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Proper way to check headspace?

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KneverKnew

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In an effort to maintain the utmost safety, I need to make sure I am checking my headspace correctly on my AC44 G43 build. I have a complete bolt/carrier/cover assembly from another G43. I have two sets of flappers.
I have Forster No Go and Field 8mm Mauser gauges.
I use a live 8mm round as my GO gauge. The "green box" Romanian steel cased ammo will not chamber/ bolt with not go all the way forward, by the way.

I have removed extractor from bolt. I am using an allan wrench down in the firing pin carrier slot that the bolt carrier usually rides in to manipulate the flappers.
The bolt closes and locks easily on empty chamber, with bolt face making firm contact on barrel shoulder. The firing pin carrier moves to it's complete forward position in the bolt, slot in pin carrier all the way forward and aligned with forward edge of slot in bolt, thus locking flappers into their recesses in the receiver walls. Same thing happens with the live 8mm round, being completely locked in battery, with no wiggle to the bolt when I manipulate it with my fingers from the rear while holding pin carrier to its forward position.

When I test with the Forster NO GO gauge, the bolt seems to go all the way forward, but the firing pin carrier will only go half way forward. The flappers will press against side of receiver walls making it tight and feels like it has partially locked in the receiver recesses. But if I gently wiggle the bolt from the rear the flappers will release from the receiver. The FIELD gauge does the same thing, only the firing pin carrier will stop its forward travel slightly sooner than the NO GO gauge. It also feels tight in the receiver, but if I pull on the rear of the bolt with some force it will release from the chamber.

So, does it sound like I have excessive headspace, or am I within the outer limits of safe tolerances so that I can test fire this parts shooter build? I do have a shooters kit installed with smallest insert. I have tried a spare set of flappers and get about the same results, just slightly easier for the bolt/flappers to pull from the chamber when using NO GO and Field gauges. I'm hoping I'm withing safe limits, even if at the edge, so I don't have to send rifle off to have barrel reseated.
 
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In an effort to maintain the utmost safety, I need to make sure I am checking my headspace correctly on my AC44 G43 build. I have a complete bolt/carrier/cover assembly from another G43. I have two sets of flappers.
I have Forster No Go and Field 8mm Mauser gauges.
I use a live 8mm round as my GO gauge.

I have removed extractor from bolt. I am using an allan wrench down in the firing pin carrier slot that the bolt carrier usually rides in to manipulate the flappers.
The bolt closes and locks easily on empty chamber, with bolt face making firm contact on barrel shoulder. The firing pin carrier moves to it's complete forward position in the bolt, slot in pin carrier all the way forward and aligned with forward edge of slot in bolt, thus locking flappers into their recesses in the receiver walls. Same thing happens with the live 8mm round, being completely locked in battery, with no wiggle to the bolt when I manipulate it with my fingers from the rear while holding pin carrier to its forward position.

When I test with the Forster NO GO gauge, the bolt seems to go all the way forward, but the firing pin carrier will only go half way forward. The flappers will press against side of receiver walls making it tight and feels like it has partially locked in the receiver recesses. But if I gently wiggle the bolt from the rear the flappers will release from the receiver. The FIELD gauge does the same thing, only the firing pin carrier will stop its forward travel slightly sooner than the NO GO gauge. It also feels tight in the receiver, but if I pull on the rear of the bolt with some force it will release from the chamber.

So, does it sound like I have excessive headspace, or am I within the outer limits of safe tolerances so that I can test fire this parts shooter build? I do have a shooters kit installed with smallest insert. I have tried a spare set of flappers and get about the same results, just slightly easier for the bolt/flappers to pull from the chamber when using NO GO and Field gauges. I'm hoping I'm withing safe limits, even if at the edge, so I don't have to send rifle off to have barrel reseated.

In the interest of personal safety you do NOT want the bolt to close on the NoGo gauge.
 
In the interest of personal safety you do NOT want the bolt to close on the NoGo gauge.

