head space |
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sc-sarge
Newbie Joined: March 23 2015 Location: United States Status: Offline Points: 4 |
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Posted: August 12 2015 at 8:40am |
There are no gunsmiths in my area that has go no-go gages for my no 4 mk1*. Is there a way I can check the headspace without the use of gages. I tried using tape on the back of the cartridge and measuring with a micrometer but this does not seem too accurate. Any suggestions out there for a way to test this without the expense for gages which I will seldom if ever use.
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W.R.Buchanan
Senior Member Joined: September 21 2014 Location: Ojai CA Status: Offline Points: 373 |
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Sarge: take a fired round and measure the OAL and record.Then push the primer part way out. Chamber and close the bolt. Re-measure and subtract the first measurement from the second.
Then measure the thickness of the rim of the cartridge you used and add the result of the first two measurements. The headspace for these guns should be between .064 and .074 That's the easiest way to accomplish this task. Randy
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It's not how well you do what you know how to do,,, It's how well you do what you DON'T know how to do.
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Canuck
Special Member Donating Member Joined: January 17 2012 Location: Agassiz BC Status: Offline Points: 3535 |
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I ordered and received head space gauges spoken about in a previous thread. I'm happy with them. I also ordered the gauge that measures the striker depth of engagement. Ebay item# 261875459565. I hope I am allowed to post an active auction? I know the original post asked about a cheap method of determining head space and there is a cost to these head spaces gauges but I feel they are worth the cost. You never know maybe in the future you will buy another Enfield and need the gauges?
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Castles made of sand slip into the sea.....eventually
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Zed
Special Member Donating Member Joined: May 01 2012 Location: France Status: Offline Points: 5585 |
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Randy, with regards to your method. Would it not be better to use an unfired empty case? Because if the Fired case has expanded rearwards; how can you be sure that the front edge of the rim is actually contacting the seating face of the chamber. If it contacts on the shoulder first it could give you a false reading. A new case should seat more consistently in my opinion.
(However proper gauges are to be recommended)
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It's nice to be important, but it's more important to be nice!
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Shamu
Admin Group Logo Designer / Donating Member Joined: April 25 2007 Location: MD, USA. Status: Offline Points: 17603 |
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Or you could just cut off the front end of the case before the shoulder.
Nothing in front of the rim counts anyway! |
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Don't shoot till you see the whites of their thighs. (Unofficial motto of the Royal Air Force)
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MJ11
Senior Member Joined: September 18 2008 Location: Oregon Status: Offline Points: 1882 |
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Oh for god sakes just buy them use them then rent them out . I did. Resell them down the road if you like.
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The Spartans do not ask how many the enemies are but where they are
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W.R.Buchanan
Senior Member Joined: September 21 2014 Location: Ojai CA Status: Offline Points: 373 |
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Zed: you could use a new case but really if the case was fired in your gun then it should be fine.
You could also bump the shoulder back a few thou and be good to go. The whole point here is getting the rim against the end of the barrel, and however much is added to that when the bolt closes and shoves the primer back in is what you are looking for. Lets say your rim is .060 thick and after squeezing it the primer is sticking out .010 then the headspace is .070 or good to go. Since it would be impossible to measure that relationship with calipers normally available to the home smith taking a before and after reading on the length of the case is the easiest way to measure accurately. The thickness of the rim plus the difference between the before and after gives headspace. Unless a gun is exhibiting some pretty bad symptoms it is doubtful that the headspace is going to be a problem. I have read that during WWII that the Brits opened the headspace up to .064-.084 or an additional .010 just to speed things up. In this case it was perfectly safe as the guns were only shooting factory new ammo. If the round chambered it was good to go. Upon firing the case was shoved to the rear against the bolt face and the shoulder was blown forward to fill the chamber. Since these cases were new unfired nothing bad happened. In fact using these case for reloads for any given gun, if you only neck sized the cases they would perform just like my cases that I reload for my #4Mk1 which has an .066 headspace. If you Full Length Resized those stretched cases then they would separate in short order due to repeated stretching, just like they do in guns with acceptable headspace. Maybe faster? The agreed upon case life for cases FL sized is usually around 3-4 reloads before separation. There is a substantial difference in the position of the shoulder in a fired case versus an unfired case. This was/is done deliberately to insure the round will chamber in a lot of different rifles as Enfields are known to have widely varying chamber dimensions. And with Factory ammo it matters not as like Shamu said,,, "Nothing in front of the rim counts anyway!" I got this method off the Canadian Gun Nutz Forum from a guy in Pennsylvania. This simple and effective method that has zero investment in tooling will work for ANY rimmed cartridge. Anyone got a .30-30? Randy |
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It's not how well you do what you know how to do,,, It's how well you do what you DON'T know how to do.
