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View Full Version : Swapping barrel and Setting Headspace



DennisH87
03-29-2010, 01:36 AM
Hello, new to this and have a lot of questions. After searching the threads I found a lot of answers but still have some questions. I'm pretty sure I'm on the right track but I want to check my understanding before I embark on this and worst case scenario, screw something up.

I just bought a .223 A&B barrel in 1:14 twist to replace my .22-250 barrel. Also bought a Wheeler Engineering Barrel Nut Wrench, Wheeler Engineering Action Wrench as well as the appropriate bolt face and GO/NO-GO gauges. Now as far as I understand this is all the tools and equipment to complete this job. I'm I correct?

http://www.midwayusa.com/viewProduct/?productnumber=288765

http://www.midwayusa.com/viewProduct/?productnumber=321862

http://www.midwayusa.com/viewProduct/?productnumber=710783

http://www.midwayusa.com/viewProduct/?productnumber=548296

http://www.midwayusa.com/viewProduct/?productnumber=217300

http://www.midwayusa.com/viewProduct/?productnumber=217440



DISASSEMBLY

Is heat needed to loosen the barrel nut or can I just use brute force to get it off? If heat is needed how would I apply it? (ie heat gun)


HEADSPACE

Current Barrel:(.22-250) I am going to be switching these barrels back and forth and want to keep the current headspace dimensions on my .22-250 barrel that's on the gun now. Could I take a case that's been fired in my rifle, neck size it like all of the ammo I have loaded, and fill it with epoxy to use as a "set to" gauge? That way when I reinstall the .22-250 barrel the current dimensions are retained.

New Barrel: (.223) I want to make this a "tight chamber" rifle so in order to do that I should just screw it down on the GO gauge and tighten everything up? I know it will say in the directions but for me it's much easier to understand it when its explained and not in a manual. I will be shooting .223 brass and some 5.56x45 brass. Is there anything I have to watch for when setting the headspace or can I just tighten it down on the GO gauge?
Is there any special reloading processes that need to be done to the 5.56 brass to fit my .223 Remington chamber?


BARREL BREAK IN PROCEDURE

I read somewhere they were using bore paste to break in the barrel. I'm confused as to what this does.
Also, I'm confused as to what exactly bore lapping is.
This is a chrome moly barrel. What would the proper break in procedure be?

REASSEMBLY

I read the sticky "Hand tight or factory tight" but it seemed rather lengthy and controversial. Is there a general consensus on how tight to make the barrel nut?
I have some nickel anti-seize compound that I got from work. Should I put a small dab on the barrel threads or would this possibly throw something off?

Off topic but what kind of bolt grease would you guys recommend?

Thanks in advance. I realize there's a lot of questions for one thread but I thought by answering these questions it will help a lot of other beginners out. After looking through the other threads these are the ones that still went unanswered.

gotcha
03-29-2010, 10:15 AM
Dennis, how ya' doin'? Lots to consider but, you seem to have a pretty good handle on it all! I'll address headspace. You won't be duplicating the chamber dimensions of your 22-250 with a fire formed case. You'll only be duplicating the dimension of the case. Remember, the case expands on ignition then rings back to allow easy extraction! It's only a few thou. but critical. You could get the headspace so short that your full length die won't be able to move the shoulder back far enough to chamber the cartridge. I once had a gunsmith/blacksmith do this to me!! The specifications on chamber reamers run all over the place within the "saami" spec. I think that to be safe, a 22-250 go-gauge would be in order, especially on your first build. Jim @ NSS gave me a good tip on head spacing my .223. Set the headspace to the go-gauge then apply a piece of scotch tape to the "head" end of the gauge. Trim the excess tape and chamber the go-gauge. The bolt should NOT close. Tighten just a tad, if necessary, 'til the go-gauge goes and the taped go- gauge won't. The scotch tape will measure .0015" to .0018" Send the no-go back to Mid way and exchange for a 22-250 go-gauge! Works for me!! Good luck and keep us posted on build. Almost forgot, nothing special to do with .223/ mil spec brass. just keep it seperated as case capacity "due to thickness" varies between the two. A good shootin' .223 rem. load COULD be too hot for the military stuff. This isn't always the case ,Pardon the pun, but better safe than sorry!!

sha-ul
04-04-2010, 12:04 AM
good stuff in this write up, thank you.

Uncle Jack
04-04-2010, 12:22 AM
"... The scotch tape will measure .0015" to .0018"

One of the major problems with the Scotch tape school of gunsmithing is that there are no SAAMI standards for Scotch tape. I'm sitting here with a double layer of Wall Mart "Scotch tape" and my digital calipers tell me it's .0005" thick. Perhaps we need an industry standard legend of various brands of transparent tape thicknesses that we can hang on the wall next to the powder burning rate chart.

uj

DennisH87
04-04-2010, 06:51 AM
DISASSEMBLY

I used two pieces of 1/2" thick rubber between my standard vise jaws. It worked OK but not great. The good thing is no matter how much it spun it didn't mar the bluing on the barrel. I attached the action wrench to the action with a piece of shop towel on the top part so it didn't scratch the finish. It took quite amount of torque to get it off but I attached a 1/2" breaker bar to the barrel nut wrench and I was able to get it off. The one thing I did wrong was tighten the action wrench too much bc after I broke the nut free it was still kind of tough to get the action to spin. After I loosened the action wrench a little the action spun freely.

