DPMS head space questions

[Punisher29073]

1) If I remove the barrel nut to replace the hand guard with a different style, will I need to recheck the headspace when it put all back together?

2) If i get another upper, already assembled, minus the BCG, will I need to check the headspace with my BCG?

Thanks

Ryan

 

[ORD]

1) If I remove the barrel nut to replace the hand guard with a different style, will I need to recheck the headspace when it put all back together?

2) If i get another upper, already assembled, minus the BCG, will I need to check the headspace with my BCG?

Thanks

Ryan

As to Question 1 above...NO, a simple handguard swap (incl removal/reinstallation of your barrel/nut/etc.) does not require a headspace check.

As to Question 2 above...YES! Some will tell you its no big deal, it'll be fine, waste of time, if it works in one AR it'll be fine in another, etc., BUT...anytime you start stacking tolerances with ARs or other plug and play platforms, you really need to do your due-diligence (which takes <5min by the way) and double-check that it is within tolerances before dropping the hammer on a live round. Its cheap insurance to make certain that you aren't getting into a potentially dangerous situation with an unsafe setup.

 

[Punisher29073]

That was my gut feeling. Thanks for the reply.

Ryan

 

[mtrmn]

No
No

The headspace is determined by the barrel extension (locking lugs) which is pinned to the barrel. The relationship of these locking lugs and the lugs on the bolt determine your headspace. All parts of an AR15 are held to a standard dimension and supposedly ANY barrel/bolt combination which is not badly worn should headspace within specs. PERSONALLY, I checked all mine with headspace gages anyway to settle this in my own mind. In reality it shouldn't be necessary. And the barrel nut has nothing to do with the headspace so you're good there.

 

[KULT]

No and No.

If you are using the same bolt and barrel you can swap uppers. The carrier has nothing to do with head space. Mtrmn already explained it. Now it is a good idea to check the headspace on the barrel and bolt if its old to make sure its not worn.

1) If I remove the barrel nut to replace the hand guard with a different style, will I need to recheck the headspace when it put all back together?

2) If i get another upper, already assembled, minus the BCG, will I need to check the headspace with my BCG?

Thanks

Ryan

 

[hotbrass]

No
And emphatically YES!

I bought a DPMS 308 barrel and put an upper together. DPMS had used a worn out chamber reamer on the barrel and it would close on a go gauge and not on a nogo gauge, but it would not chamber a round because the neck was too small and the gunsmith said it was really jacked up with tool marks and rings cut in the chamber.

And of course I took my time putting it together and by the time I figured out what was wrong, DPMS would not do anything. SO I had to have it rechambered at an added cost of $148.

Always check your chamber, you never know what you will get.