Recoil lug thickness question

[davidjoe]

Probably should have put this question here originally. Basically it’s about truing receivers and the effect on lugs…

I have a new to me set of several 700 actions that some degree of truing was performed on. My plan is to use existing cut 700 spec barrels I have on these.

I need to order recoil lugs but I don’t know whether standard or shading thicker is in order, since these were slightly modified.

I’m getting .6790” from the receiver ring to the bolt face.

I’m getting 1.1415” from the receiver ring to its lug face.

I don’t have a stock 700 without a barrel on it to compare to, but I can measure from the ejection port to the ring on a stock rifle, indicating 1.6150 versus 1.6070 to 1.6075 on the trued versions.

What I don’t know is whether smiths attempt to take the same amount off the face of the lugs that came off of the ring face.

I can’t measure a discernible difference between bolt lug thickness from stock to these new ones.

Would those measurements lend themselves to standard lugs or should I shade thicker?

 

[jkohler]

Those numbers aren’t adding up to me. You should be somewhere around .700 from the action face to the front of the bolt lugs then a few tho less from the ring to the boltface. If your going to use factory takeoffs you’ll need custom ground lugs or the barrels will need some work to get them headspaced correctly

 

[davidjoe]

Those numbers aren’t adding up to me. You should be somewhere around .700 from the action face to the front of the bolt lugs then a few tho less from the ring to the boltface. If your going to use factory takeoffs you’ll need custom ground lugs or the barrels will need some work to get them headspaced correctly

I didn’t take a measurement to the front of the bolt’s lugs, just from the face of the bolt to the trued face of the receiver.

I don’t think the bolt’s lugs were trued because they are actually a bit thicker than an untouched bolt I compared them to.

I did get a depth around the .700 you mention, but on the shallow side, at .6790”. If .700” is factory spec, quite a bit was removed.

On a measurement I took from an original and trued action from the the face to the ejection port, it looks like about 75 thousandths came off the face of the trued action. I don’t know how exact a “landmark” the ejection port’s placement is, though, action to action. Maybe solid, but may also be the same width while being placed non-critically relative to these small increments, from front to back on the receiver.

Even the smaller of the two seems like quite a bit. I don’t have an action free to see what the depth of the factory spec is, from receiver face to receiver lug, though.

I saw .190” lugs available, and that .187 is the apparent factory lug spec.

 

[jkohler]

The only measurements you need to figure out what has to be done are.
1 receiver face to front of the bolt lugs
2 receiver face to bolt face
3 bolt nose to the front of the bolt lug. That’s your counter bore depth.
Then check the measurements on the barrel you have to use and see what work needs done. But if the threads have been recut on them don’t plan on using factory takeoff‘s.

 

[Dusty Stevens]

Nobody takes any off the front of the lugs nor the nose. Dont fit parts to air and touching the bolt nose severely weakens it. When you fit a barrel it doesnt matter if the lug is .125 thick or 2” thick it gets fit the same way

 

[DaveTooley]

.021" shorter HS is significant compared to what we normally see. You're attempting to use barrels like light bulbs. They all fit but in this case they won't. Maybe and this is a big maybe, a custom ground recoil lug might bring the measurements back to a more normal range. An experienced smith needs to make a thorough inspection and determine what work was done.
I've never subscribed to the idea that a thicker lug was needed. It's a solution in search of a problem put forth by the marketing dept.

 

[davidjoe]

I don’t know if this picture showing the threads to the faces’ distance is able to be indicative of anything, to the experienced eye.

I’m going to select my least favorite untouched 700 RR series, like these three are, take it apart, and measure all these dimensions properly. I have numerous 700’s and 40-X’s, but never a modified one.

I’m very curious now how similar they all are, my suspicion is that they are all three very similar to each other, and trued by the same person with high expertise, near the same point in time, although I didn’t ask who that was. I base this on the customer of that unknown smith, I got them from, who did not do the work but is very particular, the three original boxes, and what I measured so far.

The rightmost is a long action and has a PTG bolt, and two of them were cerakoted, if they appear different, though I’d say lightly. That long action’s face and gap looks different.

 

[DaveTooley]

I don’t know if this picture showing the threads to the faces’ distance is able to be indicative of anything, to the experienced eye.

I’m going to select my least favorite untouched 700 RR series, like these three are, take it apart, and measure all these dimensions properly. I have numerous 700’s and 40-X’s, but never a modified one.

I’m very curious now how similar they all are, my suspicion is that they are all three very similar to each other, and trued by the same person with high expertise, near the same point in time, although I didn’t ask who that was. I base this on the customer of that unknown smith, I got them from, who did not do the work but is very particular, the three original boxes, and what I measured so far.

