This question just might fit better in the thread of "tight chamber".

But ..just found the perfect example if why Bubba should seek out a real gunsmith

Client sent a REM. P-17 to build a 500 A Square..Some damn fool drilled and tapped a hole right through the upper recoil abuttment.

This round develops a pretty stiff 63-64000 PSI according to Wikipedia.

I thought putting a tight as hell plug might bridge the obviously weakened area, since the L bolt lug is split, thrust might be distributed to either side of the hole????

Is this overthink, logical. or what

quote:

Originally posted by Duane Wiebe (CG&R):
This question just might fit better in the thread of "tight chamber".

But ..just found the perfect example if why Bubba should seek out a real gunsmith

Client sent a REM. P-17 to build a 500 A Square..Some damn fool drilled and tapped a hole right through the upper recoil abuttment.

This round develops a pretty stiff 63-64000 PSI according to Wikipedia.

I thought putting a tight as hell plug might bridge the obviously weakened area, since the L bolt lug is split, thrust might be distributed to either side of the hole????

Is this overthink, logical. or what

It is difficult to judge just how much weaker a lock up area is after work has been undertaken around these areas. A tight plug would replace the drilled out metal in your Rem P17, whether the upper abutment has been weakened
to be concerned about and whether this restores the original strength of the upper recoil lug abutment, who knows. I would plug it for some unscientific peace of mind

Take for example actions that have been opened up for larger cartridges by qualified gunsmiths, or bubbas, where the lower lug abutment and sometimes the upper lug abutment are ground away or scalloped out to allow longer cartridges to fed from the magazine and eject from the action e.g. The Winchester factory undertook such opening up work on their standard length pre64 M70 actions for the long 300 and 375 H&H cartridges. Have a look at the amount of grinding and scalloping they make to the lower and upper recoil abutments in the images below. How much does this weaken the bolt lock up, how would you measure it considering someone designing the original action would have calculated the amount of metal required for the cartridges intended for use in the standard action? Normally in design there will be some margin of error allowance, but how much we never know.

quote:

Originally posted by Duane Wiebe (CG&R):
This question just might fit better in the thread of "tight chamber".

But ..just found the perfect example if why Bubba should seek out a real gunsmith

Client sent a REM. P-17 to build a 500 A Square..Some damn fool drilled and tapped a hole right through the upper recoil abuttment.

This round develops a pretty stiff 63-64000 PSI according to Wikipedia.

I thought putting a tight as hell plug might bridge the obviously weakened area, since the L bolt lug is split, thrust might be distributed to either side of the hole????

Is this overthink, logical. or what

I have a similar situation.

What is your conclusion, have you decided?
If you go the plug route how would you install it in a permanent manner, friction it, solder, epoxy, sweat etc. ?
BB

I’ve repaired a few Oberndorf sporters with the same issue.
I drilled out the threads then used press fit plugs, machined parallel but flared slightly at the head.
They were invisible after finishing but that might not concern you if scope bases are to be installed.

My personal opinion (as a bubba) would be to do the math.

I would not trust a repair like that. If it is strong enough to handle the force hole and all, I would use it.
And I would go further and do the math for a head-separated case condition.

The math is actually very simple. Case head cross-sectional area (case head radius squared times PI) in front of the belt multiplied by maximum chamber pressure gives you the force exerted on the bolt. Divide that by the area of contact between the bolt and the receiver gives you the stress applied to the metal. If that stress is lower than the yield stress of both the bolt and the receiver, it will be safe to use.

quote:

Originally posted by Duane Wiebe (CG&R):

I thought putting a tight as hell plug might bridge the obviously weakened area, since the L bolt lug is split, thrust might be distributed to either side of the hole????

Is this overthink, logical. or what

The top lug is indeed split and that leaves solid metal on either side of the hole. I don't think it is as bad as the bullet nose scallops done on Mauser receivers. Does drilling a scope base hole through the web in front of the lug abutment weaken the receiver? It certainly bears tension load on firing. Maybe, don't know.

Case head back thrust is greatly mitigated with a dry chamber; the brass case alone can withstand up to 40 K psi. Only on an oiled case will the bolt take 100% of the pressure. So be careful with math. You can get numbers, but context matters too.
That is why the British used to oil cases in testing.
Is that receiver weakened? Yes. Enough to matter? No.

