Can anyone explan what is a SAAMI chamber

[Balljoint]

Have purchased a DPMS upper 223 1-8 barrel info from dpms states it has a SAAMI chamber with a list of ammo NOT to fire in this rifle including RELOADS, so what exactly is a SAAMI spec chamber

[Blue Avenger]

http://www.saami.org/

[Balljoint]

Thanks for the info BUT had trouble and not finding specification's on chamber size

[Uncle Jack]

Try doing a Google on:

SAAMI .308 (or whatever caliber you want)

uj

[BillPa]

Thanks for the info BUT had trouble and not finding specification's on chamber size


Try this.
http://i43.tinypic.com/96gsw3.jpg

If you have trouble reading it, shoot me a PM.

Bill

[Blue Avenger]

.223 Rem as apposed to 5.56 nato .
that what your asking?

Sammi for a .223 rem would be the ones you see listed everywhere for the .223

One of the biggest change difference I know of was the 6.5x55 swead. OAL shrunk a lot from the original mauser to the us version. original import ammo will not fit a modern US made rifle

[knight_dive]

Have purchased a DPMS upper 223 1-8 barrel info from dpms states it has a SAAMI chamber with a list of ammo NOT to fire in this rifle including RELOADS, so what exactly is a SAAMI spec chamber


the .223 and 5.56 Nato chambers are very similar, with I believe a slight change in the shoulder and slightly larger chamber for 5.56 ammo to facilitate feeding in automatic and dirty weapons with hot barrels. The tight .223 chamber is generally beneficial to accuracy, but 5.56 ammo is loaded to higher pressure specs than standard .223 remington ammunition. If yours is a tight chamber you will likely experience even higher chamber pressures because the casing doesn't have as much room to expand and therefore it is typically considered unsafe to fire 5.56 ammo in a .223 chamber. If I were you, I would call DPMS directly and ask them what ammo is safe or unsafe to fire in that barrel. You will find examples of people on both sides of that argument, with actual experience and without, but I would either get it from the horse's mouth so to speak, or get a chamber gauge and verify it yourself.

ETA: http://ammo.ar15.com/ammo/ should give you a pretty fair idea on the differences between the two chambers

[knight_dive]

a lot of barrels marked .223 actually have 5.56 chambers, or so close that the difference is indeed negligible, and my own 16" carbine AR is marked .223 and has never seen anything but 5.56. However, there ARE differences, tighter chambers CAN cause higher pressure, and the key word is that 5.56 is CONSIDERED to be dangerous in a .223 chamber. That's why I recommended that he call the manufacturer instead of taking the "I saw on the internet that you can shoot 44 mag out of a 100 year old 44-40 cuz it looks like it fits" route. The more gun owners that make intelligent decisions, like asking a question when they are unsure and before they are picking bits of receiver out of their face, the better it is for everyone. Of course he'll probably be fine running 5.56 in his .223, but on the other hand, DPMS has been rumored to have had some unintentionally tight chambers so why not be sure?

ETA: per Ammo Oracle linked above, DPMS uses 5.56 chambers but marks their barrels .223.

[Balljoint]

In another post about Mil. ammo here on this form was given a site on Ar15.com Ammo Oracle on which is a section on 223/556 chambers with how different Mfg. chamber their barrels and says DPMS uses the 556 chamber size.

[sharpshooter]

You might want to expand on the "tight chambers" statement. The only thing that will cause higher pressure is a lack of clearance in the neck. Hi-teck is right about the same proof loads.

[knight_dive]

Perhaps tighter throat would be better phrasing. This page from the ammo oracle, http://ammo.ar15.com/ammo/project/hist_diff.html explains it better than I can short of copying and pasting and includes the relevant throat drawings (and includes the reference posted above that DPMS marks 5.56 chambered barrels .223). SAAMI also lists 5.56 as being unsafe in .223 chambers on page 7 of this link http://www.saami.org/specifications_and_information/publications/download/SAAMI_ITEM_211-Unsafe_Arms_and_Ammunition_Combinations.pdf. The link from ammo oracle to this guide no longer works.