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Sticky please :)
 

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very good info indeed.
 

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There are two different standards for measuring headspace: Military and SAAMI specifications. Military specifications are more lenient in tolerances than the SAAMI specifications. Military firearms are purposely designed to have very lenient specifications so a variance in ammo supplies and adverse weather conditions would not cause the weapon to malfunction. Also military brass is thicker and can tolerate more stretching than a commercial case and because of this they can tolerate excessive headspace better than commercial ammunition, greatly reducing the chance for cases rupturing.
Please keep the above quotation when checking headspace.
I have access to 4 Bulgarian AK74 kits.
Two plums and two folders.
One of the plums has been built, the others still untouched.
I took one of the guages from the group buy and checked them.
None of the kits nor the built rifle would close on the GO or NO-GO gauge, YET all would close on a live round.
All of them were MATCHING #'s, and ALL were DPHARM's unfired kits.
What does this mean??
The military gauges allow for a shorter chamber then the GO gauge allows.

Is the weapon safe to fire???
YES, if you can close the bolt on a live round then it should be safe to fire. I had a I/O romanian kit a while back that would not close on a GO gauge, but did close on a live round. I fired 150 rounds out of it with NO problems.
 

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Discussion Starter · #6 · (Edited)
DrugRunR...

You are correct. This is where I stated that I didn't want to get to technical. In my post on what to expect from your gauges, I didn't get the bolt carrier to move fully forward when using the "GO" gauge on 6 out of the 7 rifles I tested but I did get bolt lockup on all of them which is really what I'm concerned about when using the "GO" gauge. The cartridge is more forgiving especially when loaded for sem-auto or auto firearms. Remember that were dealing with a solid piece of steel ("GO" gauge) as opposed to a hollow, very thin cartridge case. To prove my point I used one of the slightly corroded gauges (these are the ones I sent back to Manson) and inserted it into the chamber. The bolt would lockup correctly but the bolt carrier would not move fully forward. I exerted just a little more effort (more than you want to check headspace) and the bolt carrier moved into position. You must understand that I said the "bolt carrier" moved into postion. The bolt did not move past the bolt lockup position.

Not wanting anyone to feel that they were getting an erroneous reading from their "GO" gauge (this is where your statement about the military chamber versus the comercial SAAMI chamber comes into play), I decided that using the Bolt Lockup (same as with the AR-15) was a way to provide the information we are all looking for....does the bolt (not the bolt carrier) lockup at the same place with the "GO" gauge as without.

As the "GO" gauge is not meant to be a cartridge my only concern is if the bolt will close on the "GO" gauge. I'm not concerned about what the carrier does.

LOL...I hope the above information will help people understand just what the "GO" gauge is provided for (and not confuse) and they put most of their concern into the "NOGO" gauge because that is where problems are first detected.
 

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You were on the money with your post, I just wanted people to know that there is a difference in specs on the factory military guages and these.
Basically I use a LIVE round as my GO guage when dealing with MATCHING # kits.

It would be cool if they could make some military spec GO guages, I would be interested in one in 5.45 and 7.62.
 

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Discussion Starter · #8 ·
DrugRunR said:
You were on the money with your post, I just wanted people to know that there is a difference in specs on the factory military guages and these.
Basically I use a LIVE round as my GO guage when dealing with MATCHING # kits.

It would be cool if they could make some military spec GO guages, I would be interested in one in 5.45 and 7.62.
I agree with you, but until CIP, SAAMI and the former Com-bloc (primary manufactures of AK-47 rifles) get on the same page were kinda stuck between all of them. With SAAMI leading the way in the U.S., that's why the 5.56mm/7.62mm gauges (M16/M14-M60) are more expensive than .223/.308 caliber.
 

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Discussion Starter · #10 ·
qbeanie said:
Do you have to do anything with the bolt like removing the extractor with a FAL?
We've been talking about AK-47/74 type rifles which do not need to have the extractor removed. I don't know about FAL's.

From what I know the only reason for having to remove anything from the bolt is if the ejector is incorporated into the bolt (like an M16)...then you might get a weird reading. In that case I would removed the ejector. But as for the FAL, I don't know.
 

