5.56 barrels

[palepainter]

I have purchased two barrels in the past couple months. Colt carbine barrel and a Ballistics Advantage 13.7 5.56 barrel. Both failed headspace check. The companies were both, not interested in hearing that information as they just ran checks with Field gages. I am using a Fail Zero BCG. We checked both with multiple bolts from different manufacturers. All hit no go on SAAMI spec gauges. I work at Phoenix Weaponry in Berthoud doing coatings for them. I had the guys look it over for me. They are seeing an awful lot of this in the industry these days. Just don?t understand how the companies can produce products with such unsafe QC. Anyone else running into these issues with barrels ?

[ray1970]

I am sure you are aware that there are different specs for go/no go/field for the 5.56 vs the 223.

I always use the mil-spec no go for 5.56 which off the top of my head is 1.4736.

I believe I have two rifles that will easily close on a 223 no go gauge that will not close on a 223 field gauge (1.4696) which is less than the 1.4736 limit for the 5.56. Both rifles function and shoot just fine.

[ray1970]

Link for the allowable difference between a 223 and 5.56 chamber.

https://www.forsterproducts.com/pdf/brochures/hi-res-for-print/Forster-Products-NATO%20Chamber%20Headspace%20Gages%20Sales%20Sheet _NATO-001_Issue%204_July%202018_print.pdf

[Joe_K]

I have purchased two barrels in the past couple months. Colt carbine barrel and a Ballistics Advantage 13.7 5.56 barrel. Both failed headspace check. The companies were both, not interested in hearing that information as they just ran checks with Field gages. I am using a Fail Zero BCG. We checked both with multiple bolts from different manufacturers. All hit no go on SAAMI spec gauges. I work at Phoenix Weaponry in Berthoud doing coatings for them. I had the guys look it over for me. They are seeing an awful lot of this in the industry these days. Just don?t understand how the companies can produce products with such unsafe QC. Anyone else running into these issues with barrels ?

What gauges did you use? Just curious.

[ray1970]

I have actually seen guys at gun shops say a 556 had excessive head space and they were using a 223 no go gauge to make that determination.

Also, any time I see someone trying to check headspace without removing the ejector it just makes me cringe. The forward and angular pressure put on the gauge by the ejector can give false results.

[palepainter]

I would have to get the name of gauges. But yes. We were using 5.56 gauge set. I’ll get the company.

[palepainter]

Manson and pacific tool is what I’m told. And ejectors were removed.

[palepainter]

I am sure you are aware that there are different specs for go/no go/field for the 5.56 vs the 223.

I always use the mil-spec no go for 5.56 which off the top of my head is 1.4736.

I believe I have two rifles that will easily close on a 223 no go gauge that will not close on a 223 field gauge (1.4696) which is less than the 1.4736 limit for the 5.56. Both rifles function and shoot just fine.
We hit 1.476

[ray1970]

Well, then I guess you have excessive headspace. Lol.

I have had a lot of barrels from a lot of manufacturers pass through my possession over the years and I think I had one that was barely over on headspace. I think I had one other that I had to play with different bolts but finally had it come in to allowable tolerances. Guess I?ve just been lucky.

[Hoser]

I would not trust a gauge from PTG even if my life depended on it. They have gone to complete shit in the past 5-10 years.

[Madusa]

I’ve had ammo fit case length gauges but not chamber. Girth can be an issue also.

[BPTactical]

I have found my best headspace gauge is a factory loaded match round from a REPUTABLE manufacturer such as Hornady, Black Hills or Barnes.
They are manufactured to very tight specifications.
Bolt should close on a round, take same round and put a piece of vinyl electrical tape on the case head. Bolt should either not close or close with effort and smudge the tape.
If the bolt closes then try it again with a second layer of tape, it should absolutely NOT come anywhere close to closing.
I like Scotch 88 tape, it is about .003 thick.