Help with Desert Tech SRS barrel

[Jeffd]

Hi - I purchased a proof barrel for my Desert Tech SRS rifle and I cannot use the locking bolt as it appears that you need a shoulder on the barrel to use it? Is this normal and OK to use the rifle without the locking bolt and just the barrel screws to hold the barrel in place?
Thanks

 

[waveslayer]

You need the barrel extension

 

[Curt1521]

I never use the locking screw. Just the 4 bolts

 

[deersniper]

I don't use the barrel lock either.

 

[Jeffd]

It worked fine today without using the lock - Thanks everyone