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JK-47

Filing down the "ring" on the bolt face...?

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I ground mine flush with a dremel. Simply because I reload and that wasting of smashed brass bothered me. I'm that cheap. I'm no gunsmith either,,,.

I ground the pin just below the face. I was getting occasional double taps/slam fires with reloads.

She doesn't shoot the 5.56 ammo consistently, it seems like the primer is dented enough but no fire. Does 5.56 spec have hardened primers?? It consistently shoots the 223 recipe reloads with small rifle primers, but not "factory 5.56" ammo consistently.

I seemed to have gained the ability to reload for it, but lost the ability to shoot 5.56 consistently.

 

this is why I keep recomending to not fuck with the geometry of your bolt face...

 

no one listens to me though.

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It looks like your lost your rounded profile on your firing pin.

 

Did you remove the pin to modify your bolt face? If so How?

 

I am sure that this bolt face deformity is an attempt at making handloading as difficult as possible. Seems like the obvious thing to do in the Russian system.

 

I didn't remove the pin. I pulled on it with some needle nose pliers (from the backside) but couldn't get it to come out so I just left it.

The pin does seem like it has some extra space in their to move around near the bolt face. I don't know what to make of that.

 

Pardon my ignorance here. I too would be interested in not trashing good brass. But what about headspace? Will this grinding the ring flush not affect that?

 

I didn't think so, because the outside of the brass still contacts the same area on the bolt face. My attempt was to stop that dimple from smashing the brass around the primer.

 

Hopefully I will get out Sunday to see if the M193 works consistently. I'm thinking its not going to. I pulled some bullets and powder out of some M193s last night and the firing pin didn't penetrate very deep into the primer when I "shot" them in my basement. I should take a pic of those cases and post that. Maybe the ammo oracle website has some info on hardened primers I can read about.

 

dude,

 

do you own headspeace gauges?

 

do you even know what headspace is?

 

You don't even know how to take apart the bolt, yet you think it's a good idea to go grinding on the part of your gun that holds in 50,000 psi of hot gas? :ded:

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that is almost as stupid (no offence) as grinding a feed ramp into the chamber area (to allow feeding of unmodified mags (or in leu of installing a proper feed ramp)

 

So what about factory guns with the chamber area ramped? I guess they all blew up too.

 

I played russian roulette and didn't die, so it must be safe, right?

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Yes it will change head space, will it change it to a dangerous level?

I'll let you pull the trigger.

That ring will not affect reloading the cases.

I see no reason to remove the ring from the factory bolt for the sake of pretty brass.

Or any other reason for that matter.

I suggest everyone just leave it alone.

That step measures .008 in.

3 Forster headspace gauges for .223 Rem / 5.56 Nato

 

.223 (5.56 Nato) Match Gauge, 1.4636" GO

.223 (5.56 Nato) Match Gauge, 1.4666" NO-GO

.223 (5.56 Nato) Match Gauge, 1.4696" Field

I'll let you do the math but go to field is .006 in

 

 

SaigaRing.jpg

Edited by gunnysmith

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Just remember, if it closes on a no-go, the field gage is next.

If it closes tightly on the field it will work.

The brass will stretch with each firing.

An annular ring will form near the head of the cartridge where the brass starts thin to out.

I can't guess the number of firings one would get from the brass under these conditions.

That would depend entirely upon how much excess headspace there is.

Failure will be in the form of a head seperation.

Gas escaping under high pressure, from the separation in the case, will damage the firearm, and very possibly the shooter as well.

A very dangerous condition has been created.

Edited by gunnysmith

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If you look here you will find 2 classic cases of head seperation.

In the 57 pistol post one must realize the action of the FN 57 is a retarded blowback action.

The casing adheres to the chamber wall for a short duration upon firing.

This has been an acceptable and reliable type of action for many years.

It does not however support reloading. The brass stretches on each firing.

The brass is weakened severly and if reloaded can cause what was pictured in the thread.

 

In the case of the FS 2000, the claim was an out of battery firing.

Just seeing the pictures one realizes the case head is missing and was never found.

The bolt on the rifle will not allow the pin to reach the primer until locked.

Ask me how I know, I'll tell youI own two of them.

The owner was using a mix of ammo and some of it was reloaded.

My best guess is:

The rifle was new or fairly new.

There is no reason to believe the headspace was excessive.

Upon firing, the round in the chamber seperated near the head.

As described in the earlier post that gas is no longer contained within the case and escapes under very high pressure.

The pictures show the result.