So from my description, are you saying the bolt is closing on the NO GO? The edge of the flappers seem to be grabbing the edge of their recesses in the receiver, but not seating all the way down in. Is that still beyond safe?
One thing I don't understand is that when I close the bolt on a live round, the bolt has zero play in it. It appears to be closed tight on the round in the chamber.

But I do want to be safe. So other than reseating the barrel for proper headspace, what are my options to try and fix it? Try more flappers, or firing pin carrier, or bolt?
 
So from my description, are you saying the bolt is closing on the NO GO? The edge of the flappers seem to be grabbing the edge of their recesses in the receiver, but not seating all the way down in. Is that still beyond safe?
One thing I don't understand is that when I close the bolt on a live round, the bolt has zero play in it. It appears to be closed tight on the round in the chamber.

But I do want to be safe. So other than reseating the barrel for proper headspace, what are my options to try and fix it? Try more flappers, or firing pin carrier, or bolt?

You said the bolt closes and locks on a live round. Since neither the Field nor the NoGo gauge allows you to push the firing pin housing all way forward, the headspace is not excessive. This means your rifle has its headspace in spec and you can use it as is.

On another note, from the aspect of understanding and getting a feel for your rifle's headspace, using a commercial live round and thin copper or aluminum foil shims like I previously recommened would have been more precise and explanatory than using SAMII gauges.
 
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headspace?

So from my description, are you saying the bolt is closing on the NO GO? The edge of the flappers seem to be grabbing the edge of their recesses in the receiver, but not seating all the way down in. Is that still beyond safe?
One thing I don't understand is that when I close the bolt on a live round, the bolt has zero play in it. It appears to be closed tight on the round in the chamber.

But I do want to be safe. So other than reseating the barrel for proper headspace, what are my options to try and fix it? Try more flappers, or firing pin carrier, or bolt?

Interesting quote by Pete (me).
"You shoot a cartridge not a headspace gauge"
If I were checking that rifle (or rifles I work on regularly) I'd feel it was just fine if it closes (locks) fully with no or minimal slop on an example of a cartridge I was going to shoot.
A good tool to have is made by pulling the bullet from a round, dumping the powder, removing the primer, tapping the flash hole 6/32 or 8/32 , welding a screw to the end of a piece of rod and screwing it into the case from the front, rod long enough to extend out the muzzle.
Chamber it with the FP and extractor removed. You can then feel for what the actual HS is and rig an indicator.
to the rod if you want to actually measure it.
Pieces of shim stock could be cut to fit and added to the rear of the case to see how much it would close on. Even masking tape (usually .005/.006 thick) can be used. Yeah, crude but it works.
Having perfect HS is wonderful but if shooting virgin brass or steel cases most of these guns will be ok with HS that exceeds (within reason) no go or field spec. Reloaded brass gets cold worked and can get brittle leading to possible separations though. Or one can resize cases a bit long if reloading to accommodate long HS.
I'd think long and hard before considering setting back a press/pin barrel for a bit of long HS if in fact you have same.
Sounds like your gun is ok from what you say.
Pete
 
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In an effort to maintain the utmost safety, I need to make sure I am checking my headspace correctly on my AC44 G43 build. I have a complete bolt/carrier/cover assembly from another G43. I have two sets of flappers.
I have Forster No Go and Field 8mm Mauser gauges.
I use a live 8mm round as my GO gauge. The "green box" Romanian steel cased ammo will not chamber/ bolt with not go all the way forward, by the way.

New lacquered Romanian ammo is garbage.
http://www.k98kforum.com/showthread.php?27043-Noob-ammo-question/
 
You said the bolt closes and locks on a live round. Since neither the Field nor the NoGo gauge allows you to push the firing pin housing all way forward, the headspace is not excessive. This means your rifle has its headspace in spec and you can use it as is.

On another note, from the aspect of understanding and getting a feel for your rifle's headspace, using a commercial live round and thin copper or aluminum foil shims like I previously recommened would have been more precise and explanatory than using SAMII gauges.

I think I'm finally getting the help I was looking for, thank you. My concern was if "passing" a NO GO or FIELD gauge test was contingent on the bolt not closing fully, i.e. firing pin carrier not going fully forward, or if I were able to pull the bolt rearward by hand while the bolt was fully seated against the NO GO or FIELD guages. From what I've read here, The fact that the firing pin carrier would NOT fully close indicates the headspace is adequate.

Here are the rounds I have to test. All chambered and locked up tightly with the exception of the Romanian "green box" ammo, which acted as if it were a field gauge. The bolt would not close at all.
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As you can see in the pictures below, the bolt would close and lock up fully on the live round with firing pin carrier in it's fully forward and locked position. But with both the NO GO and FIELD gauges, the firing pin carrier would only close half way forward.
9p2kjquXubg2gnH1Z13df9ZUJ0ew8WmyYpOcu-fPIizOaxiWRW_qTbQzs90mY_YFPywSXUCG9qXc43N1K8N-nNXcZmpJ_womEkhekbgbn5TbiGdO7B2bTg1c5C72AsVRYIpgUOuFMlk_cWSAMnJSZiWHAWd_Z5ijR_ZAUXMxpfuphHRi87OhhEe0RxMKoXYGF0jRLN6CaJPhqKlLsQ0XosauBnxQzBgGgHLVYVtblUB6MmRhuCM3EQZe0XSCh8hLk-zvMB0Akqqzxg2D3U7EWOTtaAQ_A0DHbAwtV_H6iY2lBmb5sbhlUItKqRbozl1OaPu7NoMytDhVhwghsI7tp0ctXb9Infzr5hPQGBN2p8TMnj_PUr-91do5EStT7Zk-70wyj1WnkrstHejYYaouNqfBYhOjkcgvl5_1lpU5fgM5ZbjXdCySpckayIf6JsVtownq9UJs1cYAX1l6j9fStEBMKLcYT49K5xPaOaQq3TLFn8VOm9UfcLCQUKY6z3f-cJ033j6Om3wp__VkkziTvH6Nut-m6uLIUFr85DVamemDSwdxL30nzPPE_Nvg640zqwPPUgdI6RCgUew0xZKri-f8zd0vS5xzGJdRNRXyuStGc7_DOc2KZqcf=w1229-h921-no

Bolt fully forward and locked on a live milsurp round.
3eM9asSrQ_PBGRQo6HkTVXbltdHxaA5zlFDjVF4b90MaF2JZe9zHKebucoRfdni8bYvw5c4ZJ7L1g9aR76zoKX1xpRitJu1Ptdwdi-voPGo7tbqi7c0oRly8dqjOQtVhcXdGXiRa5d6-4wS27FNNOUMHSv81H2OFV21A_33dM4FkUZKOcUCVavP6PCFOKTvHx6wranfcuBGwiIvzMspuY9otY_GA0I8icG1BGmp82JRnVJwnVvUzNAPQgOq2tVjlKQCd3olGd2o21u4hOxskSBLmWCuaQ1MPi041oW96aMgR89QeKCx_P3ySz6OU9Sq4tYZSOk9IU649qi3G1bHCqYOKPZaZT4uMQ2uAgTIPiRhdz6xl9t_xYC0SuFNcGJStuJDN-tyqWE9Uy3MuwO1jg47oti_4YrEtgMOm9WAQqgJBOjV_u17P2QBooB9qyyt381OekQ12qsP7Zd0f-JJmSI3TUvGCzRobXbeIkX6pTX7NYjdaW2h84wIBfwQTq4NgB83UdWo6dg25IRnl9oPmsWjOC1SvI5m1QV3yoCfx2By_PZ8tcFDLGTVC6imIkjd14Wofxwoz8NmC7s8c4EosTHDs79NE_SwSw_y4gqLQ2X6Z5Obm8ZI4uB-T=w1229-h921-no

