Turk Mauser barrel install

[rtracy2001]

My winter project is to build a 308 sporter out of one of the cheap Turks that I got for Christmas. This is my first custom rifle project. I was able to round up a barrel for my project on Gunbroker, and it arrived in the mail yesterday. Well last night I worked on cleaning up the threads in the receiver and the new barrel, and so far this is what I have.

The threads in the receiver are clean and shinny.

The threads on the replacement barrel are also clean and shinny, and I have lapped off all of the visible burrs and imperfections in the lathe cut threads.

I lapped the threads on the barrel and receiver using toothpaste as a fine lapping compound (Works so well it makes you wonder if you should brush with it).

As of bedtime last night, both the replacement barrel and the original barrel thread smoothly into the receiver until they are about 1 to 1/5 turns from bottoming on the torque shoulder. At that point the barrel gets stiff and it gets increasingly difficult to turn the barrel into the receiver by hand. If I mounted the barrel into a vice and used my action wrench I think I could turn it home, but I am uncertain if that is right. When it came time to put everything up, i washed the toothpaste off everything, dried thoroughly and coated all threads with 3 in 1 oil. I also tried threading things together one last time with the oil, just to see if the lube would make a difference, and it did not.

Questions:

1. Should the barrel thread all the way into the torque shoulder by hand, or is the stiffness at the end normal?

2. At final assembly, how tight should I tighten the barrel, is there a torque requirement, a simple way to tell when you are tight enough, or what?

Thanks All

[waksupi]

It sounds like the barrel needs faced off a bit. I like a barrel just snugged up well, past hand tight, but not needing a cheater bar to set them. No sense in cranking them down as hard as some do.

[deltaenterprizes]

I did a Turk rebarrel and had the same problem until I put a relief groove at the end of the threads.
Have you measured with a depth micrometer the spacing of the inner and outer shoulder? the barrel shank should be within .001-.002'' of that dimension.

[rtracy2001]

It sounds like the barrel needs faced off a bit.

Not quite sure what you mean by this. Neither the inner nor outer torque shoulder is yet in contact with the barrel. I can see that the shoulder of the barrel is not in contact with the receiver, and I smeared some grease on the inner shoulder of the reciever. The grease was undisturbed (no grease on the barrel face).



Delta,

I have not yet measured the barrel and receiver. My thought was to get the threads in line first, then take the measurements.

[waksupi]

Not quite sure what you mean by this. Neither the inner nor outer torque shoulder is yet in contact with the barrel. I can see that the shoulder of the barrel is not in contact with the receiver, and I smeared some grease on the inner shoulder of the reciever. The grease was undisturbed (no grease on the barrel face).


.

What I mean is, you need to chuck it up in the lathe, cut off enough of the barrel to fit the reciever, then chamber to headspace. You can't buy a barrel, and expect it to just screw onto your action and fit.

[swheeler]

Turkish mausers used many reciever variations and dimensions. Get a measurement from front of reciever to inner torque shoulder, then measure the thread shank length on your barrel. The perfect set up would be barrel shank aprox .003" longer than threads in reciever. Last Turk I did was large ring, small shank and LONG SHANK, .980"dia X .775" long IIRC. Not the nominal small ring mauser thread of .980" dia X.625"long shank.

[rtracy2001]

I went ahead and measured the barrel and the receiver. I don't have a depth micrometer, so I used my dial caliper. It does well up to about .001, so it should at least give a good idea what is happening.

The receiver measures .627" from the front face to the inner torque shoulder. The barrel measures .630 from the end of the chamber to the shoulder.

When I hand tighten the barrel into the receiver, I get a visible gap of about 1/16". I can see the gap on the outside of the receiver, and I can insert a small o-ring pick between the inner torque shoulder and the end of the barrel. The barrel is NOT bottoming out in the receiver, but I cannot turn it any more by hand. If I mounted the barrel in a barrel vise and used my receiver wrench to tighten it up, I could probably get the barrel to bottom against the inner shoulder.

The original question was: "Is this normal"

Do I need to continue lapping the threads until I can bottom the barrel before I tighten everything up with the action wrench/barrel vise?


Oh, BTW the barrel was cut on a lathe and is short chambered. Once I get it together I will finish ream to headspace.

[swheeler]

I would guess read post #3, you may need a relief cut on the breech end of barrel shank. If you have the barrel that came off, see if it had a thread relief.

[Antietamgw]

Sounds like you got lucky with the shank length, that's about perfect. Could just be the reciever threads against the inside shoulder are a tad tight, tapered, etc. Hand tight is a pretty subjective thing - I know what it is to me but it likely isn't the same for all of us. Do you have any high spot blue or a Sharpie pen? Sharpie might be best - put a small amount on the threads in the areas you think it might be hitting, check it out. You might need to go to your reciever wrench and barrel vise and snug it up enough to rub the Sharpie mark off. Happy tinkering!

[rtracy2001]

I would guess read post #3, you may need a relief cut on the breech end of barrel shank. If you have the barrel that came off, see if it had a thread relief.

No relief cut in the original barrel. The original was quite difficult to get off, I thought it was just getting the barrel vise set up, but the receiver could have a bit of taper to the threads, that would explain the trouble getting it off.