Both shooters were very lucky in my opinion.

That being said, always ask before performing any modifications on any firearm.

If you don't get a satisfactory answer, there are many like myself with the experience, lerking on one or more of the boards.

I was a practicing gunsmith from 1968 until quitting the industry in 1987.

http://fnforum.net/viewtopic.php?t=8953

http://fnforum.net/viewtopic.php?t=7781

Edited to include:

In the first photo it is easy to see the shoulder moved forward on both fired cases.

This is a result of the retarded blowback action of both the PS 90 and the FN 57 pistol.

Please understand, these are both fine firearms and are well designed, just remember using reloaded ammunition in each of the firearms is not supported by the manufacturer.

FN57X28.jpg

The bolt mass of the PS 90 quit clearly retards the extraction phase of firing to a greater degree than the FN 57 pistol. The case from the pistol shows more ballooning at the shoulder.

FN57X285.jpg

One can easily equate this, to firearms having excessive headspace.

Base line is this, with locked breach firearms:

Head space within specification reloading is OK

Anything other than that, requires attention to correcting the problem before reloading is acceptable.

 

 

BE SAFE in all you do whether at work or at Home

Edited by gunnysmith

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I would appreciate it if someone would get a headspace gauge and check out this mod...then post some definitive answers. This thread is not safe to have on this forum if this mod is potentially dangerous.

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Actually, I think this thread is ESPECIALLY NECESSARY on this forum to CLEARLY STATE something that SHOULD NOT BE DONE!!!

 

I am sure there are many others out there who have thought the very same thing, maybe some have even dont the change without even a clue as to the repercussions... This thread will serve as warning to those that have that question.

 

In fact, I would ponder stickying this thread... maybe deleting the posts that have little "factual relevance" and keeping the few from gunnysmith as "WHY YOU DO NOT MODIFY" the boltface on the .223...

 

:smoke:

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Cobra, This is not a "Mod" , it is a critical dimension change.

 

Thanks gunnysmith...DUH! :rolleyes: I was trying to help here...

 

Carry on... :ph34r:

Thanks for understanding.

I just wanted to clarify for those who may not know the difference.

Your expertize was never in question I assure you.

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this thread is full of FAIL

 

first of all, the bolt face is what determines headspacing.

 

By grinding the bolt face, you are increasing the headspace, which could lead to a kaboom.

 

second, why the heck are you modifying such a critical location. that is almost as stupid (no offence) as grinding a feed ramp into the chamber area (to allow feeding of unmodified mags (or in leu of installing a proper feed ramp)

 

:ded:

 

DON'T DO IT!!!!!!!!

santanatwo, I would like to thank you for this post in particular.

I normally scan over such things and read them lightly.

The way you posted raised the "Red Flag" Immediately.

Thank you again for your getting the point across on the

danger of such a change in critical dimension.

My subsequent post are only because of your concern for the safety of your fellw shooters.

Good go !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

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:super:Thank You, Gunnysmith, your praise means a lot.

 

 

but we have another fail thread on isle 4

 

paging gunny...

 

:ded:

 

http://forum.saiga-12.com/index.php?showto...mp;#entry262127

 

 

for the record I have a 20% warning for calling out a paying member (dumbass) for trying to sell an illegal SBR to unsuspecting members on the open forums.

 

<----------

 

I did it with a fair ammount of cursing... (lord forgive me, I get a little wound up when I see highly illegal, crazy, dangerous, deadly stuff going on) I should "should have handled it with IM" to quote a Mod.. but I got the results that needed getting (ad. was withdrawn and thread deleted)... :zorro:

Edited by santanatwo

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And for the record, nobody but the Staff here (and yourselves of course) can see all your warning levels.

<----------

 

Santana2 and gunnysmith thanks for helping watch out for the noobies when they try to do stupid things. We are watching too but sometimes it takes us a while to get to the thread in question, with ALL the others we have to read through.

It helps a lot when people use the report post to mod button. Santana if you had used that before, instead of taking it upon yourself to break the rules and troll in the for sale section, your warning level (<--------) would still be at zero.

;)

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And for the record, nobody but the Staff here (and yourselves of course) can see all your warning levels.

<----------

 

Santana2 and gunnysmith thanks for helping watch out for the noobies when they try to do stupid things. We are watching too but sometimes it takes us a while to get to the thread in question, with ALL the others we have to read through.

It helps a lot when people use the report post to mod button. Santana if you had used that before, instead of taking it upon yourself to break the rules and troll in the for sale section, your warning level (<--------) would still be at zero.

;)

 

Thank you, sir.

 

I just found the report button today :angel:

 

I noticed it on arfcom a while back, and when I saw that new thread in the 308 section, I was like OMG WTF BBQ, and thought to myself "I wonder if there is a report button?"

 

:unsure:

 

:lolol:

Edited by santanatwo

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that is almost as stupid (no offence) as grinding a feed ramp into the chamber area (to allow feeding of unmodified mags (or in leu of installing a proper feed ramp)

 

So what about factory guns with the chamber area ramped? I guess they all blew up too.

 

 

BTW, those aren't "factory" guns, they are modified by irresponsible third party distributors (it's teh cheap way), here in the USA :ded:

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Yes it will change head space, will it change it to a dangerous level?

I'll let you pull the trigger.

That ring will not affect reloading the cases.

I see no reason to remove the ring from the factory bolt for the sake of pretty brass.

Or any other reason for that matter.

I suggest everyone just leave it alone.

That step measures .008 in.

3 Forster headspace gauges for .223 Rem / 5.56 Nato

 

.223 (5.56 Nato) Match Gauge, 1.4636" GO

.223 (5.56 Nato) Match Gauge, 1.4666" NO-GO

.223 (5.56 Nato) Match Gauge, 1.4696" Field

I'll let you do the math but go to field is .006 in

 

 

SaigaRing.jpg

 

 

Gunny, I'm totally confused. I want to start reloading for use in my saiga's (specifically .223 and later .308, & 7.62x39). I have a few questions but please bear with me.

 

1. Can I assume that in my relatively new saiga(bolts etc not f'ed with in anyway) rifles that my headspace is in spec for me to reload casings and fire reloaded rounds from this weapon?

1.1 Or do I need to have my headspace measured prior to reloading with a particular weapon?

 

2. In Can I reload brass with the 'ak kiss' dings in them? (as I understand it the brass will begin to fail at the neck area long before the center of the lower casing would become over stressed right?)

2.2 Or should I try to install a buffer to prevent the ding from occurring?

 

Sorry I'm such a newb to all this stuff, I just want to BE SAFE, and successfully reload for my weapons if possible.

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:super:Thank You, Gunnysmith, your praise means a lot.

 

 

but we have another fail thread on isle 4

 

paging gunny...

 

:ded:

 

http://forum.saiga-12.com/index.php?showto...mp;#entry262127

I also posted the following over on the .308 Saiga thread, where some guy was thinking about grinding one of the locking lugs ('just the little one') off his bolt:

 

***

 

Allow me to provide another example. A few years back, I built a 'compliant' AK, using a name-brand US-made 'compliance' receiver, a 'compliance' fire control group, sufficient other 'compliance' parts to stay legal, and a low mileage AMD-65 kit with matching numbers. Not being a purist, I shortened a Bulgy gas tube (with HG retainers) so I could mount an upper hand guard (this was a common modification discussed over at The AKFiles at the time).

 

Everything went together very nicely (it was not my first AK build, and I had built several FALs before I got interested in AKs). Everything seemed to function fine when cycling the action by hand. Took it to the range to function fire, and on the second round, it doubled (I had five rounds in the magazine - won't do that again).

 

Turns out that, on recoil, the bolt carrier wasn't always depressing the hammer far enough for the disconnector to lock the hammer back, which allowed the hammer to follow the bolt/bolt carrier forward. The cause of this malfunction was probably a combination of:

 

(1) Using the wrong gas tube. The AMD-65 piston was significantly shorter than a stock AK piston, and (IIRC) the head of the AMD piston recoiled out of the ribbed portion of the Bulgy gas tube, possibly allowing the bolt carrier to 'wobble' as it passed over the hammer;

 

(2) Using a 'compliance' receiver. Even though the manufacturer was extremely respectable (they actually purchased the offending receiver & parts kit from me to evaluate, after the malfunction), it appeared to me (after measuring several AK receivers from different manufacturers with a micrometer) that the rails may have been attached too close to the top of the receiver, which would allow the bolt carrier to pass over the hammer higher than it was supposed to; and

 

(3) Also potentially influencing the situation were a used (just slightly worn, but still used) parts kit, and the 'compliance' FCG (which, by the way, was also name-brand).

 

Bottom line is this - one or more tiny changes produced a very big result. Who the heck would figure that swapping a gas tube could contribute to a potentially dangerous (even fatal) malfunction? Or that using 'compliance' parts from respected manufacturers could do the same? But add enough non-factory tolerances together, and it's entirely possible to get a non-factory result.