Appreciate the input. I think I'll go with a taper pin , pressed in with great vigor'

Then test fire remotely.. Thanks much

Easy with the taper pin. If the hole is close to the abutment, it could push metal.

quote:

Originally posted by Duane Wiebe (CG&R):
Appreciate the input. I think I'll go with a taper pin , pressed in with great vigor'

Then test fire remotely.. Thanks much

quote:

Originally posted by dpcd:
Case head back thrust is greatly mitigated with a dry chamber; the brass case alone can withstand up to 40 K psi. Only on an oiled case will the bolt take 100% of the pressure. So be careful with math. You can get numbers, but context matters too.
That is why the British used to oil cases in testing.
Is that receiver weakened? Yes. Enough to matter? No.

I am fully aware that the normal load will be far less than my calculation applies for.
But I have had enough cases fail on me to want to know that a rifle will be safe to fire if it happens again.

I can't help you right now Duane, but I have several actions in my "test" pile that will be destructively tested that have such holes drilled through the upper lug.

There is even a 1903 receiver with I think 5 holes through the top ring, one of which is in the top lug. My hope is that it splits like a hard shell taco.

Personally... and this is my current "I don't know" opinion, they don't make a lick of difference in the normal spectrum. On a properly heat treated action we didn't see substantial (ie detrimental to headspace) setback until 85k + psi, at which point the brass was already liquifying. The amount of setback while substantial from our standpoint, was minimal from what I would call a structural standpoint.

That being said, I don't think it is over thinking and I think it is logical. A tapered pin would be a good remedy.

Thanks again...really thoughful infomation..Maybe I'm too much of a "belt AND suspenders" type

Consider all of the rifles out there with magnum chamberings, and 50% actual lug contact. Those seem to soldier on just fine.

Just a thought.

Duane,
In my opinion (definitely in the "for what its worth" realm), pressing a tapered pin into the hole will accomplish absolutely nothing as far as adding strength to the action. For cosmetic filling, it's great, but it won't do anything for strength. How far back from the locking surface is the hole?
1917 Enfield actions are not so rare that the client couldn't just find one sans holes. Opening up a 1917 for the A-Square is enough work that I would want to waste the effort on a flawed receiver. I'm sure I,ve seen at least a hundred Mausers drilled this way; I can't imagine why. Regards, Bill.

There was a time when off-set bases and/or rings weren't as common as they are now. I think the front base may have been set as far back as it could so proper scope eye relief could be obtained. Or perhaps folks just eye-balled the ring and centered the base without thinking of where the lug abutment was? There have been a few I've seen with the hole in the abutment face. I have a M94 Swedish receiver that has the rear hole drilled as far back as you can get and it is a blind hole. I don't have any concern of it.

quote:

Originally posted by Bill Leeper:
Duane,
In my opinion (definitely in the "for what its worth" realm), pressing a tapered pin into the hole will accomplish absolutely nothing as far as adding strength to the action. For cosmetic filling, it's great, but it won't do anything for strength. How far back from the locking surface is the hole?
1917 Enfield actions are not so rare that the client couldn't just find one sans holes. Opening up a 1917 for the A-Square is enough work that I would want to waste the effort on a flawed receiver. I'm sure I,ve seen at least a hundred Mausers drilled this way; I can't imagine why. Regards, Bill.

quote:

Originally posted by Bill Leeper:
Duane,
In my opinion (definitely in the "for what its worth" realm), pressing a tapered pin into the hole will accomplish absolutely nothing as far as adding strength to the action. For cosmetic filling, it's great, but it won't do anything for strength. How far back from the locking surface is the hole?
1917 Enfield actions are not so rare that the client couldn't just find one sans holes. Opening up a 1917 for the A-Square is enough work that I would want to waste the effort on a flawed receiver. I'm sure I,ve seen at least a hundred Mausers drilled this way; I can't imagine why. Regards, Bill.

Sadly, a lot of imported Husqvarnas with FN actions are D&T'd in this way. I do think accommodating eye relief may have been a factor. to

I think it is just as likely that the "smith" just didn't know any better. I say this because many of those drilled this way are also drilled off-center. There is a right way and a wrong way to do everything and drilling back there is the wrong way. Regards, Bill

I've seen some of the Husqvarna drilled that way and off center too. Proves just that Swedish Bubba is no difference than ours.

