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Posted: 11/9/2003 6:12:30 PM EDT
Hey. I need to find out the best place to get a new locking shoulder. I had to replace the bolt in my FAL, and when I headspaced it I found that I need a different diameter one. Any suggestions?

Thanks,

Brad
Link Posted: 11/9/2003 6:25:57 PM EDT
Gunthings.com are great folks to do business with. If our old LS hasn't been ground or filed upon, they'll even offer a discount on the trade-in.

As a bonus for you, they're in MN too, and one of the guys is name Brad.
Link Posted: 11/10/2003 12:48:48 AM EDT
I'll second the reccomendation for Gunthings.com.

Have had nothing but good experiences with them.
Link Posted: 11/10/2003 12:11:33 PM EDT
Are you positive about that? Are you sure it headspaced correctly to begin with? I've never seen, nor heard of one changing, although it is possible in theory.

How did you check your headspace?
Link Posted: 11/13/2003 3:55:05 PM EDT
Hey. Thanks for the info on gunthings.com. I will give them a call. I also tried Dans Ammo, and he said he would check to see if he had any that were the right size. I am supposed to call him back tomorrow.

I am pretty sure about the headspace. I had it checked by a good gunsmith. I had to replace the bolt and carrier, and that cause the headspace to change. When we head spaced it we used a no go gauge, and it was a definite no-go! The gunsmith then took out what looked like a set of steel dowels, with sizes increasing by .001 inches, and tried diferent ones until we got to .268 or .269, both of which seemed to be the right fit.

Thanks,

Brad
Link Posted: 11/14/2003 9:49:19 AM EDT
[Last Edit: 11/14/2003 9:50:49 AM EDT by cliffy109]
I've still got a few questions. First, did the smith check the HS with the original bolt and carrier? I swear, you're the first person I have ever heard of who changed HS to any real degree by changing the bolt and carrier. If any change happens, it shouldn't be more than a thousandths or so.

Headspacing isn't rocket science, but it is easy to screw up. The no-go gauge doesn't help much.

Here's the correct way to do this:

Remove the extractor from your bolt and re-install it into the the carrier. Use METAL pins of known diameter, but veryify them with good quality calipers. Use the go gauge until you find the size that allows the bolt to close with fairly hard pressure. By hard, I mean it requires 2 thumbs on the back of the carrier to close it. Do it several times to make sure.

Look at the pin size. If you are using Forrester gauges, you have just found the size to get a 1.630 chamber. That's as small as you would ever want. Your goal is to get a 1.632 chamber so you have to deduct .002 from the pin you used. Therefore, if you used a .268 pin, a .266 will get you the chamber size you need. That is... unless you believe in setback.

I personally believe in setback. As you shoot the gun, things do tend to settle. Current theory holds that it will settle about .001, thereby opening up the HS a bit. To comepnsate for this, I add .001 to my final reading. This makes for a bit tight of a chamber at first, but I've found that it does settle in.

There is a much more detailed description of this at www.falfiles.com/forums/showthread.php?s=&threadid=21938. Read this carefully.

Oh yes... the only reason you even need a no-go is to double check yourself after installing the LS. It should not close on the no-go and should close on the go.
Link Posted: 11/14/2003 12:59:31 PM EDT

That is... unless you believe in setback.
I personally believe in setback. As you shoot the gun, things do tend to settle. Current theory holds that it will settle about .001, thereby opening up the HS a bit. To comepnsate for this, I add .001 to my final reading. This makes for a bit tight of a chamber at first, but I've found that it does settle in.



I've used your method to headspace a few rifles and I've been finding that only leaving the .001 I have had frequent feeding issues when shooting mil-surp ammo. It's amazing how that extra .001 really makes a difference.
I have been keeping track of the rounds through my last rifle build just so I can recheck at the 250 + 500 round mark to see how much things loosen up.
Link Posted: 11/14/2003 1:25:54 PM EDT
Well, I've done 5 of my own rifles and several with friends. Of my 5, I've checked 4 of them after only 100 rounds. Prior to the first shot, I checked with the go gauge. It required just a slight nudge to close it. It took far less pressure than the 2 thumbs. After only 100 rounds, all 4 of them slid shut without any pressure at all. It is my opinion that this represents set-back.

The 5th of the batch is yet to be tested. I just shot it for the first time the other night. I had some feeding issues. The rounds were jamming on the breech face. It only did this with the "new in wrap" Belgium mags. The STG mags didn't do this. This is a barrel that I had to file a fair amount of metal from the breech face due to it bottoming out. I have to decide if I want to use a Dremel to angle the feed ramp of if I just stick with STG mags.
Link Posted: 11/14/2003 4:58:18 PM EDT
Now you've made me nervous!

When the rifle was built last year, it was head spaced, but I don't think it was head spaced correctly. The guy who did it used a fired 308 case, which he said was "properly headspaced"?, rather than a go or no go gauge. Knowing next to nothing about FAL's, or head spacing at the time, I thought nothing of it. Now, I think that it was way off.

After the rifle was built, I took it to the range twice, and I had 2 problems:
1) Failure to feed. Every other round would jam. Even with the feed ramp polished, I could not get it to reliably feed when cycling by hand or firing.
2) Even if it would have fed, the rifle would not function firing semi auto, even with the gas port all of the way open. It was a bolt action FAL. I thought that the gas plug was bad, so I bought a new one of those when I bought the bolt and carrier.

After a total of 40 rounds fired, I gave up on it and put it in the back of the vault.

This fall I decided that I wanted to get the FAL going, so I dragged it out and headed off to get it head spaced and looked at.