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maxwell smart
Senior Member Joined: January 23 2009 Status: Offline Points: 236 |
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I've heard of the part-seated-primer method for some time now. The mechanics of achieving this state escapes me though... If you run the fired case up into the resizing die and allow the decapping pin to push the primer part way out, the standard she!!-holder won't release it! Similar problem if you run a used primer into an empty case with the hand priming tool - it jams on the she!!-holder. |
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MJ11
Senior Member Joined: September 18 2008 Location: Oregon Status: Offline Points: 1882 |
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Push it out and put it back in the case. Easy peasy.
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The Spartans do not ask how many the enemies are but where they are
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Shamu
Admin Group Logo Designer / Donating Member Joined: April 25 2007 Location: MD, USA. Status: Offline Points: 17603 |
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You're not backing it out by much, just thousandths of an inch. I agree it will eventually jam as you back it out more & more, but my RCBS will handle a few thou.
Personally I don't use this technique, but I'd think a better way would be to slowly back off the die so the primer ram stopped short of fully seating the primer? |
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Don't shoot till you see the whites of their thighs. (Unofficial motto of the Royal Air Force)
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Zed
Special Member Donating Member Joined: May 01 2012 Location: France Status: Offline Points: 5585 |
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I have had to use DIY methods as I do not own the proper gauges yet (to do it properly). What I realised early on when testing one of my rifles was the possible error when using a fired case. If the case has moved back to the bolt head when expanding; the shoulder will make contact before the front of the rim makes contact. It will give a false reading by measuring smaller than the actual headspace. Which is why I started using an unfired case. If you bump the shoulder back on resizing then obviously that should be ok. But it's worth mentioning, because it's safety related.
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It's nice to be important, but it's more important to be nice!
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Shamu
Admin Group Logo Designer / Donating Member Joined: April 25 2007 Location: MD, USA. Status: Offline Points: 17603 |
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Yep.
Or just cut off the front part of a fired one behind the shoulder. A correct gauge really is the right way though.. |
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Don't shoot till you see the whites of their thighs. (Unofficial motto of the Royal Air Force)
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Canuck
Special Member Donating Member Joined: January 17 2012 Location: Agassiz BC Status: Offline Points: 3535 |
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Concerning the 'coin style' gauges, one thing I wish is if they would be slightly magnetic, this way they wouldn't slip off the bolt head while inserting them. I tilted the rifles vertically with the magazines removed, but still they move around a bit but once seated in the chamber everything is hunky dory.
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Castles made of sand slip into the sea.....eventually
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W.R.Buchanan
Senior Member Joined: September 21 2014 Location: Ojai CA Status: Offline Points: 373 |
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Obviously if you've got the gauges that is the way to go. However most people couldn't justify buying a set of headspace gauges for .308's or .30-06's which can be used in many different calibers, as opposed to being able to use for only one rifle, and especially if you are only going to use them on one or maybe guns, one time.
I have two Enfield Rifles, and I have head spaced both of them three times. (only to insure proper repeatable results) This took @15 minutes. There will probably never be a need to check the headspace on those guns again. If I got another Enfield I'd probably check it, just for something to do. Headspace is not something that just goes bad. It's kind of an either or type thing. It is usually a result of Bubba or some catastrophic failure. If a gun progressively goes long then it is probably best hung on a wall or better yet destroyed. Randy |
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It's not how well you do what you know how to do,,, It's how well you do what you DON'T know how to do.
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