I have an FN Action with controlled feed.. I purchased an FN Takeoff barrel for the action.. Had to take .oo1 off of the shoulder of the barrel to get it indexed correctly. The go guage went in fine but so did the no go guage. I found out that I have .007 too much headspace. What is the easiest to fix this? would it be easier to take .007 off the face of the action? Any info or suggestions would be appreciated.. since I do not have a mill.....
Gunsmithing Headspace Issue
- Thread starter Westtexan
- Start date
Re: Headspace Issue
In a given caliber there are three headspace gauges. Go, no-go and field. They get larger in that order. Go is minimum, no-go is maximum, and field is unsafe. Idealy the bolt will close on a go but not on the no-go. In practise it can close on the no-go and still be perfectly safe to shoot. You don't want it to close on a field gauge. That is when "adjustment" is needed.
If "adjustment" is needed it is done to the barrel to shorten the chamber and allow the barrel to seat further into the action.
In a given caliber there are three headspace gauges. Go, no-go and field. They get larger in that order. Go is minimum, no-go is maximum, and field is unsafe. Idealy the bolt will close on a go but not on the no-go. In practise it can close on the no-go and still be perfectly safe to shoot. You don't want it to close on a field gauge. That is when "adjustment" is needed.
If "adjustment" is needed it is done to the barrel to shorten the chamber and allow the barrel to seat further into the action.
Re: Headspace Issue
I had to add .007 to the no go for the bolt not to close... since the barrel is notched for the ejector on the bolt it complicates things... if I take ,007 off of the shoulder, the notch will end up where the bullet feeds into the chamber...
I had to add .007 to the no go for the bolt not to close... since the barrel is notched for the ejector on the bolt it complicates things... if I take ,007 off of the shoulder, the notch will end up where the bullet feeds into the chamber...
Re: Headspace Issue
how much longer is a field guage than a no go on a 308?
how much longer is a field guage than a no go on a 308?
Re: Headspace Issue
This is fairly new to me so if I ask a dumb question, just let me know...
This is fairly new to me so if I ask a dumb question, just let me know...
Re: Headspace Issue
Can you reface the breach and shoulder to allow the barrel to screw in one full turn more and time correctly, then you could ream the chamber and set the headspace correctly
Can you reface the breach and shoulder to allow the barrel to screw in one full turn more and time correctly, then you could ream the chamber and set the headspace correctly
Re: Headspace Issue
That is something I thought about... One full turn looks to be about .050 I will look at it tomorrow and see about that. I appreciate the help.
That is something I thought about... One full turn looks to be about .050 I will look at it tomorrow and see about that. I appreciate the help.
Re: Headspace Issue
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Westtexan</div><div class="ubbcode-body">how much longer is a field guage than a no go on a 308? </div></div>
IIRC .003" but from what you said at .007" over No-go that rifle is unsafe until the barrel gets redone.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Westtexan</div><div class="ubbcode-body">how much longer is a field guage than a no go on a 308? </div></div>
IIRC .003" but from what you said at .007" over No-go that rifle is unsafe until the barrel gets redone.
Re: Headspace Issue
Will there be enough space between the bolt and breech face if he goes another full turn in?
Will there be enough space between the bolt and breech face if he goes another full turn in?
Re: Headspace Issue
I dont know if there would be... That is why I thought taking .007 off of the action would be the easiest way to do it. If not I am going to have to go in quite a bit and then re-ream which is going to mess up the chrome inside and probably eat the reamer...
I dont know if there would be... That is why I thought taking .007 off of the action would be the easiest way to do it. If not I am going to have to go in quite a bit and then re-ream which is going to mess up the chrome inside and probably eat the reamer...
Re: Headspace Issue
One of the rules Jim has taught me (be it cars, bikes, or guns) always fix the cheapest part. If you screw up a barrel, you're out a barrel. Wreck an action and... well, you get it.
One of the rules Jim has taught me (be it cars, bikes, or guns) always fix the cheapest part. If you screw up a barrel, you're out a barrel. Wreck an action and... well, you get it.
Re: Headspace Issue
Westtexan,
If you take it off the barrel or the action, either way, the extractor will no longer line up. The ONLY thing to do is to shorten the barrel one full turn, Deepen the extractor cut to match and re-chamber. Since your barrel is chrome lined, you will not have this option as it will ruin your reamer....
Not much you can do at this point.
PS, Im in Monahans, just a hop skip and jump from you.
Westtexan,
If you take it off the barrel or the action, either way, the extractor will no longer line up. The ONLY thing to do is to shorten the barrel one full turn, Deepen the extractor cut to match and re-chamber. Since your barrel is chrome lined, you will not have this option as it will ruin your reamer....
Not much you can do at this point.
PS, Im in Monahans, just a hop skip and jump from you.
Re: Headspace Issue
Well I went ahead and turned the barrel down one full turn, recut part of the groove and rechambered... Its shooting 1/2" moa at 2ooyds... Also... the reamer is still just like new..
Well I went ahead and turned the barrel down one full turn, recut part of the groove and rechambered... Its shooting 1/2" moa at 2ooyds... Also... the reamer is still just like new..
Re: Headspace Issue
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: GunjunkieM24</div><div class="ubbcode-body">Westtexan,
If you take it off the barrel or the action, either way, the extractor will no longer line up. The ONLY thing to do is to shorten the barrel one full turn, Deepen the extractor cut to match and re-chamber. Since your barrel is chrome lined, you will not have this option as it will ruin your reamer....