 

All of which is why I love Saigas. The bolt/bolt carrier/receiver/etc. are all installed, head spaced & tested at the factory. Do I use 'compliance' parts for the FCG? Sure - but that's the only change to the mechanism, so there isn't the same potential for slightly 'out-of-spec' parts adding up to an accident.

 

(Did I mention it? I love Saigas! ;>)

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OK, excellent thread. Thanks, Indy, for linking to it. I've got a .223 Saiga on the way and was wondering what it did to the brass. I plan to reload for it....as I do for the half dozen other .223s that are kicking around here.

 

My question is whether brass fired in the .223 Saiga and reloaded (using a full-length resizing die) can be safely fired in my other U.S. made flat-breech-face .223s? If I were to alternate firing a case between the Saiga and my Remington 700, wouldn't the brass of the case head be worked excessively?

 

It seems the Saiga bolt face would impress a dished-out area around the primer (or a ring around the outside of the case head) while the M700 would remove it. Is that right? After several firings (alternating between the two guns), could the case crack at the head or rim as a result? Would the case rim become so work-hardened that it could be torn off by the extractor? Is there any abnormal case-wall stretching going on when that ring is formed around the outside of the case head? It seems the safest approach would be to restrict brass fired in the Saiga to the Saiga for all subsequent firings.

 

I've been reloading since the '70s. Got burned once by headspace thanks to an improperly made .223 resizing die. Ever since, I've been closely monitoring case length (shoulder datum-to-base) using the RCBS Precision Mic. Ain't gonna happen again.

Bob

Edited by 555JM

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Gunnysmith, you listed dimension for match grade go and no-go gages. They differ quite a bit from Military and civilan go and no-go dimensions. Example The No-Go for Military .223 (which should be the same OUTSIDE dimesion as .223 Remington) lists it at 1.4706" Quite a bit differece from your example of 1.4696"

 

 

 

Notes:

 

Go Gage:

 

Ascertains correct headspace dimensions by duplicating the minimum allowable distance, from the case head (or boltface) to the datum line of the cartridge's shoulder, allowed within the chamber to secure a loaded cartridge and allow the breech to be closed in a safe manner for firing.

 

If the firearm locks up in battery when the gage is inserted, then it is within acceptable minimum headspace dimensions and may be used.

 

No-Go Gage:

 

Duplicates the distance over the maximum allowable, from the case head (or boltface) to the datum line of the cartridge's shoulder, allowed within the chamber to secure a loaded cartridge and allow the breech to be closed in a safe manner for firing.

 

If the firearm locks up in battery when the gage is inserted, then it is not within acceptable maximum headspace dimensions. The firearm should not be used and should be examined further by a knowledgeable gunsmith.

 

Field Gage

 

Duplicates the maximum allowable distance, from the case head (or boltface) to the datum line of the cartridge's shoulder, allowed within the chamber to secure a loaded cartridge and allow the breech to be closed in a safe manner for firing.

 

If the firearm locks up in battery when the gage is inserted, then it is at the maximum acceptable headspace and should be examined further by a knowledgeable gunsmith.

 

 

Reference this link for some of the variances in headspace on the .223 or 5.56 NATO: http://www.ar15barrels.com/data/headspace.pdf It's a PDF link that anyone can download or print for reference.

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One other thought that came to mind when I was shooting reloads. On fresh, unfired, undinged-by-the-primer-raise brass, the headspace is good. I also had the headspace on mine checked at the local gunsmith with Go, No-Go, and Field headspace gages. However, the headspace gage is a solid piece of steel and measures whether the head space is correct on a closed chamber. Now, with once or twice fired brass your cartridge is no longer flat on the head near the primer. It is now indented and now fits into that button of raise material on the bolt face. Wouldn't the headspace be off NOW that the brass is now fired and has been re-shaped? It would presumably get no worse, as the brass is now about as deep as it's going to get.

 

Point is, that on any other rifle, the headspace is the WHOLE cartridge head, not just that raised portion near the center. That center is taking all the pressure and all the recoil until it smashes in and then the outer part can take some of the pressure. The slight ding on the side looks insignificant to the pressure build at around the primer. Also, because the primer area is now recessed, it is most difficult to determine if the round is nearing excessive pressures, as one of the tell tale signs is flattened primers and no rounding on the edges. With this system they are ALL flattened. Only non fired brass still would show a true pressure indicator from the spent primer.

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