As you can see in the second image of a Pre64 M70 I posted earlier the scalloping behind the abutment of the top locking area has removed quite a substantial amount of metal.
Although camera angles can be deceiving, compared with the lower abutment face it doesn't look as though there is much metal left behind the centre part of the upper abutment. I guess the abutment is still supported by the outer ends and in Duane's case the same scenario applies.
Winchester must be quite happy with the safety aspect of their opening up work on the standard length action to fit the H&H magnums.

quote:

Originally posted by Bill Leeper:
Duane,
In my opinion (definitely in the "for what its worth" realm), pressing a tapered pin into the hole will accomplish absolutely nothing as far as adding strength to the action. For cosmetic filling, it's great, but it won't do anything for strength. How far back from the locking surface is the hole?
1917 Enfield actions are not so rare that the client couldn't just find one sans holes. Opening up a 1917 for the A-Square is enough work that I would want to waste the effort on a flawed receiver. I'm sure I,ve seen at least a hundred Mausers drilled this way; I can't imagine why. Regards, Bill.

No idea of this is relevant to this particular scenario. But pinning cast machinery is probably the most effective way to repair cracks in a lot of huge machinery that sees considerable stress.
The problem I see with the tapered pin is that it still leaves a void. May be better to use a tight fitting straight pin. The aim of the pin should be to fill the void, which although still weakened, should still be stronger than keeping the hole.

WH, you ream the hole out with a tapered pin reamer first.

quote:

Originally posted by metal:
WH, you ream the hole out with a tapered pin reamer first.

Ah, that makes sense.

quote:

Originally posted by Wstrnhuntr:

quote:

Originally posted by Bill Leeper:
Duane,
In my opinion (definitely in the "for what its worth" realm), pressing a tapered pin into the hole will accomplish absolutely nothing as far as adding strength to the action. For cosmetic filling, it's great, but it won't do anything for strength. How far back from the locking surface is the hole?
1917 Enfield actions are not so rare that the client couldn't just find one sans holes. Opening up a 1917 for the A-Square is enough work that I would want to waste the effort on a flawed receiver. I'm sure I,ve seen at least a hundred Mausers drilled this way; I can't imagine why. Regards, Bill.

No idea of this is relevant to this particular scenario. But pinning cast machinery is probably the most effective way to repair cracks in a lot of huge machinery that sees considerable stress.
The problem I see with the tapered pin is that it still leaves a void. May be better to use a tight fitting straight pin. The aim of the pin should be to fill the void, which although still weakened, should still be stronger than keeping the hole.

In this case, there is no crack which is being pinned and it's not a casting. The pin would serve to transmit force to the metal behind the hole but will do little to add to the integrity of the piece. I do agree with the concept of using a plug to fill the hole, and do so often, but consider it to be a primarily cosmetic repair. Regards, Bill.

quote:

Originally posted by Duane Wiebe (CG&R):
This question just might fit better in the thread of "tight chamber".

But ..just found the perfect example if why Bubba should seek out a real gunsmith

Client sent a REM. P-17 to build a 500 A Square..Some damn fool drilled and tapped a hole right through the upper recoil abuttment.

This round develops a pretty stiff 63-64000 PSI according to Wikipedia.

I thought putting a tight as hell plug might bridge the obviously weakened area, since the L bolt lug is split, thrust might be distributed to either side of the hole????

Is this overthink, logical. or what

Does the hole split the face of the locking surface ?
BB

Dad always told me bubba would drill them that way because they were scared to drill and tap a blind hole over the barrel threads. Moving them back they could get the forward hole in the lug recess and the rear one in the abutment and they would both be through holes.

John

What s the consensus here? Can an action be used if there is one screw hole in the rear portion of the front ring on a g.33/40 action?

As ignoramus who has already asked that hole-in-abutment question in regard to a 1951 Famage FN Mauser .30-06 and been told it probably doesn't matter much: would a tapered plug be much stronger than just a 'glued-in' screw in the drilled-and-tapped hole?

In regard to my son's rifle, not only does it have four screw holes in the receiver ring marring the Colombian crest but the 'scallop' Famage inflicted to allow clip loading of the longer cartridges.