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How do I know if I have a head-space problem?

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Category: Enfields
Forum Name: Enfield Gunsmithing
Forum Description: Submit any how-to's or other gunsmithing suggestions here.
URL: http://www.enfield-rifles.com/forum_posts.asp?TID=5394
Printed Date: April 13 2024 at 9:28pm
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Topic: How do I know if I have a head-space problem?
Posted By: flanker
Subject: How do I know if I have a head-space problem?
Date Posted: August 19 2012 at 1:29am
I see people mention it, but how would I recognise it? (I'm talking about the head space in my No.4 - not between my ears!) LOL

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Life is full of possibilities, 50% of them are likely to good....



Replies:
Posted By: saffer
Date Posted: August 19 2012 at 3:07am
Here is what you do. Take a piece of A4 paper the type used in photo copiers. Tear a couple of small strips about 5mm wide and about 20-30mm long.
Take a resized cartridge, and try and close the bolt on 4-5 pieces of the paper between the bolt face and the cartridge head. If the bolt cloese, you have a head space problem.
You can try one piece first till you cannot close the bolt any further. On my one enfield, I battle to close on one piece, and the other 3 pieces, so it can vary.
This is the quick at home DIY method. You realy need go-nogo guages.
 


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Not a complete idiot. Still missing a few parts.


Posted By: Shamu
Date Posted: August 19 2012 at 5:55am
I'm a bit more scientific than saffer, I buy a headspace gauge & check it that way. Failing that get a smith with UK MOD mil-spec gauges to check it for you.
 
Do you think you might have a problem & if so please give details, we can help sort out fact from fiction.


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Don't shoot till you see the whites of their thighs. (Unofficial motto of the Royal Air Force)


Posted By: flanker
Date Posted: August 19 2012 at 6:26am
Thanks very much gents.

I've just started using my 303, up till now I've mainly been using my 223 Ruger. It has a mild recoil and the 303 is quite the opposite. I have fired my clubs 7.62 quite a bit and it seems mild by comparison to the 303, I thought they'd be similar. I think I've read that head space problems can cause heavy recoil. Of course the ammunition could be a factor. The 303 was South Africa surplus MK 7 from 1961, the 7.62 was German NATO surplus.

By the way, has anyone else tried using that old South African stuff? I tried it in two No4 rifles and didn't get better than a 5-6 inch group at 100m. I can shoot 1-2 inch quite easily with my Ruger 223 at that range.


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Life is full of possibilities, 50% of them are likely to good....


Posted By: Lithgow
Date Posted: August 19 2012 at 6:32am
The only true way of telling that the rifle is in spec is with a heaspace guage. Not a SAAMMI spec guage but a mil spec guage.
I dont believe that excessive headspace would cause a noticeable difference in recoil.
I have not used the SA ammo but believe that it is good stuff.
Bear in mind that the old rifle shooters used to say the if a standard military rifle with military ammo would group 3 inches at 100 yds, then it was a good rifle.


Posted By: 303Guy
Date Posted: August 19 2012 at 8:10am
All true.  I prefer the head-space to be on the minimum side and even then, I head-space on the shoulder after the first firing.  That's because I reload.  Some rifles have a generous chamber which allows a new case to lie rather randomly in the chamber which results in bullet misalignment with the bore.  This can be reduced with the O-ring trick but isn't worth the trouble when shooting milsurp ammo and probably won't make any difference anyway.  

You don't mention the bore condition.  Bore condition can have a huge impact on accuracy but hand loading can make even a worn bore shoot well.  A rough bore may need some cleaning and de-roughing.  A rust damaged bore is not the end of the world.  A bit of fire-lapping and they can shoot as good as new.

And no, the head-space will not have any effect on recoil.  Lee Enfield's do have a stern recoil,  The target rifle would be heavier and have a better fitting stock so the recoil will feel much less.  The propellant burn rate will have an impact on felt recoil.  Faster powder gives a sharper 'kick' which is felt more.

I have a head-space gauge which I broke by placing a piece of paper on the rear.  The rifle had a tight head-space and also has a strong camming action plus the gauge is hard and brittle!  Oh well.  Anyway, it was a go gauge.  One needs a no-go gauge


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303Guy


Posted By: Shamu
Date Posted: August 19 2012 at 9:49pm
Headspace won't effect recoil, what it will do is allow excessive stretching of the brass leading to a shortened case life.
 
Again, I urge all posters on here to remember that emember that with a rimmed case headspace is determined exclusively by the case rim, there may be other chamber dimensions that can vary & have an effect on case life but they are 100% emphatically NOT headspace.
Headspace on the .303 British round is between 0.064" minimum & 0.074" maximum, so anything beyond 0.074" forward of the rear of the case is something else. That's why you can use coin type gauges to check headspace, because everything else is 100% irrelevant to headspace.
 
Making adjustments to fix any issues with the chamber in front of the case rim will absolutely not fix any headspace problems, it will, however mask them until there is a possibly catastrophic incident. I'd suggest being wary of any information that suggests or implies anything different.
 