Bolt closed with pin carrier slightly more than half way forward on NO GO.
y0b-NsSby76VqxzgBX1d6bZYGn1hpK4fHF0LadVjqm1sXW_fV9u3oX30zB-ZV26e-FmGbaLrg6kJjo3QUxLyeOdCOiwDSvJmB4Gb8fB22KXuzSPYekr4pvFpBmKsjSUdLdNZZAJkXUE5Nr81Q7UbdNZgF37eniLPndsXALukCMF2S8YOSDXiWUIbC0He9c6BOm6ff1WZB5iaqdQfdIl5vEFANTBNKccDIm4kjtPUB3lAYfC9Jy70LG-cXrq447Hz2RJkAV4At7LRJ2sHFjp2DZOe6NDQwoh34HmXAXXdWuqYR0JgLOYumsSq1qHtUVUjjEYzyOD0XDxwhm3LZz5R3i5-UefuyZq4z-MekFqtEG-z6Zf0xMClGDthXHC7eSPurPNw3YwqIzsKfHroPxLE-kJw6U9qdAlLZF2kuWCo-seLJf6VdxL4BUaSqTN46eJ2TxwaYj3-NOgWG0L3hA7lpv5zYXtpVLUYWQT2BwSJMRRgc5diDPhJ9K_rn54Y0F_lhCHPWZa5Fr_CH-i0dLv19I56QPsJcHkWM_OOj2y7MdxVUObaphlJJLhS9-oFoEpj8cPLFdes9F5qOZDQ3rkkQVD1kj51n861-cE07jkU24mXYg7G-eAJ1WfX=w1229-h921-no

Similar situation with FIELD gauge, but slightly less forward than NO GO.


So, as you mentioned, I think the lockup/headspace is plenty tight for safe firing. I do plan on getting some Federal 8mm ammo (under powered) and starting with it before moving up to any of the surplus ammo's, which I assume are more full powered. If any of the ammo's I show are questionable, please let me know. I will be using the smallest Shooters Kit insert as well. All springs have been changed. All that remains is installing the gas block and front sight base.
I do like your method of using the live ammo with shims/ tape/ etc. to check headspace. I will do that as well with the Federal ammo before firing.

I appreciate all the knowledge shared here.
 
I would follow Pete's ( Shortfal's) advice, he builds and re-build rifles all day, also I would never shoot that Warsaw pact ammo in anything, but a russian capture. Most is to hot and corrosive, when testing and trial shooting its always commercial or under reloaded cartridges. also keep in mind the metallurgy that was utilized in G-43 production, slave labor and material shotages

sorry as a G-43 owner, I believe they belong in the safe and not the range
 
I'm curious what is meant by new Romanian.
The Romanian I think of is the surplus that was around some years back, 2 tins in a wood crate, cheap (then).
It's always run perfect for me in various MG42's I built or worked on.
Is there current production steel case lacquered Romanian available now?
Pete

Yep. The "green box" I have says made in ROMANIA. It is steel cased. I have not fired any of it and will not be shooting any through my G43 since it will not chamber.
 
I'm curious what is meant by new Romanian.
The Romanian I think of is the surplus that was around some years back, 2 tins in a wood crate, cheap (then).
It's always run perfect for me in various MG42's I built or worked on.
Is there current production steel case lacquered Romanian available now?
Pete

Yes, this is current production. You're referring to the 1950's-70's surplus stuff that's OK to shoot. The new stuff is garbage with out of spec dimensions, preventing the rounds from chambering properly.
 
new Romanian

Yes, this is current production. You're referring to the 1950's-70's surplus stuff that's OK to shoot. The new stuff is garbage with out of spec dimensions, preventing the rounds from chambering properly.

Good to know as I was not aware of that ammo.
Fortunate to have a stash of the surplus.
Pete
 
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