The first thing the smith noticed was the bolt. It was in bad shape, and he suggested getting a new bolt. I ended up buying a new carrier too (from Dans Ammo), and they looked great. Putting in the new bolt and carrier into the rifle, I tried manually cycling the rifle, and it did feed reliabaly out of 3 of the 4 (probably bad) magazines that I have, and did not jam. I then brought the rifle back to the smith to have it head spaced.

I was with the smith when he head spaced the rifle, and in fact he let me "feel", or push the bolt closed, on the gauge, so I would know what it felt like. It did take two thumbs worth of pressure (he told me to use both thumbs, in fact). The metal pins were of known diameter. To me, they looked like a professional gunsmith set of pins. Definetly not a home made set.

When we found the right size pin it was .268 or .269. Both seemed to close with about the same amount of pressure. So what size locking should would I want?

About the gauge, I think he said no-go, but he may have said go. I can't really remember now, he just mentioned it in passing.

So, my new questions:
1) If it was in fact a no go gauge that was used to check the headspace, then is something wrong? Could he even have head spaced it w/ a no go gauge? He has been doing this for a long time, so I trust him.

2) The "original" headspacing using a fired .308 case....bad idea? Looking back at it, i now thaink that that method of headspacing wouldn't work, but I still don't know much about FAL's or headspacing.

3) Could bad headspacing have caused the rifle to not function? Would that have somehow caused gas pressure to drop?

Thanks for any input. I have not ordered the new locking shoulder yet. I figured I'd wait until we got this hammered out.

Brad

Link Posted: 11/15/2003 5:23:44 AM EDT

Originally Posted By Brad76:

So, my new questions:
1) If it was in fact a no go gauge that was used to check the headspace, then is something wrong? Could he even have head spaced it w/ a no go gauge? He has been doing this for a long time, so I trust him.

2) The "original" headspacing using a fired .308 case....bad idea? Looking back at it, i now thaink that that method of headspacing wouldn't work, but I still don't know much about FAL's or headspacing.

3) Could bad headspacing have caused the rifle to not function? Would that have somehow caused gas pressure to drop?

Thanks for any input. I have not ordered the new locking shoulder yet. I figured I'd wait until we got this hammered out.

Brad




In order and I hope this helps. If not, PM me for my cell phone, I'll be glad to talk you through this as well:

1. If he headspaced until a no-go required two thumbs of pressure, he has just measured the maximum chamber length, not the minimum which is recommended. If the max length is achieved with a .268, you need to add .002 to get the chamber length to 1.632 and an additional .001 if you want to account for set-back. This assumes he is using a Forrester gauge which has a no-go of 1.634. It can be done this way, its just backwards.

Because you mention roughly equal pressure with both the .268 and .269, I would probably choose a .271 locking shoulder. That is a pretty big locking shoulder and will mean a custom job from Vanden Berg. I suspect your smith was using the go gauge.

2. Never, never, never use brass to headspace. Bass is maleable. It molds to the contours of the chamber. Even virgin brass will give a bit and tolerances can be wide. Use known sizes by using a proper gauge.

3. Probably not but I guess it is possible. Bad headspace is dangerous and can cause excess pressure at the chamber. The FAL is fairly forgiving but the most likely result of bad headspacing is VERY poor accuracy.

This actually leads me to another question about your post. You indicated that the rifle wouldn't function, "even with the gas port all of the way open." You're going backwards. If it isn't cycling, you need to close the gas port. Closing the gas port means less gas escaping and more being used to cycle the action. Its a common error. The more of that little hole you can see, the less gas is making it to the piston.

Does this help?
Link Posted: 11/15/2003 11:54:34 AM EDT
This helps a lot. Thank you!

1) I called the smith today, and it was a go gauge. I must have mis-heard.

2) In hindsight, using fired brass was a very poor way of headspacing. This time I am confident in the headspacing. It makes sense that the brass would conform to the size of the chamber.

3) I can't comment on the accuracy as I have yet to fire the rifle for accuracy. I did make a mistake when I posted that I had the gas port all the way open....I meant all the way closed.

4) So, what size locking shoulder would you recomend? If the size is .269, subtract .002 for headspace, then .001 for set back, I would want a .266, right??

Thanks Cliffy. I'm not so nervous any more!!

Brad
Link Posted: 11/15/2003 12:04:10 PM EDT
[Last Edit: 11/15/2003 12:05:42 PM EDT by cliffy109]
Good to hear on all counts. As to LS size, you mentioned that it was about the same with both the .268 and .269 right? Well the formula is to minus .002 to get from the minimum of 1.630 to the average of 1.632, then add one back for setback. Therefore, if you choose to allow for setback, you would have a choice between the .267 or .268. I think I'd probably do the .267 myself, but this may lead to a slightly loose chamber. It will not be anything dangerous though and will be well within spec.

I'm glad to hear you're getting this worked out correctly.
Link Posted: 11/18/2003 3:18:22 PM EDT
.267 locking shoulder ordered from Gunthings.com today. I should have by Thursday, and hope to take out on Saturday.

Brad
Link Posted: 11/22/2003 7:39:01 PM EDT
Thanks for all of the help! I got the new locking shoulder on Friday night, installed it, then cleaned the rifle.

Today I test fired. Only 40 rounds, but it was snowing. I had absolutely no problems, and the rifle was hitting in the black at 25 yards! I didn't touch the sites, so I finally had some luck with this rifle.

Anyway, all seems to be fixed.

Thank you for the help!

Brad
Link Posted: 11/24/2003 10:58:24 AM EDT
That's great news! I've been on vacation for the last week and I was wondering how you made out.
Link Posted: 11/25/2003 4:01:22 PM EDT
Everything is great. This rifle went from a "I should probably sell it" rifle to a "front row in the vault" rifle.

I appreciate all of your help. I now understand headspacing better, and have confidence in the rifle.

Thanks Cliffy!

Brad
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