 


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Don't shoot till you see the whites of their thighs. (Unofficial motto of the Royal Air Force)


Posted By: A square 10
Date Posted: August 20 2012 at 1:25am
excellent point shamu all reaming the chamber will do is alter the shoulder and neck area allowing more stretch to occur


Posted By: 303Guy
Date Posted: August 20 2012 at 7:29am
That's true, BUT - a maximum of .074 is excessive!  That's a military spec and no-way should that be used as a standard if one intends to reload.  But if that is what you have then head-space on the shoulder after first firing.  No need to 'fix' .074 head-space.  That is true of any reloaded cartridge..  A 'standard' head-space has clearance.  For reloading and maximum accuracy one does not want clearance - one wants a close fit, preferably some compression (very slight resistance on locking the bolt).  But for hunting one wants a little bit of clearance for reliability in the field.  I don't give shoulder clearance even for hunting.  The Brit case is thin enough to accommodate a little bit of foreign matter with the bolt camming.  I don't recommend that because although the bolt will close and the gun fire, the problem is what happens if one doesn't take the shot?  Now the extraction falls onto the extractor and the unfired cartridge could jamb and the rim pull through or even break the extractor if it doesn't match the cut-out on the breach face and that can and does happen when bolt heads have been swapped around or the barrel replaced.  If I know there is the possibility of dangerous game where I'm going I will make sure my gun is reliable for the conditions.  We do have dangerous' game here - feral cattle.  The bulls can be cantankerous.  Some folks have been attacked by red deer too.

But I stand by what I say regarding head-spacing on the shoulder.  The normal head-space must be correct, then convert to shoulder head-spacing.  One can head-space on the shoulder with an excess head-spaced gun but that should not be the accepted cure because someone else could get hold of the gun.  Excess head-space damages the gun and will eventually ruin it.

By the way, a cartridge that requires some force to close the bolt actually reduces the loading on firing.  It's called pre-loading and it reduces the shock load.  Think of this, if the wheel nuts on your car are not tight enough the studs will eventually break and the wheels fall off.  Don't ask me how I know.Embarrassed


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303Guy


Posted By: A square 10
Date Posted: August 20 2012 at 11:16am
agreed ,


Posted By: Shamu
Date Posted: August 21 2012 at 12:11am
"That's true, BUT - a maximum of .074 is excessive! "
No sir it is not. It is a safe maximum. Not ideal, but in no way dangerous as long as it is not exceeded.
 
Anything over 0.074 is excessive.


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Don't shoot till you see the whites of their thighs. (Unofficial motto of the Royal Air Force)


Posted By: A square 10
Date Posted: August 21 2012 at 4:50am
ahhh , missed that "silly millimeter" nuance , are we splitting hairs ?


Posted By: Shamu
Date Posted: August 21 2012 at 6:28am
Yes, but slightly off center, about a 40/60 splitStar

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Don't shoot till you see the whites of their thighs. (Unofficial motto of the Royal Air Force)


Posted By: Lithgow
Date Posted: August 21 2012 at 6:58am
I agree with Shamu on this one. I personally would not accept anything outside the specs.
Remember that the Lee Enfield was not designed to be used with reloaded ammo and all military ammo was made to certain tolerances. Modern commercial ammo is made with thinner rims and so headspace if anything should be reduced and if that was the ammo I was using, I would use SAAMMI spec guages.
Central, who made gauges and tools for the target shooters, made an .062 guage so that shooters could close their headspace up below spec.


Posted By: Shamu
Date Posted: August 21 2012 at 9:34pm
Originally posted by Lithgow Lithgow wrote:

I agree with Shamu on this one. I personally would not accept anything outside the specs.
Remember that the Lee Enfield was not designed to be used with reloaded ammo and all military ammo was made to certain tolerances.
 
This is worth repeating. I only know of 2 military rounds designed from the start to be reloaded. 20mm PAK from Germany in WW2 & the Gau-8 cannon in the A-10 Warthog!
 
Nothing else was designed to be reloaded by the military so every time we reload we're actually making the case & action do spmething it wasn't designed to do. Worth remembering when we complain about dimensioning or case life expectancy. The military life expectancy of a case was 1 firing!Wink


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Don't shoot till you see the whites of their thighs. (Unofficial motto of the Royal Air Force)


Posted By: A square 10
Date Posted: August 22 2012 at 2:20am
no sence policing that brass with all those bullets whizzin around your head .....


Posted By: Shamu
Date Posted: August 22 2012 at 5:56am
That too!

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Don't shoot till you see the whites of their thighs. (Unofficial motto of the Royal Air Force)


Posted By: 303Guy
Date Posted: September 01 2012 at 4:10pm
Originally posted by Shamu Shamu wrote:

"That's true, BUT - a maximum of .074 is excessive! "
No sir it is not. It is a safe maximum. Not ideal, but in no way dangerous as long as it is not exceeded.
 
Anything over 0.074 is excessive.
Ah, but .... !Wink  Of course you are quite correct.  But, I was only saying it was excessive from a reloaders point of view.  I did specify but should have said it differently.   It is indeed safe.  Actually, it doesn't have to be a problem for reloading either but that takes us to a more advanced level (like centering the case on first firing - which is not a case life factor, and starting out with lower level loads and so on).  But without any fancy tricks, as long as one only neck sizes and keeps loads moderate, case life should be good anyway.


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303Guy



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