Not much you can do at this point.
This is the kind of stuff that leads to confusion. The guy is talking Mauser, it does NOT have a cut for the extractor in the barrel.
PS, Im in Monahans, just a hop skip and jump from you.
</div></div>
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: GunjunkieM24</div><div class="ubbcode-body">Westtexan,
If you take it off the barrel or the action, either way, the extractor will no longer line up. The ONLY thing to do is to shorten the barrel one full turn, Deepen the extractor cut to match and re-chamber. Since your barrel is chrome lined, you will not have this option as it will ruin your reamer....
Not much you can do at this point.
This is the kind of stuff that leads to confusion. The guy is talking Mauser, it does NOT have a cut for the extractor in the barrel.
PS, Im in Monahans, just a hop skip and jump from you.
</div></div>
Re: Headspace Issue
It does have a cut in barrel for the extractor to fit into.. It is the old controlled feed bolt from the pre 64 actions...
It does have a cut in barrel for the extractor to fit into.. It is the old controlled feed bolt from the pre 64 actions...
Re: Headspace Issue
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: gundoktr</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: GunjunkieM24</div><div class="ubbcode-body">Westtexan,
If you take it off the barrel or the action, either way, the extractor will no longer line up. The ONLY thing to do is to shorten the barrel one full turn, Deepen the extractor cut to match and re-chamber. Since your barrel is chrome lined, you will not have this option as it will ruin your reamer....
Not much you can do at this point.
PS, Im in Monahans, just a hop skip and jump from you.
</div></div>
This is the kind of stuff that leads to confusion. The guy is talking Mauser, it does NOT have a cut for the extractor in the barrel.
</div></div>
Who was talking Mauser? I think everyone's been talking about the controlled round feed FN SPR actions.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: gundoktr</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: GunjunkieM24</div><div class="ubbcode-body">Westtexan,
If you take it off the barrel or the action, either way, the extractor will no longer line up. The ONLY thing to do is to shorten the barrel one full turn, Deepen the extractor cut to match and re-chamber. Since your barrel is chrome lined, you will not have this option as it will ruin your reamer....
Not much you can do at this point.
PS, Im in Monahans, just a hop skip and jump from you.
</div></div>
This is the kind of stuff that leads to confusion. The guy is talking Mauser, it does NOT have a cut for the extractor in the barrel.
</div></div>
Who was talking Mauser? I think everyone's been talking about the controlled round feed FN SPR actions.
Re: Headspace Issue
That is correct...
That is correct...
Re: Headspace Issue
Glad you got it If he reamer survived the trip it probably was not chrome lined
Glad you got it If he reamer survived the trip it probably was not chrome lined
Re: Headspace Issue
Great to hear West texan.
I am glad the reamer survived. I have not had any luck cutting chrome lined barrels, mainly tried the M14 barrels back a few years ago, ruined my reamer within seconds.
Anyhow, Glad everything worked out.
Great to hear West texan.
I am glad the reamer survived. I have not had any luck cutting chrome lined barrels, mainly tried the M14 barrels back a few years ago, ruined my reamer within seconds.
Anyhow, Glad everything worked out.
Re: Headspace Issue
Question:
Are you certain that it's .007? If so fine. If not completely sure here's a trick:
Plop the GO in there and cut off a little piece of soft solder. Dab it on the bolt with grease and then clam everything up. It'll close hard, but not so hard as to hurt anything.
Then pull the bolt and measure the "smoosh" on the solder. This will give you a "no chit" dimension.
Good luck.
C
Question:
Are you certain that it's .007? If so fine. If not completely sure here's a trick:
Plop the GO in there and cut off a little piece of soft solder. Dab it on the bolt with grease and then clam everything up. It'll close hard, but not so hard as to hurt anything.
Then pull the bolt and measure the "smoosh" on the solder. This will give you a "no chit" dimension.
Good luck.
C
Re: Headspace Issue
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: C. Dixon</div><div class="ubbcode-body">Question:
Are you certain that it's .007? If so fine. If not completely sure here's a trick:
Plop the GO in there and cut off a little piece of soft solder. Dab it on the bolt with grease and then clam everything up. It'll close hard, but not so hard as to hurt anything.
Then pull the bolt and measure the "smoosh" on the solder. This will give you a "no chit" dimension.
Good luck.
C </div></div>
That would work similar to Plastigage to check engine clearances, right?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: C. Dixon</div><div class="ubbcode-body">Question:
Are you certain that it's .007? If so fine. If not completely sure here's a trick:
Plop the GO in there and cut off a little piece of soft solder. Dab it on the bolt with grease and then clam everything up. It'll close hard, but not so hard as to hurt anything.
Then pull the bolt and measure the "smoosh" on the solder. This will give you a "no chit" dimension.
Good luck.
C </div></div>
That would work similar to Plastigage to check engine clearances, right?
Re: Headspace Issue
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Kbrady</div><div class="ubbcode-body">
That would work similar to Plastigage to check engine clearances, right? </div></div>
Yes, except you'd be measuring the actual thickness of the crushed piece, as opposed to the width produced by crushing the piece, as you do with Plastigage.
-matt
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Kbrady</div><div class="ubbcode-body">
That would work similar to Plastigage to check engine clearances, right? </div></div>
Yes, except you'd be measuring the actual thickness of the crushed piece, as opposed to the width produced by crushing the piece, as you do with Plastigage.
-matt
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