Head space gauge |
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Honkytonk
Senior Member Joined: December 30 2017 Location: Brandon Mb Status: Offline Points: 4770 |
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I haven't talked to my machinist buddy for a while. The plant where I used to work at has had several unfortunate mechanical outages this year, so buddies workload is substantial. He has the design, but I suspect it'll be a while before I see the product.
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Goosic
Senior Member Joined: September 12 2017 Location: Phoenix Arizona Status: Offline Points: 8792 |
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In reading all these posts,I started thinking about one thing, bolt head size,and not the obvious #0,#1,#2,and #3 size,I mean the actual size of the bolt head between the same size numbered head,and then between the other three. The rifle I just built has a #2 bolt head,the Forester .070" Field gauge won't close on it. I measured the bolt head and it reads .0631. For sts and giggles I measured all my spares. I have four #1's, two #3's,and three #2's. Three of the #1 measured .631,just like the #2 in my rifle however,one of those #1 boltheads read at .0632". Guess what I did. One of the #3's measured at .0637",and one of the #2's measured at .0636. The main thing here is that I have a rifle that passed the field gauge test with two different boltheads sizes and the shorter #1 is actually.001" longer then the #2. Use the head space gauges accordingly but take into careful consideration the actual wear on the bolt head face itself.
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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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As long as they clock at less than 15° overturn that's great.
There is a guy who has done a lot of research into head number Vs bolt length & you've confirmed his results. |
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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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Goosic
Senior Member Joined: September 12 2017 Location: Phoenix Arizona Status: Offline Points: 8792 |
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None of mine clock any more then 12°. I went one more step in this endeavor of mine. I have three spare No4 bolts,the shortest one measured in at 5.525" and the longest one at 5.530". I'm looking at this from a functionality perspective too,so bear with me on this. If you are building an Enfield rifle for whatever reasons and you have discovered that you have a headspace issue even after you have installed the dreaded #3 bolt head. Go back,and if you have a couple of spare bolts,or bolt heads, gauge them,make sure they're measuring out to the standard size,and if not,check if you have one that is a couple of thousands of an inch longer,maybe an unissued one. Check the fit and functionality along with the headspace. You might discover that the issue was with a very worn bolt or bolthead,or both...
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Goosic
Senior Member Joined: September 12 2017 Location: Phoenix Arizona Status: Offline Points: 8792 |
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Think of it like this.
Everytime,that you pull,or squeeze the trigger on that Enfield,that tiny .303 British hammer/case,beats the crud out of that bolt face,smashes that against the bolt,and then all that pressure is put onto the locking lugs. After awhile those items will get shortened in length. The face of the chamber wear comes from excessive chambering and rechambering of cartridges that wear out the area were the rim of the cartridge sits. Look at the bottom of the barrel were the bullet hits it after the feed ramp. If it's real bad, a barrel replacement will be necessary but,if it still has retained it's flat edge, check the bolt and bolt head. |
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Zed
Special Member Donating Member Joined: May 01 2012 Location: France Status: Offline Points: 5585 |
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I replaced the bolt on my SMLE to get the headspace better. It was at the field limit. The new one has to be sufficiently long enough to be stoned to fit. It is essential that you have equal load on the lugs.
It is a delicate operation to stone it to fit and not remove too much material; so as to retain the extra length. You've got 5 thou to play with and you may need to stone 2 or 3 of that to fit. So the actual improvement may only be 2 thou depending on how lucky you are.
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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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That's also the reason for the max 15° over-clock! Its so the forces will be transmitted to the bolt face by the shoulder on the bolt & the rear face of the head, not the threads!
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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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Ranch Dog
Groupie Joined: February 21 2018 Location: Texas Status: Offline Points: 63 |
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A buddy of mine, Al Nelson, who owns NOE Bullet Moulds, called me today to visit. He has done a number of projects that I have suggested so he is going to look into these headspace coins. I sent Al the dimensions of the 303 British "coins" and if anybody has the same for the other cartridges offered, please post them.
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Canuck
Special Member Donating Member Joined: January 17 2012 Location: Agassiz BC Status: Offline Points: 3535 |
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That's great, Ranch Dog! Please keep us posted.
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Castles made of sand slip into the sea.....eventually
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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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The coin style for the .303 British also work for the mosin Nagant 7.62X54R round
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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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GreySaber
Newbie Joined: October 26 2018 Location: Atlanta Status: Offline Points: 4 |
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Bump. Does anyone have a source for military spec gauges?
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englishman_ca
Senior Member Joined: September 08 2009 Location: Almaguin Status: Offline Points: 1089 |
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My 0.074 FIELD gauge was made for me by a machinist on his lathe. It is accurate within less than 0.0005 inch which is well good enough for me. Top hat shaped, made from silver steel, it is heat treated and hardened.
Easy peasy for somebody with a decent metal lathe and accurate vernier calipers that knows how to use them. The chap that was making the Okie disc ones passed away, so they are no longer in production. So if you do see a set for sale, grab em! There are ex-military head space guages that pop up on auction sites from time to time, but they are Lee Enfield collectables in themselves and can fetch silly prices.
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. Look to your front, mark your target when it comes! |
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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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Thisa should be the same as M-N & L-E are the same specs, just double check its really 0.074" |
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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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