HEADSPACE

Well I've got the rifle headspaced and shootin without a headspace gauge. A guy at Sinclairs told me to just use a piece of new unfired virgin brass as a headspace gauge. I did the same technique with the scotch tape. How I did it was screw the barrel down on the unfired brass until the bolt closes with just a little tension. The same as when you fire a case and lift the bolt. Put one piece of tape on the case head and close it (while the nut is semi tight to keep things in place). It should take an abnormal amount of force to close the bolt. So if it was that tight after firing a case you would know you have a problem. Then put another piece of tape on and it should not close. The key is to only use on piece of brass once. Each time you close the bolt get a new piece of brass b/c everytime you close the bolt when its real tight i may have crushed the brass ever so slightly. Also, this way you get a good average measurement bc each piece of brass is not the EXACT same size. They're all really close, but not exact. I went outside the shop and fired a round. Now make sure if you do it this way don't put your head right next to the bolt and keep your hands away from the little holes on the front of the action. If things are too long and the case head separates gasses will come out of those holes.

Everything turned out allright. I measured the diffence between a fired case and an unfired case and the heaspace jump was at about .005-6. This is about perfect because you won't over-stretch your brass and over work it in your dies. Now before all the sheep start yelling use a headspace gauge or you'll blow yourself up, I have headspace gauges on the way and I'm going to check it before I do any load development. I fired about 50 rounds through the barrel to break it in and not one case showed signs of excessive headspace nor tight headspace. This method worked just fine as long you be careful with it. It's not ideal but it DOES work. I would still advise anyone reading this to use headspace gauges but it did work just fine for me.

On a side note the rifle shot about 1moa with the occasional flyer. I was using sellier and bellot .223/5.56x45 ammo. Just some cheap stuff off midway. I allready had about 100 once fired cases from a buddies AR-15 so I figured I'd stick with the same brand. Some of the cases were stamped .223 Rem and others were stamped S&B 5.56x45 60. Either headstamped brass shot fine and consistent. some groups were fired with .223 and 5.56 all in the same group.

http://www.midwayusa.com/viewProduct/?productNumber=545674

I mainly got the ammo for the brass. Since this is my first .223 I need to stock up on brass and what better way than using it to break in my barrel.

REASSEMBLY

Simply reinstalled everything as it came apart (as well as set headspace as described above) and changed the bolt face as well as its components. Although I couldn't get the ejector out. Either I'm not sure how it comes out, which I'm fairly certain I do, or the retaining pin was just really stuck in there. I ordered all the components for the new bolt face from midway that way all I have to do is just swap bolt faces next time I swap barrels. I don't want to have to mess with changing all the springs, ejector and extractor. For about $12 you can buy all those parts from midway.

http://www.midwayusa.com/viewProduct/?productnumber=107108
http://www.midwayusa.com/viewProduct/?productnumber=117919
http://www.midwayusa.com/viewProduct/?productnumber=149221
http://www.midwayusa.com/viewProduct/?productnumber=194256
http://www.midwayusa.com/viewProduct/?productnumber=444465
http://www.midwayusa.com/viewProduct/?productnumber=782010

^ Thats all you need to swap out the components of your bolt face. The bolt face retaining pin will be the same no matter the bolt face.

I ended up tightening the barrel nut snug then gave it a couple good "umfs" to tighten it down. Excuse my lack of technical terms when it comes to shadetree torquing. I didn't use toque wrench although I should have. I know how tight I made it so I'll be able to make it that tight next time as well.
I was going to use some anti-sieze compound but I decided agianst it. I wasn't sure if it would interfere with the headspacing of the barrel since the lube takes up space between the threads it may throw the headspace off ever so slightly. Besides, I gave it a light oiling so it won't seize anyway.

BARREL BREAK IN PROCEDURE

I shot one round and clean for about 6 - 10 rounds. The barrel could be cleaned with 3-4 patches after the 10 round so I decided that was good enough for the one shots. I fired 3 rounds and cleaned until the barrel cleaned out with 3-4 patches. and then finally fired 5 rounds 3 times and cleaned after each set. After doing this I have to say I never want to do it again. It was the most boring time I've ever had with this gun! lol.


One of the major problems with the Scotch tape school of gunsmithing is that there are no SAAMI standards for Scotch tape.

I should have used some kind of shim gauge. Like a filler gauge thats cut to the size of the case head. But unfortunately I didn't feel like cutting up my good filler gauge to stick behind a case head. If you were that serious about making sure just how much headspace you have you could buy a cheap filler gauge at harbor freight and cut it up to fit.


good stuff in this write up, thank you.

Thanks, I hope I can help someone else that is doing the same swap. I've learned a lot about this. While it's not brain surgery or rocket science, it can be very confusing if it's your first time like it was for me. After a little research and talking to a guy at Sinclairs I think I got it nailed down.

DennisH87
04-06-2010, 07:51 AM
EDIT:
How I did it was screw the barrel down on the unfired brass until the bolt closes with just a little tension.
It's supposed to say action not barrel