feeding issues as well and maybe I'll deal with them in January. Thanks JK.

27 November 2012, 17:59

Jim Kobe

There is another issue that comes into play here. If a new bolt handle has been welded on and the action needed to be notched, it may not have been notched deep enough so the bolt is not closing all the way; or maybe too far!

Jim

27 November 2012, 19:30

z1r

quote:
Originally posted by Jim Kobe:
There is another issue that comes into play here. If a new bolt handle has been welded on and the action needed to be notched, it may not have been notched deep enough so the bolt is not closing all the way; or maybe too far!

Jim

And this has what exactly to do with the cocking piece scoring the tang? That is done when the bolt is pushed forward, not when in battery.

27 November 2012, 23:39

Jim Kobe

Yes true, but if the bolt don't close all the way, the pin won't engage the and the cocking piece (held in place by the bolt shroud) won't rotate enough to enter the action cut.

28 November 2012, 00:15

z1r

Actually, the safety notch, located at 12 o'clock on the bolt, rotates to the 9 o'clock position when the bolt is opened. It is here that the locking plunger engages the notch to lock the shroud and consequently the cocking piece into place.

The bolt handle might prevent a safety from engaging due to misalignment of the notch and safety nose but it won't affect the position of the cocking piece when the bolt is open.

28 November 2012, 01:37

Jim Kobe

I stand corrected, I must have been thinking about something ekse!

However, if there is some slop in the pin or the bolt notch, it may cause the shroud to not rotate enough so the cocking piece would not enter the action slot correctly. The notch in the back of the bolt for the cocking piece in the correct spot will allow the cocking piece to enter the slot in the action.

I have a hunch both of us know what we are talking about but it seems to be lost in translation somewhere.

Peace!!

30 November 2012, 09:42

Bill Leeper

I ran into the same problem with a pretty sloppy Siamese Mauser upon which I built a 30/40 thirty-some years ago. I slimmed the tang too much and with all the slop in the bolt, it would hit on the right side of the slot. I welded up the bolt lock notch and moved it a bit and slightly tapered the cocking piece on the right side and it worked OK. I never thinned a tang that much again!
Tom Burgess told me of splitting a receiver bridge and welding it back up to tighten the clearance. I've not felt inclined to go that far on one. Regards, Bill

30 November 2012, 19:09

z1r

quote:
Originally posted by Bill Leeper:
I ran into the same problem with a pretty sloppy Siamese Mauser upon which I built a 30/40 thirty-some years ago. I slimmed the tang too much and with all the slop in the bolt, it would hit on the right side of the slot. I welded up the bolt lock notch and moved it a bit and slightly tapered the cocking piece on the right side and it worked OK. I never thinned a tang that much again!
Tom Burgess told me of splitting a receiver bridge and welding it back up to tighten the clearance. I've not felt inclined to go that far on one. Regards, Bill

Yeah, I shared another one of Tom's bridge tightening techniques with teh OP.