Crooked Recoil lug. Headspace question?

[adam32]

I would just use two vices, one holding the barrel and the other holding the action. Then slightly loosen the barrel nut and tap the recoil lug into the correct location. By using two vices the barrel will not turn on the action so headspace will not be affected.

 

[MNbogboy]

How many fractions of a turn is safe headspace slop? I kinda feel like it's too small for me to eyeball back in place, even with some bubble levels on the various pieces. Wouldn't a fired piece of brass get me way closer than sighting across several surfaces?

The Marlin has been said to have same threads as small shank savage (1.055x20). If this is true the shank thru the nut is probably close (1.062). One full turn is .050. ...1/8 inch along the barrels circumference will be approximately .002.
A straight edge mark with a "sharpie" on the top of the receiver across the nut & recoil and onto the barrel & receiver will get you very close to where you were.(Sharpie marks clean off with rubbing alcohol or kroil)
Before you start, remove the ejector pin from your bolt and see how many thicknesses of "scotch" tape(trim with scissors) on the head of your "fired" but not sized brass it takes so the bolt will not close. This will be your benchmark to check for same fit once you are finished. The fired brass should just barely close with one thickness (depends on springback).

However, without the proper action wrench or barrel vise and barrel nut wrench damage to your action and nut is at risk. A local gunsmith will have all the tools (including the headspace gauge)necessary and bringing him the rifle disassembled as shown should hopefully only take him a matter of minutes to correct.
My .02,
Randy

 

[entoptics]

The Marlin has been said to have same threads as small shank savage (1.055x20). If this is true the shank thru the nut is probably close (1.062). One full turn is .050. ...1/8 inch along the barrels circumference will be approximately .002...
Randy

Didn't occur to me to calculate the distance from the thread pitch...

I should be able to return it to within ± 0.001" just by eyeballing a straight edge mark (±1/16").

I'll also check the headspace (minus ejector) with fired and/or sized brass and some tape shims before I take it apart. I'll make several pieces that just barely close, and some that just barely won't close, and check that they all behave the same after the lug is corrected.

I have a vice and v-jaws for barrel clamping, as well as the Savage barrel nut wrench, so I should be good to go. I swapped a Savage barrel without any trouble, so this should be the same.

Thanks everyone for the information.

 

[Mram10us]

I have remedied a canted lug by simply tapping it with a good ole hammer. Don't laugh or cringe. I don't torque my stuff down to 1000 gorilla lbs/sqin though. Put it on a table and put a level on a top section to verify (scope rail, etc).

 

[MNbogboy]

As J.E. mentioned it would also be wise to pin the lug to the action. Any future barrel swap or even headspace adjustment may result in a mislocation that would not match your "soon to be" bedding job.
Although you are not using an action wrench, this is my setup for holding an unpinned lug while tightening. Shown is a savage (which is pinned) for illustration. The action wrench is tapped for the stud and the "washer/shims" stop the lug from following the barrel or nut when tightening.

 

[entoptics]

Got it all apart and back together, and the recoil lug is definitely not pinned. How would one go about doing that? Presumably drill through the lug just into the receiver? I'm not going to do it, as that's a little more "hands on" than I'm comfortable with, but I'm curious.

Everything seems to be in good order, though I spent about 2 hours dinking with it.

My dad used to say "You can do it 3 ways...The easy way, the hard way, or my way. But my way makes the hard way look easy!" He even had "Making the hard way look easy for over 30 years" on his farm business card.

My homemade action block slipped, so I had to correct that to get the nut broken loose. Then like an idiot, I spent 45 minutes trying to time the recoil lug under torque. Loosening nut and vice, rotating, checking level, swearing and cursing, reset vice, try again. About 7 times of that before my dumb @ss it dawned on me to just level it, put some sharpie marks on, then torque till they lined up. Sigh...

Anyway, the lug is now true and the headspace feels identical to before. Little bit of resistance on fired brass (last 1/3 of throw), barely any on -0.002" shoulder bumped sized (last 1/8th throw), and REALLY hard bolt close on +0.003" fired brass with tape (smeared the tape it was so tight).

Once the bedding is done, I'll take my comparator with me to the field and fire one round then measure to see if the shoulder moved forward more than before. I'm guessing I got it within a thousandth of where it was though.

I've definitely proven to the world that having skills and proper tools is definitely the way to go though...Making the hard way look easy!

Honestly though, I'm doing this whole project as much to learn as anything else. If I somehow destroy the rifle in the process, I'm only out a beater Marlin that was given to me in the first place.

 

[Mram10us]

Nice job. Next time, try tapping with the hammer first

 

[entoptics]

Nice job. Next time, try tapping with the hammer first

That's all on you! I checked the thread a little while before I got started, and didn't see the suggestion. Had you posted it 10 minutes sooner, I'd have the bedding job done by now!

 

[Gater]

If y

Normally a rifle that uses a barrel nut has a pin to hold the lug in place. If it doesn't, you should buy a few tools to do a good job. Some jobs require special tools and they can save lots of time and money. if the pin has/is sheared of it can be replaced and the make up will not change.

With this type of action that uses a barrel nut. proper head space is only achieved using a head space gauge. brass cases have spring and can give you a false reading. the ejector will/can also give you a false reading so it should be removed. If you are going to keep this rifle a head space gauge could be very handy and could be used to occasionally check the head space.

What I was trying to tell you about the head space not changing was for a shouldered barrel, once it is machined to the correct head space, it should not change except over time and many shots. With a barrel nut you have to use a hard method of head spacing and a gauge is it. Lining up the lug can be accomplished many different ways but head space should be done properly. Short cuts can only cause problems.

The best thing that I can recommend is to take it to a smith that has the tools and have it done right. He shouldn't charge you very much because he should have the tools and the only thing he has to spend is time. this job should take him less than 1 hour and everything will be properly torqued.

Just my advice at this point.

J E CUSTOM

If your gun has a notch where the recoil lug is supposed to sit then buy a new recoil lug and gauges do it right it's not worth taking a chance only to find out that you have to do it again and end up buying the tools anyway

 

[ThrdKllr]

The Marlins do not have a knotch in the receiver and the recoil lugs are not pinned. Just like the 700's. The Marlins have the same threads as a Savage but the bolt heads are deeper on the Marlins. Incidentally it is the same bolt head as a 783 Remington. They are set up the same way.

 

[entoptics]

Well...Reset the headspace using my brass collection. Twice actually, as I let Devcon go up through front action screw hole, into where the bolt head cams around to lock, and had to pull barrel again to chip/scrape it out of there...

Pretty much screwed the pooch with redneck headspace tricks. I fired several rounds, and my new base to shoulder datum is almost 10 ten thousandths shorter!

Just kidding. It worked like a charm. My caliper has a 0.0005 digit, which I don't trust, but if I did, it appears my new BTSD is averaging 1.920. Brass fired previous to my amateur gunsmithing is averaging 1.925 to shoulder datum. In other words, new is same as old within error, but perhaps just a smidge shorter.



Rifle shoots fine, and my bedding may have improved things. Too early to tell if it's its a lot of improvement, or just a hair. Testing started with a couple "mehhh..." groups (using reject concentricity reloads) and ended with a couple "Ohhh??..." groups (with my best loads I crafted/culled for hunting).

Planning to do a little bit of re-development of loads with new conditions, but otherwise happy with the job.

 

[ThrdKllr]

Good deal. Glad you got it worked out. My 7s also had a crooked recoil lug. Grouped a lot better after I straightened it up. It's a 308.