The rightmost is a long action and has a PTG bolt, and two of them were cerakoted, if they appear different, though I’d say lightly.

View attachment 1370966

Light bulbs are similar. Actions are individuals.

 

[jkohler]

Honestly I’d just take them to your smith and have new barrels put on them. If a customer asked me to fit up takeoffs I’d decline the job.

 

[AlNyhus]

Not much scarier than an action that's been 'trued up' by an unknown person with an unknown plan.

Except trying to fit already chambered barrels to 'em......

 

[LVLAaron]

What I don’t know is whether smiths attempt to take the same amount off the face of the lugs that came off of the ring face.

I wouldn't. You'd want to take as little off the lugs as possible. The face might need 10 thou, and the lugs might only need 2 removed. You shorten your lugs and you start messing with the timing and extraction.

 

[Fisher T&C]

The most likely scenario to make these work is to get recoil lugs that are .240", like the Sunny Hill lug, and have the shoulders moved forward to set headspace on each individual barrel for the particular action it's going on. This is highly unlikely to be a plug and play situation.

 

[davidjoe]

Not much scarier than an action that's been 'trued up' by an unknown person with an unknown plan.

Except trying to fit already chambered barrels to 'em......

I know. I don’t know how my calipers measured depth yesterday because today I can’t seem to drop it perfectly square on the bolt face and still reach the receiver faces.

Friend is going to spot me some recoil lugs he has. Headed his way now to get them. I won’t have to disassemble a rifle to see what I’m working with, at least. Not to worry guys, no live fire testing just because the bolt might close.

I have ended up in the last few years with some very good extra chambered barrels, some of them new. I have found 700 to 40X to Stiller clones to be very compatible, unaltered that is. Defiance has been, defiant, it’s a trip to the gunsmith every time.

 

[tobnpr]

What Dave said.
The recoil lugs probably will not fit.
The take-off M-700 barrels probably will not fit.
If the actions were trued by a "reputable" smith, the threads were single-pointed oversize.

The barrel tenons will likely need to be .010 oversize- and if you can't confirm with the smith, each receiver will need to be checked individually to determine the major diameter of the internal threads.

 

[Dusty Stevens]

Those look like they had the tap treatment

 

[davidjoe]

The bolt is closed on a bare piece of Lapua .308 brass. I retrieved these three Remington .187 lugs, put bees’ wax into the threads of the tenon, then oil on top of the wax and into the receiver, and hand turned it on. There was no play in the fit, even considering the wax. I had been told that the only truing was to the receiver ring and its lugs.

I played with the unpinned lug’s alignment, got it to my usual tightness, and closed the bolt. Worked. Next found a piece of unfired brass, and it closed on it. Pretty lucky so far. Tomorrow I’ll gauge the HS, test bolt face clearance. This a Palma contour Krieger 5R, from someone who has done many barrels for me, and never risks excessive unsupported case head, which is my big hang up in all of this. Seem to have gotten lucky so far with this one, at least.

 

[Walt Krafft]

I have been keeping a log of the Remington actions I have worked on the last few years. All have been RR or the new RAR prefix. This has included long actions, short actions, 223, std, and mag bolt faces. The headspace dimension (action face to bolt face) averages 0.6976 over a total of 62 actions. High of 0.6990, low of 0.6958.
I have 5 that I got from PTG with their bolts. They range from 0.6794 to 0.6766. I have no idea why they feel they need to leave 0.020 extra. Also don't know why they sell a complete action with a note that says a gunsmith needs to fix it before use. But I digress.

 

[DaveTooley]

I have been keeping a log of the Remington actions I have worked on the last few years. All have been RR or the new RAR prefix. This has included long actions, short actions, 223, std, and mag bolt faces. The headspace dimension (action face to bolt face) averages 0.6976 over a total of 62 actions. High of 0.6990, low of 0.6958.
I have 5 that I got from PTG with their bolts. They range from 0.6794 to 0.6766. I have no idea why they feel they need to leave 0.020 extra. Also don't know why they sell a complete action with a note that says a gunsmith needs to fix it before use. But I digress.

It's my understanding that PT&G left that extra .020" so a smith can set the HS when using it as a direct replacement in an unaltered factory barreled action. Kind of makes sense but then it doesn't.
Will the bolt close? If not face the lugs off until the bolt closes, check HS, then possibly remove more off the back of the lugs. All the while losing manual extraction. That's assuming it had some to start with.

 

[LVLAaron]

What a great opportunity to learn how to relocate bolt handles and modify cams!