Back to lapping the threads again. Fun!

[deltaenterprizes]

Is there a groove that goes completely around the barrel in front of the last thread ? You can not thread up to a shoulder without a relief groove or removing the first thread in the receiver.

Look closely at the end of the threads next to the barrel:http://www.sportsmansguide.com/net/cb/cb.aspx?a=506927

CNCed threads usually do not have a relief groove.

Read this:http://www.gswagner.com/turk/turkmain.html

[rtracy2001]

OK, its picture time.

here is a shot of both barrels (new barrel on top)

http://i156.photobucket.com/albums/t23/tracraym/sidebyside.jpg

Here is the old barrel as tight as I can get it without tools.

http://i156.photobucket.com/albums/t23/tracraym/original-1.jpg

New barrel, same situation

http://i156.photobucket.com/albums/t23/tracraym/new-1.jpg

I am sure it is not bottomed yet

http://i156.photobucket.com/albums/t23/tracraym/pick.jpg

More thread lapping?

[deltaenterprizes]

Thanks for the pics, the new barrel does have a relief groove, that eliminates that potential problem.
Since it does it with both barrels I would suspect the receiver is the problem, a burr or something like that .
How clean is the inside of the receiver?
Who removed the original barrel?

[rtracy2001]

The inside of the receiver is shiny clean (as much as I can see anyway) I can work at it with the pick some more just in case there is something stuck between the threads that I can't see.

I removed the original barrel, well, the one that was installed when I got the gun anyway. It looks like it was rebarreld at least once as the serial numbers don't match. That is why it became the project it is.

Looks like it is time to paint the threads as mentioned previously.

[deltaenterprizes]

Someone machined the front of the receiver?

[rtracy2001]

I got it, finally. The very last thread in the receiver, part of the lead out, rolled over when the original barrel was taken out. some careful work with a dremmel removed the offending lead out and the barrel went another 1/4 turn. After removing the barrel expecting to do more work on the receiver, I found, or rather my left index finger found that the barrel lead in thread was split and had a very sharp edge. Once that was removed, the barrel went right in. the bolt won't close on factory ammo, so I should have enough room ro finish ream.



Someone machined the front of the receiver?

The turks come with a handguard retaining ring. Since I am not installing a handguard, I took the retaining ring off to improve the looks. I'll round the edges later.

Before
http://i156.photobucket.com/albums/t23/tracraym/before.jpg

After (I did not take off so much material as to change the position of the front shoulder.)
http://i156.photobucket.com/albums/t23/tracraym/after.jpg

[Ben]

A Turk 98' can be made into a fine rifle.
Here is my .280 Rem " Stalker " rifle made on a Turk
Click on the photo to see the slide show :

http://img.photobucket.com/albums/v494/haysb/Stalker%20280%20Remington/th_96.jpg (http://smg.photobucket.com/albums/v494/haysb/Stalker%20280%20Remington/?action=view&current=2c514754.pbw)

[waksupi]

Dremel? Dremel??!! DREMEL!!!!?????

Arghhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh! :veryconfu

[docone31]

Dremel is better than a file, or hack saw.

[rtracy2001]

Dremel is better than a file, or hack saw.

I've used all three, on this project in fact.

IMO if used for the correct application, with prudence and caution, there is no reason not to. In fact, most gunsmithing books lists all three as indespensible tools for the home or pro smith.

I will confess that I was sweating bullets while removing the damaged thread, but I took it slow, and checked my progress often.

Here is what it looked like last night (before I finished fitting the barrel)

http://i156.photobucket.com/albums/t23/tracraym/IMG_0454.jpg

[izzyjoe]

look's like you are gona have one nice rifle when you finish it. i've been kick'n around the ideal of building a lw 257rob. on a 98 that i have. and seeing pic's like these get my heart racing. thanks guy's :razz:

[S.R.Custom]

Dremel? Dremel??!! DREMEL!!!!?????

Arghhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh! :veryconfu

What would you have used?

[nanuk]

What would you have used?


Let me guess.

an inside threading bar, on a lathe

[deltaenterprizes]

A thread chasing tap would be my first choice, but is kind of expensive for a one time use. Internal thread chasing on a lathe under power is a tricky job. I have done with hand power and the feed in neutral and a tap of the same pitch as a chaser.
The gentleman completed the job with what he felt was the was the right tool for his skill level, it may have been all he had, and it worked!

[rtracy2001]

I would love to have half of the equipment that some people take for granted around here, but I don't. Someday I may have the equipment, but for now, it is a simple math equation;

Dremmel tool with small burr: $30

Mauser thread chasing die: $60-$90 + $10 shipping (min)

Lathe: $3,000 and up (for one with all needed abilities and future expansion)

Place to put the lathe: $200,000 (max) no room here, need new house.

Even if I ruined my $75 receiver, I'm still money ahead.

Besides if you want to get technical, the tool that has ruined more firearms than any other (except perhaps the tools in DC) is the screwdriver, and even master gunsmiths still use those.

I am very glad that it worked out this time. :bigsmyl2:

[S.R.Custom]

...if you want to get technical, the tool that has ruined more firearms than any other (except perhaps the tools in DC) is the screwdriver, and even master gunsmiths still use those...

He shoots, he scores! :mrgreen: