AR15.Com Archives
 match chamber?
silenthunter1984  [Member]
4/1/2006 6:03:01 PM EST
Alright guys heres my deliema I am fixing to order a upper reciever from Fulton Armory. I'm trying to decide whether to get the 16" heavy contour chrome moly or the 16" govt. profile chrome lined. It comes with a 5.56 match chamber.

I was wandering if it was usless to have a match chamber and a govt. profile 16" chrome lined barrel?

How bad exactly is the chrome lining going to affect my accuracy?

And finally in your opion do the advantages of one outweigh those of the other?

Thanks Adam
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silenthunter1984  [Member]
4/3/2006 8:10:59 PM EST
Anybody???
metroplex  [Team Member]
4/4/2006 2:51:43 AM EST
I've never heard of a 5.56x45 match chamber. Is it a Wylde style chamber (in-between 5.56N and .223 Rem)? Match chambers are generally supposed to be tighter for "more accuracy".

IMHO I stick with 5.56x45 chambers so that I can shoot 5.56N ammo and .223 Remington ammo.
rebel_rifle  [Member]
4/4/2006 3:31:26 AM EST
In the world of the AR, the term match can mean damn near anything. There are no true match specs. for the AR as was true with the M1 and M14. In *most* cases the term match is a marketing gimmick used to lure more money out of your wallet. FA is very good at that.

Caveat Emptor!!!
stiles  [Team Member]
4/4/2006 3:51:00 AM EST
You would have to ask Fulton Armory what their 5.56 Nato Match chamber is to get more information. Who knows, is it a CLE like chamber with a shorter throat length or a Wylde type chamber which is pretty much just a 5.56 Nato chamber with a tighter throat diameter (.2240) but has the same throat length and angle (not what I would call an in between chamber, but that's me). And it could just be copy from a marketing type too, don't know.

For that type of a rifle I'd get the government profile but that is because of weight.
rebel_rifle  [Member]
4/4/2006 4:11:14 AM EST

Originally Posted By stiles:
You would have to ask Fulton Armory what their 5.56 Nato Match chamber is to get more information. Who knows, is it a CLE like chamber with a shorter throat length or a Wylde type chamber which is pretty much just a 5.56 Nato chamber with a tighter throat diameter (.2240) but has the same throat length and angle (not what I would call an in between chamber, but that's me). And it could just be copy from a marketing type too, don't know.

For that type of a rifle I'd get the government profile but that is because of weight.




The throat length on the Wylde is shorter than the NATO chamber. It is not as short as the CLE chamber, but definately shorter than NATO.


This is explained on several different web sites, White Oak being one as I recall.
jmart  [Member]
4/4/2006 4:25:06 AM EST
Click on "Reloading Stuph"
stiles  [Team Member]
4/4/2006 4:39:23 AM EST

Originally Posted By rebel_rifle:
The throat length on the Wylde is shorter than the NATO chamber. It is not as short as the CLE chamber, but definately shorter than NATO.



JGS Wylde throat length is .0619" but the JGS Nato reamer is .0566", it's longer not shorter.

Link1
Link2
rebel_rifle  [Member]
4/4/2006 5:53:42 AM EST

Originally Posted By stiles:

Originally Posted By rebel_rifle:
The throat length on the Wylde is shorter than the NATO chamber. It is not as short as the CLE chamber, but definately shorter than NATO.



JGS Wylde throat length is .0619" but the JGS Nato reamer is .0566", it's longer not shorter.

Link1
Link2




All I know is this.

When you seat an 80 grain Sierra bullet to touch the lands in a Wylde chambered rifle, you touch the lands at +/- 2.465" to +/- 2.475" OAL. With the NATO chamber, the same Sierra 80 grain bullet will touch the lands at +/- 2.550" OAL.

I have found this with 3 different barrels of each chamber.
stiles  [Team Member]
4/4/2006 6:27:08 AM EST
That's pretty interesting. You never really know what an OEM does unless you cast the chamber. One thing that's obvious is that the NATO chambers are .0025" greater in throat diameter and then trig out the throat angle and the point that the throat meets the bullet may be longer on the Nato chamber (sorry I don't want to do trig this morning ). A secant ogive (not sure if the 80gr SMK is a secant) will just make the OAL difference more pronounced. I'm probably all messed up on the ogive / OAL issue, I don't do trig in my head very well.
PaulE  [Industry Partner]
4/4/2006 12:02:02 PM EST
The SMKs have tangent ogives. The reason the OAL can be longer is the .2265" freebore diameter of the 5.56 NATO chamber versus the .2240 freebore diameter of the .223 Wylde chamber. VLD bullets with even larger ogive calibers will go even farther into the bore before they touch the lands (except they have to be single loaded).
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