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Thanks, That good news. FALs require the extractor to be removed to get an accurate reading and requires a special tool to do the job correctly.
 

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Here's a question for you headspace guys...I am hoping to receive my new k-var krinkov .223 kit this week. Anyways, I was wondering your opinion on the best procedure for headspacing this "new" kit. Will american .223 guages work? Also, I am not sure if this kit is .223 Rem. or .223 nato. I know that they are very similar but not the same. I looked at the dimensions for the chamber reamers and the .223 Nato is a couple thousandths larger on a few of the dimensions. Therefore, if it is .223 nato, the .223 Rem. gauges should work right? I just know I have to headspace it and I hate to spend $40 on .223 Rem. gauges if they will not work. What are you guys thoughts?
 

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Discussion Starter · #13 · (Edited)
magicald_223...

I'd call K-VAR and let them anwser your question. I think that if anyone would know which chamber was used they would, if not they could no doubt find out.

You definately want to get the right gauges.
 

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If someone could convert this document to .RTF, .TXT, or .PDF I would be quite thankful. :thumbup1:
 

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Magic, I would chamber it in 5.56 Nato (there is not a 223 nato, it is called 5.56)
Calling K-var will not help. The kit you have is a BRAND NEW never assembled kit.
The COM-BLOCK countries are going to 5.56 NATO standard. That is why we are seeing all of the 5.45 weapons hit the market. I suspect that in this next year we will see all of the 7.62 kits dry up and a HUGE influx of 5.45 kits.

Helios, Attached is the PDF version of the headspace document.

CHARLES
 

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Thank you very much Toten Kopf and DrugRunR - This is the info I've been looking for.
 

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DrugRunR, See Clymer has the 5.56 gauges, but Foster sells them also, but they have the same part # as the .223 Rem.? So, do I still use the 5.56 gauges? Also, I know how you mentioned that your AK74 kits wouldn't close on a Go gauge because of the difference in the American gauges. So what do I do? Will american 5.56 gauges work to set the proper headspace?? Also, the main difference between the 5.56 Nato and .223 Rem. is the Leade or throat length. (.223 Rem = .085", 5.56 = .162") So do headspace gauges even test the throat length??? I don't think they do. I appreciate help on this matter, since headspace is so important. Especailly with the .223 or 5.56 round.
 

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Discussion Starter · #19 ·
I would be leary if a manufacturer lists the same part number for .223 and 5.56mm. There is a difference so you should have different part numbers. During the Group Buy it was asked if 5.56mm gauges were available. I checked with Dave Manson and he said that the 5.56mm gauges are considered "Special" and would cost $48.00 each where as the .223 were considered standard and would cost $26.00 each. So there is a differnece.

The only way to really find out what the difference is would be to compare SAAMI .223 drawings with the 5.56mm. I haven't been able to find these drawings to do the comparison. I think if you pay, SAAMI will provide their drawings. But I know that I've seen them online, just don't know where.

If I were doing a build in 5.56mm, that's the gauges I would want, not .223.

Just got off the phone with Dave Manson. I asked him about the difference and he said that there isn't that much of a difference and if you loosely headspace your rifle using .223 gauges you could use them instead of the 5.56mm. Loosely headspace...LOL, You have to remember that this guy is a "GREAT" machinist and he has the experiance/equipment to do this loosley headspace thing.

Just get the 5.56mm gauges and don't look back. Hope this helps.
 

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magicald_223 said:
Will american 5.56 gauges work to set the proper headspace??
Heck yeah.
Buy a good set of 5.56 guages Like Clymer.
Your Krink kit has NEVER been assembled. Therefore has no barrel pin notch in the barrel.

The problem you run into is the difference in MILITARY SPEC and COMMERCIAL spec.
Commercial spec is much tighter then Military spec. In other words there is basically a football fields difference between GO and NO-GO in the military guages. ALOT of room.

If you set your rifle up with .223 guages there might be a small chance that surplus military ammo will not function in your weapon.
On the other hand, if you set it up for 5.56 then .223 will work just fine.

My Sam 5 is set up for 5.56
 
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